From SWODY2 at goshenarc.org Sat Apr 1 06:37:50 2006 From: SWODY2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 01 Apr 2006 01:37:50 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 010635 SWODY2 SPC AC 010634 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1234 AM CST SAT APR 01 2006 VALID 021200Z - 031200Z ...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF EASTERN IOWA...NORTHERN MISSOURI...AND NORTHERN ILLINOIS... ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK AREA FROM THE SRN/CNTRL PLAINS TO THE OH/TN VALLEYS AND PORTIONS OF THE LOWER MS VALLEY... ...SIGNIFICANT SEVERE WEATHER EPISODE APPEARS POSSIBLE ACROSS PORTIONS OF THE MIDDLE MS VALLEY AND MIDWEST ON SUNDAY... ...SYNOPSIS... ACTIVE AND PROGRESSIVE WAVE TRAIN WILL CONTINUE TO CROSS THE LOWER 48 STATES THROUGH THE WEEKEND. A LEAD SHORT WAVE TROUGH WILL CROSS THE NORTHEAST TODAY AS THE NEXT SHORT WAVE TROUGH MOVES QUICKLY OVER THE WRN STATES AND THEN EMERGES OVER THE GREAT PLAINS THROUGH EARLY SUNDAY MORNING. THIS NEXT SIGNIFICANT SHORT WAVE FEATURE WILL THEN APPROACH THE MS VALLEY DURING THE DAY SUNDAY WITH 70KT MID LEVEL JET FORECAST TO ROTATE THROUGH THE BASE OF THE TROUGH AND ACROSS MO AND IL THROUGH LATE SUNDAY EVENING. STRONG DYNAMICS ON THE NOSE OF THE MID/UPPER LEVEL JET CORE AND LARGE SCALE HEIGHT FALLS OF 90-120M PER 12H WILL INDUCE SURFACE CYCLOGENESIS OVER THE HIGH PLAINS THROUGH THE DAY 1 PERIOD. THE SURFACE CYCLONE SHOULD TRACK INTO IA BY SUNDAY AFTERNOON AS ASSOCIATED WARM FRONT LIFTS ENEWD ACROSS ERN IA AND NRN IL. AS THE INTENSIFYING LOW TRACKS ALONG THE WARM FRONT OVER ERN IA AND NRN IL THROUGH SUNDAY EVENING...ASSOCIATED STRENGTHENING COLD FRONT SHOULD SWEEP ESEWD FROM THE CNTRL PLAINS TO THE LOWER OH RIVER VALLEY THROUGH EARLY MONDAY. ...CNTRL PLAINS ACROSS THE MS VALLEY/MIDWEST... WIDESPREAD DEEP CONVECTION EXPECTED TO BE ONGOING EARLY IN THE DAY IN AN ARC FROM NEB/IA SEWD TO THE CONFLUENCE OF THE MS/OH RIVERS. THIS ACTIVITY WILL BE SUSTAINED ALONG A WARM FRONT RETREATING NWD ACROSS THE REGION AS SURFACE LOW CONSOLIDATES AND STRENGTHENS OVER ERN NEB. THERE IS GOOD AGREEMENT AMONG A VARIETY OF NCEP MODEL GUIDANCE THAT THIS CONVECTION...PRIMARILY ELEVATED IN NATURE WITH SOME POTENTIAL FOR HAIL...WILL LIFT ENEWD ACROSS THE MS VALLEY THROUGH THE AFTERNOON. RAIN-COOLED AIR AND CLOUD COVER ASSOCIATED WITH THE MORNING CONVECTION WILL ACT TO REINFORCE THE WARM FRONT EXPECTED TO EXTEND EWD FROM THE SURFACE LOW NEAR IA. WARM SECTOR AIRMASS IS LIKELY TO BECOME INCREASINGLY UNSTABLE THROUGH THE AFTERNOON AS STRONG DYNAMICS AND COOLER TEMPERATURES ALOFT SPREAD EAST WITH THE MID/UPPER LEVEL IMPULSE. IN ADDITION TO POTENTIAL FOR RELATIVELY LOW-TOPPED STORMS FORMING WITHIN THE MID LEVEL VORTEX ACROSS ERN NEB AND KS...INCREASINGLY DIFFLUENT MID LEVEL FLOW WILL SPREAD ACROSS THE WARM SECTOR FROM MO INTO IA AND NRN IL. GIVEN CAPE VALUES INCREASING TO OVER 1000 J/KG NEAR THE SURFACE LOW AND WARM FRONT...LARGE SCALE FORCING IS EXPECTED TO RESULT IN RAPID THUNDERSTORM DEVELOPMENT DURING THE AFTERNOON. OVERALL PATTERN AS CURRENTLY FORECAST BY NAM AND GFS STRONGLY SUGGESTS AN ENHANCED POTENTIAL FOR LONG-TRACK SUPERCELLS FORMING ACROSS SRN IA/NRN MO AND THEN MOVING ACROSS THE MS RIVER FROM AFTERNOON INTO EARLY EVENING. FORECAST STORM RELATIVE SHEAR AND POTENTIALLY LOW LFC NEAR THE WARM FRONT AND SURFACE LOW...FROM SERN IA INTO NRN IL...APPEAR SUPPORTIVE OF STRONG TORNADOES IN THIS AREA. VERY LARGE HAIL WILL ALSO BE POSSIBLE FROM MUCH OF THE ACTIVITY AND CELLS MAY MERGE THROUGH THE EVENING HOURS...FORMING INTO A FAST MOVING BAND OF CONVECTION ON THE NOSE OF MID LEVEL JET STREAK. ATTENDANT THREAT OF DAMAGING WINDS COULD THEN SPREAD EAST ACROSS PARTS OF IL AND IND...AND PERHAPS AS FAR AS SRN MI AND ERN OH THROUGH EARLY MONDAY AS INTENSIFYING SURFACE LOW TRACKS INTO LOWER MI. IT IS POSSIBLE THAT PARTS OF THIS REGION MAY BE UPGRADED TO HIGHER PROBABILITIES AND PERHAPS EVEN A HIGH RISK IN LATER OUTLOOKS AS OVERALL SEVERE WEATHER SCENARIO BECOMES CLEARER. ...OZARKS TO LOWER OH/MS VALLEYS AND TN VALLEY... A MORE COMPLICATED FORECAST SCENARIO EXISTS ACROSS SRN PORTIONS OF THE HIGH-PROBABILITY SLIGHT RISK AREA. SOME CONVECTION MAY BE ONGOING EARLY IN THE PERIOD WITHIN WEAKLY UNSTABLE WARM CONVEYOR BELT FROM NERN TX TO SERN MO/WRN TN. DEGREE OF DESTABILIZATION WITHIN THIS CORRIDOR WILL DEPEND ON HOW RAPIDLY THIS EARLY ACTIVITY DISSIPATES. EXPECT THAT FORCING AND INSTABILITY WILL GRADUALLY INCREASE THROUGH LATE AFTERNOON AND THAT STORMS MAY TAKE SOME TIME TO BECOME SURFACE-BASED GIVEN POTENTIAL FOR GREATER INHIBITION. EVENTUALLY...AND PERHAPS NOT UNTIL EVENING...STRONGER STORMS SHOULD DEVELOP IN A BAND FROM AR EWD ACROSS THE MS RIVER VALLEY AS LARGE SCALE FORCING/PRE-FRONTAL TROUGH SPREAD EAST INTO THE REGION. SHEAR AND INSTABILITY CURRENTLY APPEAR FAVORABLE FOR A FEW INTENSE STORMS...POSSIBLY SUPERCELLS...WITHIN THIS BAND OF CONVECTION. INCREASINGLY STRONG MID LEVEL FLOW AND MID LEVEL DRY INTRUSION THROUGH LATE SUNDAY NIGHT ALSO SUGGEST THE DEVELOPMENT OF A SQUALL LINE WITH OCCASIONAL DAMAGING WINDS MOVING EAST ACROSS THE TN VALLEY...AND PERHAPS AS FAR EAST AS THE APPALACHIANS... THROUGH MONDAY MORNING. ..CARBIN.. 04/01/2006  From SWODY2 at goshenarc.org Sat Apr 1 17:14:54 2006 From: SWODY2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 01 Apr 2006 12:14:54 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 011712 SWODY2 SPC AC 011711 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1111 AM CST SAT APR 01 2006 VALID 021200Z - 031200Z ...THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF IA...MO AND MUCH OF IL... ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE GREAT LAKES SWD INTO THE MID SOUTH AND ARKLATEX... --POTENTIALLY SIGNIFICANT SEVERE WEATHER EPISODE IS BEING FORECAST ACROSS THE MIDWEST AND MID MS VALLEY SUNDAY AND SUNDAY NIGHT-- ...SYNOPSIS... MID AND UPPER-LEVEL TROUGH NOW OVER THE PACIFIC NW AND GREAT BASIN WILL TRANSLATE EWD INTO THE GREAT PLAINS LATE SATURDAY NIGHT INTO SUNDAY MORNING...PRIOR TO INTENSIFYING INTO A CLOSED CIRCULATION OVER THE UPPER MIDWEST SUNDAY NIGHT. AS THIS OCCURS...ACCOMPANYING MID AND HIGH-LEVEL JET STREAKS WILL PROPAGATE THROUGH THE TROUGH BASE INTO MO AND IL/IND SUNDAY AFTERNOON AND EVENING. IN THE LOW-LEVELS...PRIMARY SURFACE LOW INITIALLY OVER ERN NEB WILL DEVELOP ENEWD INTO LOWER MI BY MONDAY MORNING. ASSOCIATED WARM FRONT WILL CONCURRENTLY LIFT NEWD THROUGH THE OH VALLEY AND GREAT LAKES WHILE TRAILING COLD FRONT SURGES EWD THROUGH THE MID/LOWER MO AND MS VALLEYS AND INTO THE OH AND TN VALLEYS THROUGH THE FORECAST PERIOD. ...MID/LOWER MO VALLEY INTO THE GREAT LAKES...MID MS AND OH VALLEYS... A NW-SE ORIENTED BAND OF MAINLY ELEVATED TSTMS IS EXPECTED TO BE ONGOING 02/12Z FROM VICINITY OF THE SURFACE LOW OVER ERN NEB/WRN IA INTO WRN KY AND MIDDLE TN...LARGELY DRIVEN BY WAA ALONG BROAD SWLY LLJ. THIS ACTIVITY WILL LIKELY CONTINUE THROUGH THE PERIOD AHEAD OF RETREATING WARM FRONT INTO THE GREAT LAKES WITH THE STRONGEST STORMS CAPABLE OF MAINLY LARGE HAIL. IN THE WAKE OF THIS INITIAL ACTIVITY...THE PRESENCE OF STEEP MID-LEVEL LAPSE RATES / 7-8 C/KM / COUPLED WITH BOUNDARY-LAYER DEWPOINTS IN THE LOW TO MID 60S WILL CONTRIBUTE TO A MODERATELY UNSTABLE AIR MASS ACROSS SYSTEM WARM SECTOR WITH MLCAPES INCREASING TO 1500-2500 J/KG FROM SERN SE/CNTRL MO SWWD INTO THE ARKLATEX AND LOWER MS VALLEY. INCREASED FORCING FOR ASCENT AHEAD OF MID-LEVEL TROUGH AND EXIT REGIONS OF ACCOMPANYING JET STREAKS WILL CONTRIBUTE TO RAPID SURFACE-BASED TSTM DEVELOPMENT BY EARLY TO MID AFTERNOON FROM NEAR SURFACE LOW OVER WRN OR CNTRL IA SWD ALONG COLD FRONT INTO MO. ADDITIONAL SURFACE-BASED STORMS WILL ALSO BE POSSIBLE AT THIS TIME ALONG WARM FRONT. FORECAST SOUNDINGS INDICATE A POTENT COMBINATION OF INSTABILITY AND VERTICAL SHEAR ACROSS MODERATE RISK AREA...WHICH SHOULD SUPPORT INTENSE SUPERCELL DEVELOPMENT WITH THE POTENTIAL FOR A FEW STRONG TORNADOES IN ADDITION TO VERY LARGE...DESTRUCTIVE HAIL AND DAMAGING WINDS. WITH TIME...STORMS MAY EVOLVE INTO BOWING LINE SEGMENTS OR A MESOSCALE LEWP STRUCTURE WITH CORRIDORS OF DAMAGING WINDS POSSIBLE EWD ACROSS THE OH VALLEY SUNDAY NIGHT. ...MID SOUTH INTO ARKLATEX... AS MENTIONED ABOVE...PRE-FRONTAL AIR MASS IS FORECAST TO BECOME MODERATELY UNSTABLE BY AFTERNOON OWING TO STEEPENING LAPSE RATES AND A MOIST BOUNDARY-LAYER. GIVEN A STRONGER CAP AND THAT LARGE-SCALE FORCING FOR ASCENT AND LOW-LEVEL FRONTAL CONVERGENCE WILL TEND TO WEAKEN WITH SWD EXTENT...SOME UNCERTAINTY EXISTS WITH REGARD TO EVENTUAL CONVECTIVE COVERAGE AND INTENSITY ACROSS REGION. LATEST SHORT TERM MODEL GUIDANCE SUGGESTS THAT TSTMS SHOULD BEGIN TO BUILD SWWD ALONG FRONT BY MID TO LATE AFTERNOON FROM NEAR THE CONFLUENCE OF THE OH AND MS RIVERS INTO PORTIONS OF ERN AR...WRN TN AND PERHAPS SWD INTO NRN LA AND NRN MS. THE COMBINATION OF MODERATE INSTABILITY AND 45-55 KT WLY MID-LEVEL FLOW SUGGEST THE THREAT FOR A FEW SUPERCELLS AND BOWING LINE SEGMENTS CAPABLE OF DAMAGING WINDS...LARGE HAIL AND A FEW TORNADOES. THIS SEVERE THREAT WILL LIKELY CONTINUE SUNDAY NIGHT ACROSS THE TN VALLEY AND NRN PORTIONS OF MS AND AL. ..MEAD.. 04/01/2006  From SWODY2 at goshenarc.org Sun Apr 2 06:24:03 2006 From: SWODY2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 02 Apr 2006 01:24:03 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 020622 SWODY2 SPC AC 020621 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1221 AM CST SUN APR 02 2006 VALID 031200Z - 041200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF SRN PA...WV AND THE MID ATLANTIC REGION... ...SYNOPSIS... PROGRESSIVE LARGE SCALE TROUGH RESULTING IN WIDESPREAD SEVERE THUNDERSTORMS ACROSS THE PLAINS AND MIDWEST THROUGH SUNDAY WILL MOVE FROM THE GREAT LAKES/OH VALLEY TO THE EAST COAST ON MONDAY. AS PRIMARY SURFACE LOW ASSOCIATED WITH THIS SYSTEM TRACKS ENEWD TOWARD THE ST. LAWRENCE VALLEY AND UNDERGOES OCCLUSION...TRIPLE POINT LOW MAY TAKE FORM OVER WRN PA/WV AREA DURING THE DAY BEFORE STRONG COLD FRONT SURGES EAST ACROSS THESE AREAS. SIGNIFICANT HEIGHT FALLS AND INCREASINGLY STRONG WSWLY MID LEVEL FLOW WILL THEN SPREAD EAST ACROSS THE APPALACHIANS THROUGH THE DAY AND RESULT IN SECONDARY CYCLOGENESIS NEAR THE DELMARVA REGION BY LATE AFTERNOON. WARM FRONT AND SECONDARY LOW WILL LIFT SLOWLY NWD ALONG THE MID ATLANTIC SEABOARD AS COLD FRONT SWEEPS QUICKLY EWD ACROSS THE CAROLINAS AND VIRGINIA...AND THEN OFFSHORE AFTER DARK. ...WRN PA/WV AND MID ATLANTIC REGION... BAND OF CONVECTION ASSOCIATED WITH LIFT WITHIN LARGE SCALE WARM CONVEYOR BELT MAY BE ONGOING AT THE START OF THE DAY FROM THE CAROLINAS NWD/NWWD TO THE UPPER OH VALLEY/WRN TO CNTRL PA. ANOTHER BROKEN LINE OF SHOWERS AND THUNDERSTORMS MAY ALSO BE ONGOING AHEAD THE COLD FRONT...FROM ERN TN TO OH. POCKET OF DESTABILIZATION IS INDICATED IN LATEST GUIDANCE ACROSS ERN OH/WRN PA DURING THE MORNING AS MID LEVEL DRY SLOT CROSSES THIS AREA. DYNAMIC FORCING NEAR THE NOSE OF CYCLONICALLY CURVED MID LEVEL WIND MAX...AND LIFT ALONG THE ADVANCING FRONT...MAY SUPPORT STORM INTENSIFICATION ACROSS ERN OH/WRN PA. GIVEN MAGNITUDE OF FORCING...WEAK INSTABILITY MAY BE SUFFICIENT MAINTAIN A LINE OF LOW-TOPPED SUPERCELLS WITH DAMAGING WINDS AND HAIL MOVING EAST OVER SRN PA AND WV. FARTHER SOUTH...STRONG LOW LEVEL MOISTURE FLUX AHEAD OF THE DEEP TROUGH AND COLD FRONT IS EXPECTED TO AID IN THE TRANSPORT OF LOW TO MID 60S F DEWPOINTS NWD ACROSS THE CAROLINAS AND INTO SRN VA THROUGH EARLY AFTERNOON. BREAKS IN COLD COVER IN THE WAKE OF ANY MORNING CONVECTION SHOULD CONTRIBUTE TO THE DEVELOPMENT OF WEAK TO MODERATE INSTABILITY...CAPE 500-1000 J/KG...ACROSS PARTS OF SC/NC AND SERN VA. ADDITIONAL STORMS WILL DEVELOP RAPIDLY AS DEEP FRONTAL CIRCULATION MOVES EAST OF THE MOUNTAINS. THIS WILL OCCUR COINCIDENT WITH INTENSIFYING DEEP LAYER FLOW. PRIMARILY UNIDIRECTIONAL SHEAR AND FOCUSED FORCING OR ASCENT ALONG THE ADVANCING FRONT SUGGESTS LINEAR STORM MODE WITH FORECAST SOUNDINGS INDICATING CELL MOTIONS IN EXCESS OF 50KT. STORM ORGANIZATION MAY BE FURTHER ENHANCED NEAR THE SECONDARY SURFACE LOW AS IT BEGINS TO TAKE FORM NEAR DELMARVA AREA THROUGH THE AFTERNOON. POTENTIAL FOR ENHANCED SHEAR NEAR THE LOW AND WARM FRONT COULD RESULT IN A FAVORABLE ENVIRONMENT FOR SUPERCELLS AND PERHAPS A TORNADO OR TWO...IN ADDITION TO HAIL AND WIND. ..CARBIN.. 04/02/2006  From SWODY2 at goshenarc.org Sun Apr 2 17:03:32 2006 From: SWODY2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 02 Apr 2006 13:03:32 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 021701 SWODY2 SPC AC 021700 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1200 PM CDT SUN APR 02 2006 VALID 031200Z - 041200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF THE CNTRL APPALACHIANS EWD INTO THE MIDDLE ATLANTIC STATES AND CAROLINAS... ...SYNOPSIS... MID-LEVEL TROUGH...ANCHORED BY LOW OVER ONTARIO...IS FORECAST TO BECOME NEGATIVELY-TILTED OVER THE ERN U.S. AS STRONG MID AND HIGH-LEVEL JET STREAKS DEVELOP SEWD FROM THE MID MS VALLEY INTO THE CAROLINAS. IN THE LOW-LEVELS...OCCLUDING SURFACE LOW OVER LOWER MI WILL DEVELOP NEWD INTO WRN QUEBEC WHILE TRAILING COLD FRONT SURGES EWD THROUGH THE UPPER OH VALLEY...APPALACHIAN CHAIN INTO THE ADJACENT COASTAL PLAIN. MEANWHILE...WARM FRONT WILL SLOWLY LIFT NWD THROUGH THE MIDDLE ATLANTIC STATES INTO SRN NEW ENGLAND WITH SECONDARY CYCLOGENESIS OCCURRING AT INTERSECTION OF WARM AND COLD FRONTS. THIS SECONDARY SURFACE LOW WILL DEVELOP NEWD FROM NRN VA INTO SRN NEW ENGLAND BY TUESDAY MORNING. ...CNTRL APPALACHIANS / MIDDLE ATLANTIC COAST SWD INTO THE CAROLINAS... A BROKEN BAND OF PRE-FRONTAL CONVECTION IS EXPECTED TO BE ONGOING AT THE ONSET OF THE FORECAST PERIOD FROM PORTIONS OF THE UPPER OH VALLEY SWWD ALONG THE SPINE OF THE APPALACHIANS AND INTO NRN PORTIONS OF MS/AL/GA. THIS ACTIVITY MAY TEND TO WEAKEN THROUGH THE DAY AS IT SHIFTS EWD AWAY FROM THE STRONGER FORCING FOR ASCENT AND INSTABILITY. IN IT/S WAKE...STRONG HEIGHT FALLS...DAYTIME HEATING AND LOW-LEVEL MOISTENING FROM THE S AND SW WILL ALL CONTRIBUTE TO AIR MASS DESTABILIZATION AHEAD DEEP COLD FRONTAL ZONE RAPIDLY SWEEPING EWD. THIS DESTABILIZATION WILL RESULT IN SBCAPES INCREASING TO 250-500 J/KG OVER PORTIONS OF PA...TO AS HIGH AS 1000-2000 J/KG OVER SERN VA INTO THE CNTRL AND ERN CAROLINAS. A MORE FOCUSED LINE OF VIGOROUS TSTM DEVELOPMENT IS ANTICIPATED BY EARLY AFTERNOON ALONG FRONT...INITIALLY ALONG NRN PORTION OF INSTABILITY AXIS OVER ERN OH/WRN PA...WITH SUBSEQUENT SWD DEVELOPMENT INTO THE CNTRL APPALACHIANS. WHILE NRN EXTENSION OF THIS DIURNAL DEVELOPMENT MAY EXHAUST AVAILABLE INSTABILITY OVER PA/NY BY LATE AFTERNOON...OTHER STORMS MOVING INTO VA AND THE CAROLINAS SHOULD CONTINUE TO INTENSIFY AS THEY ENCOUNTER INCREASINGLY UNSTABLE AIR MASS. IT APPEARS THAT THE MOST CONCENTRATED ZONE OF SEVERE TSTMS WILL OCCUR ALONG AND S OF SECONDARY SURFACE LOW TRIPLE POINT OVER CNTRL AND ERN PORTIONS OF VA AND NC PERHAPS INTO SC. HERE...STRONG VERTICAL SHEAR PROFILES OWING TO PROXIMITY OF MID AND UPPER-LEVEL JET STREAKS WILL BECOME CO-LOCATED WITH THE MODERATE INSTABILITY. WHILE LINE SEGMENTS AND BOWS CAPABLE OF LARGE HAIL AND DAMAGING WINDS WILL BE THE PRIMARY CONVECTIVE MODE...RELATIVELY STRONG LOW-LEVEL SHEAR SUGGESTS THE POTENTIAL FOR SUPERCELLS CAPABLE OF TORNADOES. THESE STORMS SHOULD EVENTUALLY MOVE OFFSHORE BY MID TO LATE MONDAY EVENING. FARTHER TO THE SW OVER SC INTO GA...ADDITIONAL MORE ISOLATED TSTMS WILL BE POSSIBLE DURING THE AFTERNOON AND EVENING HOURS. MODERATE INSTABILITY COUPLED WITH MODEST DEEP-LAYER SHEAR SUGGESTS SOME POTENTIAL FOR ISOLATED DAMAGING WINDS AND HAIL...THOUGH THE WEAKER LARGE-SCALE FORCING WITH SWD EXTENT SHOULD TEND TO LIMIT THE OVERALL SEVERE THREAT. ..MEAD.. 04/02/2006  From SWODY2 at goshenarc.org Mon Apr 3 06:27:17 2006 From: SWODY2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 03 Apr 2006 02:27:17 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 030624 SWODY2 SPC AC 030623 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0123 AM CDT MON APR 03 2006 VALID 041200Z - 051200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... POWERFUL TROUGH NOW CROSSING THE MIDWEST IS FORECAST TO PHASE WITH A STRONG NRN STREAM IMPULSE DROPPING SOUTH FROM CNTRL CANADA AND PROMOTE EAST COAST CYCLOGENESIS THROUGH THE DAY 1 PERIOD. RESULTING NOREASTER WILL TRACK TOWARD THE GULF OF MAINE AND UNDERGO OCCLUSION AS A DEEP LAYER CYCLONE FORMS ACROSS NEW ENGLAND THROUGH MIDWEEK. MEANWHILE...A BRIEF RESPITE FROM SEVERE WEATHER WILL ENSUE ACROSS THE PLAINS AND MIDWEST TUESDAY AS UPPER RIDGE STRENGTHENS OVER THESE REGIONS. HOWEVER...INTENSIFYING WARM AIR AND MOISTURE ADVECTION BENEATH PLAINS CAPPING/SUBSIDENCE INVERSION COULD PROMOTE MCS DEVELOPMENT WITHIN ZONE OF LARGE SCALE JET COUPLING...FROM THE SRN PLAINS ACROSS THE MO OZARKS...BY EARLY WEDNESDAY. IN THE WEST...COLD UPPER TROUGH IS FORECAST TO DEVELOP INLAND FROM THE ERN PACIFIC WITH STRONG HEIGHT FALLS SPREADING EWD FROM CA TO THE GREAT BASIN AND LOWER CO VALLEY. ...CNTRL CA... LATEST WATER VAPOR LOOP DEPICTS CONSIDERABLE SHORT WAVE ENERGY CONSOLIDATING WITHIN THE LARGE CLOSED LOW OFF THE WEST COAST. MODEL GUIDANCE CONTINUES TO PREDICT THAT THIS COMPLEX TROUGH/LOW WILL REDEVELOP INLAND THROUGH TUESDAY AS 100KT MID LEVEL JET STREAK CROSSES SRN CA AND THE LOWER CO VALLEY. DESPITE RELATIVELY WEAK SHEAR NEAR THE CORE OF THE LARGE MID/UPPER LOW...VERY COLD MID LEVEL TEMPERATURES OF -26C TO -30C WILL MOVE OVER PORTIONS OF CNTRL CA THROUGH THE DAY. LOW STATIC STABILITY COMBINED WITH MARGINAL MOISTURE...OROGRAPHIC FORCING...AND POSSIBILITY OF POCKETS OF MODEST DIURNAL HEATING...SHOULD PROMOTE SCATTERED TSTM DEVELOPMENT FROM THE COAST INLAND ACROSS THE CENTRAL VALLEY. MARGINAL HAIL SHOULD BE THE PRIMARY HAZARD FROM THIS CONVECTION. ...SRN PLAINS TO KS/MO LATE... NAM-ETA WAS FORECASTING SOME POTENTIAL FOR ELEVATED TSTMS OVER CNTRL/NWRN TX THROUGH EARLY TUESDAY WHERE LEADING EDGE OF LOW LEVEL MOISTURE RETURN WILL BE LIFTED ACROSS RETREATING SYNOPTIC FRONT. HOWEVER...THIS CONVECTIVE POTENTIAL MAY BE QUICKLY INHIBITED BY INCREASING SUBSIDENCE AND WARMING TEMPERATURES WITHIN BUILDING MID/UPPER LEVEL RIDGE....AT LEAST THROUGH LATE AFTERNOON. ELEVATED MIXED LAYER IS EXPECTED TO STRENGTHEN ACROSS THE PLAINS THROUGH THE DAY AND PROMOTE EFFICIENT CHANNELING OF LOW LEVEL MOISTURE NWD/NEWD WITHIN INTENSIFYING LOW LEVEL JET. A WEAK IMPULSE...POSSIBLY EMANATING FROM SRN PORTION OF WEST COAST TROUGH...IS FORECAST TO CREST THE RIDGE OVER THE PLAINS AND COULD SUPPORT ISOLATED HIGH-BASED CONVECTION OVER PARTS OF THE TX PANHANDLE/WRN OK/SWRN KS IF STRONG HEATING IN THESE AREAS CAN OVERCOME THE CAP. A MORE LIKELY SCENARIO IS THAT THE WEAK MID LEVEL IMPULSE WILL CONTINUE TO TRACK EAST AND....COUPLED WITH PERSISTENT ISENTROPIC LIFT AND MOISTENING ON THE NOSE OF THE LOW LEVEL JET...PROMOTE LATE NIGHT ELEVATED STORMS TO FORM NEAR THE EDGE OF THE CAP...FROM NERN OK/SERN KS INTO MO. BY EARLY WEDNESDAY...SHEAR AND INSTABILITY ACROSS THESE AREAS SHOULD PROVE ADEQUATE FOR A FEW HAIL EVENTS...IF STORMS CAN DEVELOP IN THIS REGIME. ..CARBIN.. 04/03/2006  From SwoDy2 at goshenarc.org Mon Apr 3 17:42:59 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 03 Apr 2006 13:42:59 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 031740 SWODY2 SPC AC 031739 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1239 PM CDT MON APR 03 2006 VALID 041200Z - 051200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... HIGHLY AMPLIFIED UPPER AIR PATTERN FCST THROUGH PERIOD...WITH MEAN TROUGHS OVER E AND W COASTS AND RIDGE ACROSS PLAINS STATES. MIDDLE-UPPER LEVEL CYCLONE -- NOW CENTERED OVER SERN LOWER MI -- IS FCST TO EJECT NEWD AS OPEN WAVE WHILE ANOTHER MIDDLE-UPPER LEVEL LOW OVER NRN ONT DIGS SEWD ACROSS GREAT LAKES AND NY. ASSOCIATED SFC COLD FRONT WILL SWEEP OFFSHORE MOST OF ATLANTIC COAST FROM MID ATLANTIC STATES SWD TO CENTRAL/NRN FL. WRN REMNANT OF THIS FRONT WILL STALL LATE DAY-1 OVER NRN GULF AND S TX...THEN BECOME DIFFUSE AND RETURN NWD OVER SRN/CENTRAL TX DAY-2. MEANWHILE...DEEP UPPER LOW -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY AROUND 36N134W -- IS FCST TO PIVOT EWD THROUGH DAY-2 WITH STRONG SHORTWAVE TROUGH MOVING ONSHORE SRN CA AROUND 5/06Z. BROAD PLUME OF WAA AND MIDLEVEL MOIST ADVECTION WILL OVERSPREAD MUCH OF WRN CONUS AHEAD OF THIS SYSTEM. NET RESULT WILL BE SEVERAL AREAS OF MRGL AND OR CONDITIONAL SEVERE POTENTIAL. ...EARLY MORNING -- TX/SERN NM... MRGL/CONDITIONAL HAIL PROBABILITIES EXIST OVER THIS REGION FOR FIRST FEW HOURS OF PERIOD...AMIDST EXTENSION OF LATE DAY-1 WAA/MOISTURE RETURN REGIME. ELEVATED BUOYANCY IS FCST TO BE SMALL -- GENERALLY AOB 500 J/KG MOST AREAS. HOWEVER...ANY SUSTAINED CONVECTION WILL HAVE POTENTIAL FOR HAIL GIVEN STRONG VEERING AND SPEED SHEAR WITH HEIGHT THROUGH CONVECTIVE COLUMN...WHICH SHOULD BE ROOTED IN 800-850 MB LAYER BASED ON FCST SOUNDINGS. ACTIVITY SHOULD DIMINISH DURING LATE MORNING AS LLJ WEAKENS. ...AFTERNOON/EVENING -- CA... CONDITIONAL THREAT FOR SEVERE EXISTS BOTH OVER CENTRAL VALLEY AND COASTAL AREAS...AMIDST WEAK CINH AND AT LEST MRGL MUCAPES OF 100-400 J/KG. LOW LEVEL MOIST ADVECTION AND STEEPENING LAPSE RATES ALOFT SHOULD SUPPORT SCATTERED TSTMS...PARTICULARLY DURING AFTERNOON WHERE BREAKS IN CLOUD COVER CAN ALLOW POCKETS OF DIABATIC SFC HEATING. VERTICAL SHEAR PROFILES ACROSS PORTIONS COASTAL SRN CA ARE FCST TO BE LARGE -- CHARACTERIZED BY STRONG VEERING WITH HEIGHT AND STRENGTHENING MIDLEVEL FLOW GRADIENTS AHEAD OF SHORTWAVE TROUGH. BASIC PATTERN RESEMBLES THAT OF SOME L.A. BASIN SUPERCELL CASES AND THIS AREA MAY REQUIRE ENHANCED PROBABILITIES ONCE TIMING/STRENGTH OF FEATURES ALOFT BECOMES BETTER ESTABLISHED. INLAND...DEEP-LAYER WINDS WILL BE MORE UNIDIRECTIONAL WITH STRONG MERIDIONAL COMPONENT...THOUGH OROGRAPHICALLY FORCED BACKING SHOULD ENHANCED SHEAR OVER PORTIONS CENTRAL VALLEY. ...AFTERNOON/EVENING -- GREAT BASIN... WIDELY SCATTERED TSTMS ARE EXPECTED TO DEVELOP OVER PORTIONS BASIN -AND-RANGE REGION -- SHIFTING/EVOLVING NWD TOWARD SNAKE RIVER VALLEY. MAIN CONCERN IS ISOLATED GUSTS NEAR SEVERE LEVELS. MAIN LIMITING FACTOR IS WEAK BOUNDARY LAYER MOISTURE...WHICH WILL LIMIT MLCAPES TO BELOW 250 J/KG MOST AREAS. STRONG VERTICAL MIXING IS LIKELY DURING AFTERNOON...WEAKENING CINH AND RESULTING IN POTENTIAL FOR TSTM FORMATION. STRONG MIDLEVEL FLOW WILL SUPPORT 40-60 KT DEEP-LAYER SHEAR IN SUPPORT OF POTENTIAL FOR STRONG-SEVERE GUSTS FROM MOST VIGOROUS CONVECTION. ...LATE OVERNIGHT -- OZARKS TO E-CENTRAL PLAINS... SCATTERED TSTMS SHOULD DEVELOP MAINLY AFTER 5/06Z IN THIS REGION...WITH ISOLATED HAIL POSSIBLE. LOW LEVEL WAA/MOIST ADVECTION REGIME WILL INTENSIFY THROUGH PERIOD...CULMINATING IN RETURN OF FAVORABLE INCREASING LOW LEVEL MOISTURE AFTER DARK FROM MUCH OF AR NWWD OVER PORTIONS NERN OK...ERN KS AND WRN MO. ETA/SPECTRAL FCSTS OF CONVECTIVE DEVELOPMENT OVER THIS REGION APPEAR REASONABLE BASED ON UPSTREAM MOISTURE PROFILES EVIDENT ACROSS S TX AND WRN GULF. EXPECT From SwoDy2 at goshenarc.org Mon Apr 3 17:42:59 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 03 Apr 2006 13:42:59 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 031740 SWODY2 SPC AC 031739 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1239 PM CDT MON APR 03 2006 VALID 041200Z - 051200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... HIGHLY AMPLIFIED UPPER AIR PATTERN FCST THROUGH PERIOD...WITH MEAN TROUGHS OVER E AND W COASTS AND RIDGE ACROSS PLAINS STATES. MIDDLE-UPPER LEVEL CYCLONE -- NOW CENTERED OVER SERN LOWER MI -- IS FCST TO EJECT NEWD AS OPEN WAVE WHILE ANOTHER MIDDLE-UPPER LEVEL LOW OVER NRN ONT DIGS SEWD ACROSS GREAT LAKES AND NY. ASSOCIATED SFC COLD FRONT WILL SWEEP OFFSHORE MOST OF ATLANTIC COAST FROM MID ATLANTIC STATES SWD TO CENTRAL/NRN FL. WRN REMNANT OF THIS FRONT WILL STALL LATE DAY-1 OVER NRN GULF AND S TX...THEN BECOME DIFFUSE AND RETURN NWD OVER SRN/CENTRAL TX DAY-2. MEANWHILE...DEEP UPPER LOW -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY AROUND 36N134W -- IS FCST TO PIVOT EWD THROUGH DAY-2 WITH STRONG SHORTWAVE TROUGH MOVING ONSHORE SRN CA AROUND 5/06Z. BROAD PLUME OF WAA AND MIDLEVEL MOIST ADVECTION WILL OVERSPREAD MUCH OF WRN CONUS AHEAD OF THIS SYSTEM. NET RESULT WILL BE SEVERAL AREAS OF MRGL AND OR CONDITIONAL SEVERE POTENTIAL. ...EARLY MORNING -- TX/SERN NM... MRGL/CONDITIONAL HAIL PROBABILITIES EXIST OVER THIS REGION FOR FIRST FEW HOURS OF PERIOD...AMIDST EXTENSION OF LATE DAY-1 WAA/MOISTURE RETURN REGIME. ELEVATED BUOYANCY IS FCST TO BE SMALL -- GENERALLY AOB 500 J/KG MOST AREAS. HOWEVER...ANY SUSTAINED CONVECTION WILL HAVE POTENTIAL FOR HAIL GIVEN STRONG VEERING AND SPEED SHEAR WITH HEIGHT THROUGH CONVECTIVE COLUMN...WHICH SHOULD BE ROOTED IN 800-850 MB LAYER BASED ON FCST SOUNDINGS. ACTIVITY SHOULD DIMINISH DURING LATE MORNING AS LLJ WEAKENS. ...AFTERNOON/EVENING -- CA... CONDITIONAL THREAT FOR SEVERE EXISTS BOTH OVER CENTRAL VALLEY AND COASTAL AREAS...AMIDST WEAK CINH AND AT LEST MRGL MUCAPES OF 100-400 J/KG. LOW LEVEL MOIST ADVECTION AND STEEPENING LAPSE RATES ALOFT SHOULD SUPPORT SCATTERED TSTMS...PARTICULARLY DURING AFTERNOON WHERE BREAKS IN CLOUD COVER CAN ALLOW POCKETS OF DIABATIC SFC HEATING. VERTICAL SHEAR PROFILES ACROSS PORTIONS COASTAL SRN CA ARE FCST TO BE LARGE -- CHARACTERIZED BY STRONG VEERING WITH HEIGHT AND STRENGTHENING MIDLEVEL FLOW GRADIENTS AHEAD OF SHORTWAVE TROUGH. BASIC PATTERN RESEMBLES THAT OF SOME L.A. BASIN SUPERCELL CASES AND THIS AREA MAY REQUIRE ENHANCED PROBABILITIES ONCE TIMING/STRENGTH OF FEATURES ALOFT BECOMES BETTER ESTABLISHED. INLAND...DEEP-LAYER WINDS WILL BE MORE UNIDIRECTIONAL WITH STRONG MERIDIONAL COMPONENT...THOUGH OROGRAPHICALLY FORCED BACKING SHOULD ENHANCED SHEAR OVER PORTIONS CENTRAL VALLEY. ...AFTERNOON/EVENING -- GREAT BASIN... WIDELY SCATTERED TSTMS ARE EXPECTED TO DEVELOP OVER PORTIONS BASIN -AND-RANGE REGION -- SHIFTING/EVOLVING NWD TOWARD SNAKE RIVER VALLEY. MAIN CONCERN IS ISOLATED GUSTS NEAR SEVERE LEVELS. MAIN LIMITING FACTOR IS WEAK BOUNDARY LAYER MOISTURE...WHICH WILL LIMIT MLCAPES TO BELOW 250 J/KG MOST AREAS. STRONG VERTICAL MIXING IS LIKELY DURING AFTERNOON...WEAKENING CINH AND RESULTING IN POTENTIAL FOR TSTM FORMATION. STRONG MIDLEVEL FLOW WILL SUPPORT 40-60 KT DEEP-LAYER SHEAR IN SUPPORT OF POTENTIAL FOR STRONG-SEVERE GUSTS FROM MOST VIGOROUS CONVECTION. ...LATE OVERNIGHT -- OZARKS TO E-CENTRAL PLAINS... SCATTERED TSTMS SHOULD DEVELOP MAINLY AFTER 5/06Z IN THIS REGION...WITH ISOLATED HAIL POSSIBLE. LOW LEVEL WAA/MOIST ADVECTION REGIME WILL INTENSIFY THROUGH PERIOD...CULMINATING IN RETURN OF FAVORABLE INCREASING LOW LEVEL MOISTURE AFTER DARK FROM MUCH OF AR NWWD OVER PORTIONS NERN OK...ERN KS AND WRN MO. ETA/SPECTRAL FCSTS OF CONVECTIVE DEVELOPMENT OVER THIS REGION APPEAR REASONABLE BASED ON UPSTREAM MOISTURE PROFILES EVIDENT ACROSS S TX AND WRN GULF. EXPECT ISENTROPIC LIFT OF PARCELS TO LFC WITH ELEVATED MUCAPES INCREASING TO AROUND 250-500 J/KG. 35-40 KT EFFECTIVE SHEARS IN FCST SOUNDINGS SUGGEST SOME POTENTIAL FOR TSTMS TO BECOME ORGANIZED AND PRODUCE HAIL. ..EDWARDS.. 04/03/2006  From SwoDy2 at goshenarc.org Tue Apr 4 06:24:43 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 04 Apr 2006 02:24:43 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 040622 SWODY2 SPC AC 040621 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0121 AM CDT TUE APR 04 2006 VALID 051200Z - 061200Z ...THERE IS A SLGT RISK OF SVR TSTMS LATE WEDNESDAY/EARLY THURSDAY ACROSS SD AND NERN NEB... ...SYNOPSIS... LARGE AND COMPLEX UPPER TROUGH OFF THE WEST COAST IS FORECAST TO ACCELERATE INLAND AND CROSS THE GREAT BASIN/INTERMOUNTAIN REGIONS THROUGH THE DAY 1 PERIOD BEFORE A LARGE AREA OF STRONG HEIGHT FALLS ASSOCIATED WITH THIS DISTURBANCE SPREADS OVER GREAT PLAINS WEDNESDAY NIGHT THROUGH THURSDAY. MEANWHILE...A STRONG UPPER RIDGE CURRENTLY ACROSS THE PLAINS WILL SHIFT EAST TO THE MS VALLEY AND GRADUALLY DEAMPLIFY. DOWNSTREAM FROM THE CNTRL U.S. UPPER RIDGE...A DEEP POLAR VORTEX WILL FORM OVER THE NORTHEAST AND DRIFT EWD. HIGH AMPLITUDE FLOW REGIME ACROSS THE WRN AND CNTRL STATES WILL ALLOW DEEP LAYER SLY/SWLY WINDS TO PERSIST AND STRENGTHEN AHEAD OF THE WRN TROUGH THROUGH WEDNESDAY. SUBSIDENCE BENEATH THE UPPER RIDGE AND STEADY WARMING ACROSS THE HIGH PLAINS THROUGH WEDNESDAY WILL RESULT IN AN EXTENSIVE ELEVATED MIXED LAYER AIRMASS DEVELOPING FROM THE SOUTHERN ROCKIES/HIGH PLAINS NWD TO THE DAKOTAS. LEE CYCLOGENESIS IS EXPECTED TO COMMENCE ACROSS CO/WY/MT BY WEDNESDAY EVENING AS STRONG DYNAMIC FORCING AHEAD OF THE UPPER TROUGH MOVES NEWD OVER THESE AREAS. ASSOCIATED WARM FRONT SHOULD FORM AND LIFT NWD ACROSS THE NRN PLAINS OVERNIGHT AS STRONG PACIFIC COLD FRONT SPREADS EAST FROM THE ROCKIES AND INTO THE HIGH PLAINS THROUGH THURSDAY MORNING. ...HIGH PLAINS /WRN TX TO WRN NEB/ THROUGH WEDNESDAY EVENING... DESPITE STRONG LOW LEVEL SLY FLOW DEVELOPING ACROSS THE PLAINS THROUGH THE PERIOD...LATEST GUIDANCE CONTINUES TO SUGGEST THAT MOISTURE RETURN ACROSS THE PLAINS WILL BE LESS THAN ROBUST INTO THE DAY 2 PERIOD. MODELS APPEAR TO SUGGEST THAT EITHER A POCKET...OR NARROW AXIS...OF GREATER LOW LEVEL MOISTURE /850MB DEWPOINTS AROUND 10C/ WILL ADVECT NWD AND THEN NEWD FROM LOWER RIO GRANDE VALLEY...ACROSS THE SRN PLAINS...TO THE MO RIVER VALLEY THROUGH THE PERIOD. WEAK HEIGHT FALLS COUPLED WITH DEEP MIXING/HEATING AND CONFLUENT FLOW NEAR DRYLINE/LEE TROUGH...FROM WEST TX TO THE NEB PANHANDLE...MAY PROMOTE HIGH-BASED TSTM DEVELOPMENT BY WEDNESDAY EVENING. EXPECT THE BULK OF THIS ACTIVITY TO STRUGGLE TO PERSIST GIVEN POTENTIAL FOR STRONG INHIBITION... ESPECIALLY FROM KS/NEB AREA SWD AFTER DARK. HOWEVER...A FEW HIGH-BASED SUPERCELLS COULD RESULT IN A COUPLE OF ISOLATED HAIL/WIND EVENTS. ...NRN PLAINS... CONDITIONS FOR VIGOROUS DEEP CONVECTION SHOULD IMPROVE THROUGH LATE WEDNESDAY EVENING FROM ERN WY/MT EWD ACROSS NEB AND SD. STRONG DYNAMIC FORCING ASSOCIATED WITH INCREASINGLY DIFFLUENT FLOW ALOFT WILL SPREAD NEWD ATOP INTENSIFYING ZONE OF WARM AIR ADVECTION OVER THE NRN PLAINS. SCATTERED TSTMS WITH A MARGINAL THREAT OF HAIL AND STRONG WINDS MAY FIRST INITIATE ACROSS THE HIGHER TERRAIN OF WY/MT WHERE INHIBITION AND CAPE WILL BE WEAKER. WHILE WARM SECTOR SURFACE PARCELS WILL LIKELY REMAIN CAPPED BY STRONG ELEVATED MIXED LAYER THROUGH THE EVENING...HIGH-BASED STORMS SHOULD DEVELOP EAST AND PERSIST AS MOISTENING...LIFT...AND DESTABILIZATION ALL INCREASE WITHIN THE WARM FRONTAL ZONE. LATEST GUIDANCE WOULD SUPPORT A SEVERE MCS MOVING EAST ACROSS SD/NERN NEB THROUGH DAYBREAK THURSDAY WITH THE PRIMARY HAZARD BEING LARGE HAIL. ..CARBIN.. 04/04/2006  From SwoDy2 at goshenarc.org Wed Apr 5 06:21:20 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 05 Apr 2006 02:21:20 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 050618 SWODY2 SPC AC 050617 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0117 AM CDT WED APR 05 2006 VALID 061200Z - 071200Z ...THERE IS A MDT RISK OF SVR TSTMS OVER A LARGE AREA OF THE CENTRAL AND SOUTHERN PLAINS FROM NEBRASKA/AND SOUTHWEST IOWA TO EASTERN NEBRASKA AND OKLAHOMA...MUCH OF MISSOURI AND NORTHWEST ARKANSAS... ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK AREA FROM THE SRN/CNTRL PLAINS TO THE OH VALLEY... ...SIGNIFICANT SEVERE WEATHER OUTBREAK APPEARS INCREASINGLY LIKELY OVER THE PLAINS/MIDWEST ON THURSDAY... ...SYNOPSIS... VERY ACTIVE WEATHER PATTERN WILL CONTINUE TO EVOLVE WEDNESDAY INTO THURSDAY WITH THE POTENTIAL FOR WIDESPREAD SEVERE WEATHER DEVELOPING ACROSS THE PLAINS...AND POSSIBLY SPREADING EAST ACROSS THE MIDWEST AND OH VALLEY AREAS FROM THURSDAY THROUGH EARLY FRIDAY. THE SYSTEM EXPECTED TO BRING ABOUT THE NEXT ROUND OF SPRINGTIME SEVERE WEATHER WAS CROSSING THE WEST COAST IN THE FORM OF A COMPLEX DOUBLE-VORTEX UPPER TROUGH EARLY TODAY. STRONG DEEP-LAYER ASCENT WAS OBVIOUS AHEAD OF THE TROUGH AND RADAR AND SATELLITE IMAGERY WERE INDICATING PRONOUNCED DIFFLUENT MID/UPPER LEVEL FLOW PROMOTING CONVECTION FROM CA TO ID. UPSTREAM FROM THE WEST COAST TROUGH... ANOTHER POTENT IMPULSE WAS DEPICTED ON SATELLITE IMAGERY MOVING SOUTH OF THE GULF OF AK. DESPITE RELATIVELY HIGH AMPLITUDE FLOW REGIME...CONSIDERABLE JET ENERGY WITH THE UPSTREAM SYSTEM WILL DISLODGE THE WEST COAST TROUGH INLAND AND ACROSS THE ROCKIES THROUGH DAY 1. A BELT OF 80-90KT MID LEVEL FLOW OF WILL ROTATE THROUGH THE BASE OF THE TROUGH AND NOSE OUT ATOP THE SRN/CNTRL HIGH PLAINS THROUGH 36 HOURS...BY THURSDAY MORNING. STRONG DYNAMIC FORCING ACCOMPANYING THE UPPER SYSTEM WILL INDUCE LEE-SIDE CYCLOGENESIS ACROSS WY/MT TONIGHT AND THEN THE DEEPENING SURFACE LOW WILL REFORM EWD ACROSS NEB THROUGH THURSDAY MORNING. LATEST MODEL FORECASTS SUGGEST AN OVERALL SCENARIO STRONGER AND SOMEWHAT FURTHER SOUTH WITH THE CYCLONE THAN MODEL GUIDANCE FROM 24 HOURS AGO. WHILE THIS SUGGESTS A POSSIBLE TREND...ALL THE LATEST DETERMINISTIC GUIDANCE IS IN GOOD AGREEMENT WITH TIMING AND INTENSITY OF THE LARGE SCALE FEATURES TO AFFECT SEVERE WEATHER EVOLUTION FROM THE PLAINS TO THE MIDWEST ON THURSDAY. ...NEB/IA... THERE MAY BE AN ARC OF DEEP CONVECTION UNDERWAY EARLY IN THE DAY FROM NEAR/NORTH OF THE SURFACE LOW...EWD AND SEWD ALONG AND NORTH OF THE WARM FRONT...FROM NEB/SD...ACROSS IA...AND PERHAPS OVER IL. THIS ACTIVITY WILL LIKELY BE SUSTAINED BY INTENSIFYING LARGE SCALE ISENTROPIC LIFT OCCURRING ON THE EDGE OF EXTENSIVE PLAINS CAPPING INVERSION. WHILE ELEVATED IN NATURE...SOME OF THESE STORMS STILL PRODUCE HAIL. STRONG CAP ACROSS MUCH OF THE WARM SECTOR WILL AID IN EFFICIENT LOW LEVEL MOISTURE TRANSPORT NWD ACROSS KS/MO/ERN NEB AND IA WITH A GENERAL CONSENSUS AMONG AVAILABLE GUIDANCE THAT AT LEAST LOW 60S F DEWPOINTS SHOULD DEVELOP ACROSS THESE AREAS BY AFTERNOON. DEEP LAYER WIND FIELDS SURROUNDING THE INTENSIFYING CYCLONE OVER NEB WILL STRENGTHEN THROUGH THE DAY AS WARM FRONT LIFTS NWD ACROSS ERN NEB AND MUCH OF IA...AND DRYLINE SHARPENS FROM NEB SWD ACROSS KS/OK. STRONG ASCENT BENEATH THE NOSE OF THE MID LEVEL JET...AND NEAR SURFACE LOW/WARM FRONT WILL EFFECTIVELY OVERCOME THE CAP ACROSS NEB/IA THROUGH AFTERNOON. STEEP MID LEVEL LAPSE RATES OF ABOUT 8 C/KM ATOP MOISTENING BOUNDARY LAYER WILL CONTRIBUTE TO MLCAPE IN THE RANGE OF 500-1000 J/KG...AND PERHAPS LOCALLY HIGHER IN AREAS WHERE MOISTURE/HEATING CAN BE MAXIMIZED. ROBUST SURFACE-BASED TSTM DEVELOPMENT SHOULD COMMENCE AS CAP IS BREACHED ACROSS NEB AND INTO IA FROM AFTERNOON INTO EVENING. SHEAR WILL BE MORE THAN ADEQUATE FOR SUPERCELLS AND VERY LARGE HAIL...HIGH WIND...AND TORNADOES APPEAR LIKELY. TORNADO POTENTIAL WILL DEPEND ON QUALITY OF MOISTURE RETURN INTO THE AREA...AND SPECIFIC LOCATION OF THE SURFACE LOW....WARM FRONT...AND MESOSCALE BOUNDARIES. FORECAST SOUNDINGS FROM ERN NEB...ACROSS THE MO RIVER INTO WRN IA APPEAR TO SUGGEST THAT CONDITIONS FOR STRONG TORNADOES COULD DEVELOP IN THIS AREA THROUGH THE THURSDAY EVENING. ...ERN KS/OK...MO...AR... CLASSIC DRYLINE SURGE WILL DEVELOP EAST FROM KS/OK INTO MO/AR FROM AFTERNOON THROUGH EVENING. STRONG CAPPING ACROSS LOW LEVEL MOIST AXIS WILL CONTRIBUTE TO THE DEVELOPMENT OF MODEST INSTABILITY INTO THE AFTERNOON BEFORE STRONG HEIGHT FALLS AND MIXING ON THE ADVANCING DRYLINE PROMOTE STORM INITIATION IN MODERATE TO LOCALLY STRONG CAPE ENVIRONMENT. ALREADY STRONG DEEP LAYER SHEAR WILL INTENSIFY FURTHER THROUGH LATE AFTERNOON AS 80KT MID LEVEL JET SPREADS ACROSS THE DRYLINE AND LOW LEVEL JET INTENSIFIES TO 50KT ACROSS THE OZARKS. A SECONDARY AREA OF POSSIBLY LONG-TRACK AND FAST MOVING TORNADOES...IN ADDITION TO VERY LARGE HAIL AND HIGH WINDS....COULD DEVELOP AHEAD OF THE DRYLINE THROUGH THE EVENING. PARTS OF BOTH NEB/IA AND THE ERN KS/OK AND WRN MO/AR AREAS MAY BE UPGRADED TO HIGH RISK IN LATER OUTLOOKS IF MODEL GUIDANCE OVER THE NEXT DAY CONTINUES TO SUGGEST A STRONG POTENTIAL FOR THE DEVELOPMENT OF DANGEROUS WEATHER IN THESE AREAS. ....EAST FROM THE MS RIVER TO IL/IND/OH... WHILE THE PRIMARY CYCLONE UNDERGOES OCCLUSION OVER THE PLAINS THROUGH LATE IN THE DAY 2 PERIOD...INTENSE MID LEVEL WIND MAX WILL SPREAD EAST ACROSS THE MIDWEST THROUGH LATE THURSDAY NIGHT. MODELS SUGGEST A FRONTAL WAVE...POSSIBLY CONVECTIVELY INDUCED....MAY DEVELOP RAPIDLY EWD ALONG THE WARM FRONT...FROM ERN IA/MO TO IND THROUGH LATE EVENING. DESPITE WEAKENING INSTABILITY WITH EWD EXTENT...A PLUME OF STRONGER INSTABILITY MAY STREAM INTO THESE AREAS FROM THE LOWER OH VALLEY. THREAT FOR DAMAGING WINDS AND POSSIBLY SOME LATE NIGHT TORNADOES MAY ACCOMPANY AN MCS OR TWO EVOLVING OUT OF THE PLAINS CONVECTION AND SUPPORTED/MAINTAINED BY LARGER SCALE DYNAMICS. ..CARBIN.. 04/05/2006  From SwoDy2 at goshenarc.org Wed Apr 5 17:35:21 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 05 Apr 2006 13:35:21 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 051732 SWODY2 SPC AC 051731 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1231 PM CDT WED APR 05 2006 VALID 061200Z - 071200Z ...THERE IS A MDT RISK OF SVR TSTMS FROM PARTS OF THE SRN AND CNTRL PLAINS THROUGH THE LOWER AND MIDDLE MS VALLEY... ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE SRN AND CNTRL PLAINS THROUGH THE LOWER AND MIDDLE MS VALLEY AND INTO THE OH VALLEY... ...SYNOPSIS... LARGE SCALE PATTERN WILL REMAIN PROGRESSIVE THIS PERIOD. THE UPPER TROUGH NOW OVER THE WRN STATES WILL MOVE INTO THE CNTRL AND SRN HIGH PLAINS THURSDAY...REACHING THE MIDDLE AND LOWER MS VALLEY THURSDAY EVENING. LEE CYCLOGENESIS WILL COMMENCE OVER THE CNTRL HIGH PLAINS TONIGHT WITHIN ZONE OF HEIGHT FALLS ACCOMPANYING THE UPPER TROUGH. SYNOPTIC WARM FRONT WILL DEVELOP AND EXTEND EWD FROM THE LOW THROUGH NEB AND INTO THE MID MS VALLEY BY EARLY THURSDAY. THE LEE CYCLONE WILL CONTINUE EAST THROUGH NEB THURSDAY WITH TRAILING PACIFIC FRONT EXTENDING SWD THROUGH THE CNTRL AND SRN PLAINS. THIS BOUNDARY IS FORECAST TO ADVANCE INTO THE MIDDLE MS VALLEY THURSDAY NIGHT...WHILE THE SURFACE LOW OCCLUDES OVER ERN NEB. ...CNTRL AND ERN NEB...IA THROUGH NERN KS AND NRN MO... PARTIALLY MODIFIED GULF AIR WITH DEWPOINTS IN THE LOW 60S IS ADVANCING NWD THROUGH THE SRN PLAINS AS FAR NORTH AS SRN OK. HOWEVER...12Z RAOB DATA FROM DFW...CRP...AND BRO SHOW THE DEPTH OF THE MOIST BOUNDARY LAYER IS SHALLOW...GENERALLY AOB 950 MB. THIS IMPLIES THAT AFTERNOON MIXING MAY LOWER THE DEWPOINTS AND SLOW THE NWD ADVANCE OF THE RICHER LOW LEVEL MOISTURE. THE STRONG SLY LOW LEVEL JET TONIGHT INTO THURSDAY WILL CONTINUE TO ADVECT PARTIALLY MODIFIED GULF AIR NWD INTO THE CNTRL PLAINS WITH SURFACE DEWPOINTS AROUND 60 INTO ERN NEB AND IA DURING THE DAY. PLUME OF STEEP MID LEVEL LAPSE RATES AND COOL MID LEVEL TEMPERATURE PROFILES WILL FURTHER CONTRIBUTE TO DESTABILIZATION WITH MODERATE MLCAPE EXPECTED BY MID DAY FROM ERN NEB...WRN IA SWD INTO NERN KS AND WRN MO. ELEVATED STORMS WILL LIKELY BE ONGOING WITHIN ZONE OF WARM ADVECTION AND ASCENT N OF WARM FRONT FROM THE CNTRL/NRN PLAINS SEWD INTO PARTS OF THE MID/UPPER MS VALLEY. ADDITIONAL STORMS ARE EXPECTED TO DEVELOP OVER ERN NEB NEAR TRIPLE POINT WITHIN ZONE OF ASCENT ASSOCIATED WITH THE CYCLONICALLY CURVED JET EXIT REGION. THIS ACTIVITY WILL LIKELY BUILD SEWD INTO NERN KS AND NWRN MO ALONG AND AHEAD OF PACIFIC FRONT. STRONG DEEP LAYER SHEAR PROFILES WILL SUPPORT SUPERCELL STRUCTURES. STRONGEST EFFECTIVE LOW LEVEL SHEAR IS EXPECTED EAST AND SE OF TRIPLE POINT WHERE THE LOW LEVEL FLOW WILL REMAIN BACKED TO ESELY IN VICINITY OF THE WARM FRONT FROM ERN NEB INTO PARTS OF WRN/SRN IA AND NRN MO. ...CNTRL AND SRN MO THROUGH NRN AND CNTRL AR...ERN OK AND NE TX... POTENTIAL FOR A STRONGER CAP WILL EXIST IN THIS REGION AS THE EML IS ADVECTED EWD THROUGH THE WARM SECTOR. ELEVATED CONVECTION MAY BE ONGOING EARLY THURSDAY ACROSS PARTS OF THE LOWER MS VALLEY WITHIN ZONE OF WARM ADVECTION ALONG THE LOW LEVEL JET. THIS ACTIVITY WILL LIKELY SPREAD NEWD DURING THE DAY. THE ATMOSPHERE WILL LIKELY DESTABILIZE IN WAKE OF EARLY STORMS FROM PARTS OF MO...WRN AR...ERN OK...NERN TX DURING THE DAY ALONG MOIST AXIS WITH MLCAPE FROM 2000 TO 2500 J/KG LIKELY. STRONGER CAP WILL LIKELY LIMIT THE POTENTIAL FOR SURFACE BASED DEVELOPMENT MOST OF THE DAY. HOWEVER...MODELS SUGGEST A STRONG VORT LOBE WILL ROUND THE BASE OF THE TROUGH DURING THE LATE AFTERNOON AND EVENING. INCREASING LARGE SCALE ASCENT AND BOUNDARY LAYER WARMING MAY WEAKEN THE CAP SUFFICIENTLY FOR SURFACE BASED DEVELOPMENT ALONG EWD ADVANCING PACIFIC FRONT FROM PARTS OF SRN MO THROUGH ERN OK AND NERN TX. ACTIVITY WILL LIKELY SPREAD EWD THROUGH THE LOWER MS VALLEY DURING THE EVENING. SUPERCELLS WITH LARGE HAIL AND A FEW TORNADOES WILL BE POSSIBLE. ...WRN/CNTRL TN THROUGH OH VALLEY AREAS... STORMS WILL HAVE CONSOLIDATED INTO ONE OR MORE MCSS AS THEY SPREAD EWD INTO THE OH VALLEY OVERNIGHT. INSTABILITY WILL BE MORE LIMITED WITH ERN EXTENT INTO THIS AREA. HOWEVER...SOME DESTABILIZATION IS EXPECTED ALONG THE STRONG SWLY LOW LEVEL JET. VERTICAL SHEAR PROFILES WILL BE SUFFICIENT FOR ORGANIZED SEVERE STORM STRUCTURES WITHIN THE MCS. PRIMARY THREAT IS EXPECTED TO TRANSITION TO DAMAGING WIND. HOWEVER...ISOLATED TORNADOES WILL REMAIN POSSIBLE. ..DIAL.. 04/05/2006  From SwoDy2 at goshenarc.org Thu Apr 6 06:21:46 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Thu, 06 Apr 2006 02:21:46 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 060618 SWODY2 SPC AC 060618 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0118 AM CDT THU APR 06 2006 VALID 071200Z - 081200Z ...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF EASTERN ARKANSAS...NORTHEAST LOUISIANA...MUCH OF TENNESSEE... MISSISSIPI...NORTHERN ALABAMA...AND NORTHERN GEORGIA...EXTREME SOUTHWEST NORTH CAROLINA... ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK FROM LA/AR/MO...ACROSS THE MIDWEST/OH VALLEY...EAST TO WV...WRN VA/NC/SC...AND NWRN GA..AND THE FL PANHANDLE... ...WIDESPREAD AND POSSIBLY SIGNIFICANT SEVERE WEATHER EPISODE APPEARS INCREASINGLY LIKELY ACROSS PARTS OF THE LOWER MS VALLEY AND TN VALLEY DURING FRIDAY.... ...SYNOPSIS... AN ACTIVE SPRINGTIME SEVERE WEATHER PATTERN WILL LIKELY CONTINUE INTO DAY 2/FRIDAY AS POTENT TROUGH AND BELT OF 80-90KT MID LEVEL FLOW SPREAD EAST FROM THE PLAINS TO THE MS AND TN VALLEYS. THE FORECAST PERIOD WILL BEGIN WITH A DEEP OCCLUDED CYCLONE OVER THE PLAINS...AND A MORE PROGRESSIVE NRN STREAM TROUGH DIGGING SEWD TOWARD THE NRN GREAT LAKES. A BROAD RIDGE WILL COVER THE MUCH OF THE INTERMOUNTAIN WEST...WHILE ANOTHER PACIFIC DISTURBANCE APPROACHES THE WEST COAST. NRN STREAM HEIGHT FALLS AND AMPLIFYING WRN RIDGE WILL INDUCE THE LOW OVER THE PLAINS TO OPEN UP AND REDEVELOP EWD/SEWD ACROSS THE MS VALLEY AS A FRONTAL WAVE/LOW. THIS WILL OCCUR AS THE LARGER SCALE POSITIVE TILT TROUGH AXIS...AND ASSOCIATED DEEP LAYER BAROCLINIC ZONE...SPREAD SEWD FROM THE GREAT LAKES/OH VALLEY...AND ANOTHER FRONTAL SURFACE WAVE TRACKS EWD FROM OH TO NEW ENGLAND. GREAT LAKES AND TN VALLEY SHORT WAVES WILL BEGIN TO PHASE BY SATURDAY WITH RESULTING/ASSOCIATED COLD FRONT MOVING TOWARD THE ATLANTIC SEABOARD. ...ERN AR/LA ACROSS THE TN VALLEY... GFS AND NAM APPEAR QUITE CONSISTENT WITH SYNOPTIC SCALE FEATURES THAT SHOULD RESULT IN WIDESPREAD SEVERE WEATHER ACROSS THE SOUTH ON FRIDAY. GFS HAS SHOWN A SLIGHT TREND TOWARD A SLOWER AND MORE AMPLIFIED MID LEVEL TROUGH. THIS APPEARS REASONABLE AND ALLOWS FOR THE DEVELOPMENT OF GREATER INSTABILITY ACROSS THE LOWER MS VALLEY PRIOR TO ARRIVAL OF STRONGER FORCING. GUIDANCE IS ALSO INDICATING THAT A POSSIBLE MCS WILL MOVE ACROSS PARTS OF THE TN VALLEY THROUGH EARLY FRIDAY MORNING. THIS WOULD BE WHAT REMAINS FROM PLAINS CONVECTION DURING DAY 1...SPREADING EAST AND BEING SUSTAINED BY ISENTROPIC LIFT ON THE NOSE OF THE LOW LEVEL JET. LOW LEVEL SSWLY FLOW IN THE WAKE OF THIS POTENTIAL MORNING CONVECTION WILL TRANSPORT HIGHER THETAE AIRMASS FROM THE GULF INLAND ACROSS LA/ERN AR/MS/AL AND TN. IT SEEMS REASONABLE TO EXPECT AT LEAST MID 60S DEWPOINTS SPREADING NEWD ACROSS THESE AREAS BENEATH A PLUME OF INCREASING STEEP LAPSE RATES AND STRENGTHENING MID LEVEL FLOW. FORCING ALONG POSSIBLE RESIDUAL MCS OUTFLOW BOUNDARY ACROSS THE TN VALLEY...AND INCREASING LARGE SCALE ASCENT ASSOCIATED WITH THE EJECTING UPPER TROUGH AND SURFACE WAVE ACROSS AR/LA...WILL CONTRIBUTE TO STORM INITIATION FROM LATE MORNING INTO THE AFTERNOON. MODERATE INSTABILITY...ESPECIALLY ACROSS THE LOWER MS VALLEY...WILL FUEL ROBUST STORM UPDRAFTS AS SHEAR AND FORCING CONTINUE TO STRENGTHEN ACROSS THE REGION INTO THE EVENING. EXPECT VERY STRONG...PRIMARILY UNIDIRECTIONAL...DEEP LAYER FLOW TO RESULT IN A NUMBER OF FAST MOVING BANDS...OR LINES...OF STORMS. SUPERCELLS APPEAR LIKELY AND ACTIVITY NEAR THE SURFACE LOW...AND TRACKING NEAR/ALONG ANY RESIDUAL OUTFLOW BOUNDARIES...COULD POSE A GREATER RISK OF TORNADOES. WIDESPREAD DAMAGING WINDS...VERY LARGE HAIL...AND POSSIBLY A COUPLE OF STRONGER FAST-MOVING TORNADOES COULD OCCUR. SPECIFIC SEVERE PROBABILITIES FOR PARTS OF THE AREA MAY NEED TO BE INCREASED IN LATER OUTLOOKS. ...MIDWEST/OH VALLEY... EXPECT AIRMASS TO RECOVER ALONG THE OH RIVER VALLEY IN THE WAKE OF MORNING CONVECTION...OR CONVECTIVE DEBRIS. GUIDANCE SUGGESTS THE POSSIBILITY OF MODEST INSTABILITY FORMING AHEAD OF THE STRENGTHENING COLD FRONT FORECAST TO MOVE INTO THE AREA AHEAD OF STRONG NRN STREAM TROUGH. STORMS SHOULD INCREASE IN COVERAGE AND INTENSITY INTO THE LATE AFTERNOON/EARLY EVENING AS FRONTAL CIRCULATION MOVES INTO THE INSTABILITY AXIS FROM IL TO OH. LARGE HAIL AND DAMAGING WINDS APPEAR TO BE PRIMARY THREATS. ...ERN PLAINS/MO... A FEW LOW-TOPPED STORMS WITH HAIL COULD DEVELOP NEAR/WITHIN THE MID LEVEL COLD POOL AS IT MOVES ESEWD ACROSS THE OZARKS THROUGH THE LATE AFTERNOON. GENERALLY WEAK SHEAR AND INSTABILITY SHOULD LIMIT STORM INTENSITY/DURATION. ..CARBIN.. 04/06/2006  From SwoDy2 at goshenarc.org Thu Apr 6 17:21:41 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Thu, 06 Apr 2006 13:21:41 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 061717 SWODY2 SPC AC 061716 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1216 PM CDT THU APR 06 2006 VALID 071200Z - 081200Z ...THERE IS A HIGH RISK OF SVR TSTMS ACROSS NE MS...NRN AL...SCNTRL TN AND FAR NW GA... ...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF MS...AL...TN...GA...LA...ERN AR...WRN NC AND FAR WRN SC... ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE LOWER MS VALLEY...OH VALLEY...SRN AND CNTRL APPALACHIANS AND IMMEDIATE GULF COAST... A POTENT UPPER-LEVEL TROUGH OVER THE PLAINS STATES WILL SHIFT SEWD INTO THE OZARKS FRIDAY AHEAD OF A MOIST AND VERY UNSTABLE WARM SECTOR ACROSS THE TN VALLEY. THE SHEAR ENVIRONMENT WILL BE VERY FAVORABLE FOR TORNADOES AND A SIGNIFICANT TORNADO OUTBREAK IS EXPECTED FRIDAY AFTERNOON AND EVENING ACROSS NRN AL...NE MS...SCNTRL TN AND FAR NW GA. ...TN VALLEY... SEVERAL MESOSCALE CONVECTIVE SYSTEMS ONGOING AT THE BEGINNING OF THE PERIOD IN THE MID-MS VALLEY WILL DRIFT QUICKLY NEWD AS A 90-100 KT MID-LEVEL JET EJECTS NEWD OUT OF THE CNTRL PLAINS TROUGH. THIS WILL INCREASE MOISTURE ADVECTION STRENGTHENING A 40-50 KT LOW-LEVEL JET TRANSPORTING MID TO UPPER 60S F SFC DEWPOINTS NNEWD ACROSS THE TN VALLEY. THE MODELS ARE IN GOOD AGREEMENT SHUNTING MORNING CONVECTION AWAY FROM THE HIGH RISK AREA DURING THE MORNING LEAVING THE AIRMASS UNDISTURBED MIDDAY FRIDAY ACROSS MS...AL...TN AND NRN GA. AS STORMS INITIATE FRIDAY AFTERNOON...SUPERCELLS WILL BE LIKELY DUE TO THE STRONG VERTICAL SHEAR ASSOCIATED WITH THE MID-LEVEL JET. NAMKF FORECAST SOUNDINGS FOR TUPELO MS...FLORENCE ALABAMA AND HUNTSVILLE ALABAMA FRIDAY AFTERNOON SEEM REASONABLE WITH MODERATE TO STRONG INSTABILITY (MLCAPE VALUES 2500-3000 J/KG)...0-6 KM SHEAR VALUES AT/ABV 60 KT AND IMPRESSIVE LOW-LEVEL SHEAR PROFILES (0-3 KM SRH AT/ABV 350 M2/S2). IN THIS ENVIRONMENT...STORMS SHOULD REMAIN DISCRETE FOR THE LATE AFTERNOON AND EARLY EVENING HOURS. IN ADDITION...LCL HEIGHTS ARE FORECAST TO REMAIN LOW WHICH COMBINED WITH THE INSTABILITY AND STRONG LOW-LEVEL SHEAR WILL BE VERY FAVORABLE FOR TORNADOES. LONG-TRACK STRONG OR EVEN VIOLENT TORNADOES WILL BE POSSIBLE ESPECIALLY WITH SUPERCELLS THAT TRACK ALONG ANY PRE-EXISTING BOUNDARIES OR CONVERGENCE ZONES. THE INSTABILITY...SHEAR AND STEEP MID-LEVEL LAPSE RATES NEAR 8.0 C/KM SHOWN ON THE FORECAST SOUNDINGS WILL ALSO BE FAVORABLE FOR LARGE HAIL AND WIND DAMAGE WITH THE SUPERCELLS. VERY LARGE HAIL WILL ALSO BE POSSIBLE WITH THE STRONGER SUPERCELLS. STORM COVERAGE WILL LIKELY EXPAND DURING THE EVENING AS THE UPPER-TROUGH APPROACHES FROM THE NORTHWEST. ALTHOUGH CONVECTION MAY GRADUALLY ORGANIZE INTO A LINEAR ORIENTATION BY LATE EVENING...THE WIND SHEAR ENVIRONMENT SHOULD REMAIN SUPPORTIVE OF DISCRETE SUPERCELLS AS THE LOW-LEVEL JET INCREASES AND EXPANDS NWD ACROSS THE HIGH RISK AREA. THE WIND DAMAGE POTENTIAL WILL LIKELY BE ENHANCED WITH SUPERCELLS AND/OR BOW ECHOES THAT DEVELOP DURING THE LATE EVENING. THE SEVERE THREAT ACROSS THE TN VALLEY SHOULD BEGIN TO DROP OFF AFTER MIDNIGHT AS INSTABILITY DECREASES AND A COLD FRONT ADVANCES EWD ACROSS THE REGION. ...OH VALLEY... VERY STRONG LARGE-SCALE ASCENT WILL SPREAD EWD ACROSS THE OH VALLEY FRIDAY MORNING AS A LARGE AREA OF CONVECTION SPREADS NEWD ACROSS THE REGION. THIS WILL LIKELY DELAY DESTABILIZATION ACROSS MUCH OF THE OH VALLEY AND UNCERTAINTY REMAINS CONCERNING THE DEVELOPMENT OF INSTABILITY IN THE AFTERNOON HOURS. THE NAM AND GFS INITIATE POST-FRONTAL CONVECTION IN THE EARLY IN THE AFTERNOON NORTH OF A FRONTAL BOUNDARY EXTENDING WSWD TO ENEWD ACROSS THE OH VALLEY. FORECAST SOUNDINGS FOR THIS AREA FRIDAY AFTERNOON SHOW SUFFICIENT INSTABILITY/SHEAR PROFILES AND STEEP LAPSE RATES THAT SHOULD BE FAVORABLE FOR SUPERCELLS WITH LARGE HAIL. FURTHER SOUTH ACROSS KY...SFC DEWPOINTS IN THE UPPER 50S TO NEAR 60 F SHOULD BE ALLOW MODERATE INSTABILITY TO DEVELOP. ALTHOUGH CONVECTIVE INITIATION MAY HOLD OFF UNTIL LATER IN THE AFTERNOON...SFC-BASED STORMS APPEAR LIKELY TO DEVELOP ALONG AND SOUTH OF THE BOUNDARY DURING THE LATE AFTERNOON AND EVENING HOURS. STEEP LOW-LEVEL LAPSE RATES...GREATER MOISTURE AND STRONG LOW-LEVEL SHEAR WILL FAVOR LARGE HAIL...WIND DAMAGE AND A FEW TORNADOES WITH SUPERCELLS THAT TRACK ENEWD ACROSS THE REGION. THE SEVERE THREAT SHOULD CONTINUE INTO THE EVENING HOURS WITH THE THREAT GRADUALLY BECOMING MARGINAL FORWARD MIDNIGHT AS INSTABILITY DECREASES. ..BROYLES.. 04/06/2006  From SwoDy2 at goshenarc.org Thu Apr 6 17:39:36 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Thu, 06 Apr 2006 13:39:36 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 061737 SWODY2 SPC AC 061735 DAY 2 CONVECTIVE OUTLOOK CORR 1 NWS STORM PREDICTION CENTER NORMAN OK 1235 PM CDT THU APR 06 2006 VALID 071200Z - 081200Z ...THERE IS A HIGH RISK OF SVR TSTMS ACROSS NE MS...NRN AL...SCNTRL TN AND FAR NW GA... ...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF MS...AL...TN...GA...LA...ERN AR...WRN NC AND FAR WRN SC... ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE LOWER MS VALLEY...OH VALLEY...SRN AND CNTRL APPALACHIANS AND IMMEDIATE GULF COAST... CORRECTED FOR WORDING LAST PARAGRAPH A POTENT UPPER-LEVEL TROUGH OVER THE PLAINS STATES WILL SHIFT SEWD INTO THE OZARKS FRIDAY AHEAD OF A MOIST AND VERY UNSTABLE WARM SECTOR ACROSS THE TN VALLEY. THE SHEAR ENVIRONMENT WILL BE VERY FAVORABLE FOR TORNADOES AND A SIGNIFICANT TORNADO OUTBREAK IS EXPECTED FRIDAY AFTERNOON AND EVENING ACROSS NRN AL...NE MS...SCNTRL TN AND FAR NW GA. ...TN VALLEY... SEVERAL MESOSCALE CONVECTIVE SYSTEMS ONGOING AT THE BEGINNING OF THE PERIOD IN THE MID-MS VALLEY WILL DRIFT QUICKLY NEWD AS A 90-100 KT MID-LEVEL JET EJECTS NEWD OUT OF THE CNTRL PLAINS TROUGH. THIS WILL INCREASE MOISTURE ADVECTION STRENGTHENING A 40-50 KT LOW-LEVEL JET TRANSPORTING MID TO UPPER 60S F SFC DEWPOINTS NNEWD ACROSS THE TN VALLEY. THE MODELS ARE IN GOOD AGREEMENT SHUNTING MORNING CONVECTION AWAY FROM THE HIGH RISK AREA DURING THE MORNING LEAVING THE AIRMASS UNDISTURBED MIDDAY FRIDAY ACROSS MS...AL...TN AND NRN GA. AS STORMS INITIATE FRIDAY AFTERNOON...SUPERCELLS WILL BE LIKELY DUE TO THE STRONG VERTICAL SHEAR ASSOCIATED WITH THE MID-LEVEL JET. NAMKF FORECAST SOUNDINGS FOR TUPELO MS...FLORENCE ALABAMA AND HUNTSVILLE ALABAMA FRIDAY AFTERNOON SEEM REASONABLE WITH MODERATE TO STRONG INSTABILITY (MLCAPE VALUES 2500-3000 J/KG)...0-6 KM SHEAR VALUES AT/ABV 60 KT AND IMPRESSIVE LOW-LEVEL SHEAR PROFILES (0-3 KM SRH AT/ABV 350 M2/S2). IN THIS ENVIRONMENT...STORMS SHOULD REMAIN DISCRETE FOR THE LATE AFTERNOON AND EARLY EVENING HOURS. IN ADDITION...LCL HEIGHTS ARE FORECAST TO REMAIN LOW WHICH COMBINED WITH THE INSTABILITY AND STRONG LOW-LEVEL SHEAR WILL BE VERY FAVORABLE FOR TORNADOES. LONG-TRACK STRONG OR EVEN VIOLENT TORNADOES WILL BE POSSIBLE ESPECIALLY WITH SUPERCELLS THAT TRACK ALONG ANY PRE-EXISTING BOUNDARIES OR CONVERGENCE ZONES. THE INSTABILITY...SHEAR AND STEEP MID-LEVEL LAPSE RATES NEAR 8.0 C/KM SHOWN ON THE FORECAST SOUNDINGS WILL ALSO BE FAVORABLE FOR LARGE HAIL AND WIND DAMAGE WITH THE SUPERCELLS. VERY LARGE HAIL WILL ALSO BE POSSIBLE WITH THE STRONGER SUPERCELLS. STORM COVERAGE WILL LIKELY EXPAND DURING THE EVENING AS THE UPPER-TROUGH APPROACHES FROM THE NORTHWEST. ALTHOUGH CONVECTION MAY GRADUALLY ORGANIZE INTO A LINEAR ORIENTATION BY LATE EVENING...THE WIND SHEAR ENVIRONMENT SHOULD REMAIN SUPPORTIVE OF DISCRETE SUPERCELLS AS THE LOW-LEVEL JET INCREASES AND EXPANDS NWD ACROSS THE HIGH RISK AREA. THE WIND DAMAGE POTENTIAL WILL LIKELY BE ENHANCED WITH SUPERCELLS AND/OR BOW ECHOES THAT DEVELOP DURING THE LATE EVENING. THE SEVERE THREAT ACROSS THE TN VALLEY SHOULD BEGIN TO DROP OFF AFTER MIDNIGHT AS INSTABILITY DECREASES AND A COLD FRONT ADVANCES EWD ACROSS THE REGION. ...OH VALLEY... VERY STRONG LARGE-SCALE ASCENT WILL SPREAD EWD ACROSS THE OH VALLEY FRIDAY MORNING AS A LARGE AREA OF CONVECTION SPREADS NEWD ACROSS THE REGION. THIS WILL LIKELY DELAY DESTABILIZATION ACROSS MUCH OF THE OH VALLEY AND UNCERTAINTY REMAINS CONCERNING THE DEVELOPMENT OF INSTABILITY IN THE AFTERNOON HOURS. THE NAM AND GFS INITIATE POST-FRONTAL CONVECTION EARLY IN THE AFTERNOON NORTH OF A FRONTAL BOUNDARY EXTENDING WSWD TO ENEWD ACROSS THE OH VALLEY. FORECAST SOUNDINGS FOR THIS AREA FRIDAY AFTERNOON SHOW SUFFICIENT INSTABILITY/SHEAR PROFILES AND STEEP LAPSE RATES THAT SHOULD BE FAVORABLE FOR SUPERCELLS WITH LARGE HAIL. FURTHER SOUTH ACROSS KY...SFC DEWPOINTS IN THE UPPER 50S TO NEAR 60 F SHOULD ALLOW MODERATE INSTABILITY TO DEVELOP. ALTHOUGH CONVECTIVE INITIATION MAY HOLD OFF UNTIL LATER IN THE AFTERNOON...SFC-BASED STORMS APPEAR LIKELY TO DEVELOP ALONG AND SOUTH OF THE BOUNDARY DURING THE LATE AFTERNOON AND EVENING HOURS. STEEP LOW-LEVEL LAPSE RATES...GREATER MOISTURE AND STRONG LOW-LEVEL SHEAR WILL FAVOR LARGE HAIL...WIND DAMAGE AND A FEW TORNADOES WITH SUPERCELLS THAT TRACK ENEWD ACROSS THE REGION. THE SEVERE THREAT SHOULD CONTINUE INTO THE EVENING HOURS WITH THE THREAT GRADUALLY BECOMING MARGINAL TOWARD MIDNIGHT AS INSTABILITY DECREASES. ..BROYLES.. 04/06/2006  From SwoDy2 at goshenarc.org Fri Apr 7 05:24:27 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Fri, 07 Apr 2006 01:24:27 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 070522 SWODY2 SPC AC 070521 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1221 AM CDT FRI APR 07 2006 VALID 081200Z - 091200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE GULF COAST AND SERN U.S.... ...SERN U.S... CENTRAL PLAINS SHORTWAVE TROUGH WILL BE ABSORBED WITHIN LONG WAVE TROUGH AXIS AND SHIFT EAST ACROSS THE CNTRL/ERN GULF STATES LATER IN THE DAY2 PERIOD. THIS FEATURE WILL BE RESPONSIBLE FOR INDUCING SEVERAL WEAK ELONGATED LOW PRESSURE AREAS ALONG ADVANCING COLD FRONT FROM NRN AL INTO SERN VA. MORE CONCENTRATED CYCLOGENESIS/CONVERGENCE WILL OCCUR ACROSS THE MIDDLE ATLANTIC INTO NC WHERE VEERED LLJ WILL FOCUS ASCENT WITH RETREATING WEAK WARM ADVECTION ZONE. IT APPEARS CONSIDERABLE AMOUNT OF LATE DAY1 CONVECTION WILL BE ONGOING AT THE BEGINNING OF THE PERIOD ALONG A GOOD PORTION OF THE FRONTAL ZONE. THIS WILL AID SWD FRONTAL SURGE DURING THE DAYTIME HOURS IN THE WAKE OF TROUGH PASSAGE. FORECAST SOUNDINGS ACROSS THE WARM SECTOR SUGGEST MORE THAN ADEQUATE DEEP SWLY SHEAR FOR SUSTAINING ANY UPDRAFTS THAT MANAGE TO DEVELOP WITHIN MODEST CAPE ENVIRONMENT. AT THIS TIME IT SEEMS REASONABLE THAT AN UPWARD EVOLVING SQUALL LINE WILL EMERGE BY MID DAY ALONG WIND SHIFT AS IT DROPS SWD ACROSS AL/GA/COASTAL CAROLINAS. THERE IS SOME REASON TO BELIEVE THAT SUFFICIENT HEATING MAY ALLOW ISOLATED DEEP CONVECTION TO DEVELOP AHEAD OF SQUALL LINE ACROSS PORTIONS OF THE NRN FL PENINSULA AND PANHANDLE...IF SO SUPERCELL STRUCTURES ARE POSSIBLE. DAMAGING WIND APPEARS THE MOST LIKELY SEVERE THREAT WITH ORGANIZED SQUALL LINE...WHILE LARGE HAIL MAY ACCOMPANY MORE DISCRETE STRUCTURES THAT ROTATE. ...NWRN U.S./NRN ROCKIES... MID LEVEL THERMAL TROUGH WILL ROTATE NWD ACROSS THE NWRN U.S./NRN ROCKIES DURING THE DAY AS UPPER TROUGH AND STRONG SPEED MAX SHIFT INTO NRN CA. STEEP LAPSE RATE ENVIRONMENT WITH INCREASING SUN ANGLE WILL ENHANCE CONVECTIVE UPDRAFT POTENTIAL MAINLY DURING THE AFTERNOON HOURS. AS A RESULT...ISOLATED THUNDERSTORMS ARE POSSIBLE ACROSS THIS REGION WITH THE POSSIBILITY FOR A CONCENTRATED AREA OF CONVECTION MOVING INTO CNTRL MT ALONG SFC WIND SHIFT AROUND 00Z. ..DARROW.. 04/07/2006  From SwoDy2 at goshenarc.org Fri Apr 7 17:16:14 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Fri, 07 Apr 2006 13:16:14 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 071712 SWODY2 SPC AC 071711 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1211 PM CDT FRI APR 07 2006 VALID 081200Z - 091200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SERN GULF COAST STATES AND CAROLINAS... ...NERN GULF COAST STATES... A LARGE MCS WILL LIKELY BE ONGOING ACROSS THE SRN APPALACHIAN MTNS AT THE BEGINNING OF THE PERIOD AHEAD OF AN UPPER-LEVEL TROUGH APPROACHING FROM THE WEST. STRONG LARGE-SCALE ASCENT AHEAD OF THE TROUGH AND DESTABILIZATION AROUND MID-DAY SHOULD SUPPORT ADDITIONAL THUNDERSTORM DEVELOPMENT FURTHER SOUTH ACROSS SRN/ERN AL...CNTRL/SRN GA AND NRN FL. STORMS WILL MOST LIKELY DEVELOP AHEAD OF A COLD FRONT AND SFC LOW MOVING SEWD ACROSS THE REGION DURING THE AFTERNOON. FORECAST SOUNDINGS IN THIS AREA FOR SATURDAY AFTERNOON SHOW MOIST PROFILES WITH STRONG VERTICAL SHEAR AND MODERATE INSTABILITY. IN ADDITION...AS THE TROUGH DIGS SEWD...TEMPS ALOFT WILL COOL AS THE CORE OF THE UPPER-TROUGH PASSES. THIS WILL STEEPEN LAPSE RATES FROM NW TO SE ACROSS THE REGION WHICH COMBINED WITH THE INSTABILITY AND STRONG SHEAR SUGGESTS DISCRETE SUPERCELLS WILL HAVE A POTENTIAL FOR LARGE HAIL. IF STORMS ORGANIZE INTO A LINEAR ORIENTATION DURING THE AFTERNOON AS SOME OF THE MODELS SUGGEST...THEN ISOLATED WIND DAMAGE WOULD ALSO BE LIKELY DUE TO ABUNDANT MOISTURE AND STEEP LAPSE RATES AT LOW-LEVELS. IF THE CELLS TEND TO REMAIN DISCRETE THROUGH EARLY EVENING AN ISOLATED TORNADO THREAT MAY ALSO DEVELOP ACROSS SRN AND CNTRL GA TO THE WEST OF THE LOW-LEVEL JET. THE SEVERE THREAT SHOULD TRANSITION EWD INTO NRN FL AS A COLD FRONT MOVES SEWD ACROSS THE REGION WITH THE THREAT SLOWLY DECREASING DURING THE EVENING HOURS DUE TO WEAKENING INSTABILITY. ...CAROLINAS... A POSITIVELY-TILTED UPPER-LEVEL LOW/TROUGH OVER THE OZARKS TONIGHT WILL OPEN AND DIG SEWD INTO THE GULF COAST STATES. WIDESPREAD LARGE-SCALE ASCENT AHEAD OF THE TROUGH WILL SPREAD EWD INTO THE SRN APPALACHIAN MTNS AND CNTRL CAROLINAS DURING THE DAY. THUNDERSTORMS WILL LIKELY BE ONGOING AT THE BEGINNING OF THE PERIOD ALONG A FRONTAL BOUNDARY EXTENDING SWWD FROM A SFC LOW IN VA ACROSS THE WRN CAROLINAS. WARMING SFC TEMPS AND DEWPOINTS IN THE 60S F MAY RESULT IN POCKETS OF MODERATE INSTABILITY ACROSS THE ERN CAROLINAS BY AFTERNOON. THIS COMBINED WITH VERY STRONG VERTICAL SHEAR PROFILES (0-6 KM SHEAR 55-65 KT) WILL BE FAVORABLE FOR SEVERE STORMS. IF MODERATE INSTABILITY DEVELOPS SATURDAY AFTERNOON IN ERN NC/ERN SC AS SUGGESTED BY NAM FORECAST SOUNDINGS...SHEAR PROFILES WILL BE SUFFICIENT FOR SUPERCELLS WITH LARGE HAIL. DAMAGING WIND GUSTS WILL ALSO BE POSSIBLE WITH THE STRONGER STORMS ESPECIALLY WITH SHORT-LINES AND BOW ECHOES THAT DEVELOP IN THE LATE AFTERNOON AND EARLY EVENING WHEN LOW-LEVEL LAPSE RATES SHOULD BE STEEPEST. AS THE UPPER-TROUGH APPROACHES FROM THE WEST...THE ACTIVITY SHOULD MOVE EWD INTO THE ATLANTIC DURING THE EVENING HOURS ALLOWING THE SEVERE THREAT TO DECREASE FROM WEST TO EAST ACROSS THE REGION. ..BROYLES.. 04/07/2006  From SwoDy2 at goshenarc.org Sat Apr 8 05:18:04 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 08 Apr 2006 01:18:04 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 080516 SWODY2 SPC AC 080515 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1215 AM CDT SAT APR 08 2006 VALID 091200Z - 101200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF CENTRAL/SOUTHERN FL... ...CENTRAL/SOUTHERN FL PENINSULA... CONVECTIVELY-ACTIVE COLD FRONT WILL BE FORCED SWD ACROSS THE CNTRL FL PENINSULA EARLY IN THE DAY2 PERIOD. THIS BOUNDARY WILL CONTINUE ITS SWD MOVEMENT DURING THE DAY AS STRONG UPPER SHORTWAVE IS ABSORBED WITHIN LONG WAVE TROUGH...THEN SHEARS SW-NE ACROSS THE SRN PENINSULA. IT APPEARS BOUNDARY LAYER WILL HEAT RAPIDLY SOUTH OF THE WIND SHIFT AND ASSOCIATED CONVECTIVE CLUSTERS ALONG IT. THIS WILL AID DESTABILIZATION FORCING MLCAPE VALUES AOA 2000 J/KG. WITH DEEP SWLY SHEAR VECTORS ON THE ORDER OF 30-35KT...IT APPEARS SUPERCELL DEVELOPMENT IS POSSIBLE. NUMEROUS THUNDERSTORMS ARE LIKELY ALONG/SOUTH OF ADVANCING COLD FRONT WITHIN AN ENVIRONMENT SEEMINGLY FAVORABLE FOR AT LEAST LARGE HAIL AND DAMAGING WINDS. OF COURSE...ANY SEA BREEZE INTERACTIONS WOULD AID LOW LEVEL SHEAR AND ENHANCE STORM ROTATION FOR POSSIBLE ISOLATED TORNADOES. ACTIVITY SHOULD SPREAD OFF THE SRN TIP OF FL BY EARLY EVENING. ...NWRN U.S... ANOTHER IN A SERIES OF UPPER TROUGHS WILL MOVE INTO THE GREAT BASIN SUNDAY. COLD MID LEVEL TEMPERATURES AND STEEPENING LAPSE RATES WILL AID SCATTERED CONVECTIVE POTENTIAL...MAINLY INLAND DURING THE AFTERNOON HOURS. ..DARROW.. 04/08/2006  From SwoDy2 at goshenarc.org Sat Apr 8 17:10:13 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 08 Apr 2006 13:10:13 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 081707 SWODY2 SPC AC 081706 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1206 PM CDT SAT APR 08 2006 VALID 091200Z - 101200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF CENTRAL/ SOUTHERN FL... ...CENTRAL/SRN FL PENINSULA... STRONG GULF COAST STATES SHORT WAVE TROUGH WILL CONTINUE TO BECOME ABSORBED BY NRN STREAM TROUGH ACROSS/EAST OF THE MID ATLANTIC STATES FIRST HALF OF DAY 2 PERIOD...WITH SRN EXTENT SHEARING SW-NE ACROSS THE SRN FL PENINSULA. ASSOCIATED SURFACE COLD FRONT WILL MOVE SWD ACROSS THE CENTRAL/SRN FL PENINSULA SUNDAY. GIVEN THE POTENTIAL FOR WEAK UPPER FORCING AND VEERED LOW-LEVEL FLOW S OF COLD FRONT LIMITING BETTER CONVERGENCE...SURFACE HEATING WITHIN A MOIST BOUNDARY LAYER BENEATH MODEST LAPSE RATES IS EXPECTED TO PROVIDE THE MAIN IMPETUS FOR WARM SECTOR THUNDERSTORMS. IN ADDITION...THUNDERSTORMS WILL BE POSSIBLE ALONG THE COLD FRONT AS IT MOVES SWD INTO THE MODERATELY UNSTABLE AIR MASS /MUCAPE UP TO 2000 J/KG/. 30-35 KT OF SFC-6 KM SHEAR SUGGESTS SUPERCELLS WILL BE POSSIBLE WITH THE PRIMARY THREATS BEING HAIL AND STRONG WIND GUSTS. HOWEVER...ISOLATED TORNADOES CAN NOT BE RULED OUT...ESPECIALLY WITH ANY STORMS THAT DEVELOP AND/OR INTERACT WITH SEA/LAKE BREEZE BOUNDARIES WHERE LOW-LEVEL SHEAR WILL BE ENHANCED. SEVERE THREAT SHOULD DIMINISH SUNDAY EVENING AS THE COLD FRONT MOVES OFFSHORE SRN FL. ...WRN STATES... ANOTHER IN A SERIES OF UPPER TROUGHS...CURRENTLY ORIENTED WSW-ENE FROM THE ERN PACIFIC TO THE PAC NW...IS EXPECTED TO ROTATE INLAND ACROSS THE WRN STATES SUNDAY. A SHORT WAVE TROUGH NOW MOVING AROUND THE WRN/SWRN PERIPHERY OF THIS TROUGH NEAR 33N 142W IS EXPECTED TO MOVE INLAND ACROSS SRN CA AND THEN TOWARD THE GREAT BASIN/FOUR CORNERS REGION SUNDAY NIGHT. MODELS SUGGEST A FORCED LINE OF CONVECTION IS POSSIBLE LATE SUNDAY AFTERNOON/EVENING ACROSS NV/SRN ID INTO UT AS A PACIFIC COLD FRONT ASSOCIATED WITH THE MID-LEVEL IMPULSE SPREADS EWD ACROSS THIS REGION. LIMITED INSTABILITY SHOULD PRECLUDE A SEVERE WEATHER THREAT WITH THIS ACTIVITY. ELSEWHERE ACROSS THE WEST...COLD MID LEVEL TEMPERATURES AND STEEPENING LAPSE RATES WILL AID SCATTERED CONVECTIVE POTENTIAL...MAINLY INLAND DURING THE AFTERNOON HOURS. ..PETERS.. 04/08/2006  From SwoDy2 at goshenarc.org Sun Apr 9 05:58:10 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 09 Apr 2006 01:58:10 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 090555 SWODY2 SPC AC 090555 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1255 AM CDT SUN APR 09 2006 VALID 101200Z - 111200Z ...NO SVR TSTM AREAS FORECAST... ...NRN PLAINS... LATE EVENING MODEL GUIDANCE CONTINUES TO SUGGEST A STRONG SPEED MAX WILL EJECT FROM BASE OF LONG WAVE TROUGH ACROSS THE SRN/CNTRL ROCKIES BY THE END OF THE PERIOD. A MINOR SHORTWAVE TROUGH WILL ADVECT AHEAD OF THIS FEATURE ACROSS WY INTO THE DAKOTAS BY EARLY EVENING ENHANCING ASCENT AHEAD OF WEAK SFC LOW WITHIN WARM ADVECTION ZONE. FORECAST SOUNDINGS SUGGEST BOUNDARY LAYER HEATING WILL BE EFFICIENT WITH STEEP LAPSE RATE ENVIRONMENT EXPECTED TO AID POTENTIAL CONVECTIVE DEVELOPMENT ALONG LEE TROUGH FROM WRN SD INTO PORTIONS OF NWRN NEB. IT APPEARS THUNDERSTORMS SHOULD EVOLVE ACROSS THIS REGION AROUND 00Z WITH AN UPWARD EXPANSION POSSIBLE ACROSS THE DAKOTAS AS LLJ INCREASES IN RESPONSE TO UPPER SHORTWAVE. MEAGER MOISTURE RETURN ACROSS THE PLAINS WILL LIMIT INSTABILITY AND THIS SHOULD REDUCE THE OVERALL SEVERE THREAT ACROSS THE NRN PLAINS TO ISOLATED ACTIVITY. HAIL MAY ACCOMPANY THE STRONGEST STORMS WITHIN ELEVATED CONVECTIVE MODE NORTH OF WARM FRONT...AND PERHAPS GUSTY WINDS FOR ANY STORMS THAT FORM NEAR THE WARM SECTOR WHERE CONVECTION WILL BE NEAR-SFC BASED. THUNDERSTORMS WILL SPREAD ACROSS THE DAKOTAS INTO NWRN PORTIONS OF MN BY THE END OF THE PERIOD TUESDAY MORNING. ..DARROW.. 04/09/2006  From SwoDy2 at goshenarc.org Sun Apr 9 17:21:00 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 09 Apr 2006 13:21:00 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 091718 SWODY2 SPC AC 091717 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1217 PM CDT SUN APR 09 2006 VALID 101200Z - 111200Z ...NO SVR TSTM AREAS FORECAST... ...NRN PLAINS... LEAD SHORT WAVE TROUGH IN BASE OF WEST COAST TROUGH EXPECTED TO TRACK NEWD ACROSS SRN CA SUNDAY EVENING IS PROGGED TO DE-AMPLIFY AS IT MOVES FARTHER INLAND...REACHING THE NRN HIGH PLAINS BY LATE MONDAY AFTERNOON /TOWARD 11/00Z/. WSWLY MID-UPPER LEVEL FLOW ACROSS THE ROCKIES WILL MAINTAIN LEE-SIDE TROUGH...WITH SURFACE CYCLOGENESIS EXPECTED IN SERN MT/ERN WY BY MONDAY AFTERNOON IN RESPONSE TO HEIGHT FALLS WITH APPROACH OF LEAD IMPULSE. PLUME OF STEEP LAPSE RATES ACROSS THE NRN/CENTRAL PLAINS ATOP MEAGER MOISTURE RETURN WILL RESULT IN A CAPPED AIR MASS FOR MUCH OF THE AFTERNOON ACROSS THE CENTRAL/NRN PLAINS. HOWEVER...SURFACE HEATING IS EXPECTED TO PROVE EFFICIENT FOR THUNDERSTORM DEVELOPMENT NEAR/ JUST AFTER PEAK HEATING IN THE VICINITY OF SURFACE LOW/HIGHER TERRAIN OF SERN MT/ERN WY/WRN PARTS OF SD/NEB. THE WEAK MOISTURE RETURN WILL ALSO LIMIT THE DEVELOPMENT OF A MORE UNSTABLE AIR MASS...REDUCING THE OVERALL SEVERE THREAT TO ISOLATED ACTIVITY. NAMKF/NAM FORECAST SOUNDINGS DO SUGGEST THE POTENTIAL FOR A NARROW AXIS OF STRONGER STORMS ALONG THE LEE TROUGH FROM MT/WRN ND SWD TO WRN NEB...GIVEN THE FAVORABLE DEEP LAYER SHEAR AND STEEP LAPSE RATE ENVIRONMENT. HOWEVER...SMALL TIME/SPACE ASPECTS OF THIS THREAT WILL PRECLUDE INTRODUCTION OF HIGHER SEVERE PROBABILITIES/CATEGORICAL RISK AT THIS TIME. STRENGTHENING SLY LLJ ALONG THE PLAINS MONDAY NIGHT IS EXPECTED TO SUPPORT INCREASING COVERAGE OF CONVECTIVE ACTIVITY ENEWD ACROSS THE DAKOTAS...REACHING NRN/WRN MN BY 12Z TUESDAY. ISOLATED HAIL/STRONG WIND GUSTS WILL BE POSSIBLE WITH THE INITIAL THUNDERSTORMS LATE MONDAY AFTERNOON/EARLY EVENING...WHILE HAIL WILL BE POSSIBLE WITH A FEW OF THE STRONGER CORES OVERNIGHT. ..PETERS.. 04/09/2006  From SwoDy2 at goshenarc.org Mon Apr 10 07:37:49 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 10 Apr 2006 03:37:49 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 100734 SWODY2 SPC AC 100734 DAY 2 CONVECTIVE OUTLOOK RESENT 1 NWS STORM PREDICTION CENTER NORMAN OK 0234 AM CDT MON APR 10 2006 VALID 111200Z - 121200Z ...NO SVR TSTM AREAS FORECAST... ...NERN KS TO WI... NRN PLAINS SHORTWAVE TROUGH WILL TOP CNTRL U.S. RIDGE FORCING COLD FRONT ACROSS THE NRN/CNTRL PLAINS INTO THE MID/UPPER MS VALLEY REGION BY EARLY EVENING. THIS BOUNDARY WILL LIKELY SERVE AS A FOCUS FOR DEEP CONVECTION DURING THE AFTERNOON HOURS...ESPECIALLY GIVEN THE LARGE SCALE ASCENT AHEAD OF SHORTWAVE TROUGH. BOUNDARY LAYER AIRMASS ACROSS THE WRN GULF OF MEXICO WILL BE SLOW TO MODIFY OVER THE NEXT FEW DAYS AS SFC RIDGING AND LARGE SCALE SUBSIDENCE WILL NOT PROVE FAVORABLE FOR MEANINGFUL RETURN FLOW. RESULTANT LOW LEVEL MOISTURE WILL THUS BE LIMITED ALONG/AHEAD OF ADVANCING COLD FRONT FROM MN INTO CNTRL KS. IT APPEARS STEEP LAPSE RATE ENVIRONMENT DUE TO STRONG HEATING WILL BE INSTRUMENTAL IN LATE AFTERNOON THUNDERSTORM DEVELOPMENT. FORECAST SOUNDINGS SUGGEST SCATTERED CONVECTION WILL EVOLVE WITH A FEW STRONG STORMS POSSIBLE...ESPECIALLY FROM NERN KS INTO CNTRL IA. LIMITED MOISTURE APPEARS TO BE THE MAIN IMPEDIMENT FOR ORGANIZED SEVERE THUNDERSTORMS ACROSS THIS REGION. FOR THIS REASON...LOW PROBABILITIES WILL BE MAINTAINED FOR THE POSSIBILITY FOR SOME HAIL OR GUSTY WINDS. ..DARROW.. 04/10/2006  From SwoDy2 at goshenarc.org Mon Apr 10 17:35:25 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 10 Apr 2006 13:35:25 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 101732 SWODY2 SPC AC 101730 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1230 PM CDT MON APR 10 2006 VALID 111200Z - 121200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF NE KS...SERN NEB...SWRN IA AND NWRN MO... ...SYNOPSIS... LEAD SHORTWAVE TROUGH NOW OVER THE NRN ROCKIES WILL CONTINUE NEWD INTO SRN CANADA BY EARLY TUESDAY. IN WAKE OF THIS FEATURE A COLD FRONT WILL MOVE SEWD THROUGH THE NRN PLAINS AND INTO THE UPPER MS VALLEY BY THE START OF THIS PERIOD. BY LATE TUESDAY AFTERNOON THE FRONT SHOULD EXTEND FROM PARTS OF MN SWWD THROUGH WRN IA...SERN NEB INTO NERN KS. A STRONGER UPSTREAM SHORTWAVE TROUGH NOW APPROACHING CA WILL EJECT NEWD INTO THE CNTRL PLAINS TUESDAY AFTERNOON. IN RESPONSE TO THIS FEATURE...A WEAK WAVE WILL DEVELOP ALONG THE SWRN PORTIONS OF THE FRONT AND LIFT NEWD INTO N CNTRL OR NERN KS BY LATE AFTERNOON. ...NERN KS...SERN NEB...SWRN IA AND NWRN MO... MOISTURE OVER THE GULF REMAINS LIMITED WITH ELY TRAJECTORIES EMANATING FROM HIGH PRESSURE OVER THE ERN STATES MAINTAINING AN INFLUX OF CP AIR. DEWPOINTS CURRENTLY RANGE FROM THE UPPER 50S OVER THE WRN GULF TO AROUND 50 NWD OVER CNTRL TX. A STRONG LOW LEVEL JET THAT WILL PERSIST TONIGHT INTO EARLY TUESDAY OVER THE PLAINS WILL CONTRIBUTE TO ADVECTION OF MODEST LOW LEVEL MOISTURE NWD. DEWPOINTS FROM 50 TO 55 WILL BE POSSIBLE INTO PORTIONS OF THE CNTRL PLAINS AND MIDDLE MS VALLEY TUESDAY. IN ADVANCE OF SWRN U.S. UPPER TROUGH...A PLUME OF STEEP MID LEVEL LAPSE RATES ASSOCIATED WITH THE ELEVATED MIXED LAYER WILL SPREAD EWD ABOVE THE MODEST MOIST AXIS AND CONTRIBUTE TO DESTABILIZATION DURING THE AFTERNOON. DESPITE LIMITED MOISTURE...COLD MID LEVEL TEMPERATURES AND SURFACE HEATING SHOULD SUPPORT MLCAPE FROM 500-1000 J/KG BY LATE AFTERNOON FROM PARTS OF NERN KS INTO SERN NEB AND SWRN IA. THE EML WILL LIKELY CONTRIBUTE TO A CAP MOST OF THE DAY IN THIS REGION. SOME ELEVATED STORMS MAY BE POSSIBLE EARLIER IN THE PERIOD IN WARM ADVECTION REGIME OVER PARTS OF THE UPPER MS VALLEY. STRONGER STORMS ARE EXPECTED TO DEVELOP BY LATE AFTERNOON ALONG AND AHEAD OF THE FRONT FROM NERN KS INTO SERN NEB AS LARGE SCALE AS ASCENT INCREASES DOWNSTREAM FROM APPROACHING SHORTWAVE TROUGH. VERTICAL SHEAR PROFILES WILL BE SUFFICIENT FOR UPDRAFTS TO ROTATE WITH ISOLATED HAIL AND STRONG WIND GUSTS THE PRIMARY THREATS. STORMS MAY EVOLVE INTO LINE SEGMENTS AND CLUSTERS AS THEY SPREAD EWD THROUGH THE MIDDLE MS VALLEY WITH A DIMINISHING SEVERE THREAT BY MID EVENING. ..DIAL.. 04/10/2006  From SwoDy2 at goshenarc.org Tue Apr 11 05:05:54 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 11 Apr 2006 01:05:54 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 110502 SWODY2 SPC AC 110501 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1201 AM CDT TUE APR 11 2006 VALID 121200Z - 131200Z ...NO SVR TSTM AREAS FORECAST... ...OH VALLEY... WEAK HEIGHT FALLS WILL PRECEED UPPER SHORTWAVE TROUGH OVER PORTIONS OF THE OH VALLEY EARLY IN THE DAY2 PERIOD. THIS FEATURE WILL FORCE ASSOCIATED SFC FRONT ACROSS IL INTO IND MID DAY...WITH TRAILING PORTIONS OF THIS BOUNDARY EXPECTED TO STALL OVER NRN AR LATE IN THE DAY. UPPER RIDGING OVER THE GULF OF MEXICO WILL MAINTAIN WEAK SUBSIDENT ENVIRONMENT THAT IS NOT PARTICULARLY FAVORABLE FOR SIGNIFICANT BOUNDARY LAYER MODIFICATION/ADAPTATION OF GULF ENVIRONMENT. RESULTANT DOWNSTREAM LOW LEVEL MOISTENING ACROSS THE SRN PLAINS INTO THE OH VALLEY WILL BE SUPPRESSED WITH 50S SFC DEW POINTS POSSIBLE AHEAD OF ADVANCING COLD FRONT. FORECAST SOUNDINGS DO HOWEVER SUGGEST CONVECTION SHOULD EVOLVE ALONG COLD FRONT BY EARLY AFTERNOON...ESPECIALLY IMMEDIATELY AHEAD OF UPPER VORT WHERE ASCENT WILL BE MAXIMIZED. THUNDERSTORMS SHOULD DEVELOP SWWD ACROSS ERN IL/IND ALONG THE OH RIVER VALLEY TOWARD THE BOOTHEEL OF MO WHERE WEAKENING CONVERGENCE AND UPPER RIDGING WILL SUPPRESS CONVECTIVE DEVELOPMENT. STRONGEST STORMS MAY PRODUCE ISOLATED HAIL OR GUSTY WINDS...HOWEVER MEAGER MOISTURE/INSTABILITY APPEAR TOO LOW TO WARRANT A RISK OF ORGANIZED SEVERE THUNDERSTORMS THIS PERIOD. ..DARROW.. 04/11/2006  From SwoDy2 at goshenarc.org Tue Apr 11 17:17:13 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 11 Apr 2006 13:17:13 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 111714 SWODY2 SPC AC 111713 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1213 PM CDT TUE APR 11 2006 VALID 121200Z - 131200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... UPPER FLOW REGIME WILL BECOME MORE AMPLIFIED THROUGH MID-WEEK AS THE UPPER LOW OVER THE EPAC DIGS SWD AND FORCES A LARGE SCALE RIDGE DOWNSTREAM OVER THE CNTRL/SRN PARTS OF NOAM. AS A RESULT...THE STRONG SHORTWAVE TROUGH NOW CROSSING THE CNTRL PLAINS WILL EJECT ENEWD ACROSS THE OH VLY/GRTLKS REGION ON WED. A REINFORCING SHORTWAVE TROUGH...NOW OVER THE NRN GRT BASIN...WILL QUICKLY FOLLOW THE LEAD DISTURBANCE...REACHING THE MIDWEST BY WED AFTN. AT THE SFC...PRIMARY LOW WILL DEVELOP NEWD FROM THE UPPER MIDWEST INTO QUE THROUGH EARLY THU. A TRAILING COLD FRONT...ACCOMPANYING THE SECONDARY UPPER TROUGH...WILL SETTLE SEWD THROUGH THE GRTLKS AND OH VLY BY WED EVENING. WRN PORTION OF THIS FRONT WILL STALL OVER THE SRN PLAINS AND OZARKS AS IT ENCOUNTERS THE PERSISTENT RIDGE OF HIGH PRESSURE SITUATED ACROSS THE GULF OF MEXICO. ...OH VLY... BOUNDARY LAYER MODIFICATION ACROSS THE GULF OF MEXICO WILL BE LIMITED THROUGH MID-WEEK OWING TO SUBSIDENCE BENEATH THE GULF OF MEXICO RIDGE. THUS...LOW-LEVEL MOISTURE TRANSPORT ACROSS THE SRN PLAINS TO THE OH VLY WILL BE WEAK WITH MAINLY 50S SFC DEW POINTS EXPECTED AHEAD OF THE APPROACHING COLD FRONT...LIMITING OVERALL INSTABILITY. THERE WILL LIKELY BE BANDS OF CONVECTION TIED TO THE LEAD SHORTWAVE TROUGH AND WITHIN THE WARM CONVEYOR ACROSS THE CNTRL GRTLKS AND OH VLY REGION EARLY WED. IN WAKE OF MORNING CLOUDS/PCPN...BOUNDARY LAYER SHOULD HEAT ALONG THE LWR OH VLY NWD INTO WRN/CNTRL OH. AS THE SECONDARY IMPULSE TRANSLATES SEWD...TSTMS ARE EXPECTED TO DEVELOP ALONG/AHEAD OF THE ASSOCIATED FRONT IN ERN IND/WRN OH BY MID-AFTN...THEN DEVELOP SWWD ALONG THE OH RVR DURING THE EVE. MAIN LIMITING FACTOR FOR ORGANIZED SEVERE TSTMS WILL BE THE LOW INSTABILITY...DESPITE THE SUPERCELL WIND PROFILES. ATTM...IT APPEARS THAT ONLY ISOLD TSTMS MAY GROW STRONG ENOUGH TO PRODUCE HAIL/GUSTY WINDS. BUT...LATER OTLKS WILL NEED TO ASSESS MOISTURE TRANSPORT CLOSELY AND A SLGT RISK MAY BE JUSTIFIED CLOSER TO THE EVENT. ..RACY.. 04/11/2006  From SwoDy2 at goshenarc.org Wed Apr 12 05:44:29 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 12 Apr 2006 01:44:29 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 120541 SWODY2 SPC AC 120540 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1240 AM CDT WED APR 12 2006 VALID 131200Z - 141200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM SERN MN INTO WRN IND... ...MID-UPPER MS VALLEY/OH VALLEY... WEAK HEIGHT FALLS WILL SPREAD ACROSS THE NRN PLAINS LATE IN THE PERIOD AS SHORTWAVE TROUGH FLATTENS UPPER RIDGE AND DIGS SEWD TOWARD THE UPPER GREAT LAKES REGION. THIS FEATURE WILL INDUCE SFC CYCLOGENESIS ALONG PSEUDO WARM FRONT OVER ERN SD...WHICH WILL THEN TRACK SEWD ACROSS SRN PORTIONS OF LAKE MI INTO NRN OH LATE IN THE PERIOD. WARM ADVECTION AND ASCENT AHEAD OF SHORTWAVE WILL BE CONFINED TO AREAS NORTH OF THIS BOUNDARY...WHILE VEERED BOUNDARY LAYER FLOW AND WEAK CONVERGENCE WILL DOMINATE THE WARM SECTOR. LATEST ETA MODEL GUIDANCE APPEARS TOO AGGRESSIVE IN MOISTURE RETURN WHICH ERRONEOUSLY GENERATES SBCAPE VALUES IN EXCESS OF 3500J/KG ACROSS PORTIONS OF IA. NO DOUBT STEEP LAPSE RATE ENVIRONMENT AND STRONGLY SHEARED PROFILES WILL FAVOR POTENTIAL SUPERCELL DEVELOPMENT WITHIN WARM ADVECTION ZONE...HOWEVER INSTABILITY WILL LIKELY FALL WITHIN 1000-1500 J/KG RANGE ALONG/NORTH OF FRONTAL BOUNDARY AS WARM SECTOR MOISTURE SHOULD BE GREATLY REDUCED. IT APPEARS SLIGHTLY ELEVATED THUNDERSTORMS WILL EVOLVE JUST NORTH OF BOUNDARY DURING THE LATE AFTERNOON HOURS WHERE WSWLY LLJ WILL BE FOCUSED OVER SERN MN/WCNTRL WI. THIS ACTIVITY...POTENTIALLY SUPERCELLULAR...SHOULD SPREAD SEWD ACROSS SRN WI/NRN IL INTO WRN IND DURING THE EVENING HOURS. FORECAST SOUNDINGS SUGGEST THERE IS SOME POTENTIAL FOR WARM SECTOR DEVELOPMENT AROUND 00Z WITHIN AXIS OF STRONGEST HEAT FROM ERN IA INTO NRN MO. GIVEN WEAK CONVERGENCE ANY CONVECTION THAT EVOLVES WITHIN THIS ZONE SHOULD BE SHORT LIVED AND DISSIPATE AFTER DARK. MORE CONCENTRATED ACTIVITY WILL SPREAD/DEVELOP SEWD INTO PORTIONS OF THE OH VALLEY WHERE ASCENT SHOULD AID CONVECTION WELL INTO THE OVERNIGHT HOURS. AT THIS TIME HAIL APPEARS TO BE THE PRIMARY CONCERN...ESPECIALLY IF PARCELS ARE FORCED TO CONVECT NORTH OF FRONTAL ZONE. ..DARROW.. 04/12/2006  From SwoDy2 at goshenarc.org Wed Apr 12 17:21:38 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 12 Apr 2006 13:21:38 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 121718 SWODY2 SPC AC 121717 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1217 PM CDT WED APR 12 2006 VALID 131200Z - 141200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE UPPER MS VALLEY INTO THE GREAT LAKES...... ...SYNOPSIS... BROAD UPPER RIDGE SLOWLY BUILDING OVER THE ROCKIES IS FORECAST TO PROGRESS EWD ACROSS THE PLAINS...AS DOWNSTREAM UPPER TROUGH CURRENTLY OVER THE GREAT LAKES MOVES INTO THE NERN STATES TONIGHT. WEAK SHORT WAVE TROUGH CURRENTLY OVER BRITISH COLUMBIA IS EXPECTED TO MOVE ESEWD AS A LOW AMPLITUDE SYSTEM ACROSS THE NRN PARTS OF THE ROCKIES AND PLAINS...WITH WNWLY UPPER FLOW DEVELOPING ACROSS THE UPPER MS VALLEY TOMORROW NIGHT. AT THE SURFACE...LOW PRESSURE OVER NRN/CENTRAL PLAINS WILL GRADUALLY SPREAD EWD TOWARD THE UPPER MS VALLEY...AS A WARM FRONT ACROSS THE OH VALLEY WWD INTO KS AT THE START OF THE PERIOD LIFTS NWD INTO THE UPPER MS VALLEY/SRN GREAT LAKES BY EVENING. THE LOW IS EXPECTED TO CONTINUE EWD INTO THE GREAT LAKES REGION OVERNIGHT. ...UPPER MS VALLEY INTO GREAT LAKES... LOW LEVEL MOISTURE IS EXPECTED TO SPREAD RAPIDLY NWD TOWARD THE UPPER MS VALLEY DURING THE DAY AS WARM FRONT LIFTS NWD INTO THE REGION...WITH SURFACE DEW POINTS OF 55-60F MOVING INTO PARTS OF SERN MN/WRN WI BY 00Z. STEEPER MID LEVEL LAPSE RATES OF 7.0-7.5 C/KM ARE FORECAST TO SPREAD EWD ACROSS THE MIDDLE AND UPPER MS VALLEY TOWARD THE WRN GREAT LAKES IN ASSOCIATION WITH STRONG WESTERLY MID LEVEL WINDS FROM THE NRN ROCKIES INTO THE GREAT LAKES. AIR MASS WILL DESTABILIZE NWD AS LOW LEVEL MOISTURE SPREADS NWD BENEATH THE STEEPER LAPSE RATES...WITH ELEVATED CAPE OF 1000-1500 J/KG DEVELOPING NORTH OF THE WARM FRONT AND MLCAPE OF 2000-2500 J/KG WITH WARM SECTOR. PRIMARY CONVECTIVE DEVELOPMENT IS EXPECTED TO BEGIN DURING THE LATE AFTERNOON OR EVENING OVER PARTS OF MN AND WI ALONG/NORTH OF THE WARM FRONT AS THE SWLY LOW LEVEL JET PROVIDES INCREASING WARM ADVECTION LIFT. THIS ACTIVITY IS EXPECTED TO SPREAD EWD/ESEWD DURING THE OVERNIGHT HOURS AS THE LOW LEVEL JET VEERS WITH TIME AND WARM ADVECTION ZONE SHIFTS TOWARD LOWER MI. FORECAST WIND PROFILES EXHIBIT STRONG VEERING WITH HEIGHT...WITH SUFFICIENT VERTICAL SHEAR WITHIN THE CLOUD LAYER TO SUPPORT ELEVATED SUPERCELLS. LARGE HAIL WILL BE POSSIBLE WITH STRONGER CELLS...WITH ADDITIONAL THREAT FOR STRONG WIND GUSTS WITH NEAR SURFACE-BASED STORMS CLOSE TO THE WARM FRONT. THIS ACTIVITY IS LIKELY TO PERSIST THROUGH THE NIGHT AS IT SPREADS ESEWD ACROSS THE LOWER GREAT LAKES AREA. THERE IS ALSO A POSSIBILITY OF ISOLATED THUNDERSTORMS FORMING DURING THE AFTERNOON IN THE WARM SECTOR...HOWEVER THE PRESENCE OF A WEAK CAP IS LIKELY TO LIMIT THE OVERALL COVERAGE OF DEEP CONVECTION. SINCE THE STRONGER VERTICAL SHEAR EXTENDS SWD INTO PARTS OF MO AND SRN IL...THERE IS A LOW CONDITIONAL PROBABILITY OF SEVERE WITH ANY STORM THAT DEVELOPS. THE CONVECTIVE POTENTIAL SOUTH OF THE WARM FRONT SHOULD DIMINISH AFTER SUNSET. ..WEISS.. 04/12/2006  From SwoDy2 at goshenarc.org Thu Apr 13 17:34:11 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Thu, 13 Apr 2006 13:34:11 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 131731 SWODY2 SPC AC 131730 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1230 PM CDT THU APR 13 2006 VALID 141200Z - 151200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE OH VALLEY AND CNTRL APPALACHIAN MTNS... ...CNTRL APPALACHIAN MTNS... A WEST TO NORTHWEST FLOW PATTERN WILL REMAIN IN PLACE ACROSS THE NERN U.S FRIDAY AS SEVERAL EMBEDDED SHORTWAVE TROUGHS MOVE QUICKLY ESEWD ACROSS REGION. THE FIRST SHORTWAVE TROUGH IS FORECAST TO MOVE ACROSS THE OH VALLEY TONIGHT WITH A SEVERE LINEAR MCS DEVELOPING AND REACHING OH BY DAYBREAK FRIDAY. ALTHOUGH THIS CONVECTIVE COMPLEX MAY BE IN A WEAKENING STAGE JUST AFTER DAYBREAK...REINTENSIFICATION BY MID-DAY WILL BE POSSIBLE AS DESTABILIZATION OCCURS ACROSS WV..SWRN PA...WRN MD AND WRN VIRGINIA. OTHER STORMS SHOULD REDEVELOP IN THE CNTRL APPALACHIAN MTNS BEHIND THE FIRST LINEAR MCS AIDED BY INCREASING LARGE-SCALE ASCENT AHEAD OF AN APPROACHING MID-LEVEL JET. FORECAST SOUNDINGS ACROSS THE CNTRL APPALACHIANS QUICKLY DEVELOP MODERATE INSTABILITY BY LATE FRIDAY MORNING WITH VERY STRONG VERTICAL SHEAR PROFILES IN PLACE AS THE NOSE OF THE MID-LEVEL JET MOVES ACROSS THE REGION. THIS SHOULD BE SUFFICIENT FOR A WIND DAMAGE/HAIL THREAT AS THE FIRST LINE MOVES ACROSS DURING THE MORNING. AS MODERATE INSTABILITY DEVELOPS BY MID-DAY...LITTLE OR NO CAPPING...INCREASING ASCENT FROM THE WEST AND THE STRONGLY SHEARED ENVIRONMENT SHOULD BE FAVORABLE FOR SUPERCELLS IN THE AFTERNOON. ALTHOUGH SUPERCELLS MAY INITIALLY HAVE A TORNADO THREAT...LARGE HAIL AND WIND DAMAGE SHOULD BECOME THE FAVORED THREAT BY MID TO LATE AFTERNOON AS LOW-LEVEL WINDS VEER AND BECOME MORE UNDIRECTIONAL. THE SEVERE THREAT SHOULD DROP-OFF BY EVENING AS INSTABILITY DECREASES ACROSS THE REGION. ...OH VALLEY... A WEST TO NORTHWEST FLOW PATTERN WILL CONTINUE IN PLACE ACROSS THE OH VALLEY FRIDAY AS AN EMBEDDED SHORTWAVE TROUGH APPROACHES THE REGION FROM THE WEST. ALTHOUGH A CAPPING INVERSION MAY BE IN PLACE ACROSS MUCH OF THE REGION THROUGH MID-DAY...STRENGTHENING INSTABILITY AND INCREASING LOW-LEVEL CONVERGENCE SHOULD ALLOW STORMS TO INITIATE IN IL...IND...ERN IA AND KY SOUTH OF A FRONTAL BOUNDARY DURING THE MID AFTERNOON HOURS. STORM COVERAGE SHOULD INCREASE WITH AN MCS DEVELOPING DURING THE EVENING AS A SHORTWAVE TROUGH DRIFTS ESEWD ACROSS THE OH VALLEY. FORECAST SOUNDINGS ACROSS IL AND SRN IND BY 22Z FRIDAY SHOW SBCAPES OF 2500-3500 J/KG WITH MODERATE VERTICAL SHEAR AND VERY STEEP MID-LEVEL LAPSE RATES SUGGESTING THE ENVIRONMENT WILL BE FAVORABLE FOR SUPERCELLS WITH LARGE HAIL. IN ADDITION...A 50 KT LOW-LEVEL JET IS FORECAST TO STRENGTHEN BY EARLY EVENING FEEDING THE DEVELOPING STORM COMPLEX. ALTHOUGH SFC WINDS WILL LIKELY BE VEERED...FORECAST SOUNDINGS SHOW SUFFICIENT DIRECTIONAL SHEAR BELOW 700 MB SUGGESTING A FEW TORNADOES WILL BE POSSIBLE WITH THE STRONGER SUPERCELLS. AS AN MCS EXPANDS AND DRIFTS ESEWD ACROSS OH AND KY INTO THE WRN APPALACHIAN FOOTHILLS FRIDAY EVENING...A LARGE HAIL AND WIND DAMAGE THREAT SHOULD CONTINUE WITH THE STRONGER STORMS. AS THE INSTABILITY DECREASES OVERNIGHT...THE SEVERE THREAT SHOULD GRADUALLY DIMINISH. ..BROYLES.. 04/13/2006  From SwoDy2 at goshenarc.org Sat Apr 15 04:51:52 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 15 Apr 2006 00:51:52 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 150448 SWODY2 SPC AC 150447 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1147 PM CDT FRI APR 14 2006 VALID 161200Z - 171200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM PORTIONS OF IA/MO ESEWD THROUGH THE OH VALLEY TO THE VA/NC COASTS... ...SYNOPSIS... AMPLIFIED LARGE-SCALE PATTERN IS FORECAST DURING THE DAY TWO PERIOD...CHARACTERIZED BY INTENSIFYING TROUGH OVER THE INTERMOUNTAIN W...RIDGING FROM THE WRN GREAT LAKES INTO HUDSON BAY...AND CLOSED MID-LEVEL LOW WHICH WILL PERSIST OFF THE COAST OF NOVA SCOTIA. WITHIN THIS LARGER-SCALE CIRCULATION...CLOSED LOW INITIALLY OVER THE MID MO VALLEY SUNDAY MORNING WILL WEAKEN AS IT UNDERCUTS WRN GREAT LAKES RIDGE...AND IS EVENTUALLY ENTRAINED INTO BROADER BELT OF CYCLONIC FLOW ASSOCIATED WITH WRN ATLANTIC UPPER LOW. IN THE LOW-LEVELS...SURFACE LOW COINCIDENT WITH MID MO VALLEY UPPER LOW WILL SLOWLY FILL AS IT DEVELOPS ESEWD ALONG ATTENDANT BAROCLINIC ZONE THROUGH THE OH VALLEY. ...MIDWEST EWD THROUGH THE OH VALLEY TO THE VA/NC COASTS... MOIST BOUNDARY-LAYER CONDITIONS /I.E. DEWPOINTS IN THE UPPER 50S TO LOWER 60S/ COUPLED WITH REMNANT PLUME OF STEEP MID-LEVEL LAPSE RATES ARE EXPECTED TO CONTRIBUTE TO A MODERATELY UNSTABLE AIR MASS ALONG AND S OF LOW-LEVEL BAROCLINIC ZONE WITH MLCAPES OF 1500-2000 J/KG DEVELOPING OVER PORTIONS OF ERN MO/IL/IND...AND GENERALLY 500-1500 J/KG ESEWD THROUGH THE REMAINDER OF THE OH VALLEY INTO VA/NC. DAYTIME HEATING COUPLED WITH FORCING FOR ASCENT AHEAD OF OPENING MID-LEVEL WAVE ARE EXPECTED TO RESULT IN VIGOROUS TSTM DEVELOPMENT BY EARLY TO MID AFTERNOON FROM VICINITY OF SURFACE LOW EWD ALONG BAROCLINIC ZONE OVER ERN IA/NERN MO INTO IL/IND. GIVEN THE MODERATE INSTABILITY AND VERTICAL WIND PROFILES EXHIBITING PRONOUNCED LOW-LEVEL VEERING AND 35-45 KTS OF DEEP-LAYER SHEAR...POTENTIAL WILL EXIST FOR SUPERCELLS CAPABLE OF LARGE HAIL /SOME SIGNIFICANT/...DAMAGING WINDS AND ISOLATED TORNADOES. ADDITIONAL CLUSTERS OF STRONG TO SEVERE STORMS WILL ALSO BE POSSIBLE FARTHER DOWNSTREAM OVER THE OH VALLEY...CNTRL APPALACHIANS AND EWD TO THE VA/NC COASTAL PLAIN OWING TO PERSISTENT LOW-LEVEL WARM/MOIST ADVECTION ALONG/N OF SURFACE BOUNDARY. HERE TOO...DEEP-LAYER VERTICAL SHEAR WILL BE SUPPORTIVE OF SUPERCELLS AND BOWING STRUCTURES CAPABLE OF LARGE HAIL...DAMAGING WINDS AND A COUPLE OF TORNADOES. OVERALL LARGE-SCALE PATTERN APPEARS TO SUPPORT UPSCALE GROWTH INTO ONE OR MORE FORWARD-PROPAGATING MCS/S LATE SUNDAY AFTERNOON INTO SUNDAY NIGHT WITH AN INCREASED POTENTIAL FOR CORRIDORS OF DAMAGING WINDS. ...ERN MT... BOUNDARY-LAYER MOISTURE WILL REMAIN QUITE LIMITED AHEAD OF PACIFIC COLD FRONT MOVING OUT OF THE NRN ROCKIES. HOWEVER...DIABATIC HEATING COUPLED WITH HEIGHT FALLS AHEAD OF MID-LEVEL TROUGH DEVELOPING EWD THROUGH THE INTERMOUNTAIN W WILL RESULT IN STEEP LOW TO MID-LEVEL LAPSE RATES AND RESULTANT WEAK INSTABILITY. THE POTENTIAL FOR A FEW HIGH-BASED STORMS WILL EXIST LATE SUNDAY AFTERNOON INTO SUNDAY EVENING AS SURFACE FRONT PUSHES EWD THROUGH REGION. ISOLATED SEVERE HAIL AND LOCALLY STRONG WIND GUSTS WILL BE POSSIBLE WITH THE MOST INTENSE STORMS OWING TO THE STEEP LAPSE RATES AND DEEP...RELATIVELY DRY SUB-CLOUD LAYER. ..MEAD.. 04/15/2006  From SwoDy2 at goshenarc.org Sat Apr 15 17:32:52 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 15 Apr 2006 13:32:52 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 151729 SWODY2 SPC AC 151728 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1228 PM CDT SAT APR 15 2006 VALID 161200Z - 171200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE OH VALLEY...CNTRL APPALACHIANS AND ATLANTIC COASTAL PLAINS... ...OH VALLEY/CNTRL APPALACHIANS/ATLANTIC COASTAL PLAINS... A NEGATIVELY-TILTED UPPER-LOW OVER THE PLAINS STATES WILL SLOWLY FILL AND DRIFT EWD TOWARD THE OH VALLEY SUNDAY. LARGE-SCALE ASCENT AHEAD OF THE SYSTEM WILL SUPPORT THE DEVELOPMENT OF SCATTERED TO NUMEROUS THUNDERSTORMS ACROSS THE REGION SUNDAY AND SUNDAY NIGHT. A LARGE MCS WILL LIKELY BE ONGOING AT THE BEGINNING OF THE PERIOD ACROSS WI...IL AND IND DURING THE MORNING AHEAD OF THE APPROACHING UPPER-TROUGH. SFC DEWPOINTS SHOULD BE IN THE LOWER 60S ACROSS MUCH OF THE OH VALLEY ALLOWING MODERATE INSTABILITY TO DEVELOP BY SUNDAY AFTERNOON SOUTH OF THE MCS WHERE THE AIRMASS SHOULD REMAIN UNDISTURBED. SUBSTANTIAL DESTABILIZATION ALSO APPEARS LIKELY WEST OF THE EXITING MCS ACROSS IA AND NRN IL NEAR A SFC LOW ASSOCIATED WITH THE UPPER SYSTEM. THIS WOULD BE THE MOST LIKELY AREA FOR STRONG CONVECTIVE INITIATION EARLY SUNDAY AFTERNOON WITH STORMS EXPANDING IN COVERAGE DURING THE AFTERNOON ALONG A STATIONARY FRONTAL BOUNDARY EXTENDING ESEWD FROM THE SFC LOW. MCS DEVELOPMENT WITH THIS CONVECTIVE COMPLEX APPEARS LIKELY LATE SATURDAY AFTERNOON WITH STORMS MOVING ACROSS NCNTRL IL INTO IND...NRN KY AND SRN OH DURING THE EVENING HOURS. FORECAST SOUNDINGS LATE SUNDAY AFTERNOON ACROSS THE REGION SHOW MODERATE INSTABILITY WITH 40 TO 50 KT OF VERTICAL SHEAR AND STEEP MID-LEVEL LAPSE RATES SUGGESTING SUPERCELLS WITH LARGE HAIL AND WIND DAMAGE WILL BE LIKELY. DUE TO THE MODERATE INSTABILITY AND COLDER AIR ALOFT WITH THE UPPER-TROUGH...VERY LARGE HAIL APPEARS POSSIBLE WITH THE STRONGER SUPERCELLS IN THE LATE AFTERNOON AND EARLY EVENING. A POTENTIAL FOR TORNADOES WILL ALSO EXIST AS SUPERCELLS INCREASE IN COVERAGE AND A LARGE MCS DEVELOPS IN THE EVENING. DUE TO THE UNSTABLE AIRMASS AND MODERATE VERTICAL SHEAR...THE MCS SHOULD CONTINUE TO DRIFT ESEWD OVERNIGHT WITH A LOW-END SEVERE THREAT POSSIBLE INTO THE CNTRL APPALACHIAN MTNS AND ATLANTIC COASTAL PLAINS LATE IN THE PERIOD. ...ERN MT/FAR WRN ND... A BROAD BAND OF SOUTHWEST FLOW ACROSS THE NWRN U.S. WILL REMAIN IN PLACE SUNDAY. SEVERAL SHORTWAVE TROUGHS EMBEDDED IN THE FLOW WILL DRIFT NEWD ACROSS THE NRN PLAINS SUNDAY AND SUNDAY NIGHT. ALTHOUGH FORECAST SOUNDINGS LATE SUNDAY AFTERNOON ACROSS THE REGION SHOW WEAK INSTABILITY IN PLACE...STEEPENING LAPSE RATES AND LARGE-SCALE ASCENT AHEAD OF ANY SHORTWAVE WOULD MAKE MARGINALLY SEVERE HAIL STORMS POSSIBLE. ANY MARGINAL SEVERE THREAT WOULD LIKELY BE TIED CLOSELY TO SFC HEATING. ..BROYLES.. 04/15/2006  From SwoDy2 at goshenarc.org Sun Apr 16 05:27:58 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 16 Apr 2006 01:27:58 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 160525 SWODY2 SPC AC 160523 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1223 AM CDT SUN APR 16 2006 VALID 171200Z - 181200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER MUCH OF THE CAROLINAS... ...THERE IS A SLGT RISK OF SVR TSTMS OVER WRN PARTS OF SD AND NEB... ...SYNOPSIS... AMPLIFIED LONG WAVE PATTERN IS FORECAST THROUGH THE DAY TWO PERIOD...CHARACTERIZED BY UPPER LOWS OVER THE GULF OF AK AND OVER THE CANADIAN MARITIMES...AND EVOLVING UPPER LOW OVER THE NRN HIGH PLAINS. BETWEEN THESE FEATURES...HIGH AMPLITUDE RIDGE WILL EXIST FROM HUDSON BAY/WRN QUEBEC SWWD INTO THE GREAT LAKES...AND A WEAKER UPSTREAM RIDGE FROM THE CANADIAN ROCKIES INTO THE PACIFIC NW. IN THE LOW-LEVELS...SURFACE LOW ASSOCIATED WITH A WEAKENING MID-LEVEL VORTICITY MAXIMUM WILL DEVELOP SEWD FROM ERN KY INTO SC BY AFTERNOON WITH ASSOCIATED COLD FRONT PUSHING SWD THROUGH THE PIEDMONT AND COASTAL PLAIN. OVER THE PLAINS...SURFACE PATTERN BECOMES MORE COMPLEX. PACIFIC COLD FRONT WILL PUSH EWD OUT OF THE NRN AND CNTRL ROCKIES INTO THE HIGH PLAINS WITH LEE CYCLONE EVOLVING ALONG THIS BOUNDARY OVER SERN WY MONDAY AFTERNOON. A DRY LINE OR LEE TROUGH WILL EXTEND SWD FROM THIS LOW INTO WRN PORTIONS OF KS AND TX...WITH ATTENDANT WARM FRONT SLOWLY LIFTING NWD THROUGH KS AND NEB. ...CAROLINAS... CLUSTERS OF TSTMS ARE EXPECTED TO BE ONGOING AT THE ONSET OF THE FORECAST MONDAY MORNING INVOF SURFACE LOW AND MID-LEVEL DISTURBANCE OVER PORTIONS OF THE OH VALLEY INTO CNTRL APPALACHIANS. THIS ACTIVITY WILL LIKELY INTENSIFY BY AFTERNOON AS IT CRESTS HIGHER TERRAIN AND MOVES INTO AN ENVIRONMENT CHARACTERIZED BY STEEP LOW-LEVEL LAPSE RATES...MOIST BOUNDARY-LAYER CONDITIONS AND RESULTANT WEAK TO MODERATE INSTABILITY. FORECAST SOUNDINGS WITHIN PRE-FRONTAL AIR MASS OVER THE PIEDMONT AND COASTAL PLAIN INDICATE LARGELY UNIDIRECTIONAL WLY OR WSWLY WINDS THROUGH THE DEPTH OF THE BUOYANCY LAYER WITH SUFFICIENT DEEP-LAYER SPEED SHEAR /40-45 KTS/ TO SUPPORT ORGANIZED SEVERE STORMS. THE MODEST MID-LEVEL LAPSE RATES WILL LIMIT A MORE SUBSTANTIAL HAIL THREAT WITH DAMAGING WINDS LIKELY WITH THE MOST INTENSE STORMS. ...SD / NEB... BOUNDARY-LAYER IS EXPECTED TO REMAIN RELATIVELY DRY AHEAD OF PACIFIC COLD FRONT EMERGING FROM THE ROCKIES WITH DEWPOINTS REMAINING LARGELY IN THE 30S AND 40S. MODEL GUIDANCE SUGGESTS THAT PRIMARY LOW-LEVEL MOISTURE AXIS WILL BE FOCUSED ALONG RETREATING WARM FRONT WITH 50-55 F DEWPOINTS ADVECTING NWWD INTO CNTRL NEB BY MONDAY NIGHT. FRONTAL CONVERGENCE COUPLED WITH INCREASED LARGE-SCALE FORCING AHEAD OF APPROACHING MID-LEVEL TROUGH ARE EXPECTED TO CONTRIBUTE TO TSTM DEVELOPMENT BY AFTERNOON INTO EVENING ALONG COLD FRONT FROM THE WRN DAKOTAS INTO SERN WY AND NWRN NEB WITHIN WEAKLY UNSTABLE ENVIRONMENT. DESPITE THE MARGINAL INSTABILITY...THE STEEP LAPSE RATES AND RELATIVELY STRONG VERTICAL SHEAR PROFILES SUGGEST THE POTENTIAL FOR A FEW ORGANIZED/ROTATING STORMS CAPABLE OF DAMAGING WINDS AND LARGE HAIL. THIS ACTIVITY WILL LIKELY MOVE/DEVELOP EWD ACROSS WRN SD AND NWRN/N-CNTRL NEB MONDAY NIGHT /PERHAPS BECOMING MORE ELEVATED WITH EWD EXTENT/ WITH A CONTINUING THREAT OF MAINLY SEVERE HAIL. ..MEAD.. 04/16/2006  From SwoDy2 at goshenarc.org Sun Apr 16 17:27:41 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 16 Apr 2006 13:27:41 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 161723 SWODY2 SPC AC 161723 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1223 PM CDT SUN APR 16 2006 VALID 171200Z - 181200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE CAROLINAS... ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE NRN AND CNTRL PLAINS... ...CAROLINAS... THE UPPER-LEVEL LOW OVER THE NRN MS VALLEY WILL SLIDE ESEWD ACROSS THE OH VALLEY TONIGHT INTO THE CNTRL APPALACHIAN MTNS MONDAY MORNING. IN RESPONSE...LARGE-SCALE ASCENT WILL INCREASE ACROSS THE ATLANTIC COASTAL PLAIN MONDAY AND SCATTERED THUNDERSTORMS SHOULD INITIATE IN THE CAROLINAS MONDAY AFTERNOON. IN RESPONSE TO THE UPPER-LEVEL TROUGH...A COLD FRONT IS FORECAST TO MOVE SWD ACROSS THE REGION MONDAY. AHEAD OF THE FRONT SFC DEWPOINTS IN THE 55-60 F RANGE MAY BE SUPPORTIVE OF LOWER-END MODERATE INSTABILITY AND STORMS SHOULD INITIATE ALONG AND SOUTH OF THE BOUNDARY DURING THE EARLY AFTERNOON. THE INSTABILITY COMBINED WITH STRONG VERTICAL SHEAR PROFILES ENHANCED BY A MID-LEVEL JET SHOULD BE SUFFICIENT FOR SUPERCELLS. HAIL AND ISOLATED WIND DAMAGE WILL BE POSSIBLE AS STORM COVERAGE INCREASES AND AN MCS GRADUALLY DEVELOPS. ALTHOUGH A SEVERE THREAT SHOULD CONTINUE WITH THE MCS INTO THE EVENING HOURS...ANY THREAT ACROSS THE ERN CAROLINAS SHOULD DECREASE FROM WEST TO EAST AS THE MCS MOVES ESEWD INTO THE ATLANTIC IN THE EARLY EVENING. ...NEB/SD... AN UPPER-LEVEL TROUGH OVER THE PACIFIC NORTHWEST IS FORECAST TO GRADUALLY FILL AND MOVE EWD INTO THE NRN ROCKIES MONDAY. LARGE-SCALE ASCENT WILL SPREAD EWD ACROSS THE HIGH PLAINS AS THE TROUGH APPROACHES MAKING THUNDERSTORM DEVELOPMENT LIKELY IN THE LATE AFTERNOON AND EVENING. FORECAST SOUNDINGS ACROSS NRN NEB MONDAY AFTERNOON DEVELOP LOWER-END MODERATE INSTABILITY WITH MLCAPE VALUES INCREASING TO AROUND 1500 J/KG RANGE BY EARLY EVENING. IN ADDITION...SWLY MID-LEVEL FLOW WILL INCREASE AS A MID-LEVEL JET DRIFTS EWD INTO THE REGION. THIS WILL CREATE VERTICAL SHEAR PROFILES FAVORABLE FOR SUPERCELLS. LARGE HAIL AND ISOLATED WIND DAMAGE WILL BE LIKELY WITH THE STRONGER SUPERCELLS AS LAPSE RATES STEEPEN AND STORMS MATURE IN THE EARLY EVENING. MCS DEVELOPMENT WILL BE POSSIBLE BUT THE SEVERE THREAT SHOULD GRADUALLY DECREASE AS INSTABILITY WEAKENS DURING THE EVENING. ..BROYLES.. 04/16/2006  From SwoDy2 at goshenarc.org Mon Apr 17 05:52:55 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 17 Apr 2006 01:52:55 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 170549 SWODY2 SPC AC 170548 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1248 AM CDT MON APR 17 2006 VALID 181200Z - 191200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE MID / LOWER MO VALLEY SEWD INTO THE TN VALLEY... ...SYNOPSIS... HIGH AMPLITUDE LARGE-SCALE PATTERN WILL CONTINUE ACROSS THE CONUS THROUGH THE DAY TWO PERIOD...CHARACTERIZED BY OMEGA BLOCK FROM THE WRN ATLANTIC WWD INTO THE PLAINS. WRN PART OF THIS BLOCK IS MID-LEVEL TROUGH WHICH WILL INTENSIFY AND FORM A CLOSED LOW OVER THE NRN PLAINS. IN THE LOW-LEVELS...OCCLUSION OF NRN-MOST SURFACE LOW WILL OCCUR TUESDAY MORNING OVER THE ERN DAKOTAS AS STRONG COLD FRONT OVERTAKES NRN EXTENSION OF WARM OR QUASI-STATIONARY BOUNDARY STRETCHING FROM THE MID MO VALLEY SEWD INTO THE TN VALLEY AND SERN STATES. A SECONDARY SURFACE LOW IS EXPECTED TO DEVELOP AT THE PROGRESSIVE COLD FRONTAL OCCLUSION POINT SEWD FROM NWRN MO TUESDAY AFTERNOON INTO THE WRN TN VALLEY LATE MONDAY NIGHT. ...MID AND LOWER MO VALLEY INTO THE TN VALLEY... 17/00Z SOUNDINGS FROM CRP/LCH INDICATE THAT LOW-LEVEL MOISTURE PROFILES ARE SLOWLY IMPROVING ACROSS THE NWRN GULF COAST WITH LOWEST MEAN MIXING RATIOS OF 13-15 G/KG. WHILE THIS RICH A BOUNDARY-LAYER AIR MASS WILL NOT LIKELY BE ADVECTED NWD INTO THE CNTRL LOW PLAINS...IT DOES APPEAR THAT 60-65 F DEWPOINTS WILL BE POSSIBLE INTO MO BY TUESDAY AFTERNOON...CONTRIBUTING TO MLCAPES OF 2000-2500 J/KG. STRONG DEEP-LAYER FORCING FOR ASCENT AHEAD OF EVOLVING UPPER LOW WILL LIKELY SUPPORT AN INCREASE IN ELEVATED TSTMS DURING THE DAY NEAR AND E OF OCCLUDED FRONT FROM PORTIONS OF ERN SD/SWRN MN SWD INTO ERN NEB AND WRN IA. RATHER STEEP MID-LEVEL LAPSE RATES AND STRONG LOW-LEVEL WARM ADVECTION WILL CONTRIBUTE TO POCKETS OF MODERATE INSTABILITY FOR ELEVATED PARCELS WITH STRONGEST STORMS CAPABLE OF MAINLY SEVERE HAIL. SURFACE-BASED STORM DEVELOPMENT IS EXPECTED BY MID TO LATE AFTERNOON NEAR SECONDARY SURFACE LOW AND OCCLUSION POINT OVER NWRN MO. DESPITE THE STRONGEST MID AND HIGH-LEVEL WIND FIELDS REMAINING FARTHER TO THE NW IN CLOSER PROXIMITY OF UPPER SYNOPTIC SYSTEM...VERTICAL SHEAR PROFILES WILL BE SUPPORTIVE OF SEVERE STORMS INCLUDING SUPERCELLS. THE WARM SECTOR IS EXPECTED TO BE RATHER NARROW AT THIS INITIATION POINT WITH ANY STORMS QUICKLY MOVING EWD ACROSS NW-SE ORIENTED STATIONARY OR WARM FRONT INTO A MUCH MORE STABLE ENVIRONMENT. ADDITIONAL STORMS MAY ALSO DEVELOP BY LATE AFTERNOON/EARLY EVENING SWD ALONG COLD FRONT OR PRE-FRONTAL TROUGH/DRY LINE OVER FAR E-CNTRL/SERN KS INTO SWRN MO. HERE...WARM SECTOR WILL BE WIDER THOUGH MARGINAL DEEP-LAYER SHEAR AND STRONG LINEAR FORCING ALONG COLD FRONT MAY PROMOTE A RAPID TRANSITION TO OUTFLOW-DOMINANT MCS WITH THE MAIN THREATS BEING LARGE HAIL AND DAMAGING WINDS. THE THREAT OF PRIMARILY DAMAGING WINDS AND SEVERE HAIL IS EXPECTED TO DEVELOP SEWD INTO THE WRN TN VALLEY OVERNIGHT IN ASSOCIATION WITH WEAKENING MIGRATORY SURFACE LOW. ...NRN FL INTO SWRN GA... MOIST BOUNDARY-LAYER CONDITIONS ARE EXPECTED TO CONTRIBUTE TO A MODERATELY UNSTABLE AIR MASS TUESDAY AFTERNOON ALONG WEAK BACK DOOR FRONT SLOWLY SAGGING SWWD. WHILE MID-LEVEL LAPSE RATES ARE NOT EXPECTED TO BE PARTICULARLY STEEP...MODERATELY STRONG UNIDIRECTIONAL VERTICAL SHEAR MAY SUPPORT A FEW ORGANIZED STORMS CAPABLE OF ISOLATED DAMAGING WINDS AND PERHAPS A BRIEF TORNADO. ..MEAD.. 04/17/2006  From SwoDy2 at goshenarc.org Tue Apr 18 05:25:03 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 18 Apr 2006 01:25:03 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 180521 SWODY2 SPC AC 180520 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1220 AM CDT TUE APR 18 2006 VALID 191200Z - 201200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM PARTS OF THE SRN OH AND TN VALLEYS INTO AL AND GA... ...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE TX HILL COUNTRY AND EDWARDS PLATEAU... ...SYNOPSIS... OMEGA BLOCK FROM THE NRN PLAINS INTO THE WRN ATLANTIC WILL GRADUALLY SHIFT EWD THROUGH THE DAY TWO PERIOD WITH MORE OF A REX BLOCK PATTERN BECOMING BETTER DEFINED FROM THE NRN PLAINS/UPPER MS VALLEY INTO HUDSON BAY. A SLIGHTLY MORE PROGRESSIVE SRN BRANCH OF WESTERLIES WILL PERSIST FROM THE SWRN DESERTS EWD THROUGH THE GULF COAST STATES WITH A VORTICITY MAXIMUM TRANSLATING FROM THE SRN CA COAST EWD INTO AZ. IN THE LOW-LEVELS...LOW PRESSURE OVER WRN TN WILL SLOWLY DEVELOP EWD THROUGH THE TN VALLEY BEFORE WEAKENING WITH COLD FRONTAL SURGE ALSO SLOWING OVER THE TN VALLEY SWWD THROUGH THE LOWER MS VALLEY INTO CNTRL TX. MEANWHILE...WEAK BACK DOOR FRONT INITIALLY FROM ERN KY/TN SEWD TO OFF THE NERN FL COAST WILL SLOWLY RETREAT EWD THROUGH THE PERIOD. ...OH AND TN VALLEYS INTO THE SERN STATES... CLUSTERS OF TSTMS ARE EXPECTED TO BE ONGOING AT THE ONSET OF THE FORECAST PERIOD OVER THE TN AND SRN OH VALLEYS WEDNESDAY MORNING DRIVEN LARGELY BY WAA ALONG WSWLY LLJ AXIS. THIS ACTIVITY WILL LIKELY CONTINUE EWD OR SEWD WEDNESDAY WITH SOME THREAT OF MARGINALLY SEVERE HAIL INTO THE CNTRL/SRN APPALACHIANS. A MODERATELY UNSTABLE AIR MASS /MLCAPES OF 1000-2000 J/KG/ IS EXPECTED TO DEVELOP BY AFTERNOON IN THE WAKE OF THIS ACTIVITY AHEAD OF COLD FRONT OWING TO MOIST BOUNDARY-LAYER CONDITIONS AND DIABATIC HEATING. WHILE LARGE-SCALE FORCING IS FORECAST TO REMAIN LARGELY NEUTRAL ACROSS REGION...A RELATIVELY WEAK CAP AND SUSTAINED FRONTAL CONVERGENCE SHOULD BE SUFFICIENT TO INITIATE MORE VIGOROUS SURFACE-BASED DEVELOPMENT BY AFTERNOON OVER MIDDLE TN AND SRN KY. ADDITIONAL STORMS WILL ALSO BE POSSIBLE SEWD ALONG RETREATING BOUNDARY OVER GA. 30-40 KTS OF WLY DEEP-LAYER SHEAR COUPLED WITH THE MODERATE INSTABILITY SHOULD SUPPORT SEVERE STORMS CAPABLE OF LARGE HAIL..DAMAGING WINDS AND PERHAPS A COUPLE OF TORNADOES. ...TX HILL COUNTRY AND EDWARDS PLATEAU... ENVIRONMENT IS EXPECTED TO BECOME INCREASINGLY SUPPORTIVE OF FEW DIURNAL SEVERE STORMS ALONG WRN EXTENSION OF STALLED FRONTAL BOUNDARY. HERE...DIABATIC HEATING AND MODEST BOUNDARY-LAYER MOISTURE WILL CONTRIBUTE TO A MODERATELY UNSTABLE AIR MASS WITH MLCAPES OF 1000-1500 J/KG. THE STRONG DAYTIME HEATING ALONG WITH FRONTAL CONVERGENCE AND PERHAPS SOME WEAK OROGRAPHIC FORCING SHOULD BE SUFFICIENT TO INITIATE DEEP MOIST CONVECTION BY LATE AFTERNOON OR EARLY EVENING. LARGELY UNIDIRECTIONAL 30-40 KT DEEP-LAYER SHEAR SUGGESTS THE POTENTIAL FOR ROTATING STORMS CAPABLE OF LARGE HAIL AND LOCALLY DAMAGING WINDS. MORE ELEVATED TSTM DEVELOPMENT WILL BECOME INCREASINGLY LIKELY N OF SURFACE FRONT WEDNESDAY NIGHT OVER THE CONCHO VALLEY/ERN PERMIAN BASIN EWD INTO CNTRL TX AS WAA AND ISENTROPIC ASCENT INCREASE ALONG STRENGTHENING SLY LLJ. SOME MARGINALLY SEVERE HAIL WILL BE POSSIBLE WITH THE STRONGEST STORMS. ...MS INTO ERN TX... DEWPOINTS IN THE 60S AND DAYTIME HEATING WILL SUPPORT MODERATE INSTABILITY S OF FRONT WEDNESDAY AFTERNOON WITH MLCAPES OF 1000-2000 J/KG. WEAK CAPPING AND FRONTAL CONVERGENCE SHOULD SUPPORT SCATTERED TSTM DEVELOPMENT BY MID AFTERNOON WITH SOME POTENTIAL FOR ISOLATED STRONG WIND GUSTS AND MARGINAL HAIL. THE PRIMARY FACTOR LIMITING A MORE ORGANIZED SEVERE THREAT APPEARS TO BE THE RATHER WEAK VERTICAL SHEAR. ..MEAD.. 04/18/2006  From SwoDy2 at goshenarc.org Tue Apr 18 17:38:10 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 18 Apr 2006 13:38:10 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 181734 SWODY2 SPC AC 181733 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1233 PM CDT TUE APR 18 2006 VALID 191200Z - 201200Z ...THERE IS A SLGT RISK OF SVR TSTMS WED/WED NIGHT ACROSS A LARGE PORTION OF THE GULF STATES INTO THE TENNESSEE VALLEY.... A ZONAL BELT OF WESTERLIES PERSISTS ACROSS THE FAR SOUTHERN TIER OF THE U.S...WHILE A BLOCK DEVELOPS IN A BRANCH OF THE POLAR WESTERLIES FROM THE NORTH CENTRAL U.S. INTO THE WESTERN ATLANTIC. A STRENGTHENING UPPER RIDGE IS EVIDENT IN LATEST WATER VAPOR IMAGERY NEAR JAMES BAY...WITH CLOSED LOWS DEVELOPING OFF THE NORTH ATLANTIC COAST...AND ACROSS THE NORTH CENTRAL PLAINS. MODELS SUGGEST LITTLE CHANGE TO THE LARGE-SCALE PATTERN WILL OCCUR THROUGH THIS FORECAST PERIOD...BUT THE RIDGE MAY BEGIN TO WEAKEN AS NORTHERN PLAINS CLOSED LOW SHIFTS TOWARD THE UPPER MISSISSIPPI VALLEY. THIS SEEMS LIKELY TO OCCUR MAINLY IN RESPONSE TO A SIGNIFICANT IMPULSE ROTATING AROUND THE SOUTHERN/EASTERN PERIPHERY OF THE CYCLONIC CIRCULATION. AMPLIFICATION OF AN UPPER TROUGH IS FORECAST UPSTREAM...OVER THE EASTERN PACIFIC...LATE WEDNESDAY INTO EARLY THURSDAY. THIS IS PROGGED TO FORCE A SOUTHERN BRANCH CLOSED LOW INLAND ACROSS THE LOWER COLORADO VALLEY/SOUTHERN PLATEAU BY 12Z THURSDAY...PERHAPS IN PHASE WITH AN IMPULSE IN THE WEAKER SUBTROPICAL STREAM. ...TEXAS THROUGH EASTERN GULF STATES/TENNESSEE VALLEY... A CLUSTER OF THUNDERSTORM ACTIVITY APPEARS LIKELY TO BE SPREADING INTO PARTS OF THE TENNESSEE VALLEY EARLY WEDNESDAY IN ASSOCIATION WITH AN EVOLVING ZONE OF STRONGER LOW-LEVEL WARM ADVECTION. THIS FORCING MAY BE ENHANCED BY A WEAK LOWER/MID TROPOSPHERIC IMPULSE EMBEDDED WITHIN BELT OF FLOW UNDERCUTTING BLOCK. MODELS SUGGEST THIS FEATURE WILL EVENTUALLY TURN SOUTHEASTWARD ACROSS THE SOUTHERN APPALACHIANS/SOUTH ATLANTIC COAST STATES...MERGING INTO CYCLONIC REGIME SOUTH OF NORTH ATLANTIC CLOSED LOW. WHILE A BROADER AREA OF CONVECTION SEEMS LIKELY TO SPREAD ABOVE LINGERING SURFACE RIDGING ACROSS PARTS OF THE SOUTH ATLANTIC COAST STATE...FORCING FOR ADDITIONAL ACTIVITY AHEAD OF STALLING UPSTREAM FRONT ACROSS THE LOWER MISSISSIPPI VALLEY IS MORE UNCERTAIN. HOWEVER...INHIBITION ACROSS PARTS OF THE TENNESSEE VALLEY AND NORTHERN GULF STATES MAY BECOME WEAKENED ENOUGH TO SUPPORT DEVELOPMENT OF THUNDERSTORMS BY WEDNESDAY AFTERNOON IN RESPONSE TO DAYTIME HEATING. MIXED BOUNDARY LAYER WITH MID/UPPER 60S DEW POINTS IS EXPECTED TO BECOME MODERATELY UNSTABLE...WITH CAPE IN EXCESS OF 2000 J/KG BY PEAK HEATING. THIS SHOULD BE SUFFICIENT FOR SCATTERED SEVERE STORMS. ISOLATED SUPERCELLS APPEAR POSSIBLE WHERE SHEAR PROFILES WILL BE MORE SUPPORTIVE NEAR 30 KT WESTERLY LOW-LEVEL JET AXIS...ACROSS PARTS OF FAR SOUTHERN TENNESSEE/NORTHERN ALABAMA INTO NORTHWEST GEORGIA. A TORNADO OR TWO IS POSSIBLE...BUT DAMAGING WIND GUSTS AND LARGE HAIL SEEM TO BE PRIMARY SEVERE THREATS. WIDELY SCATTERED STRONG/SEVERE THUNDERSTORMS APPEAR POSSIBLE FARTHER UPSTREAM...ALONG STALLED FRONT ACROSS SOUTHEAST TEXAS INTO THE HILL COUNTRY AND BIG BEND REGION. SOUTHEASTERLY SURFACE FLOW ACROSS AREAS TO THE EAST/SOUTHEAST OF DEL RIO WILL CONTRIBUTE TO ISOLATED SUPERCELL POTENTIAL BENEATH MODERATELY STRONG WESTERLY MID-LEVEL FLOW. THIS ACTIVITY SHOULD DIMINISH DURING THE EVENING...BUT ADDITIONAL...PERHAPS MORE WIDESPREAD...CONVECTIVE DEVELOPMENT IS EXPECTED WEDNESDAY NIGHT WITH APPROACH OF UPSTREAM SOUTHERN BRANCH TROUGH. THIS IS EXPECTED TO OCCUR IN ZONE OF STRONGER WARM ADVECTION...NORTH OF RETREATING SURFACE FRONT ACROSS CENTRAL TEXAS. CAPE OF 1000 TO 2000 J/KG FOR PARCELS BASED IN MOIST LAYER ABOVE FRONTAL INVERSION IS EXPECTED TO SUPPORT VIGOROUS UPDRAFTS WITH RISK OF LARGE HAIL. ..KERR.. 04/18/2006  From SwoDy2 at goshenarc.org Wed Apr 19 05:46:46 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 19 Apr 2006 01:46:46 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 190543 SWODY2 SPC AC 190542 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1242 AM CDT WED APR 19 2006 VALID 201200Z - 211200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM WRN TX EWD INTO THE SRN TN VALLEY AND CNTRL GULF COAST STATES... ...SYNOPSIS... AMPLIFIED LARGE-SCALE PATTERN WILL CONTINUE THROUGH THE DAY TWO PERIOD. MID AND UPPER-LEVEL LOW OVER THE UPPER MS VALLEY WILL SLOWLY TRANSLATE EWD INTO THE WRN GREAT LAKES...WHILE A MORE PROGRESSIVE SRN STREAM IS MAINTAINED ACROSS THE SRN TIER OF STATES. IN ADDITION TO VORTICITY MAXIMUM SHIFTING EWD FROM AZ/NM INTO TX/OK...OTHER MORE SUBTLE PERTURBATIONS MAY EXIST WITH WSWLY FLOW FROM THE ARKLATEX INTO THE TN VALLEY AND CNTRL GULF STATES. IN THE LOW-LEVELS...WEAK LOW PRESSURE IS FORECAST TO DEVELOP NEWD FROM THE LOWER MS VALLEY INTO THE UPPER OH VALLEY /LIKELY ASSOCIATED WITH A LEAD UPPER DISTURBANCE/ WITH TRAILING FRONTAL BOUNDARY STRETCHING SWWD THROUGH THE WRN TN VALLEY INTO WRN TX. THE WRN EXTENSION OF THIS BOUNDARY MAY ATTEMPT TO RETREAT SLIGHTLY NWD WITH APPROACH OF AZ/NM SHORT WAVE TROUGH...BEFORE PUSHING MORE SWD WITH THE PASSAGE OF THIS WAVE LATE WEDNESDAY NIGHT. ...TX INTO SRN OK... SLY LLJ...MAINTAINED BY DIRECT THERMAL CIRCULATION ASSOCIATED WITH ENTRANCE REGION OF UPPER JET STREAK OVER THE LOWER MO VALLEY...WILL LIKELY BE SUPPORTING CLUSTERS OF ELEVATED TSTMS WEDNESDAY MORNING OVER PORTIONS OF WRN AND NRN TX. THESE STORMS MAY PERSIST THROUGH THE DAY N OF SURFACE FRONT WITH SOME THREAT OF HAIL. MORE INTENSE SURFACE-BASED DEVELOPMENT IS ANTICIPATED BY AFTERNOON FROM THE CONCHO VALLEY AND PERMIAN BASIN INTO THE BIG COUNTRY WHERE DEWPOINTS IN THE 50S...COUPLED WITH STEEPENING LAPSE RATES WILL CONTRIBUTE TO MLCAPES OF 1000-1500 J/KG. IT APPEARS THAT THE SYNOPTIC FRONT...SHARPENING DRY LINE OVER SWRN TX AND RESIDUAL OUTFLOW BOUNDARIES WILL PROVIDE THE FOCUS FOR THIS MORE VIGOROUS STORM DEVELOPMENT. FORECAST SOUNDINGS INDICATE STRONGLY VEERING WIND PROFILES WITH 40-45 KTS OF SWLY DEEP-LAYER SHEAR WHICH SHOULD SUPPORT THE DEVELOPMENT OF A FEW SUPERCELLS CAPABLE OF MAINLY LARGE HAIL /SOME IT POSSIBLY SIGNIFICANT/. GIVEN THE EXPECTED W-E OR WSW-ENE ORIENTATION OF THE SYNOPTIC BOUNDARY...POTENTIAL WILL EXIST FOR A FEW TORNADOES WITH ANY MORE DISCRETE STORMS THAT CAN PROPAGATE ALONG THIS FEATURE WHERE LOW-LEVEL SHEAR WILL BE MAXIMIZED. SURFACE-BASED STORMS WITH A THREAT OF MAINLY HAIL AND HIGH WINDS ARE EXPECTED TO SPREAD INTO PORTIONS OF CNTRL AND NRN TX WEDNESDAY NIGHT. STRENGTHENING LLJ WILL ALSO SUPPORT A FEW SEVERE ELEVATED STORMS N OF FRONT INTO SRN OK WHERE LARGE HAIL WILL BE POSSIBLE. ...AR/LA EWD INTO TN VALLEY AND CNTRL GULF STATES... A MOIST LOW-LEVEL AIR MASS /DEWPOINTS IN THE 60S/ WILL LARGELY CONTRIBUTE TO THE DEVELOPMENT OF MODERATE AFTERNOON INSTABILITY FROM THE LOWER MS VALLEY EWD ACROSS THE GULF COAST INTO THE TN VALLEY /S OF WEAK FRONT/ WITH MLCAPES OF 1000-1500 J/KG. WHILE THE MAIN FOCUS FOR CONVECTIVE INITIATION IS SOMEWHAT UNCERTAIN...THERE IS SOME SUGGESTION THAT A LEAD IMPULSE MAY EXIST NEAR THE ARKLATEX WEDNESDAY MORNING...WHICH WILL MOVE NEWD INTO THE TN VALLEY BY AFTERNOON. SHOULD THIS SCENARIO OCCUR...A THREAT OF DAMAGING WINDS AND LARGE HAIL WILL EXIST WITH ANY ORGANIZED CLUSTER OR MCS THAT CAN DEVELOP AHEAD OF THIS IMPULSE. FARTHER S ACROSS CNTRL MS INTO CNTRL AL...THE ABSENCE OF ANY DISCERNABLE BOUNDARY MAKE THE INITIATION OF DEEP MOIST CONVECTION EVEN MORE UNCERTAIN. HOWEVER...FORECAST SOUNDINGS INDICATE THAT WEAK CAP SHOULD ERODE SUFFICIENTLY BY AFTERNOON SUCH THAT STORMS SHOULD DEVELOP ON ANY SMALL-SCALE BOUNDARIES PRESENT IN BROADER WARM SECTOR. GIVEN THE INITIATION AND MAINTENENCE OF STORMS...THE MODERATE INSTABILITY IN CONJUNCTION WITH A BELT OF 40-50 KT WLY MID-LEVEL FLOW DEVELOPING EWD ACROSS THE AREA WILL SUPPORT ORGANIZED/ROTATING STORMS WITH A THREAT OF LARGE HAIL AND DAMAGING WINDS. ..MEAD.. 04/19/2006  From SwoDy2 at goshenarc.org Wed Apr 19 06:01:05 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 19 Apr 2006 02:01:05 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 190557 SWODY2 SPC AC 190556 DAY 2 CONVECTIVE OUTLOOK CORR 1 NWS STORM PREDICTION CENTER NORMAN OK 1256 AM CDT WED APR 19 2006 VALID 201200Z - 211200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM WRN TX EWD INTO THE SRN TN VALLEY AND CNTRL GULF COAST STATES... CORRECTED FOR INCORRECT DAY REFERENCE ...SYNOPSIS... AMPLIFIED LARGE-SCALE PATTERN WILL CONTINUE THROUGH THE DAY TWO PERIOD. MID AND UPPER-LEVEL LOW OVER THE UPPER MS VALLEY WILL SLOWLY TRANSLATE EWD INTO THE WRN GREAT LAKES...WHILE A MORE PROGRESSIVE SRN STREAM IS MAINTAINED ACROSS THE SRN TIER OF STATES. IN ADDITION TO VORTICITY MAXIMUM SHIFTING EWD FROM AZ/NM INTO TX/OK...OTHER MORE SUBTLE PERTURBATIONS MAY EXIST WITH WSWLY FLOW FROM THE ARKLATEX INTO THE TN VALLEY AND CNTRL GULF STATES. IN THE LOW-LEVELS...WEAK LOW PRESSURE IS FORECAST TO DEVELOP NEWD FROM THE LOWER MS VALLEY INTO THE UPPER OH VALLEY /LIKELY ASSOCIATED WITH A LEAD UPPER DISTURBANCE/ WITH TRAILING FRONTAL BOUNDARY STRETCHING SWWD THROUGH THE WRN TN VALLEY INTO WRN TX. THE WRN EXTENSION OF THIS BOUNDARY MAY ATTEMPT TO RETREAT SLIGHTLY NWD WITH APPROACH OF AZ/NM SHORT WAVE TROUGH...BEFORE PUSHING MORE SWD WITH THE PASSAGE OF THIS WAVE LATE THURSDAY NIGHT. ...TX INTO SRN OK... SLY LLJ...MAINTAINED BY DIRECT THERMAL CIRCULATION ASSOCIATED WITH ENTRANCE REGION OF UPPER JET STREAK OVER THE LOWER MO VALLEY...WILL LIKELY BE SUPPORTING CLUSTERS OF ELEVATED TSTMS THURSDAY MORNING OVER PORTIONS OF WRN AND NRN TX. THESE STORMS MAY PERSIST THROUGH THE DAY N OF SURFACE FRONT WITH SOME THREAT OF HAIL. MORE INTENSE SURFACE-BASED DEVELOPMENT IS ANTICIPATED BY AFTERNOON FROM THE CONCHO VALLEY AND PERMIAN BASIN INTO THE BIG COUNTRY WHERE DEWPOINTS IN THE 50S...COUPLED WITH STEEPENING LAPSE RATES WILL CONTRIBUTE TO MLCAPES OF 1000-1500 J/KG. IT APPEARS THAT THE SYNOPTIC FRONT...SHARPENING DRY LINE OVER SWRN TX AND RESIDUAL OUTFLOW BOUNDARIES WILL PROVIDE THE FOCUS FOR THIS MORE VIGOROUS STORM DEVELOPMENT. FORECAST SOUNDINGS INDICATE STRONGLY VEERING WIND PROFILES WITH 40-45 KTS OF SWLY DEEP-LAYER SHEAR WHICH SHOULD SUPPORT THE DEVELOPMENT OF A FEW SUPERCELLS CAPABLE OF MAINLY LARGE HAIL /SOME IT POSSIBLY SIGNIFICANT/. GIVEN THE EXPECTED W-E OR WSW-ENE ORIENTATION OF THE SYNOPTIC BOUNDARY...POTENTIAL WILL EXIST FOR A FEW TORNADOES WITH ANY MORE DISCRETE STORMS THAT CAN PROPAGATE ALONG THIS FEATURE WHERE LOW-LEVEL SHEAR WILL BE MAXIMIZED. SURFACE-BASED STORMS WITH A THREAT OF MAINLY HAIL AND HIGH WINDS ARE EXPECTED TO SPREAD INTO PORTIONS OF CNTRL AND NRN TX THURSDAY NIGHT. STRENGTHENING LLJ WILL ALSO SUPPORT A FEW SEVERE ELEVATED STORMS N OF FRONT INTO SRN OK WHERE LARGE HAIL WILL BE POSSIBLE. ...AR/LA EWD INTO TN VALLEY AND CNTRL GULF STATES... A MOIST LOW-LEVEL AIR MASS /DEWPOINTS IN THE 60S/ WILL LARGELY CONTRIBUTE TO THE DEVELOPMENT OF MODERATE AFTERNOON INSTABILITY FROM THE LOWER MS VALLEY EWD ACROSS THE GULF COAST INTO THE TN VALLEY /S OF WEAK FRONT/ WITH MLCAPES OF 1000-1500 J/KG. WHILE THE MAIN FOCUS FOR CONVECTIVE INITIATION IS SOMEWHAT UNCERTAIN...THERE IS SOME SUGGESTION THAT A LEAD IMPULSE MAY EXIST NEAR THE ARKLATEX THURSDAY MORNING...WHICH WILL MOVE NEWD INTO THE TN VALLEY BY AFTERNOON. SHOULD THIS SCENARIO OCCUR...A THREAT OF DAMAGING WINDS AND LARGE HAIL WILL EXIST WITH ANY ORGANIZED CLUSTER OR MCS THAT CAN DEVELOP AHEAD OF THIS IMPULSE. FARTHER S ACROSS CNTRL MS INTO CNTRL AL...THE ABSENCE OF ANY DISCERNABLE BOUNDARY MAKE THE INITIATION OF DEEP MOIST CONVECTION EVEN MORE UNCERTAIN. HOWEVER...FORECAST SOUNDINGS INDICATE THAT WEAK CAP SHOULD ERODE SUFFICIENTLY BY AFTERNOON SUCH THAT STORMS SHOULD DEVELOP ON ANY SMALL-SCALE BOUNDARIES PRESENT IN BROADER WARM SECTOR. GIVEN THE INITIATION AND MAINTENENCE OF STORMS...THE MODERATE INSTABILITY IN CONJUNCTION WITH A BELT OF 40-50 KT WLY MID-LEVEL FLOW DEVELOPING EWD ACROSS THE AREA WILL SUPPORT ORGANIZED/ROTATING STORMS WITH A THREAT OF LARGE HAIL AND DAMAGING WINDS. ..MEAD.. 04/19/2006  From SwoDy2 at goshenarc.org Thu Apr 20 05:30:54 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Thu, 20 Apr 2006 01:30:54 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 200527 SWODY2 SPC AC 200526 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1226 AM CDT THU APR 20 2006 VALID 211200Z - 221200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM SE TX INTO THE CNTRL AND SRN APPALACHIANS...EWD INTO CENTRAL PARTS OF VA...NC AND SC... ...SYNOPSIS... SRN STREAM SHORT WAVE TROUGH OVER THE ARKLATEX FRIDAY MORNING WILL PHASE WITH UPPER LOW OVER THE GREAT LAKES...WITH FULL LATITUDE TROUGH EVOLVING E OF THE MS VALLEY DURING THE LATTER HALF OF THE FORECAST PERIOD. IN THE LOW-LEVELS...SURFACE LOW ASSOCIATED WITH THE SRN STREAM WAVE INITIALLY OVER AR WILL DEVELOP RAPIDLY NEWD ALONG BAROCLINIC ZONE INTO THE UPPER OH VALLEY BY FRIDAY EVENING. TRAILING COLD FRONT WILL PUSH EWD THROUGH THE LOWER MS AND TN VALLEYS AND CNTRL GULF COAST...WITH NAM AND ENSEMBLE MEAN FORECASTS INDICATING THE DEVELOPMENT A SECONDARY SURFACE LOW WHICH WILL TRACK MORE EWD ACROSS NRN MS/AL INTO NRN GA OR ERN TN BY FRIDAY NIGHT. ...SERN TX EWD TO THE CNTRL / SRN APPALACHIANS... CONSIDERABLE TSTM ACTIVITY IS EXPECTED TO BE ONGOING AT THE ONSET OF THE PERIOD FROM VICINITY OF SURFACE LOW OVER AR ENEWD WITHIN WAA REGIME INTO THE TN VALLEY...AS WELL AS ALONG TRAILING COLD FRONT INTO ERN TX. CONSIDERABLE CLOUDINESS ACROSS WARM SECTOR WILL TEND TO LIMIT DAYTIME HEATING...THOUGH BOUNDARY-LAYER SHOULD REMAIN MOIST WITH DEWPOINTS IN THE 60S...WHICH WILL LARGELY CONTRIBUTE TO POCKETS OF MODERATE INSTABILITY WITH MLCAPES APPROACHING 1000-1500 J/KG. SEVERE THREAT SHOULD INCREASE FROM LATE MORNING THROUGH THE AFTERNOON AS HEIGHT FALLS ASSOCIATED WITH INTENSIFYING TROUGH BEGIN TO OVERSPREAD DESTABILIZING WARM SECTOR ACROSS THE LOWER MS INTO TN VALLEYS. STRONGEST STORMS WILL LIKELY OCCUR NEAR INITIAL SURFACE LOW DEVELOPING NEWD ALONG BAROCLINIC ZONE...AS WELL AS ALONG SECONDARY LOW TRACK OVER MS/AL WHERE STRONGER INSTABILITY IS FORECAST. LOCALLY STRONGER LOW-LEVEL SHEAR NEAR THESE SURFACE LOWS WILL ENHANCE THE POTENTIAL FOR SUPERCELLS CAPABLE OF TORNADOES...DAMAGING WINDS AND PERHAPS SOME HAIL. OTHERWISE...MAIN SEVERE THREAT SHOULD BE ASSOCIATED WITH BOWS AND OTHER EMBEDDED MORE INTENSE LINE SEGMENTS. THIS SEVERE THREAT SHOULD DIMINISH LATE FRIDAY EVENING OVER THE CNTRL APPALACHIANS INTO UPPER OH VALLEY AS AIR MASS COOLS AND STABILIZES. FARTHER S...SEVERE THREAT MAY CONTINUE OVERNIGHT INTO GA AND THE WRN FL PNHDL. ...VA / NC / SC... RETREAT OF WARM FRONT NWD INTO THE MIDDLE ATLANTIC STATES WILL ALLOW AIR MASS TO DESTABILIZE IN THE LEE OF THE APPALACHIANS WITH DEWPOINTS INCREASING INTO THE 60S...SUPPORTING MLCAPES OF AROUND 1000 J/KG. INCREASING LOW-LEVEL WAA AHEAD OF EVOLVING MID-LEVEL TROUGH COUPLED WITH BROAD LOW-LEVEL CONFLUENCE AND PERHAPS OROGRAPHIC FORCING SHOULD ALL CONTRIBUTE TO AN INCREASE IN TSTM COVERAGE THROUGH THE DAY. ISALLOBARIC RESPONSE TO DEEPENING SURFACE LOW W OF THE MOUNTAINS WILL EFFECTIVELY BACK LOW-LEVEL SURFACE WINDS...RESULTING IN VERTICAL SHEAR PROFILES EXHIBITING STRONG VEERING WITH HEIGHT. INITIALLY...MID AND HIGH-LEVEL WIND FIELDS WILL BE MARGINALLY STRONG FOR ORGANIZED...SEVERE STORMS...THOUGH THEY ARE FORECAST TO INCREASE THROUGH THE AFTERNOON INTO EVENING. THREAT WILL EXIST FOR A COUPLE BRIEF TORNADOES IN ADDITION TO DAMAGING WINDS AND PERHAPS SOME HAIL. ..MEAD.. 04/20/2006  From SwoDy2 at goshenarc.org Thu Apr 20 17:20:09 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Thu, 20 Apr 2006 13:20:09 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 201716 SWODY2 SPC AC 201715 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1215 PM CDT THU APR 20 2006 VALID 211200Z - 221200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE WRN GULF STATES INTO THE SRN APPALACHIANS... ...WRN GULF COAST TO SRN APPALACHIANS... SRN ROCKIES SHORTWAVE TROUGH WILL SHIFT EAST ACROSS TX MAINTAINING SIGNIFICANT SEPARATION WITH UPPER LOW OVER THE GREAT LAKES REGION. THIS FEATURE WILL UNDOUBTEDLY AID UPWARD ASCENT ALONG SW-NE ORIENTED FRONTAL ZONE FROM THE UPPER TX COAST INTO THE SRN APPALACHIANS. EARLY IN THE PERIOD...IT APPEARS ONE OR MORE CONCENTRATED CLUSTERS OF THUNDERSTORMS WILL BE ONGOING FROM LATE DAY1 ACTIVITY IMMEDIATELY AHEAD OF SHORTWAVE TROUGH FROM THE MIDDLE TX COAST INTO THE ARKLATEX REGION. BOUNDARY LAYER HEATING AHEAD OF CONVECTIVE OUTFLOW/SFC FRONT SHOULD ENHANCE INSTABILITY FOR RENEWED THUNDERSTORM DEVELOPMENT/INTENSIFICATION DURING THE MID DAY HOURS. STORM MODE SHOULD BE MODULATED SIGNIFICANTLY BY CONVECTIVE OUTFLOW AND MODEST SHEAR...SEEMINGLY SUPPORTIVE OF LINE SEGMENT-TYPE BANDS. AS A RESULT...CONSIDERABLE AMOUNT OF CONVECTION SHOULD SPREAD ACROSS PORTIONS OF THE WRN GULF STATES INTO ERN TN DURING THE AFTERNOON HOURS WITH DAMAGING WINDS AND LARGE HAIL THE MOST LIKELY SEVERE THREATS. ..DARROW.. 04/20/2006  From SwoDy2 at goshenarc.org Fri Apr 21 06:25:02 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Fri, 21 Apr 2006 02:25:02 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 210621 SWODY2 SPC AC 210620 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0120 AM CDT FRI APR 21 2006 VALID 221200Z - 231200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE MIDDLE AND SRN ATLANTIC STATES... ...MID-SRN ATLANTIC STATES... SRN HIGH PLAINS SHORT WAVE TROUGH MOVING EWD DAY 1 PERIOD SHOULD BE LOCATED ACROSS THE CENTRAL GULF COAST STATES AT 12Z SATURDAY. THIS TROUGH IS THEN EXPECTED TO BECOME SLIGHTLY NEGATIVELY TILTED AS IT TRACKS NEWD IN LEE OF THE SRN/CENTRAL APPALACHIANS... REACHING THE DELMARVA REGION BY 12Z SUNDAY. SURFACE LOW ASSOCIATED WITH THIS SRN STREAM TROUGH SHOULD BE LOCATED OVER THE UPPER TN VALLEY AT THE START OF THE PERIOD...AND THEN TRACK NEWD ACROSS WRN NC/WRN VA SATURDAY AFTERNOON...REACHING ERN VA TO DEL LATE IN THE PERIOD. COLD FRONT TRAILING SWD ACROSS WRN GA TO THE FL PANHANDLE AND THEN OFFSHORE WILL MOVE ENEWD ACROSS THE SERN AND MID-ATLANTIC STATES... AND SHOULD EXTEND FROM SERN VA/ERN NC SWWD TO THE CENTRAL FL PENINSULA BY THE BEGINNING OF DAY 3. THUNDERSTORMS...SOME POTENTIALLY SEVERE...ARE EXPECTED TO BE ONGOING EARLY SATURDAY SWD FROM THE SURFACE LOW ALONG THE COLD FRONT. EXTENSIVE CLOUDINESS DOWNSTREAM ACROSS THE WARM SECTOR MAY LIMIT SURFACE HEATING. HOWEVER...LOW-LEVEL MOISTURE ADVECTION ACROSS ERN GA/CAROLINAS INTO SRN VA WITH SURFACE DEWPOINTS IN THE MID 60S BENEATH MODEST LAPSE RATES SHOULD CONTRIBUTE TO MUCAPES AROUND AT LEAST 1000 J/KG...WITH POCKETS OF HIGHER INSTABILITY POSSIBLE. ONGOING ACTIVITY SHOULD INCREASE IN INTENSITY/COVERAGE AS THE COLD FRONT SPREADS ENE INTO THE GREATER INSTABILITY ACROSS THE PIEDMONT AND COASTAL PLAINS OF SC/NC/VA BY SATURDAY AFTERNOON. SSWLY UNI-DIRECTIONAL WIND PROFILES WITH SHEAR VECTORS ORIENTED NEARLY PARALLEL TO THE SURFACE FRONT SUGGEST A LINEAR MODE WITH BOWING SEGMENTS. BACKED LOW-LEVEL FLOW ALONG THE TRACK OF THE SURFACE LOW SHOULD RESULT IN STRONGER DEEP LAYER SHEAR VALUES FOR SUPERCELLS. THUS...A FEW TORNADOES...DAMAGING WINDS...AND HAIL WILL BE POSSIBLE. FARTHER S ACROSS SERN GA/FL PENINSULA...DESPITE LOW-LEVEL FLOW VEERING IN ADVANCE OF THE FRONT IN GA/NRN FL...STRONG INSTABILITY AND MODERATE DEEP LAYER SHEAR SHOULD SUPPORT MULTICELLS WITH A THREAT FOR HAIL/DAMAGING WINDS. SEA BREEZE BOUNDARY IS EXPECTED TO BE THE FOCUS FOR THUNDERSTORMS SATURDAY AFTERNOON ACROSS THE NRN/CENTRAL FL PENINSULA WITH SIMILAR CAPE/SHEAR VALUES SUPPORTING A THREAT FOR HAIL/DAMAGING WINDS. ...SRN HIGH PLAINS... MODELS DIFFER WITH THE AMOUNT OF MOISTURE RETURN INTO SWRN-WRN TX/ SERN NM SATURDAY AFTERNOON. GFS INDICATED THE STRONGEST SIGNAL SUPPORTING AN AXIS OF MODERATE INSTABILITY ACROSS THIS REGION. DESPITE THE UNCERTAINTY IN MOISTURE RETURN...THIS OUTLOOK WILL MAINTAIN LOW SEVERE PROBABILITIES SINCE INCREASING SWLY MID-LEVEL FLOW ATOP A STRENGTHENING SSELY LLJ BY EARLY EVENING WOULD RESULT SUFFICIENT DEEP LAYER SHEAR FOR ORGANIZED STORMS WITH ANY ACTIVITY THAT CAN DEVELOP. FURTHER STRENGTHENING OF THE LLJ WITH ACCOMPANYING MOISTURE ADVECTION MAY SUPPORT WIDELY SCATTERED THUNDERSTORMS SATURDAY NIGHT ACROSS PARTS OF THE SRN PLAINS... POTENTIALLY REACHING SRN MO. ..PETERS.. 04/21/2006  From SwoDy2 at goshenarc.org Fri Apr 21 17:32:37 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Fri, 21 Apr 2006 13:32:37 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 211728 SWODY2 SPC AC 211727 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1227 PM CDT FRI APR 21 2006 VALID 221200Z - 231200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE MIDDLE AND SRN ATLANTIC COASTAL STATES... ...SYNOPSIS... LARGE MID/UPPER TROUGH WILL PROGRESS SLOWLY EWD ACROSS THE WRN U.S. THIS PERIOD...WHILE SECOND TROUGH -- COMPRISED OF A DEEP UPPER LOW OVER THE GREAT LAKES REGION AND A MORE PROGRESSIVE SRN STREAM SHORT-WAVE TROUGH OVER THE SOUTHEAST -- ALSO MOVES EWD THROUGH THE PERIOD. THOUGH SCATTERED THUNDERSTORMS ARE EXPECTED ACROSS THE WRN U.S. AHEAD OF UPPER TROUGH...MAIN SEVERE THREAT THIS PERIOD SHOULD EXIST OVER THE ATLANTIC COASTAL STATES AHEAD OF ERN TROUGH/COLD FRONT. ...SRN AND MIDDLE ATLANTIC COASTAL REGION... WIDESPREAD PRECIPITATION/THUNDERSTORMS WILL LIKELY BE ONGOING AT THE START OF THE PERIOD ALONG AND E OF THE APPALACHIANS...AHEAD OF EWD-MOVING COLD FRONT AND ASSOCIATED SHORT-WAVE TROUGH CROSSING THE CENTRAL AND SRN APPALACHIANS REGION EARLY IN THE PERIOD. WIDESPREAD CLOUDS/PRECIPITATION SHOULD LIMIT HEATING/DESTABILIZATION E OF THE MOUNTAINS TO A GREAT DEGREE...THOUGH AT LEAST MARGINAL INSTABILITY /500 TO 1000 J/KG MEAN-LAYER CAPE/ IS EXPECTED BY EARLY AFTERNOON...SUPPORTED BY MOIST BOUNDARY LAYER. THIS SHOULD RESULT IN AN INCREASE/INTENSIFICATION OF STORMS AHEAD OF BOUNDARY FROM MIDDAY THROUGH THE AFTERNOON AS CONVECTION SPREADS EWD TOWARD THE ATLANTIC COAST. THOUGH FORECAST TO BE FAIRLY UNIDIRECTIONAL/MERIDIONAL...DEEP-LAYER WIND FIELD WILL BE MODERATELY STRONG/SUFFICIENT FOR ORGANIZED CONVECTION. WHERE POCKETS OF GREATER INSTABILITY CAN DEVELOP...EXPECT STORMS TO BECOME SEVERE...WITH HAIL AND LOCALLY DAMAGING WINDS POSSIBLE -- AND PERHAPS A TORNADO. THREAT MAY CONTINUE INTO THE EVENING -- PARTICULARLY ACROSS THE ERN CAROLINAS...BEFORE STORMS DIURNALLY WEAKEN/MOVE OFFSHORE. ...FL... STORMS ARE FORECAST TO DEVELOP ACROSS ERN FL -- MAINLY OVER COASTAL AREAS AS WLY/SWLY LOW-LEVEL FLOW OVER THE PENINSULA AHEAD OF FRONT SUGGESTS THAT MAIN ZONE OF LOW-LEVEL CONVERGENCE WILL EVOLVE IN ASSOCIATION WITH E COAST SEA BREEZE BOUNDARIES. SUFFICIENT SHEAR AND INSTABILITY WILL EXIST FOR STRONG/LOCALLY SEVERE STORMS...ALONG WITH ACCOMPANYING THREAT FOR MARGINAL HAIL/LOCALLY DAMAGING WINDS...AND POSSIBLY AN ISOLATED TORNADO NEAR SURFACE BOUNDARIES. ..GOSS.. 04/21/2006  From SwoDy2 at goshenarc.org Sat Apr 22 06:17:52 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 22 Apr 2006 02:17:52 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 220612 SWODY2 SPC AC 220611 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0111 AM CDT SAT APR 22 2006 VALID 231200Z - 241200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS CENTRAL PLAINS TO LOWER OH/TN VALLEYS... ...SYNOPSIS... UPPER TROUGH/CLOSED LOW MOVING INLAND OVER CA AT THIS TIME PER WATER VAPOR IMAGERY WILL CONTINUE TO UNDERGO FURTHER WEAKENING ON SUNDAY AS IT MOVES SLOWLY NEWD ACROSS THE GREAT BASIN AND NRN INTERMOUNTAIN REGION. MEANWHILE...SRN PART OF TROUGH OVER CENTRAL CANADA WILL MOVE INTO THE DAKOTAS/UPPER MS VALLEY...WITH DOWNSTREAM CLOSED LOW MOVING SLOWLY NEWD ACROSS THE LOWER GREAT LAKES/CENTRAL APPALACHIANS. IN THE LOW-LEVELS...WEAK SURFACE LOW ASSOCIATED WITH GREAT LAKES CLOSED LOW WILL TRACK SLOWLY NEWD...WITH TRAILING SURFACE FRONT MOVING EWD ACROSS NY/PA/CENTRAL APPALACHIANS ON SUNDAY. THE REMAINING PORTION OF THIS BOUNDARY EXTENDING FROM THE OH VALLEY WWD THROUGH CENTRAL MO TO CENTRAL KS...AND THEN WNWWD INTO HIGH PLAINS OF NERN CO/SERN WY EXPECTED TO REMAIN QUASI-STATIONARY THROUGH THE PERIOD. DRY LINE IS EXPECTED TO MIX EWD AND SHOULD EXTEND FROM SWRN KS INTO FAR WRN OK TO PARTS OF WRN TX. ...CENTRAL PLAINS INTO MO... ELEVATED THUNDERSTORMS SHOULD BE ONGOING AT THE START OF THE PERIOD FROM ERN KS ESEWD INTO CENTRAL/SRN MO TO LOWER OH VALLEY WITHIN WAA REGIME ALONG NOSE OF STRONG W/SWLY LLJ. THIS ACTIVITY SHOULD GRADUALLY WEAKEN SUNDAY MORNING AS STRENGTH OF LLJ DECREASES... THOUGH WAA N OF SURFACE BOUNDARY MAY REMAIN SUFFICIENT FOR ELEVATED THUNDERSTORMS SUNDAY MORNING/AFTERNOON FROM PARTS OF NRN HIGH PLAINS SEWD INTO NEB. WEAK INSTABILITY WITH THIS LATTER ACTIVITY SHOULD LIMIT THE SEVERE THREAT. MEANWHILE...MOISTURE RETURN WILL CONTINUE ACROSS THE SRN/CENTRAL PLAINS WITH SURFACE DEWPOINTS IN THE LOWER-MID 60S ALONG/S OF SURFACE BOUNDARY FROM FAR SWRN NEB SEWD TO CENTRAL MO AND WRN KY/TN. ELEVATED MIXED LAYER /STEEP MID-LEVEL LAPSE RATES 7.5+ C/KM/ SPREADING EWD ACROSS MUCH OF THE CENTRAL/SRN PLAINS TO LOWER TN/MS VALLEYS DAY 1 WILL REMAIN IN PLACE DAY 2. IN ADDITION TO CONTRIBUTING TO A MODERATE-VERY UNSTABLE WARM SECTOR...THIS EML SHOULD EFFECTIVELY CAP THE WARM SECTOR INTO THE MID-LATE AFTERNOON...ESPECIALLY SWD ALONG DRY LINE. WEAK MID-LEVEL IMPULSES EMANATING FROM WRN STATES TROUGH ARE EXPECTED TO MOVE EWD ACROSS THE PLAINS TOWARD THE MID MS VALLEY. LARGE SCALE ASCENT WITH THESE FEATURES AND HEIGHT FALLS ACROSS THE NRN/CENTRAL PLAINS IN ADVANCE OF CANADIAN TROUGH ARE EXPECTED TO SUPPORT THUNDERSTORM DEVELOPMENT BY MID-LATE AFTERNOON ALONG THE SURFACE BOUNDARY FROM SERN WY INTO CENTRAL KS. INCREASING WLY MID-LEVEL WINDS ATOP STRENGTHENING CENTRAL/SRN PLAINS SLY LLJ BY LATE SUNDAY AFTERNOON WILL RESULT IN STRONG DEEP LAYER SHEAR SUPPORTING SUPERCELLS CAPABLE OF PRODUCING TORNADOES...LARGE HAIL...AND DAMAGING WINDS. FURTHER STRENGTHENING AND EVENTUAL VEERING OF LLJ EXPECTED TO RESULT IN UPSCALE GROWTH OF AFTERNOON/EVENING STORMS INTO AN MCS MOVING EWD INTO ERN KS/MO SUNDAY NIGHT WITH CONTINUED THREAT FOR DAMAGING WINDS/HAIL. ...OH/TN VALLEYS... DESPITE RATHER WEAK CONVERGENCE ALONG THE SURFACE BOUNDARY...THE COMBINATION OF INCREASING MOISTURE/INSTABILITY AND STRONG DEEP LAYER SHEAR GIVEN NWLY MID-LEVEL FLOW ATOP WLY LLJ EXPECTED TO SUPPORT WIDELY SCATTERED STRONG TO SEVERE STORMS. PRIMARY THREATS SHOULD BE DAMAGING WINDS AND HAIL WITH THE STRONGEST ACTIVITY. THESE STORMS ARE EXPECTED TO WEAKEN SUNDAY EVENING AS THE BOUNDARY LAYER STABILIZES WITH THE LOSS OF DAYTIME HEATING. ...PARTS OF NY/PA/WV/VA/MD... COLD MID-LEVEL TEMPERATURES -20 TO -26 C AT 500 MB WITH THE CLOSED LOW WILL STEEPEN LAPSE RATES CONTRIBUTING TO WEAK INSTABILITY IN ADVANCE OF THE SURFACE TROUGH MOVING EWD ACROSS THIS REGION SUNDAY. LARGE SCALE ASCENT WITHIN EXIT REGION OF 60-70 KT JET ROUNDING BASE OF UPPER SYSTEM WILL SUPPORT THUNDERSTORM DEVELOPMENT ALONG EXTENT OF SURFACE BOUNDARY. STRONG DEEP LAYER SHEAR SUGGESTS STORMS WILL BE ORGANIZED...BUT WEAK INSTABILITY SHOULD LIMIT SEVERE COVERAGE. ..PETERS.. 04/22/2006  From SwoDy2 at goshenarc.org Sat Apr 22 17:40:20 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 22 Apr 2006 13:40:20 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 221736 SWODY2 SPC AC 221735 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1235 PM CDT SAT APR 22 2006 VALID 231200Z - 241200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE CNTRL HIGH PLAINS TO THE TN VLY... ...SYNOPSIS... COMPLEX UPPER FLOW REGIME WILL CONTINUE ON SUNDAY WITH CLOSED LOWS MOVING SLOWLY ACROSS THE NERN STATES AND THE DESERT SW AND A WEAKER NRN STREAM TROUGH SKIRTING THE NRN PLAINS. AT THE SURFACE...AN OCCLUDED LOW OVER THE LWR GRTLKS WILL TRACK NEWD WITH ITS TRAILING FRONT MOVING SEWD ACROSS THE MID-ATLANTIC REGION. WRN EXTENT OF THIS BOUNDARY WILL STALL ACROSS THE TN VLY...OZARKS AND CNTRL PLAINS THROUGH SUNDAY EVENING. A LEE-LOW OVER ERN CO WILL STRENGTHEN AND MOVE ALONG THE FRONT INTO SWRN KS BY LATE SUNDAY AFTN WITH A DRYLINE EXTENDING SWD INTO THE ERN TX PNHDL AND SWRN TX. ...CNTRL PLAINS TO THE TN VLY... LOW-LEVEL MSTR WILL CONTINUE TO ADVECT NWD BENEATH THE ELEVATED MIXED LAYER THROUGH THE SRN/CNTRL PLAINS THROUGH SUNDAY EVENING. THIS WILL CONTRIBUTE TO A VERY UNSTABLE AIR MASS ACROSS CNTRL KS ALONG/S OF THE BAROCLINIC ZONE AND AHEAD OF THE TRIPLE POINT LOW. HEATING...LOW-LEVEL CONVERGENCE AND WEAK LARGE SCALE HEIGHT FALLS IN ADVANCE OF THE SWRN STATES CYCLONE WILL AID IN WEAKENING CINH. TSTM INITIATION IS LIKELY VCNTY THE TRIPLE POINT DURING THE LATE AFTN. VERTICAL SHEAR...THOUGH SOMEWHAT WEAK EARLY IN THE DAY...WILL INCREASE DURING THE EVENING AND BE SUFFICIENT FOR SUPERCELLS WITH VERY LARGE HAIL. TORNADOES WILL BE POSSIBLE... ESPECIALLY ACROSS CNTRL KS ALONG THE BAROCLINIC ZONE WHERE LOW-LEVEL TURNING WILL BE THE STRONGEST. ACTIVITY SHOULD GROW UPSCALE INTO A FORWARD PROPAGATING MCS DURING THE EVENING AND MOVE ESEWD ACROSS ECNTRL/SERN KS INTO SRN MO WITH DAMAGING WINDS BECOMING THE PRIMARY SEVERE THREAT OVERNIGHT. ISOLD TSTMS MAY DEVELOP SWD THE LENGTH OF THE DRYLINE INTO W TX SUNDAY EVENING...THOUGH THE CAP SHOULD REMAIN STRONG. THE SW TX MOUNTAINS AND AREAS FROM ERN TX PNHDL INTO SCNTRL KS APPEAR TO BE THE MOST FAVORABLE AREAS FOR POSSIBLE ISOLD DEVELOPMENT. SUPERCELLS WILL BE POSSIBLE WITH LARGE HAIL THE PRIMARY THREAT. ...CNTRL HIGH PLAINS... AS THE PLAINS SFC LOW DEEPENS...NELY UPSLOPE FLOW WILL INCREASE SUNDAY EVENING ACROSS THE CNTRL HIGH PLAINS BENEATH INCREASING SWLY FLOW ALOFT. SUFFICIENT LOW-LEVEL MOISTURE SHOULD EXIST TO BOOST CAPE VALUES AND SUPPORT A FEW TSTMS ALONG THE FRONT RANGE AND ADJACENT PLAINS. VERTICAL SHEAR WILL SUPPORT ORGANIZED STORMS WITH PERHAPS LARGE HAIL. ...MID-ATLANTIC REGION... BAND OF MODEST H5 FLOW ALONG SRN PERIPHERY OF THE LWR GRTLKS UPPER LOW AND FAVORABLY COLD MID-LEVEL TEMPERATURES MAY BE SUFFICIENT FOR A BAND OR TWO OF STRONG THUNDERSTORMS ACROSS THE MID-ATLANTIC REGION SUNDAY. ISOLD DAMAGING WINDS/HAIL MAY ACCOMPANY THE STRONGER STORMS. ...OH/TN VLYS... E-W ORIENTED SFC BOUNDARY WILL LIKELY BE THE FOCUS FOR SPORADIC CLUSTERS OF TSTMS DESPITE THE OVERALL WEAK MASS CONVERGENCE. BUT...SUSTAINED SSWLY MOIST INFLOW AND MODEST FLOW ALOFT WILL LIKELY SUPPORT SCATTERED STRONG-SEVERE TSTMS...MAINLY ALONG WRN PORTIONS OF THE FRONT VCNTY STEEPER MID-LEVEL LAPSE RATES. LARGE HAIL AND DAMAGING WIND WILL BE THE PRIMARY SEVERE THREATS...WITH THE SEVERE THREATS DIMINISHING OVERNIGHT. ..RACY.. 04/22/2006  From SwoDy2 at goshenarc.org Sun Apr 23 06:19:36 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 23 Apr 2006 02:19:36 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 230615 SWODY2 SPC AC 230614 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0114 AM CDT SUN APR 23 2006 VALID 241200Z - 251200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE SRN PLAINS TO THE LOWER OH VALLEY... ...SYNOPSIS... LARGE WRN STATES UPPER TROUGH...THOUGH WEAKENING WITH TIME...WILL MOVE NE TOWARD ROCKIES/HIGH PLAINS...WITH SHORT WAVE TROUGH WITHIN BASE OF THIS SYSTEM APPROACHING CENTRAL/SRN HIGH PLAINS BY 12Z TUESDAY. HEIGHT FALLS WITH APPROACH OF WRN TROUGH AND ALSO WITH STRONGER UPPER TROUGH DIGGING SEWD ACROSS THE GREAT LAKES AND MID MS/OH VALLEYS EXPECTED TO EFFECTIVELY BREAK DOWN RIDGE OVER CENTRAL/SRN PLAINS. BAND OF 40-50 KT WSWLY FLOW SHOULD EXTEND FROM SWRN STATES ACROSS THE SRN PLAINS TO OH/TN VALLEY AND MID-ATLANTIC STATES. MID/UPPER LEVEL CONFLUENT FLOW REGIME TRANSLATING SEWD ALONG MID/ LOWER MO VALLEY WILL ALLOW LARGE SURFACE ANTICYCLONE TO BUILD S/SEWD ACROSS THE PLAINS/MS VALLEY IN WAKE OF STRONG/PROGRESSIVE COLD FRONT ASSOCIATED WITH NRN STREAM SYSTEM. BY LATE MONDAY AFTERNOON...COLD FRONT EXPECTED TO EXTEND FROM CENTRAL GREAT LAKES SWWD ACROSS LOWER MO VALLEY TO CENTRAL OK...AND THEN WSWWD THROUGH NWRN TX-NERN NM. A SURFACE LOW SHOULD TRACK NEWD THROUGH THE OH VALLEY MONDAY NIGHT AS NRN EXTENT OF COLD FRONT SPREADS EWD TOWARD THE LOWER GREAT LAKES/CENTRAL APPALACHIANS. ANOTHER SURFACE WAVE/TRIPLE POINT IS EXPECTED TO EVOLVE OVER CENTRAL OK BY MONDAY AFTERNOON...AS A DRY LINE MIXES EWD AND THE COLD FRONT CONTINUES ITS TREK SSEWD THROUGH THE SRN PLAINS. ...SRN PLAINS ENE TO OZARKS/LOWER MO VALLEY... LOW-LEVEL MOISTURE WILL CONTINUE TO ADVECT NWD DAY 1 INTO DAY 2 ACROSS THE SRN PLAINS BENEATH ELEVATED MIXED LAYER...WITH SOMEWHAT MORE SUBSTANTIAL WARM SECTOR MOISTENING EXPECTED MONDAY THAN HAS BEEN OBSERVED ACROSS THIS REGION PAST SEVERAL DAYS. THIS WILL CONTRIBUTE TO A VERY UNSTABLE AIR MASS /MLCAPE 2500+ J/KG/ ACROSS NRN TX TO SERN KS/SWRN MO ALONG/S OF COLD FRONT AND EAST OF TRIPLE POINT AND TRAILING DRY LINE. ONE OR TWO MCS/S SHOULD BE ONGOING 12Z MONDAY ACROSS LOWER MO VALLEY TO OZARKS REGION ALONG/N OF QUASI-STATIONARY BOUNDARY WHICH SHOULD REMAIN LOCATED FROM ERN KS/SRN MO TO TN VALLEY PRIOR TO COLD FRONTAL PASSAGE. THIS ACTIVITY WILL BE ASSOCIATED WITH WAA REGIME ALONG NOSE OF STRONG NOCTURNAL SWLY LLJ. THIS ACTIVITY SHOULD TEND TO WEAKEN MONDAY MORNING WITH EWD EXTENT AS LLJ WITHIN WARM SECTOR BACKS TO SLY IN ADVANCE OF APPROACHING SRN STREAM SHORT WAVE TROUGH. EML IS EXPECTED TO CAP WARM SECTOR THROUGH MID AFTERNOON...WITH NEW THUNDERSTORM DEVELOPMENT LIKELY BY LATE AFTERNOON ACROSS SWRN MO/SERN KS INTO NRN OK BY MID AFTERNOON AS STRONG SURFACE HEATING...INCREASING LOW-LEVEL CONVERGENCE...AND WEAK HEIGHT FALLS AID IN WEAKENING CINH. STRONG DEEP LAYER SHEAR ORIENTED NORMAL TO DRY LINE SHOULD RESULT IN POTENTIAL FOR DISCRETE SUPERCELLS WITH INITIAL ACTIVITY CAPABLE OF PRODUCING TORNADOES...VERY LARGE HAIL...AND DAMAGING WINDS. ACTIVITY SHOULD EVOLVE INTO A LINEAR STRUCTURE AS THE COLD FRONT PROGRESSES S/SEWD INTO THE LOWER OH VALLEY AND OZARKS TO NRN TX MONDAY NIGHT. ...OH/TN VALLEYS TO NC... MOISTURE RETURN IS EXPECTED INTO THE OH VALLEY ALONG NWRN PERIPHERY OF SERN STATES SURFACE HIGH. SURFACE HEATING WITHIN THIS MOISTENING AIR MASS EXPECTED TO RESULT IN SUFFICIENT INSTABILITY ACROSS THE LOWER OH VALLEY IN ADVANCE OF EARLY MORNING MCS OVER SRN MO. THIS MAY ALLOW FOR SOME INCREASE IN STORM INTENSITY AND/OR SPORADIC STORM DEVELOPMENT ALONG BAROCLINIC ZONE ACROSS PARTS OF KY/TN TO WRN NC WHERE WEAK-MODERATE INSTABILITY AND STRONG DEEP LAYER SHEAR WOULD SUPPORT ISOLATED SEVERE STORMS. GREATER STORM COVERAGE AND OVERALL SEVERE THREAT IS EXPECTED MONDAY EVENING/NIGHT AS AFTERNOON STORMS ACROSS MO GROW UPSCALE INTO A FORWARD PROPAGATING MCS THROUGH THE OH VALLEY. STRONG WSWLY LLJ DEVELOPING ALONG OH VALLEY AFTER 25/00Z IN RESPONSE TO STRONG HEIGHT FALLS MAY INCREASE THE THREAT FOR DAMAGING WINDS... WITH GREATEST THREAT INTO THE LOWER OH VALLEY WHERE INSTABILITY WILL BE THE GREATEST. ..PETERS.. 04/23/2006  From SwoDy2 at goshenarc.org Sun Apr 23 17:32:41 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 23 Apr 2006 13:32:41 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 231728 SWODY2 SPC AC 231727 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1227 PM CDT SUN APR 23 2006 VALID 241200Z - 251200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE CNTRL/SRN PLAINS EWD TO THE TN VLY... ...SYNOPSIS... SRN PARTS OF THE UPPER LOW OVER THE WRN STATES IS EXPECTED TO DEAMPLIFY WHILE TRANSLATING NEWD ACROSS THE CNTRL/SRN HIGH PLAINS ON MON. THIS IN COMBINATION WITH A PROGRESSIVE NRN STREAM IMPULSE DIGGING INTO THE GRTLKS REGION MON AFTN WILL FLATTEN THE BROAD RIDGE ACROSS SRN NOAM. BUILDING SFC HIGH PRESSURE IN WAKE OF THE NRN STREAM SYSTEM WILL FORCE A COLD FRONT RAPIDLY SWD ACROSS THE HIGH PLAINS. THE SAME FRONT WILL MOVE MORE SLOWLY SEWD ACROSS THE GRTLKS AND THE LOWER PLAINS. A TRIPLE POINT WILL DEVELOP OVER NWRN OK MON AFTN WITH A DRYLINE MIXING EWD INTO WRN/CNTRL OK AND CNTRL TX. THE LOW WILL DEVELOP SWD ALONG THE DRYLINE AS THE COLD FRONT SURGES SWD MON EVE. ...CNTRL/SRN PLAINS... SHORT TERM MODEL SUITE IS QUITE VARIED WITH THE HANDLING OF THE SURGING HIGH PLAINS COLD FRONT AND CONFIDENCE IN THE OVERALL SEVERE SCENARIO IS LOW. CURRENT LOW-LEVEL MOISTURE PROFILES SHOULD BE MAINTAINED THROUGH MON EVENING ACROSS THE CNTRL/SRN PLAINS WITH UPPER 50S TO LOWER 60S BOUNDARY LAYER DEW POINTS COMMON ALONG/S OF THE APPROACHING COLD FRONT AND EAST OF THE DRYLINE. GIVEN MID-LEVEL LAPSE RATES OF 7-8 DEG C PER KM AND HEATING...AIR MASS WILL BECOME POTENTIALLY VERY UNSTABLE. ELEVATED TSTM CLUSTERS SHOULD BE ONGOING EARLY MON MORNING ACROSS ERN KS EWD INTO THE OZARKS ALONG THE EDGE OF THE STRONGER CAP AND NOSE OF THE LLJ. AIR MASS SHOULD RECOVER SOMEWHAT ALONG SWRN EDGE OF THIS COLD DOME AND AHEAD OF THE APPROACHING COLD FRONT ACROSS NCNTRL OK AND CNTRL/ERN KS MON AFTN. GIVEN GRADUAL LARGE SCALE HEIGHT FALLS...HEATING AND CONVERGENCE ALONG THE TRIPLE POINT...TSTMS SHOULD INITIATE AS CINH WEAKENS. STORMS WILL TEND TO EXPAND NEWD ALONG THE COLD FRONT INTO ERN KS AND SWWD ALONG THE DRYLINE INTO CNTRL OK/TX DURING THE EVENING. STRONGER VERTICAL SHEAR WILL EXIST N OF THE RED RIVER WHERE 40-50 KTS WILL BE SUPPORTIVE OF SUPERCELL STRUCTURES WITH VERY LARGE HAIL. SURFACE FLOW MAY REMAINED BACK ACROSS SERN KS AND ERN OK...BOTH DUE TO DEVELOPING SFC LOW IN NWRN OK AND THE RESIDUAL CONVECTIVE BOUNDARIES. THIS MAY AUGMENT THE TORNADO THREAT OVER THESE AREAS. BUT...AS THE COLD FRONT BEGINS TO SURGE SWD DURING THE MID-EVENING HOURS...TSTMS WILL TEND TO BECOME UNDERCUT AND DEVELOP INTO A LINEAR MCS. AT THAT TIME...DAMAGING WIND POTENTIAL WILL BECOME MORE OF A THREAT ANYWHERE FROM SRN MO INTO WRN AR OVERNIGHT. ...LWR OH AND TN VLYS... PERSISTENT MOIST LOW-LEVEL INFLOW ALONG/S OF AN OLD E-W ORIENTED FRONT ACROSS THE LWR OH/TN VLYS MAY PROVE SUFFICIENT FOR TSTM CLUSTERS MON AFTN. REGION WILL REMAIN ALONG SRN PERIPHERY OF STRONGER FLOW ALOFT AND A FEW STRONGER STORMS MAY DEVELOP WITH THE THREAT FOR LARGE HAIL/HIGH WINDS. HIGHER SEVERE PROBABILITIES SHOULD EXIST UPSTREAM OVER WRN KY/TN WHERE LAPSE RATES WILL BE STEEPER. ..RACY.. 04/23/2006  From SwoDy2 at goshenarc.org Mon Apr 24 06:12:37 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 24 Apr 2006 02:12:37 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 240604 SWODY2 SPC AC 240603 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0103 AM CDT MON APR 24 2006 VALID 251200Z - 261200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS SRN TX TO THE LOWER MS AND TN VALLEYS... ...SYNOPSIS... FLAT UPPER RIDGE EXTENDING FROM THE SOUTH CENTRAL-SERN STATES IS EXPECTED TO BREAK DOWN WITH STRONGER WLY MID-LEVEL FLOW DEVELOPING ACROSS THIS REGION...AS A SHORT WAVE TROUGH MOVES EWD TOWARD THE MID MS-LOWER OH/TN VALLEYS AND AN UPPER TROUGH AMPLIFIES ACROSS ERN CANADA/NERN STATES. IN THE LOW-LEVELS...A COLD FRONT ASSOCIATED WITH NRN STREAM SYSTEM IS EXPECTED TO EXTEND SWWD THROUGH THE LOWER GREAT LAKES/OH VALLEY TO THE OZARKS REGION INTO CENTRAL TX AT 12Z TUESDAY. THIS BOUNDARY WILL REMAIN PROGRESSIVE DAY 2 AS BUILDING SURFACE HIGH PRESSURE IN THE WAKE OF NRN STREAM TROUGH FORCES THE FRONT E/SE. A TRIPLE POINT LOW SHOULD BE LOCATED OVER ERN OK BY LATE DAY 1/EARLY DAY 2...WITH THIS FEATURE DEVELOPING SSEWD INTO THE LOWER MS VALLEY. A SECOND SURFACE WAVE ASSOCIATED WITH A WEAK LEAD IMPULSE AND/OR ONGOING MCS MAY BE LOCATED OVER SERN MO OR INTO LOWER OH VALLEY. ...TN/LOWER MS VALLEYS INTO SRN TX... THUNDERSTORMS ARE EXPECTED TUESDAY ALONG/S OF PROGRESSIVE COLD FRONT FROM THE CENTRAL APPALACHIANS/MID-ATLANTIC REGION SWWD THROUGH THE TN/LOWER MS VALLEYS TO TX. HOWEVER...STRONGEST AVAILABLE MOISTURE...STEEPER LAPSE RATES...AND RESULTANT GREATER INSTABILITY ARE EXPECTED TO EXTEND FROM SRN TX THROUGH THE LOWER MS VALLEY TO CENTRAL GULF COAST STATES AND TN VALLEY REGION. THUS...GREATER POTENTIAL FOR SEVERE STORMS SHOULD BE ACROSS THESE AREAS. AN MCS IS EXPECTED TO BE ONGOING START OF DAY 2 ACROSS PARTS OF ERN KS/ERN OK THROUGH MO/OZARKS REGION INTO LOWER OH VALLEY. SURFACE HEATING EAST OF THIS COMPLEX INTO KY/TN AND ALSO SWWD INTO LOWER MS VALLEY TO S TX AHEAD OF COLD FRONT EXPECTED TO RESULT IN A MODERATELY UNSTABLE AIR MASS BY EARLY TUESDAY AFTERNOON. A FEW WEAKLY SHEARED STORMS PER NAM ARE POSSIBLE ALONG A PRE-FRONTAL TROUGH FROM SERN TX/LA INTO CENTRAL GULF COAST STATES BY LATE TUESDAY MORNING. GREATER SEVERE THREAT IS EXPECTED TO DEVELOP BY TUESDAY AFTERNOON FROM TN SWWD INTO AR...WHERE STRONGER MID-LEVEL FLOW WILL RESULT IN SUFFICIENT VERTICAL SHEAR FOR STORM ORGANIZATION. STRONGER DEEP LAYER SHEAR WILL ALSO BE FOUND FARTHER S OVER SRN TX SUPPORTING ORGANIZED STORMS...DUE TO BACKED LOW-LEVEL WINDS BENEATH MODERATE WLY MID-LEVEL FLOW. SEVERE STORMS EXPECTED TO SPREAD SWD TOWARD THE WRN-CENTRAL GULF COAST REGION TUESDAY NIGHT AS EFFECTIVE DEEP LAYER SHEAR/INSTABILITY SHOULD REMAIN SUFFICIENT FOR CONTINUED THREAT. ...PARTS OF CENTRAL/SRN APPALACHIANS TO MID-ATLANTIC STATES. ALTHOUGH INSTABILITY IS EXPECTED TO BE WEAKER EAST OF THE TN VALLEY...MODERATE-STRONG WLY MID-LEVEL WINDS WILL LIKELY SUPPORT STRONG DEEP LAYER SHEAR FOR A FEW ORGANIZED SEVERE STORMS. THIS THREAT SHOULD DIMINISH TUESDAY EVENING AS INSTABILITY DECREASES WITH THE ONSET OF BOUNDARY LAYER COOLING. ..PETERS.. 04/24/2006  From SwoDy2 at goshenarc.org Mon Apr 24 17:03:04 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 24 Apr 2006 13:03:04 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 241658 SWODY2 SPC AC 241657 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1157 AM CDT MON APR 24 2006 VALID 251200Z - 261200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM SERN TX AND THE LOWER MS VALLEY NEWD TO PORTIONS OF THE DELMARVA AND NC... ...SYNOPSIS... AMPLIFIED...SPLIT FLOW PATTERN WILL CONTINUE THROUGH THE DAY TWO PERIOD WITH DEEP UPPER LOW EVOLVING OVER THE ERN CANADA AND SRN STREAM LOW SHIFTING SEWD ALONG THE SRN CA COAST. SHORT WAVE TROUGH EJECTING EWD INTO THE CNTRL AND SRN PLAINS DURING THE DAY ONE PERIOD IS FORECAST TO WEAKEN AS IT MOVES INTO PROGRESSIVELY CONFLUENT MID-LEVEL FLOW REGIME FROM THE SRN OH VALLEY TO MIDDLE ATLANTIC COAST. IN THE LOW-LEVELS...PRIMARY SURFACE LOW ASSOCIATED WITH PLAINS SHORT WAVE TROUGH /INITIALLY OVER THE MID MS VALLEY/ WILL DEVELOP RAPIDLY EWD ALONG BAROCLINIC ZONE TO NEAR CHESAPEAKE BAY BY TUESDAY EVENING. MEANWHILE...TRAILING COLD FRONT WILL PUSH SEWD THROUGH THE REMAINDER OF TX AND THE LOWER MS VALLEY BY WEDNESDAY MORNING. ...SERN TX/LOWER MS VALLEY EWD INTO THE CNTRL AND SRN APPALACHIANS... CURRENT SURFACE OBSERVATIONS AND 24/12Z SOUNDING DATA INDICATE A MOIST LOW-LEVEL AIR MASS IN PLACE ACROSS THE SRN PLAINS INTO WRN PORTIONS OF THE LOWER MS VALLEY WITH DEWPOINTS IN THE 60S TO LOWER 70S. INCREASING SWLY LOW-LEVEL FLOW AHEAD OF SURFACE FRONT WILL ALLOW FOR EWD/NEWD ADVECTION OF THIS MOISTURE ACROSS THE GULF COAST INTO TN VALLEY...SUPPORTING MODERATE AFTERNOON INSTABILITY WITH MLCAPES INCREASING TO 1000-2000 J/KG. THIS INSTABILITY WILL WEAKEN WITH NEWD EXTENT OVER THE APPALACHIANS WHERE MLCAPES OF 500-1000 J/KG APPEAR MORE LIKELY. CLUSTERS OF TSTMS OR A COUPLE OF MCS/S WILL LIKELY BE ONGOING TUESDAY MORNING FROM VICINITY OF SURFACE LOW SWWD ALONG COLD FRONT FROM THE LOWER OH VALLEY INTO AR. SOME DIURNAL WEAKENING MAY OCCUR THROUGH THE MORNING...WITH STORMS EXPECTED TO INCREASE IN COVERAGE AND INTENSITY BY AFTERNOON AS INFLOW AIR MASS DESTABILIZES. GIVEN THE ANTICIPATED MODERATE INSTABILITY...DEEP-LAYER SPEED SHEAR OF 35-40 KTS SHOULD BE SUFFICIENT TO SUPPORT ORGANIZED STORM CLUSTERS AND/OR LINE SEGMENTS CAPABLE OF MAINLY DAMAGING WINDS AND LARGE HAIL. ...DELMARVA INTO NC... CURRENT SURFACE OBSERVATIONS AND MODEL GUIDANCE SUGGEST THAT BOUNDARY-LAYER WILL LIKELY NOT BE AS MOIST AS LOCATIONS FARTHER TO THE W...THOUGH DEWPOINTS SHOULD INCREASE THROUGH THE 50S AS SLY LOW-LEVEL WINDS INCREASE AHEAD OF APPROACHING SURFACE LOW. WHILE FORECAST SOUNDINGS INDICATE THAT INSTABILITY WILL REMAIN SOMEWHAT MARGINAL /MLCAPES OF 500-800 J/KG/...VERTICAL SHEAR PROFILES WILL BE QUITE FAVORABLE FOR SEVERE STORMS WITH 40-50 KTS OF DEEP-LAYER SHEAR AND MORE STRONGLY CURVED LOW-LEVEL HODOGRAPHS OWING TO BACKED WINDS AHEAD OF SURFACE LOW. THEREFORE...SHOULD STORMS DEVELOP AND BECOME SUSTAINED NEAR SURFACE LOW...POTENTIAL WILL EXIST FOR DAMAGING WINDS...LARGE HAIL AND PERHAPS A TORNADO OR TWO FROM MID TO LATE AFTERNOON INTO THE EARLY EVENING HOURS. ..MEAD.. 04/24/2006  From SwoDy2 at goshenarc.org Tue Apr 25 05:38:06 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 25 Apr 2006 01:38:06 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 250534 SWODY2 SPC AC 250533 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1233 AM CDT TUE APR 25 2006 VALID 261200Z - 271200Z ...NO SVR TSTM AREAS FORECAST... ...SERN STATES... SHORT WAVE TROUGH EXPECTED TO BE LOCATED OVER THE LOWER MO VALLEY/ OZARKS REGION BEGINNING OF DAY 2 WILL AMPLIFY SOME AS IT TRACKS SEWD REACHING THE SRN APPALACHIANS BY 12Z THURSDAY. BAND OF 40-50 KT WLY MID-LEVEL WINDS ACCOMPANYING THIS TROUGH WILL SPREAD ACROSS THE CENTRAL GULF COAST/SERN STATES THIS FORECAST PERIOD. SURFACE COLD FRONT SHOULD INITIALLY EXTEND WWD FROM THE CAROLINAS TO AN AREA OF LOW PRESSURE OVER THE SRN APPALACHIANS...AND THEN SWWD THROUGH THE LOWER MS VALLEY. SURFACE LOW EXPECTED TO TRACK EWD INTO SC ALONG WEDGE FRONT BY WEDNESDAY AFTERNOON WITH TRAILING COLD FRONT SETTLING SOUTH TOWARD THE GULF COAST. COLD FRONT SHOULD THEN SURGE SWD INTO CENTRAL FL WEDNESDAY NIGHT AS LOW MOVES OFFSHORE IN RESPONSE TO STRONGER HEIGHT FALLS WITH APPROACH OF AMPLIFYING MID-LEVEL TROUGH. SWLY LOW-LEVEL WINDS S OF FRONT EXPECTED TO ADVECT SURFACE DEWPOINTS IN THE MID 60S ACROSS THE WARM SECTOR. SHOWERS AND EMBEDDED THUNDERSTORMS ARE PROGGED TO BE ONGOING ALONG AND S OF THE COLD FRONT WITH ASSOCIATED CLOUDINESS LIKELY LIMITING SURFACE HEATING ACROSS MUCH OF THE WARM SECTOR. IN ADDITION...WEAK LAPSE RATES SHOULD MINIMIZE DESTABILIZATION...WITH AFTERNOON MLCAPE VALUES GENERALLY RANGING FROM 500-1000 J/KG. GIVEN THE STRENGTHENING MID-LEVEL WINDS...VERTICAL SHEAR SHOULD BECOME SUFFICIENT TO SUPPORT STORM ORGANIZATION...WITH SHEAR VECTORS ORIENTED LARGELY PARALLEL TO THE SURFACE BOUNDARY PROMOTING MAINLY A LINEAR MODE. HOWEVER... OVERALL SEVERE THREAT/COVERAGE IS EXPECTED TO BE LIMITED BY THE WEAK INSTABILITY...THUS CONTINUING THE OUTLOOK OF LOW SEVERE PROBABILITIES. ..PETERS.. 04/25/2006  From swody2 at goshenarc.org Tue Apr 25 17:26:20 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 25 Apr 2006 13:26:20 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 251722 SWODY2 SPC AC 251721 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1221 PM CDT TUE APR 25 2006 VALID 261200Z - 271200Z ...NO SVR TSTM AREAS FORECAST... ...SERN AL...CNTRL AND SRN GA...SRN SC AND NRN FL... THE SHORTWAVE TROUGH NOW OVER THE CNTRL PLAINS IS FORECAST TO CONTINUE SEWD AND MAY UNDERGO SOME AMPLIFICATION AS IT MOVES THROUGH THE TN VALLEY. EARLY WEDNESDAY A COLD FRONT SHOULD EXTEND FROM SWRN LA NEWD THROUGH NERN AL AND INTO NRN GA...THEN SEWD AS A BACK DOOR FRONT ACROSS SC. THE FRONT WILL MOVE SEWD DURING THE DAY. LOW LEVEL DEWPOINTS IN THE UPPER 60S WILL RESIDE IN THE WARM SECTOR S OF THESE BOUNDARIES. SOME DESTABILIZATION SHOULD OCCUR DURING THE DAY. HOWEVER...MODEST LAPSE RATES...AREAS OF ONGOING CONVECTION AND WIDESPREAD CLOUDS WILL LIKELY LIMIT OVERALL DEGREE OF INSTABILITY WITH MLCAPE GENERALLY AOB 1000 J/KG EXPECTED. STORMS ARE EXPECTED TO INCREASE IN COVERAGE ALONG AND AHEAD OF THE FRONT WITHIN THE WEAKLY CAPPED ENVIRONMENT AND SPREAD EWD THROUGH THE WARM SECTOR BY LATE MORNING INTO THE AFTERNOON. SIGNIFICANT MODEL DIFFERENCES EXIST BETWEEN THE NAM...GFS AND ECMWF. THE GFS AND ECMWF DEVELOP MUCH STRONGER KINEMATIC FIELDS BETWEEN 850 AND 550 MB ACROSS PARTS OF SRN GA...SC AND NRN FL AS THE UPPER TROUGH AMPLIFIES SEWD...WHILE THE NAM IS MUCH WEAKER. THE GFS AND ECMWF SOLUTIONS WOULD SUPPORT A GREATER POTENTIAL FOR ORGANIZED SEVERE/DAMAGING WIND EVENTS IF SUFFICIENT DESTABILIZATION COULD OCCUR. GIVEN THE MODEL DIFFERENCES AND POTENTIAL FOR WIDESPREAD CLOUDS TO LIMIT DESTABILIZATION...WILL MAINTAIN 5% SEVERE PROBABILITIES AT THIS TIME. HOWEVER...IF IT BEGINS TO APPEAR THAT WIND FIELDS AND INSTABILITY WILL BE GREATER THAN CURRENTLY ANTICIPATED...AN UPGRADE TO SLIGHT RISK MIGHT BE NECESSARY IN LATER OUTLOOKS. ..DIAL.. 04/25/2006  From swody2 at goshenarc.org Wed Apr 26 06:06:52 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 26 Apr 2006 02:06:52 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 260602 SWODY2 SPC AC 260601 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0101 AM CDT WED APR 26 2006 VALID 271200Z - 281200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN HIGH PLAINS THURSDAY AFTERNOON/EVENING... ...SRN HIGH PLAINS... ALTHOUGH MODELS DIFFER WITH EWD MOVEMENT OF LARGE CLOSED UPPER LOW THROUGH THE SWRN STATES ON THURSDAY...WITH THE GFS/NAM FASTER THAN THE ECMWF/UKMET...EACH MODEL SUGGESTS STRENGTHENING MID/UPPER LEVEL SWLY WINDS ACROSS THE SRN HIGH PLAINS. SELY LOW-LEVEL WINDS DEVELOPING ALONG THE RIO GRANDE VALLEY/TRANS PECOS REGION DAY 1 WILL CONTINUE DAY 2...WITH NWWD MOISTURE ADVECTION. ELEVATED MIXED LAYER WITH MID-LEVEL LAPSE RATES EXCEEDING 7.5-8 C/KM IS EXPECTED TO SPREAD EWD ATOP THE NARROW AXIS OF MOISTURE RETURN...RESULTING IN MUCAPE VALUES AROUND 1000 J/KG ALONG TRANS PECOS REGION TO SERN NM. THE EML SHOULD CAP MUCH OF THE AIR MASS THROUGH THE AFTERNOON...WITH INITIAL THUNDERSTORM DEVELOPMENT LIKELY CONFINED TO THE HIGHER TERRAIN OF SW TX AND NM. EFFECTIVE DEEP LAYER SHEAR VALUES INCREASING TO 40-50 KT WILL BE SUFFICIENT FOR PERSISTENT ROTATING UPDRAFTS...WITH HAIL AND DAMAGING WIND GUSTS THE PRIMARY THREATS AS STORMS MOVE NEWD OFF THE HIGHER TERRAIN INTO THE INSTABILITY AXIS. LLJ STRENGTHENING/VEERING TO SLY THURSDAY NIGHT SHOULD ALLOW STORMS TO PERSIST OVERNIGHT WITHIN LOW-LEVEL WAA REGIME ACROSS WRN TX...WITH AT LEAST A LOW PROBABILITY FOR ISOLATED SEVERE HAIL. ...PARTS OF CENTRAL/NRN PLAINS... SHORT WAVE TROUGH...CURRENTLY APPROACHING BC COAST...IS EXPECTED TO MOVE SEWD INTO THE NRN PLAINS DAY 2. DESPITE MEAGER MOISTURE RETURN THIS FAR NORTH...WEAK INSTABILITY MAY DEVELOP DUE TO COMBINATION OF NRN EXTENT OF EML SPREADING INTO CENTRAL PLAINS AND COLD MID-LEVEL TEMPERATURES /-18 TO -22 C/ WITH TROUGH STEEPENING MID-LEVEL LAPSE RATES. THERMODYNAMIC PROFILES SHOULD SUPPORT THUNDERSTORMS ALONG A SURFACE BOUNDARY MOVING EWD ACROSS THE NRN/CENTRAL PLAINS. DESPITE DEEP LAYER SHEAR BECOMING SUFFICIENT FOR ORGANIZED STORMS ACROSS NEB...WEAK INSTABILITY EXPECTED TO LIMIT THE POTENTIAL FOR SEVERE STORMS. THUS...WILL NOT INTRODUCE ANY SEVERE PROBABILITIES AT THIS TIME. ..PETERS.. 04/26/2006  From swody2 at goshenarc.org Wed Apr 26 17:33:04 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 26 Apr 2006 13:33:04 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 261728 SWODY2 SPC AC 261727 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1227 PM CDT WED APR 26 2006 VALID 271200Z - 281200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER THE SRN HIGH PLAINS... ...SRN HIGH PLAINS... UPPER LOW OFF THE CA COAST IS FORECAST TO MOVE EWD INTO THE SRN ROCKIES BY THURSDAY EVENING...WHILE A NRN STREAM SHORTWAVE TROUGH AMPLIFIES SEWD INTO THE NRN HIGH PLAINS. A COLD FRONT WILL SETTLE SWD INTO WRN KS AND SERN CO TUESDAY AFTERNOON. A LEE TROUGH WILL BECOME ESTABLISHED OVER THE SRN HIGH PLAINS IN ADVANCE OF THE SRN STREAM UPPER LOW. LOW LEVEL MOISTURE WITH DEWPOINTS IN THE LOW TO MID 60S WILL ADVECT NWWD THROUGH SWRN AND WRN TX THURSDAY AFTERNOON AND EVENING AS THE BOUNDARY LAYER FLOW RETURNS TO SLY AND THE LOW LEVEL JET STRENGTHENS E OF DEVELOPING LEE TROUGH. PLUME OF STEEP LAPSE RATES WILL EXIST ABOVE THE RETURNING LOW LEVEL MOISTURE AND CONTRIBUTE TO MODERATE INSTABILITY DURING THE AFTERNOON. THE ATMOSPHERE WILL LIKELY REMAINED CAPPED MUCH OF THE DAY. HOWEVER... STORMS SHOULD DEVELOP BY LATE AFTERNOON OVER THE HIGHER TERRAIN OF NM AND SWRN TX WITHIN ZONE OF SURFACE HEATING...OROGRAPHIC FORCING AND INCREASING UPPER DIVERGENCE ASSOCIATED WITH EWD ADVANCING UPPER TROUGH. THERMODYNAMIC AND DEEP LAYER SHEAR PROFILES WILL BECOME INCREASINGLY FAVORABLE FOR SUPERCELLS CAPABLE OF PRODUCING VERY LARGE HAIL FROM ERN NM INTO PARTS OF WRN TX WITH SELY BOUNDARY LAYER FLOW VEERING TO SWLY AND STRENGTHENING THROUGH 8 KM. A FEW STORMS MAY ALSO DEVELOP FARTHER NWD INTO SWRN KS AND SERN CO IN VICINITY OF THE COLD FRONT DURING THE AFTERNOON. VERTICAL SHEAR AND INSTABILITY WILL BE WEAKER IN THIS AREA...BUT INVERTED-V THERMODYNAMIC PROFILES AND STEEP MID LEVEL LAPSE RATES MAY SUPPORT A THREAT FOR HAIL AND STRONG GUSTY WINDS. STRENGTHENING LOW LEVEL JET MAY SUPPORT STORMS CONTINUING SOME DISTANCE EWD INTO THE HIGH PLAINS DURING THE EVENING WHERE THE CAP WILL BE STRONGER. OTHER STORMS WILL LIKELY DEVELOP FARTHER N INTO OK AND SRN KS WITHIN ZONE OF INCREASING WARM ADVECTION OVERNIGHT. SOME OF THESE STORMS MAY ALSO BE CAPABLE OF PRODUCING LARGE HAIL. ..DIAL.. 04/26/2006  From SwoDy2 at goshenarc.org Fri Apr 28 05:57:56 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Fri, 28 Apr 2006 01:57:56 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 280556 SWODY2 SPC AC 280555 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1255 AM CDT FRI APR 28 2006 VALID 291200Z - 301200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN AND CNTRL PLAINS AND OZARK PLATEAU... ...EAST TX/AR... A LARGE LINEAR MCS SHOULD BE ONGOING AT THE BEGINNING OF THE PERIOD SOUTH OF A DEEPENING UPPER-LOW. MODEL FORECASTS AGREE WITH THIS SCENARIO WITH A SQUALL-LINE EXTENDING FROM OK SWD ACROSS EAST AND CNTRL TX. AS THE UPPER-SYSTEM TRANSITIONS NEWD DURING THE DAY...STRONG LARGE-SCALE ASCENT SHOULD HELP SUSTAIN THE LINEAR MCS WHICH SHOULD AFFECT AREAS OF FAR EAST TX...LA...ERN OK AND THE OZARKS BY AFTERNOON. AT LOW-LEVELS...MOISTURE ADVECTION SHOULD CONTINUE TONIGHT INTO SATURDAY ACROSS THE SABINE RIVER VALLEY WITH SFC DEWPOINTS LIKELY INCREASING INTO THE LOWER TO MID 60S F AS FAR NORTH AS THE SRN OZARKS. THIS MAY ALLOW POCKETS OF MODERATE INSTABILITY TO DEVELOP BY SATURDAY AFTERNOON ACROSS THE REGION WHICH WOULD LIKELY RESULT IN INTENSIFICATION OF THE LINEAR MCS. FORECAST SOUNDINGS SATURDAY AFTERNOON IN LA AND SRN AR SHOW STRONG VERTICAL SHEAR PROFILES WITH LOW-LEVEL FLOW INCREASING DURING THE DAY. THIS WOULD AID THE WIND DAMAGE POTENTIAL WITH THE STRONGER STORMS IN THE LINE. ALTHOUGH LAPSE RATES ARE NOT FORECAST TO BE THAT STEEP...LARGE HAIL WILL ALSO BE POSSIBLE ESPECIALLY IF MODERATE INSTABILITY DEVELOPS AHEAD OF THE LINE. ADDITIONAL STORMS MAY INITIATE TO THE WEST ACROSS ERN OK AND NE TX WHERE MODERATE INSTABILITY MAY ALSO DEVELOP IN A DRY SLOT WRAPPING AROUND THE SOUTHEAST SIDE OF THE UPPER-LOW. STORMS MAY REMAIN MORE DISCRETE IN THIS AREA AND SUPERCELLS WILL BE POSSIBLE ESPECIALLY IF MODERATE INSTABILITY DEVELOPS SATURDAY AFTERNOON. LARGE HAIL AND WIND DAMAGE WOULD BE POSSIBLE WITH THE STRONGER CELLS BEFORE THE SEVERE THREAT GRADUALLY DIMINISHES IN THE EVENING HOURS. ...KS/WRN MO... AN UPPER-LOW IS FORECAST TO DEEPEN AND MOVE NEWD ACROSS THE SRN AND CNTRL PLAINS SATURDAY. LOW-LEVEL MOISTURE WILL WRAP NORTH AND WWD AROUND THE UPPER-LOW AND SFC DEWPOINTS IN THE 50S F SHOULD BE IN PLACE ACROSS WRN MO AND ACROSS THE ERN HALF KS. SFC HEATING AND THE STEEP LAPSE RATES ASSOCIATED WITH THE UPPER-LOW SHOULD ALLOW DISCRETE STORMS TO INITIATE BY THE AFTERNOON AND MOVE SLOWLY NWD ACROSS THE REGION. FORECAST SOUNDINGS SATURDAY AFTERNOON IN KS AND WRN MO SHOW MODERATE VERTICAL SHEAR PROFILES WHICH WILL LIKELY BE SUFFICIENT FOR ISOLATED STORMS CAPABLE OF PRODUCING LARGE HAIL. ANY SEVERE THREAT THAT DEVELOPS SHOULD BE CONCENTRATED NEAR PEAK HEATING. ..BROYLES.. 04/28/2006  From SwoDy2 at goshenarc.org Fri Apr 28 17:31:49 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Fri, 28 Apr 2006 13:31:49 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 281729 SWODY2 SPC AC 281728 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1228 PM CDT FRI APR 28 2006 VALID 291200Z - 301200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM SRN IA SWD TO THE TX/LA GULF COAST... ...SYNOPSIS... UPPER LOW/TROUGH OVER THE CENTRAL CONUS -- ACCOMPANIED BY STRONG DEEP-LAYER WIND FIELD -- WILL DEEPEN AND TAKE ON A MORE NEGATIVE TILT WITH TIME WHILE MOVING SLOWLY EWD THROUGH THE PERIOD. MEANWHILE...SURFACE LOW INITIALLY EXPECTED OVER NERN TX/ERN OK/ERN KS SHOULD DEEPEN AND SHIFT NWD ACROSS THE MIDDLE MO VALLEY. COLD FRONT ASSOCIATED WITH THIS LOW WILL MOVE ACROSS ERN OK/ERN KS INTO MO/AR...WHILE MOVING MORE SLOWLY SEWD ACROSS NRN LA/SERN TX THROUGH THE END OF THE PERIOD. ...ERN PORTIONS OF THE PLAINS TO THE MIDDLE/LOWER MS VALLEY... LARGE/COMMA-SHAPED AREA OF PRECIPITATION IS FORECAST TO BE ONGOING AT THE START OF THE PERIOD ACROSS THE CENTRAL CONUS. THE MOST INTENSE CONVECTION WITHIN THIS LARGER PRECIPITATION AREA -- POSSIBLY IN THE FORM OF AN ORGANIZED SQUALL LINE ALONG/AHEAD OF THE COLD FRONT -- IS EXPECTED TO EXTEND FROM ERN OK SWD INTO ERN TX. WITH STRONG SWLY MID-LEVEL FLOW LIKELY BLOWING DENSE UPPER CLOUDINESS DOWNSTREAM FROM ONGOING STORMS...DAYTIME HEATING SHOULD BE LIMITED ACROSS MUCH OF THE SLIGHT RISK AREA. THUS...DESPITE MOIST BOUNDARY LAYER SPREADING NWD ACROSS TX/LA INTO AR...INSTABILITY SHOULD REMAIN LIMITED TO 500 TO 1000 J/KG MIXED-LAYER CAPE THROUGH THE AFTERNOON. DESPITE THIS...STRONG UPPER SYSTEM AND ADVANCING COLD FRONT SHOULD HELP SUSTAIN A VIGOROUS LINEAR-TYPE MCS THROUGH THE DAY...WITH ADDITIONAL/MORE CELLULAR CONVECTION POSSIBLE AHEAD OF LINE. STRENGTH OF DEEP-LAYER SHEAR /50 TO 60 KT FLOW FROM THE S AT LOW-LEVELS VEERING TO SSWLY AT 65 TO 70 KT AT MID-LEVELS/ SHOULD SUPPORT A SEVERE THREAT -- PARTICULARLY FROM ERN TX/LA NWD INTO SERN KS/SRN MO. WITH INSTABILITY LIMITED...PRIMARY SEVERE THREAT MAY BE IN THE FORM OF WIND...THOUGH SOME HAIL AND A COUPLE OF TORNADOES WILL BE POSSIBLE. A LESSER SEVERE THREAT MAY EXTEND AS FAR N AS IA...THOUGH DECREASING INSTABILITY WITH NWD EXTENT SHOULD TEMPER THE DEGREE OF THREAT. MAIN LINE OF STORMS SHOULD CROSS SERN MO/AR/NRN LA AND REACH THE MS VALLEY DURING THE LATE AFTERNOON/EVENING...THOUGH THREAT SHOULD DIMINISH OVERNIGHT WITH INSTABILITY FORECAST TO REMAIN LIMITED E OF THE MS VALLEY. ..GOSS.. 04/28/2006  From SWODY2 at goshenarc.org Sat Apr 1 06:37:50 2006 From: SWODY2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 01 Apr 2006 01:37:50 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 010635 SWODY2 SPC AC 010634 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1234 AM CST SAT APR 01 2006 VALID 021200Z - 031200Z ...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF EASTERN IOWA...NORTHERN MISSOURI...AND NORTHERN ILLINOIS... ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK AREA FROM THE SRN/CNTRL PLAINS TO THE OH/TN VALLEYS AND PORTIONS OF THE LOWER MS VALLEY... ...SIGNIFICANT SEVERE WEATHER EPISODE APPEARS POSSIBLE ACROSS PORTIONS OF THE MIDDLE MS VALLEY AND MIDWEST ON SUNDAY... ...SYNOPSIS... ACTIVE AND PROGRESSIVE WAVE TRAIN WILL CONTINUE TO CROSS THE LOWER 48 STATES THROUGH THE WEEKEND. A LEAD SHORT WAVE TROUGH WILL CROSS THE NORTHEAST TODAY AS THE NEXT SHORT WAVE TROUGH MOVES QUICKLY OVER THE WRN STATES AND THEN EMERGES OVER THE GREAT PLAINS THROUGH EARLY SUNDAY MORNING. THIS NEXT SIGNIFICANT SHORT WAVE FEATURE WILL THEN APPROACH THE MS VALLEY DURING THE DAY SUNDAY WITH 70KT MID LEVEL JET FORECAST TO ROTATE THROUGH THE BASE OF THE TROUGH AND ACROSS MO AND IL THROUGH LATE SUNDAY EVENING. STRONG DYNAMICS ON THE NOSE OF THE MID/UPPER LEVEL JET CORE AND LARGE SCALE HEIGHT FALLS OF 90-120M PER 12H WILL INDUCE SURFACE CYCLOGENESIS OVER THE HIGH PLAINS THROUGH THE DAY 1 PERIOD. THE SURFACE CYCLONE SHOULD TRACK INTO IA BY SUNDAY AFTERNOON AS ASSOCIATED WARM FRONT LIFTS ENEWD ACROSS ERN IA AND NRN IL. AS THE INTENSIFYING LOW TRACKS ALONG THE WARM FRONT OVER ERN IA AND NRN IL THROUGH SUNDAY EVENING...ASSOCIATED STRENGTHENING COLD FRONT SHOULD SWEEP ESEWD FROM THE CNTRL PLAINS TO THE LOWER OH RIVER VALLEY THROUGH EARLY MONDAY. ...CNTRL PLAINS ACROSS THE MS VALLEY/MIDWEST... WIDESPREAD DEEP CONVECTION EXPECTED TO BE ONGOING EARLY IN THE DAY IN AN ARC FROM NEB/IA SEWD TO THE CONFLUENCE OF THE MS/OH RIVERS. THIS ACTIVITY WILL BE SUSTAINED ALONG A WARM FRONT RETREATING NWD ACROSS THE REGION AS SURFACE LOW CONSOLIDATES AND STRENGTHENS OVER ERN NEB. THERE IS GOOD AGREEMENT AMONG A VARIETY OF NCEP MODEL GUIDANCE THAT THIS CONVECTION...PRIMARILY ELEVATED IN NATURE WITH SOME POTENTIAL FOR HAIL...WILL LIFT ENEWD ACROSS THE MS VALLEY THROUGH THE AFTERNOON. RAIN-COOLED AIR AND CLOUD COVER ASSOCIATED WITH THE MORNING CONVECTION WILL ACT TO REINFORCE THE WARM FRONT EXPECTED TO EXTEND EWD FROM THE SURFACE LOW NEAR IA. WARM SECTOR AIRMASS IS LIKELY TO BECOME INCREASINGLY UNSTABLE THROUGH THE AFTERNOON AS STRONG DYNAMICS AND COOLER TEMPERATURES ALOFT SPREAD EAST WITH THE MID/UPPER LEVEL IMPULSE. IN ADDITION TO POTENTIAL FOR RELATIVELY LOW-TOPPED STORMS FORMING WITHIN THE MID LEVEL VORTEX ACROSS ERN NEB AND KS...INCREASINGLY DIFFLUENT MID LEVEL FLOW WILL SPREAD ACROSS THE WARM SECTOR FROM MO INTO IA AND NRN IL. GIVEN CAPE VALUES INCREASING TO OVER 1000 J/KG NEAR THE SURFACE LOW AND WARM FRONT...LARGE SCALE FORCING IS EXPECTED TO RESULT IN RAPID THUNDERSTORM DEVELOPMENT DURING THE AFTERNOON. OVERALL PATTERN AS CURRENTLY FORECAST BY NAM AND GFS STRONGLY SUGGESTS AN ENHANCED POTENTIAL FOR LONG-TRACK SUPERCELLS FORMING ACROSS SRN IA/NRN MO AND THEN MOVING ACROSS THE MS RIVER FROM AFTERNOON INTO EARLY EVENING. FORECAST STORM RELATIVE SHEAR AND POTENTIALLY LOW LFC NEAR THE WARM FRONT AND SURFACE LOW...FROM SERN IA INTO NRN IL...APPEAR SUPPORTIVE OF STRONG TORNADOES IN THIS AREA. VERY LARGE HAIL WILL ALSO BE POSSIBLE FROM MUCH OF THE ACTIVITY AND CELLS MAY MERGE THROUGH THE EVENING HOURS...FORMING INTO A FAST MOVING BAND OF CONVECTION ON THE NOSE OF MID LEVEL JET STREAK. ATTENDANT THREAT OF DAMAGING WINDS COULD THEN SPREAD EAST ACROSS PARTS OF IL AND IND...AND PERHAPS AS FAR AS SRN MI AND ERN OH THROUGH EARLY MONDAY AS INTENSIFYING SURFACE LOW TRACKS INTO LOWER MI. IT IS POSSIBLE THAT PARTS OF THIS REGION MAY BE UPGRADED TO HIGHER PROBABILITIES AND PERHAPS EVEN A HIGH RISK IN LATER OUTLOOKS AS OVERALL SEVERE WEATHER SCENARIO BECOMES CLEARER. ...OZARKS TO LOWER OH/MS VALLEYS AND TN VALLEY... A MORE COMPLICATED FORECAST SCENARIO EXISTS ACROSS SRN PORTIONS OF THE HIGH-PROBABILITY SLIGHT RISK AREA. SOME CONVECTION MAY BE ONGOING EARLY IN THE PERIOD WITHIN WEAKLY UNSTABLE WARM CONVEYOR BELT FROM NERN TX TO SERN MO/WRN TN. DEGREE OF DESTABILIZATION WITHIN THIS CORRIDOR WILL DEPEND ON HOW RAPIDLY THIS EARLY ACTIVITY DISSIPATES. EXPECT THAT FORCING AND INSTABILITY WILL GRADUALLY INCREASE THROUGH LATE AFTERNOON AND THAT STORMS MAY TAKE SOME TIME TO BECOME SURFACE-BASED GIVEN POTENTIAL FOR GREATER INHIBITION. EVENTUALLY...AND PERHAPS NOT UNTIL EVENING...STRONGER STORMS SHOULD DEVELOP IN A BAND FROM AR EWD ACROSS THE MS RIVER VALLEY AS LARGE SCALE FORCING/PRE-FRONTAL TROUGH SPREAD EAST INTO THE REGION. SHEAR AND INSTABILITY CURRENTLY APPEAR FAVORABLE FOR A FEW INTENSE STORMS...POSSIBLY SUPERCELLS...WITHIN THIS BAND OF CONVECTION. INCREASINGLY STRONG MID LEVEL FLOW AND MID LEVEL DRY INTRUSION THROUGH LATE SUNDAY NIGHT ALSO SUGGEST THE DEVELOPMENT OF A SQUALL LINE WITH OCCASIONAL DAMAGING WINDS MOVING EAST ACROSS THE TN VALLEY...AND PERHAPS AS FAR EAST AS THE APPALACHIANS... THROUGH MONDAY MORNING. ..CARBIN.. 04/01/2006  From SWODY2 at goshenarc.org Sat Apr 1 17:14:54 2006 From: SWODY2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 01 Apr 2006 12:14:54 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 011712 SWODY2 SPC AC 011711 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1111 AM CST SAT APR 01 2006 VALID 021200Z - 031200Z ...THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF IA...MO AND MUCH OF IL... ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE GREAT LAKES SWD INTO THE MID SOUTH AND ARKLATEX... --POTENTIALLY SIGNIFICANT SEVERE WEATHER EPISODE IS BEING FORECAST ACROSS THE MIDWEST AND MID MS VALLEY SUNDAY AND SUNDAY NIGHT-- ...SYNOPSIS... MID AND UPPER-LEVEL TROUGH NOW OVER THE PACIFIC NW AND GREAT BASIN WILL TRANSLATE EWD INTO THE GREAT PLAINS LATE SATURDAY NIGHT INTO SUNDAY MORNING...PRIOR TO INTENSIFYING INTO A CLOSED CIRCULATION OVER THE UPPER MIDWEST SUNDAY NIGHT. AS THIS OCCURS...ACCOMPANYING MID AND HIGH-LEVEL JET STREAKS WILL PROPAGATE THROUGH THE TROUGH BASE INTO MO AND IL/IND SUNDAY AFTERNOON AND EVENING. IN THE LOW-LEVELS...PRIMARY SURFACE LOW INITIALLY OVER ERN NEB WILL DEVELOP ENEWD INTO LOWER MI BY MONDAY MORNING. ASSOCIATED WARM FRONT WILL CONCURRENTLY LIFT NEWD THROUGH THE OH VALLEY AND GREAT LAKES WHILE TRAILING COLD FRONT SURGES EWD THROUGH THE MID/LOWER MO AND MS VALLEYS AND INTO THE OH AND TN VALLEYS THROUGH THE FORECAST PERIOD. ...MID/LOWER MO VALLEY INTO THE GREAT LAKES...MID MS AND OH VALLEYS... A NW-SE ORIENTED BAND OF MAINLY ELEVATED TSTMS IS EXPECTED TO BE ONGOING 02/12Z FROM VICINITY OF THE SURFACE LOW OVER ERN NEB/WRN IA INTO WRN KY AND MIDDLE TN...LARGELY DRIVEN BY WAA ALONG BROAD SWLY LLJ. THIS ACTIVITY WILL LIKELY CONTINUE THROUGH THE PERIOD AHEAD OF RETREATING WARM FRONT INTO THE GREAT LAKES WITH THE STRONGEST STORMS CAPABLE OF MAINLY LARGE HAIL. IN THE WAKE OF THIS INITIAL ACTIVITY...THE PRESENCE OF STEEP MID-LEVEL LAPSE RATES / 7-8 C/KM / COUPLED WITH BOUNDARY-LAYER DEWPOINTS IN THE LOW TO MID 60S WILL CONTRIBUTE TO A MODERATELY UNSTABLE AIR MASS ACROSS SYSTEM WARM SECTOR WITH MLCAPES INCREASING TO 1500-2500 J/KG FROM SERN SE/CNTRL MO SWWD INTO THE ARKLATEX AND LOWER MS VALLEY. INCREASED FORCING FOR ASCENT AHEAD OF MID-LEVEL TROUGH AND EXIT REGIONS OF ACCOMPANYING JET STREAKS WILL CONTRIBUTE TO RAPID SURFACE-BASED TSTM DEVELOPMENT BY EARLY TO MID AFTERNOON FROM NEAR SURFACE LOW OVER WRN OR CNTRL IA SWD ALONG COLD FRONT INTO MO. ADDITIONAL SURFACE-BASED STORMS WILL ALSO BE POSSIBLE AT THIS TIME ALONG WARM FRONT. FORECAST SOUNDINGS INDICATE A POTENT COMBINATION OF INSTABILITY AND VERTICAL SHEAR ACROSS MODERATE RISK AREA...WHICH SHOULD SUPPORT INTENSE SUPERCELL DEVELOPMENT WITH THE POTENTIAL FOR A FEW STRONG TORNADOES IN ADDITION TO VERY LARGE...DESTRUCTIVE HAIL AND DAMAGING WINDS. WITH TIME...STORMS MAY EVOLVE INTO BOWING LINE SEGMENTS OR A MESOSCALE LEWP STRUCTURE WITH CORRIDORS OF DAMAGING WINDS POSSIBLE EWD ACROSS THE OH VALLEY SUNDAY NIGHT. ...MID SOUTH INTO ARKLATEX... AS MENTIONED ABOVE...PRE-FRONTAL AIR MASS IS FORECAST TO BECOME MODERATELY UNSTABLE BY AFTERNOON OWING TO STEEPENING LAPSE RATES AND A MOIST BOUNDARY-LAYER. GIVEN A STRONGER CAP AND THAT LARGE-SCALE FORCING FOR ASCENT AND LOW-LEVEL FRONTAL CONVERGENCE WILL TEND TO WEAKEN WITH SWD EXTENT...SOME UNCERTAINTY EXISTS WITH REGARD TO EVENTUAL CONVECTIVE COVERAGE AND INTENSITY ACROSS REGION. LATEST SHORT TERM MODEL GUIDANCE SUGGESTS THAT TSTMS SHOULD BEGIN TO BUILD SWWD ALONG FRONT BY MID TO LATE AFTERNOON FROM NEAR THE CONFLUENCE OF THE OH AND MS RIVERS INTO PORTIONS OF ERN AR...WRN TN AND PERHAPS SWD INTO NRN LA AND NRN MS. THE COMBINATION OF MODERATE INSTABILITY AND 45-55 KT WLY MID-LEVEL FLOW SUGGEST THE THREAT FOR A FEW SUPERCELLS AND BOWING LINE SEGMENTS CAPABLE OF DAMAGING WINDS...LARGE HAIL AND A FEW TORNADOES. THIS SEVERE THREAT WILL LIKELY CONTINUE SUNDAY NIGHT ACROSS THE TN VALLEY AND NRN PORTIONS OF MS AND AL. ..MEAD.. 04/01/2006  From SWODY2 at goshenarc.org Sun Apr 2 06:24:03 2006 From: SWODY2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 02 Apr 2006 01:24:03 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 020622 SWODY2 SPC AC 020621 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1221 AM CST SUN APR 02 2006 VALID 031200Z - 041200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF SRN PA...WV AND THE MID ATLANTIC REGION... ...SYNOPSIS... PROGRESSIVE LARGE SCALE TROUGH RESULTING IN WIDESPREAD SEVERE THUNDERSTORMS ACROSS THE PLAINS AND MIDWEST THROUGH SUNDAY WILL MOVE FROM THE GREAT LAKES/OH VALLEY TO THE EAST COAST ON MONDAY. AS PRIMARY SURFACE LOW ASSOCIATED WITH THIS SYSTEM TRACKS ENEWD TOWARD THE ST. LAWRENCE VALLEY AND UNDERGOES OCCLUSION...TRIPLE POINT LOW MAY TAKE FORM OVER WRN PA/WV AREA DURING THE DAY BEFORE STRONG COLD FRONT SURGES EAST ACROSS THESE AREAS. SIGNIFICANT HEIGHT FALLS AND INCREASINGLY STRONG WSWLY MID LEVEL FLOW WILL THEN SPREAD EAST ACROSS THE APPALACHIANS THROUGH THE DAY AND RESULT IN SECONDARY CYCLOGENESIS NEAR THE DELMARVA REGION BY LATE AFTERNOON. WARM FRONT AND SECONDARY LOW WILL LIFT SLOWLY NWD ALONG THE MID ATLANTIC SEABOARD AS COLD FRONT SWEEPS QUICKLY EWD ACROSS THE CAROLINAS AND VIRGINIA...AND THEN OFFSHORE AFTER DARK. ...WRN PA/WV AND MID ATLANTIC REGION... BAND OF CONVECTION ASSOCIATED WITH LIFT WITHIN LARGE SCALE WARM CONVEYOR BELT MAY BE ONGOING AT THE START OF THE DAY FROM THE CAROLINAS NWD/NWWD TO THE UPPER OH VALLEY/WRN TO CNTRL PA. ANOTHER BROKEN LINE OF SHOWERS AND THUNDERSTORMS MAY ALSO BE ONGOING AHEAD THE COLD FRONT...FROM ERN TN TO OH. POCKET OF DESTABILIZATION IS INDICATED IN LATEST GUIDANCE ACROSS ERN OH/WRN PA DURING THE MORNING AS MID LEVEL DRY SLOT CROSSES THIS AREA. DYNAMIC FORCING NEAR THE NOSE OF CYCLONICALLY CURVED MID LEVEL WIND MAX...AND LIFT ALONG THE ADVANCING FRONT...MAY SUPPORT STORM INTENSIFICATION ACROSS ERN OH/WRN PA. GIVEN MAGNITUDE OF FORCING...WEAK INSTABILITY MAY BE SUFFICIENT MAINTAIN A LINE OF LOW-TOPPED SUPERCELLS WITH DAMAGING WINDS AND HAIL MOVING EAST OVER SRN PA AND WV. FARTHER SOUTH...STRONG LOW LEVEL MOISTURE FLUX AHEAD OF THE DEEP TROUGH AND COLD FRONT IS EXPECTED TO AID IN THE TRANSPORT OF LOW TO MID 60S F DEWPOINTS NWD ACROSS THE CAROLINAS AND INTO SRN VA THROUGH EARLY AFTERNOON. BREAKS IN COLD COVER IN THE WAKE OF ANY MORNING CONVECTION SHOULD CONTRIBUTE TO THE DEVELOPMENT OF WEAK TO MODERATE INSTABILITY...CAPE 500-1000 J/KG...ACROSS PARTS OF SC/NC AND SERN VA. ADDITIONAL STORMS WILL DEVELOP RAPIDLY AS DEEP FRONTAL CIRCULATION MOVES EAST OF THE MOUNTAINS. THIS WILL OCCUR COINCIDENT WITH INTENSIFYING DEEP LAYER FLOW. PRIMARILY UNIDIRECTIONAL SHEAR AND FOCUSED FORCING OR ASCENT ALONG THE ADVANCING FRONT SUGGESTS LINEAR STORM MODE WITH FORECAST SOUNDINGS INDICATING CELL MOTIONS IN EXCESS OF 50KT. STORM ORGANIZATION MAY BE FURTHER ENHANCED NEAR THE SECONDARY SURFACE LOW AS IT BEGINS TO TAKE FORM NEAR DELMARVA AREA THROUGH THE AFTERNOON. POTENTIAL FOR ENHANCED SHEAR NEAR THE LOW AND WARM FRONT COULD RESULT IN A FAVORABLE ENVIRONMENT FOR SUPERCELLS AND PERHAPS A TORNADO OR TWO...IN ADDITION TO HAIL AND WIND. ..CARBIN.. 04/02/2006  From SWODY2 at goshenarc.org Sun Apr 2 17:03:32 2006 From: SWODY2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 02 Apr 2006 13:03:32 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 021701 SWODY2 SPC AC 021700 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1200 PM CDT SUN APR 02 2006 VALID 031200Z - 041200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF THE CNTRL APPALACHIANS EWD INTO THE MIDDLE ATLANTIC STATES AND CAROLINAS... ...SYNOPSIS... MID-LEVEL TROUGH...ANCHORED BY LOW OVER ONTARIO...IS FORECAST TO BECOME NEGATIVELY-TILTED OVER THE ERN U.S. AS STRONG MID AND HIGH-LEVEL JET STREAKS DEVELOP SEWD FROM THE MID MS VALLEY INTO THE CAROLINAS. IN THE LOW-LEVELS...OCCLUDING SURFACE LOW OVER LOWER MI WILL DEVELOP NEWD INTO WRN QUEBEC WHILE TRAILING COLD FRONT SURGES EWD THROUGH THE UPPER OH VALLEY...APPALACHIAN CHAIN INTO THE ADJACENT COASTAL PLAIN. MEANWHILE...WARM FRONT WILL SLOWLY LIFT NWD THROUGH THE MIDDLE ATLANTIC STATES INTO SRN NEW ENGLAND WITH SECONDARY CYCLOGENESIS OCCURRING AT INTERSECTION OF WARM AND COLD FRONTS. THIS SECONDARY SURFACE LOW WILL DEVELOP NEWD FROM NRN VA INTO SRN NEW ENGLAND BY TUESDAY MORNING. ...CNTRL APPALACHIANS / MIDDLE ATLANTIC COAST SWD INTO THE CAROLINAS... A BROKEN BAND OF PRE-FRONTAL CONVECTION IS EXPECTED TO BE ONGOING AT THE ONSET OF THE FORECAST PERIOD FROM PORTIONS OF THE UPPER OH VALLEY SWWD ALONG THE SPINE OF THE APPALACHIANS AND INTO NRN PORTIONS OF MS/AL/GA. THIS ACTIVITY MAY TEND TO WEAKEN THROUGH THE DAY AS IT SHIFTS EWD AWAY FROM THE STRONGER FORCING FOR ASCENT AND INSTABILITY. IN IT/S WAKE...STRONG HEIGHT FALLS...DAYTIME HEATING AND LOW-LEVEL MOISTENING FROM THE S AND SW WILL ALL CONTRIBUTE TO AIR MASS DESTABILIZATION AHEAD DEEP COLD FRONTAL ZONE RAPIDLY SWEEPING EWD. THIS DESTABILIZATION WILL RESULT IN SBCAPES INCREASING TO 250-500 J/KG OVER PORTIONS OF PA...TO AS HIGH AS 1000-2000 J/KG OVER SERN VA INTO THE CNTRL AND ERN CAROLINAS. A MORE FOCUSED LINE OF VIGOROUS TSTM DEVELOPMENT IS ANTICIPATED BY EARLY AFTERNOON ALONG FRONT...INITIALLY ALONG NRN PORTION OF INSTABILITY AXIS OVER ERN OH/WRN PA...WITH SUBSEQUENT SWD DEVELOPMENT INTO THE CNTRL APPALACHIANS. WHILE NRN EXTENSION OF THIS DIURNAL DEVELOPMENT MAY EXHAUST AVAILABLE INSTABILITY OVER PA/NY BY LATE AFTERNOON...OTHER STORMS MOVING INTO VA AND THE CAROLINAS SHOULD CONTINUE TO INTENSIFY AS THEY ENCOUNTER INCREASINGLY UNSTABLE AIR MASS. IT APPEARS THAT THE MOST CONCENTRATED ZONE OF SEVERE TSTMS WILL OCCUR ALONG AND S OF SECONDARY SURFACE LOW TRIPLE POINT OVER CNTRL AND ERN PORTIONS OF VA AND NC PERHAPS INTO SC. HERE...STRONG VERTICAL SHEAR PROFILES OWING TO PROXIMITY OF MID AND UPPER-LEVEL JET STREAKS WILL BECOME CO-LOCATED WITH THE MODERATE INSTABILITY. WHILE LINE SEGMENTS AND BOWS CAPABLE OF LARGE HAIL AND DAMAGING WINDS WILL BE THE PRIMARY CONVECTIVE MODE...RELATIVELY STRONG LOW-LEVEL SHEAR SUGGESTS THE POTENTIAL FOR SUPERCELLS CAPABLE OF TORNADOES. THESE STORMS SHOULD EVENTUALLY MOVE OFFSHORE BY MID TO LATE MONDAY EVENING. FARTHER TO THE SW OVER SC INTO GA...ADDITIONAL MORE ISOLATED TSTMS WILL BE POSSIBLE DURING THE AFTERNOON AND EVENING HOURS. MODERATE INSTABILITY COUPLED WITH MODEST DEEP-LAYER SHEAR SUGGESTS SOME POTENTIAL FOR ISOLATED DAMAGING WINDS AND HAIL...THOUGH THE WEAKER LARGE-SCALE FORCING WITH SWD EXTENT SHOULD TEND TO LIMIT THE OVERALL SEVERE THREAT. ..MEAD.. 04/02/2006  From SWODY2 at goshenarc.org Mon Apr 3 06:27:17 2006 From: SWODY2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 03 Apr 2006 02:27:17 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 030624 SWODY2 SPC AC 030623 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0123 AM CDT MON APR 03 2006 VALID 041200Z - 051200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... POWERFUL TROUGH NOW CROSSING THE MIDWEST IS FORECAST TO PHASE WITH A STRONG NRN STREAM IMPULSE DROPPING SOUTH FROM CNTRL CANADA AND PROMOTE EAST COAST CYCLOGENESIS THROUGH THE DAY 1 PERIOD. RESULTING NOREASTER WILL TRACK TOWARD THE GULF OF MAINE AND UNDERGO OCCLUSION AS A DEEP LAYER CYCLONE FORMS ACROSS NEW ENGLAND THROUGH MIDWEEK. MEANWHILE...A BRIEF RESPITE FROM SEVERE WEATHER WILL ENSUE ACROSS THE PLAINS AND MIDWEST TUESDAY AS UPPER RIDGE STRENGTHENS OVER THESE REGIONS. HOWEVER...INTENSIFYING WARM AIR AND MOISTURE ADVECTION BENEATH PLAINS CAPPING/SUBSIDENCE INVERSION COULD PROMOTE MCS DEVELOPMENT WITHIN ZONE OF LARGE SCALE JET COUPLING...FROM THE SRN PLAINS ACROSS THE MO OZARKS...BY EARLY WEDNESDAY. IN THE WEST...COLD UPPER TROUGH IS FORECAST TO DEVELOP INLAND FROM THE ERN PACIFIC WITH STRONG HEIGHT FALLS SPREADING EWD FROM CA TO THE GREAT BASIN AND LOWER CO VALLEY. ...CNTRL CA... LATEST WATER VAPOR LOOP DEPICTS CONSIDERABLE SHORT WAVE ENERGY CONSOLIDATING WITHIN THE LARGE CLOSED LOW OFF THE WEST COAST. MODEL GUIDANCE CONTINUES TO PREDICT THAT THIS COMPLEX TROUGH/LOW WILL REDEVELOP INLAND THROUGH TUESDAY AS 100KT MID LEVEL JET STREAK CROSSES SRN CA AND THE LOWER CO VALLEY. DESPITE RELATIVELY WEAK SHEAR NEAR THE CORE OF THE LARGE MID/UPPER LOW...VERY COLD MID LEVEL TEMPERATURES OF -26C TO -30C WILL MOVE OVER PORTIONS OF CNTRL CA THROUGH THE DAY. LOW STATIC STABILITY COMBINED WITH MARGINAL MOISTURE...OROGRAPHIC FORCING...AND POSSIBILITY OF POCKETS OF MODEST DIURNAL HEATING...SHOULD PROMOTE SCATTERED TSTM DEVELOPMENT FROM THE COAST INLAND ACROSS THE CENTRAL VALLEY. MARGINAL HAIL SHOULD BE THE PRIMARY HAZARD FROM THIS CONVECTION. ...SRN PLAINS TO KS/MO LATE... NAM-ETA WAS FORECASTING SOME POTENTIAL FOR ELEVATED TSTMS OVER CNTRL/NWRN TX THROUGH EARLY TUESDAY WHERE LEADING EDGE OF LOW LEVEL MOISTURE RETURN WILL BE LIFTED ACROSS RETREATING SYNOPTIC FRONT. HOWEVER...THIS CONVECTIVE POTENTIAL MAY BE QUICKLY INHIBITED BY INCREASING SUBSIDENCE AND WARMING TEMPERATURES WITHIN BUILDING MID/UPPER LEVEL RIDGE....AT LEAST THROUGH LATE AFTERNOON. ELEVATED MIXED LAYER IS EXPECTED TO STRENGTHEN ACROSS THE PLAINS THROUGH THE DAY AND PROMOTE EFFICIENT CHANNELING OF LOW LEVEL MOISTURE NWD/NEWD WITHIN INTENSIFYING LOW LEVEL JET. A WEAK IMPULSE...POSSIBLY EMANATING FROM SRN PORTION OF WEST COAST TROUGH...IS FORECAST TO CREST THE RIDGE OVER THE PLAINS AND COULD SUPPORT ISOLATED HIGH-BASED CONVECTION OVER PARTS OF THE TX PANHANDLE/WRN OK/SWRN KS IF STRONG HEATING IN THESE AREAS CAN OVERCOME THE CAP. A MORE LIKELY SCENARIO IS THAT THE WEAK MID LEVEL IMPULSE WILL CONTINUE TO TRACK EAST AND....COUPLED WITH PERSISTENT ISENTROPIC LIFT AND MOISTENING ON THE NOSE OF THE LOW LEVEL JET...PROMOTE LATE NIGHT ELEVATED STORMS TO FORM NEAR THE EDGE OF THE CAP...FROM NERN OK/SERN KS INTO MO. BY EARLY WEDNESDAY...SHEAR AND INSTABILITY ACROSS THESE AREAS SHOULD PROVE ADEQUATE FOR A FEW HAIL EVENTS...IF STORMS CAN DEVELOP IN THIS REGIME. ..CARBIN.. 04/03/2006  From SwoDy2 at goshenarc.org Mon Apr 3 17:42:59 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 03 Apr 2006 13:42:59 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 031740 SWODY2 SPC AC 031739 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1239 PM CDT MON APR 03 2006 VALID 041200Z - 051200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... HIGHLY AMPLIFIED UPPER AIR PATTERN FCST THROUGH PERIOD...WITH MEAN TROUGHS OVER E AND W COASTS AND RIDGE ACROSS PLAINS STATES. MIDDLE-UPPER LEVEL CYCLONE -- NOW CENTERED OVER SERN LOWER MI -- IS FCST TO EJECT NEWD AS OPEN WAVE WHILE ANOTHER MIDDLE-UPPER LEVEL LOW OVER NRN ONT DIGS SEWD ACROSS GREAT LAKES AND NY. ASSOCIATED SFC COLD FRONT WILL SWEEP OFFSHORE MOST OF ATLANTIC COAST FROM MID ATLANTIC STATES SWD TO CENTRAL/NRN FL. WRN REMNANT OF THIS FRONT WILL STALL LATE DAY-1 OVER NRN GULF AND S TX...THEN BECOME DIFFUSE AND RETURN NWD OVER SRN/CENTRAL TX DAY-2. MEANWHILE...DEEP UPPER LOW -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY AROUND 36N134W -- IS FCST TO PIVOT EWD THROUGH DAY-2 WITH STRONG SHORTWAVE TROUGH MOVING ONSHORE SRN CA AROUND 5/06Z. BROAD PLUME OF WAA AND MIDLEVEL MOIST ADVECTION WILL OVERSPREAD MUCH OF WRN CONUS AHEAD OF THIS SYSTEM. NET RESULT WILL BE SEVERAL AREAS OF MRGL AND OR CONDITIONAL SEVERE POTENTIAL. ...EARLY MORNING -- TX/SERN NM... MRGL/CONDITIONAL HAIL PROBABILITIES EXIST OVER THIS REGION FOR FIRST FEW HOURS OF PERIOD...AMIDST EXTENSION OF LATE DAY-1 WAA/MOISTURE RETURN REGIME. ELEVATED BUOYANCY IS FCST TO BE SMALL -- GENERALLY AOB 500 J/KG MOST AREAS. HOWEVER...ANY SUSTAINED CONVECTION WILL HAVE POTENTIAL FOR HAIL GIVEN STRONG VEERING AND SPEED SHEAR WITH HEIGHT THROUGH CONVECTIVE COLUMN...WHICH SHOULD BE ROOTED IN 800-850 MB LAYER BASED ON FCST SOUNDINGS. ACTIVITY SHOULD DIMINISH DURING LATE MORNING AS LLJ WEAKENS. ...AFTERNOON/EVENING -- CA... CONDITIONAL THREAT FOR SEVERE EXISTS BOTH OVER CENTRAL VALLEY AND COASTAL AREAS...AMIDST WEAK CINH AND AT LEST MRGL MUCAPES OF 100-400 J/KG. LOW LEVEL MOIST ADVECTION AND STEEPENING LAPSE RATES ALOFT SHOULD SUPPORT SCATTERED TSTMS...PARTICULARLY DURING AFTERNOON WHERE BREAKS IN CLOUD COVER CAN ALLOW POCKETS OF DIABATIC SFC HEATING. VERTICAL SHEAR PROFILES ACROSS PORTIONS COASTAL SRN CA ARE FCST TO BE LARGE -- CHARACTERIZED BY STRONG VEERING WITH HEIGHT AND STRENGTHENING MIDLEVEL FLOW GRADIENTS AHEAD OF SHORTWAVE TROUGH. BASIC PATTERN RESEMBLES THAT OF SOME L.A. BASIN SUPERCELL CASES AND THIS AREA MAY REQUIRE ENHANCED PROBABILITIES ONCE TIMING/STRENGTH OF FEATURES ALOFT BECOMES BETTER ESTABLISHED. INLAND...DEEP-LAYER WINDS WILL BE MORE UNIDIRECTIONAL WITH STRONG MERIDIONAL COMPONENT...THOUGH OROGRAPHICALLY FORCED BACKING SHOULD ENHANCED SHEAR OVER PORTIONS CENTRAL VALLEY. ...AFTERNOON/EVENING -- GREAT BASIN... WIDELY SCATTERED TSTMS ARE EXPECTED TO DEVELOP OVER PORTIONS BASIN -AND-RANGE REGION -- SHIFTING/EVOLVING NWD TOWARD SNAKE RIVER VALLEY. MAIN CONCERN IS ISOLATED GUSTS NEAR SEVERE LEVELS. MAIN LIMITING FACTOR IS WEAK BOUNDARY LAYER MOISTURE...WHICH WILL LIMIT MLCAPES TO BELOW 250 J/KG MOST AREAS. STRONG VERTICAL MIXING IS LIKELY DURING AFTERNOON...WEAKENING CINH AND RESULTING IN POTENTIAL FOR TSTM FORMATION. STRONG MIDLEVEL FLOW WILL SUPPORT 40-60 KT DEEP-LAYER SHEAR IN SUPPORT OF POTENTIAL FOR STRONG-SEVERE GUSTS FROM MOST VIGOROUS CONVECTION. ...LATE OVERNIGHT -- OZARKS TO E-CENTRAL PLAINS... SCATTERED TSTMS SHOULD DEVELOP MAINLY AFTER 5/06Z IN THIS REGION...WITH ISOLATED HAIL POSSIBLE. LOW LEVEL WAA/MOIST ADVECTION REGIME WILL INTENSIFY THROUGH PERIOD...CULMINATING IN RETURN OF FAVORABLE INCREASING LOW LEVEL MOISTURE AFTER DARK FROM MUCH OF AR NWWD OVER PORTIONS NERN OK...ERN KS AND WRN MO. ETA/SPECTRAL FCSTS OF CONVECTIVE DEVELOPMENT OVER THIS REGION APPEAR REASONABLE BASED ON UPSTREAM MOISTURE PROFILES EVIDENT ACROSS S TX AND WRN GULF. EXPECT From SwoDy2 at goshenarc.org Mon Apr 3 17:42:59 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 03 Apr 2006 13:42:59 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 031740 SWODY2 SPC AC 031739 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1239 PM CDT MON APR 03 2006 VALID 041200Z - 051200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... HIGHLY AMPLIFIED UPPER AIR PATTERN FCST THROUGH PERIOD...WITH MEAN TROUGHS OVER E AND W COASTS AND RIDGE ACROSS PLAINS STATES. MIDDLE-UPPER LEVEL CYCLONE -- NOW CENTERED OVER SERN LOWER MI -- IS FCST TO EJECT NEWD AS OPEN WAVE WHILE ANOTHER MIDDLE-UPPER LEVEL LOW OVER NRN ONT DIGS SEWD ACROSS GREAT LAKES AND NY. ASSOCIATED SFC COLD FRONT WILL SWEEP OFFSHORE MOST OF ATLANTIC COAST FROM MID ATLANTIC STATES SWD TO CENTRAL/NRN FL. WRN REMNANT OF THIS FRONT WILL STALL LATE DAY-1 OVER NRN GULF AND S TX...THEN BECOME DIFFUSE AND RETURN NWD OVER SRN/CENTRAL TX DAY-2. MEANWHILE...DEEP UPPER LOW -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY AROUND 36N134W -- IS FCST TO PIVOT EWD THROUGH DAY-2 WITH STRONG SHORTWAVE TROUGH MOVING ONSHORE SRN CA AROUND 5/06Z. BROAD PLUME OF WAA AND MIDLEVEL MOIST ADVECTION WILL OVERSPREAD MUCH OF WRN CONUS AHEAD OF THIS SYSTEM. NET RESULT WILL BE SEVERAL AREAS OF MRGL AND OR CONDITIONAL SEVERE POTENTIAL. ...EARLY MORNING -- TX/SERN NM... MRGL/CONDITIONAL HAIL PROBABILITIES EXIST OVER THIS REGION FOR FIRST FEW HOURS OF PERIOD...AMIDST EXTENSION OF LATE DAY-1 WAA/MOISTURE RETURN REGIME. ELEVATED BUOYANCY IS FCST TO BE SMALL -- GENERALLY AOB 500 J/KG MOST AREAS. HOWEVER...ANY SUSTAINED CONVECTION WILL HAVE POTENTIAL FOR HAIL GIVEN STRONG VEERING AND SPEED SHEAR WITH HEIGHT THROUGH CONVECTIVE COLUMN...WHICH SHOULD BE ROOTED IN 800-850 MB LAYER BASED ON FCST SOUNDINGS. ACTIVITY SHOULD DIMINISH DURING LATE MORNING AS LLJ WEAKENS. ...AFTERNOON/EVENING -- CA... CONDITIONAL THREAT FOR SEVERE EXISTS BOTH OVER CENTRAL VALLEY AND COASTAL AREAS...AMIDST WEAK CINH AND AT LEST MRGL MUCAPES OF 100-400 J/KG. LOW LEVEL MOIST ADVECTION AND STEEPENING LAPSE RATES ALOFT SHOULD SUPPORT SCATTERED TSTMS...PARTICULARLY DURING AFTERNOON WHERE BREAKS IN CLOUD COVER CAN ALLOW POCKETS OF DIABATIC SFC HEATING. VERTICAL SHEAR PROFILES ACROSS PORTIONS COASTAL SRN CA ARE FCST TO BE LARGE -- CHARACTERIZED BY STRONG VEERING WITH HEIGHT AND STRENGTHENING MIDLEVEL FLOW GRADIENTS AHEAD OF SHORTWAVE TROUGH. BASIC PATTERN RESEMBLES THAT OF SOME L.A. BASIN SUPERCELL CASES AND THIS AREA MAY REQUIRE ENHANCED PROBABILITIES ONCE TIMING/STRENGTH OF FEATURES ALOFT BECOMES BETTER ESTABLISHED. INLAND...DEEP-LAYER WINDS WILL BE MORE UNIDIRECTIONAL WITH STRONG MERIDIONAL COMPONENT...THOUGH OROGRAPHICALLY FORCED BACKING SHOULD ENHANCED SHEAR OVER PORTIONS CENTRAL VALLEY. ...AFTERNOON/EVENING -- GREAT BASIN... WIDELY SCATTERED TSTMS ARE EXPECTED TO DEVELOP OVER PORTIONS BASIN -AND-RANGE REGION -- SHIFTING/EVOLVING NWD TOWARD SNAKE RIVER VALLEY. MAIN CONCERN IS ISOLATED GUSTS NEAR SEVERE LEVELS. MAIN LIMITING FACTOR IS WEAK BOUNDARY LAYER MOISTURE...WHICH WILL LIMIT MLCAPES TO BELOW 250 J/KG MOST AREAS. STRONG VERTICAL MIXING IS LIKELY DURING AFTERNOON...WEAKENING CINH AND RESULTING IN POTENTIAL FOR TSTM FORMATION. STRONG MIDLEVEL FLOW WILL SUPPORT 40-60 KT DEEP-LAYER SHEAR IN SUPPORT OF POTENTIAL FOR STRONG-SEVERE GUSTS FROM MOST VIGOROUS CONVECTION. ...LATE OVERNIGHT -- OZARKS TO E-CENTRAL PLAINS... SCATTERED TSTMS SHOULD DEVELOP MAINLY AFTER 5/06Z IN THIS REGION...WITH ISOLATED HAIL POSSIBLE. LOW LEVEL WAA/MOIST ADVECTION REGIME WILL INTENSIFY THROUGH PERIOD...CULMINATING IN RETURN OF FAVORABLE INCREASING LOW LEVEL MOISTURE AFTER DARK FROM MUCH OF AR NWWD OVER PORTIONS NERN OK...ERN KS AND WRN MO. ETA/SPECTRAL FCSTS OF CONVECTIVE DEVELOPMENT OVER THIS REGION APPEAR REASONABLE BASED ON UPSTREAM MOISTURE PROFILES EVIDENT ACROSS S TX AND WRN GULF. EXPECT ISENTROPIC LIFT OF PARCELS TO LFC WITH ELEVATED MUCAPES INCREASING TO AROUND 250-500 J/KG. 35-40 KT EFFECTIVE SHEARS IN FCST SOUNDINGS SUGGEST SOME POTENTIAL FOR TSTMS TO BECOME ORGANIZED AND PRODUCE HAIL. ..EDWARDS.. 04/03/2006  From SwoDy2 at goshenarc.org Tue Apr 4 06:24:43 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 04 Apr 2006 02:24:43 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 040622 SWODY2 SPC AC 040621 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0121 AM CDT TUE APR 04 2006 VALID 051200Z - 061200Z ...THERE IS A SLGT RISK OF SVR TSTMS LATE WEDNESDAY/EARLY THURSDAY ACROSS SD AND NERN NEB... ...SYNOPSIS... LARGE AND COMPLEX UPPER TROUGH OFF THE WEST COAST IS FORECAST TO ACCELERATE INLAND AND CROSS THE GREAT BASIN/INTERMOUNTAIN REGIONS THROUGH THE DAY 1 PERIOD BEFORE A LARGE AREA OF STRONG HEIGHT FALLS ASSOCIATED WITH THIS DISTURBANCE SPREADS OVER GREAT PLAINS WEDNESDAY NIGHT THROUGH THURSDAY. MEANWHILE...A STRONG UPPER RIDGE CURRENTLY ACROSS THE PLAINS WILL SHIFT EAST TO THE MS VALLEY AND GRADUALLY DEAMPLIFY. DOWNSTREAM FROM THE CNTRL U.S. UPPER RIDGE...A DEEP POLAR VORTEX WILL FORM OVER THE NORTHEAST AND DRIFT EWD. HIGH AMPLITUDE FLOW REGIME ACROSS THE WRN AND CNTRL STATES WILL ALLOW DEEP LAYER SLY/SWLY WINDS TO PERSIST AND STRENGTHEN AHEAD OF THE WRN TROUGH THROUGH WEDNESDAY. SUBSIDENCE BENEATH THE UPPER RIDGE AND STEADY WARMING ACROSS THE HIGH PLAINS THROUGH WEDNESDAY WILL RESULT IN AN EXTENSIVE ELEVATED MIXED LAYER AIRMASS DEVELOPING FROM THE SOUTHERN ROCKIES/HIGH PLAINS NWD TO THE DAKOTAS. LEE CYCLOGENESIS IS EXPECTED TO COMMENCE ACROSS CO/WY/MT BY WEDNESDAY EVENING AS STRONG DYNAMIC FORCING AHEAD OF THE UPPER TROUGH MOVES NEWD OVER THESE AREAS. ASSOCIATED WARM FRONT SHOULD FORM AND LIFT NWD ACROSS THE NRN PLAINS OVERNIGHT AS STRONG PACIFIC COLD FRONT SPREADS EAST FROM THE ROCKIES AND INTO THE HIGH PLAINS THROUGH THURSDAY MORNING. ...HIGH PLAINS /WRN TX TO WRN NEB/ THROUGH WEDNESDAY EVENING... DESPITE STRONG LOW LEVEL SLY FLOW DEVELOPING ACROSS THE PLAINS THROUGH THE PERIOD...LATEST GUIDANCE CONTINUES TO SUGGEST THAT MOISTURE RETURN ACROSS THE PLAINS WILL BE LESS THAN ROBUST INTO THE DAY 2 PERIOD. MODELS APPEAR TO SUGGEST THAT EITHER A POCKET...OR NARROW AXIS...OF GREATER LOW LEVEL MOISTURE /850MB DEWPOINTS AROUND 10C/ WILL ADVECT NWD AND THEN NEWD FROM LOWER RIO GRANDE VALLEY...ACROSS THE SRN PLAINS...TO THE MO RIVER VALLEY THROUGH THE PERIOD. WEAK HEIGHT FALLS COUPLED WITH DEEP MIXING/HEATING AND CONFLUENT FLOW NEAR DRYLINE/LEE TROUGH...FROM WEST TX TO THE NEB PANHANDLE...MAY PROMOTE HIGH-BASED TSTM DEVELOPMENT BY WEDNESDAY EVENING. EXPECT THE BULK OF THIS ACTIVITY TO STRUGGLE TO PERSIST GIVEN POTENTIAL FOR STRONG INHIBITION... ESPECIALLY FROM KS/NEB AREA SWD AFTER DARK. HOWEVER...A FEW HIGH-BASED SUPERCELLS COULD RESULT IN A COUPLE OF ISOLATED HAIL/WIND EVENTS. ...NRN PLAINS... CONDITIONS FOR VIGOROUS DEEP CONVECTION SHOULD IMPROVE THROUGH LATE WEDNESDAY EVENING FROM ERN WY/MT EWD ACROSS NEB AND SD. STRONG DYNAMIC FORCING ASSOCIATED WITH INCREASINGLY DIFFLUENT FLOW ALOFT WILL SPREAD NEWD ATOP INTENSIFYING ZONE OF WARM AIR ADVECTION OVER THE NRN PLAINS. SCATTERED TSTMS WITH A MARGINAL THREAT OF HAIL AND STRONG WINDS MAY FIRST INITIATE ACROSS THE HIGHER TERRAIN OF WY/MT WHERE INHIBITION AND CAPE WILL BE WEAKER. WHILE WARM SECTOR SURFACE PARCELS WILL LIKELY REMAIN CAPPED BY STRONG ELEVATED MIXED LAYER THROUGH THE EVENING...HIGH-BASED STORMS SHOULD DEVELOP EAST AND PERSIST AS MOISTENING...LIFT...AND DESTABILIZATION ALL INCREASE WITHIN THE WARM FRONTAL ZONE. LATEST GUIDANCE WOULD SUPPORT A SEVERE MCS MOVING EAST ACROSS SD/NERN NEB THROUGH DAYBREAK THURSDAY WITH THE PRIMARY HAZARD BEING LARGE HAIL. ..CARBIN.. 04/04/2006  From SwoDy2 at goshenarc.org Wed Apr 5 06:21:20 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 05 Apr 2006 02:21:20 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 050618 SWODY2 SPC AC 050617 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0117 AM CDT WED APR 05 2006 VALID 061200Z - 071200Z ...THERE IS A MDT RISK OF SVR TSTMS OVER A LARGE AREA OF THE CENTRAL AND SOUTHERN PLAINS FROM NEBRASKA/AND SOUTHWEST IOWA TO EASTERN NEBRASKA AND OKLAHOMA...MUCH OF MISSOURI AND NORTHWEST ARKANSAS... ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK AREA FROM THE SRN/CNTRL PLAINS TO THE OH VALLEY... ...SIGNIFICANT SEVERE WEATHER OUTBREAK APPEARS INCREASINGLY LIKELY OVER THE PLAINS/MIDWEST ON THURSDAY... ...SYNOPSIS... VERY ACTIVE WEATHER PATTERN WILL CONTINUE TO EVOLVE WEDNESDAY INTO THURSDAY WITH THE POTENTIAL FOR WIDESPREAD SEVERE WEATHER DEVELOPING ACROSS THE PLAINS...AND POSSIBLY SPREADING EAST ACROSS THE MIDWEST AND OH VALLEY AREAS FROM THURSDAY THROUGH EARLY FRIDAY. THE SYSTEM EXPECTED TO BRING ABOUT THE NEXT ROUND OF SPRINGTIME SEVERE WEATHER WAS CROSSING THE WEST COAST IN THE FORM OF A COMPLEX DOUBLE-VORTEX UPPER TROUGH EARLY TODAY. STRONG DEEP-LAYER ASCENT WAS OBVIOUS AHEAD OF THE TROUGH AND RADAR AND SATELLITE IMAGERY WERE INDICATING PRONOUNCED DIFFLUENT MID/UPPER LEVEL FLOW PROMOTING CONVECTION FROM CA TO ID. UPSTREAM FROM THE WEST COAST TROUGH... ANOTHER POTENT IMPULSE WAS DEPICTED ON SATELLITE IMAGERY MOVING SOUTH OF THE GULF OF AK. DESPITE RELATIVELY HIGH AMPLITUDE FLOW REGIME...CONSIDERABLE JET ENERGY WITH THE UPSTREAM SYSTEM WILL DISLODGE THE WEST COAST TROUGH INLAND AND ACROSS THE ROCKIES THROUGH DAY 1. A BELT OF 80-90KT MID LEVEL FLOW OF WILL ROTATE THROUGH THE BASE OF THE TROUGH AND NOSE OUT ATOP THE SRN/CNTRL HIGH PLAINS THROUGH 36 HOURS...BY THURSDAY MORNING. STRONG DYNAMIC FORCING ACCOMPANYING THE UPPER SYSTEM WILL INDUCE LEE-SIDE CYCLOGENESIS ACROSS WY/MT TONIGHT AND THEN THE DEEPENING SURFACE LOW WILL REFORM EWD ACROSS NEB THROUGH THURSDAY MORNING. LATEST MODEL FORECASTS SUGGEST AN OVERALL SCENARIO STRONGER AND SOMEWHAT FURTHER SOUTH WITH THE CYCLONE THAN MODEL GUIDANCE FROM 24 HOURS AGO. WHILE THIS SUGGESTS A POSSIBLE TREND...ALL THE LATEST DETERMINISTIC GUIDANCE IS IN GOOD AGREEMENT WITH TIMING AND INTENSITY OF THE LARGE SCALE FEATURES TO AFFECT SEVERE WEATHER EVOLUTION FROM THE PLAINS TO THE MIDWEST ON THURSDAY. ...NEB/IA... THERE MAY BE AN ARC OF DEEP CONVECTION UNDERWAY EARLY IN THE DAY FROM NEAR/NORTH OF THE SURFACE LOW...EWD AND SEWD ALONG AND NORTH OF THE WARM FRONT...FROM NEB/SD...ACROSS IA...AND PERHAPS OVER IL. THIS ACTIVITY WILL LIKELY BE SUSTAINED BY INTENSIFYING LARGE SCALE ISENTROPIC LIFT OCCURRING ON THE EDGE OF EXTENSIVE PLAINS CAPPING INVERSION. WHILE ELEVATED IN NATURE...SOME OF THESE STORMS STILL PRODUCE HAIL. STRONG CAP ACROSS MUCH OF THE WARM SECTOR WILL AID IN EFFICIENT LOW LEVEL MOISTURE TRANSPORT NWD ACROSS KS/MO/ERN NEB AND IA WITH A GENERAL CONSENSUS AMONG AVAILABLE GUIDANCE THAT AT LEAST LOW 60S F DEWPOINTS SHOULD DEVELOP ACROSS THESE AREAS BY AFTERNOON. DEEP LAYER WIND FIELDS SURROUNDING THE INTENSIFYING CYCLONE OVER NEB WILL STRENGTHEN THROUGH THE DAY AS WARM FRONT LIFTS NWD ACROSS ERN NEB AND MUCH OF IA...AND DRYLINE SHARPENS FROM NEB SWD ACROSS KS/OK. STRONG ASCENT BENEATH THE NOSE OF THE MID LEVEL JET...AND NEAR SURFACE LOW/WARM FRONT WILL EFFECTIVELY OVERCOME THE CAP ACROSS NEB/IA THROUGH AFTERNOON. STEEP MID LEVEL LAPSE RATES OF ABOUT 8 C/KM ATOP MOISTENING BOUNDARY LAYER WILL CONTRIBUTE TO MLCAPE IN THE RANGE OF 500-1000 J/KG...AND PERHAPS LOCALLY HIGHER IN AREAS WHERE MOISTURE/HEATING CAN BE MAXIMIZED. ROBUST SURFACE-BASED TSTM DEVELOPMENT SHOULD COMMENCE AS CAP IS BREACHED ACROSS NEB AND INTO IA FROM AFTERNOON INTO EVENING. SHEAR WILL BE MORE THAN ADEQUATE FOR SUPERCELLS AND VERY LARGE HAIL...HIGH WIND...AND TORNADOES APPEAR LIKELY. TORNADO POTENTIAL WILL DEPEND ON QUALITY OF MOISTURE RETURN INTO THE AREA...AND SPECIFIC LOCATION OF THE SURFACE LOW....WARM FRONT...AND MESOSCALE BOUNDARIES. FORECAST SOUNDINGS FROM ERN NEB...ACROSS THE MO RIVER INTO WRN IA APPEAR TO SUGGEST THAT CONDITIONS FOR STRONG TORNADOES COULD DEVELOP IN THIS AREA THROUGH THE THURSDAY EVENING. ...ERN KS/OK...MO...AR... CLASSIC DRYLINE SURGE WILL DEVELOP EAST FROM KS/OK INTO MO/AR FROM AFTERNOON THROUGH EVENING. STRONG CAPPING ACROSS LOW LEVEL MOIST AXIS WILL CONTRIBUTE TO THE DEVELOPMENT OF MODEST INSTABILITY INTO THE AFTERNOON BEFORE STRONG HEIGHT FALLS AND MIXING ON THE ADVANCING DRYLINE PROMOTE STORM INITIATION IN MODERATE TO LOCALLY STRONG CAPE ENVIRONMENT. ALREADY STRONG DEEP LAYER SHEAR WILL INTENSIFY FURTHER THROUGH LATE AFTERNOON AS 80KT MID LEVEL JET SPREADS ACROSS THE DRYLINE AND LOW LEVEL JET INTENSIFIES TO 50KT ACROSS THE OZARKS. A SECONDARY AREA OF POSSIBLY LONG-TRACK AND FAST MOVING TORNADOES...IN ADDITION TO VERY LARGE HAIL AND HIGH WINDS....COULD DEVELOP AHEAD OF THE DRYLINE THROUGH THE EVENING. PARTS OF BOTH NEB/IA AND THE ERN KS/OK AND WRN MO/AR AREAS MAY BE UPGRADED TO HIGH RISK IN LATER OUTLOOKS IF MODEL GUIDANCE OVER THE NEXT DAY CONTINUES TO SUGGEST A STRONG POTENTIAL FOR THE DEVELOPMENT OF DANGEROUS WEATHER IN THESE AREAS. ....EAST FROM THE MS RIVER TO IL/IND/OH... WHILE THE PRIMARY CYCLONE UNDERGOES OCCLUSION OVER THE PLAINS THROUGH LATE IN THE DAY 2 PERIOD...INTENSE MID LEVEL WIND MAX WILL SPREAD EAST ACROSS THE MIDWEST THROUGH LATE THURSDAY NIGHT. MODELS SUGGEST A FRONTAL WAVE...POSSIBLY CONVECTIVELY INDUCED....MAY DEVELOP RAPIDLY EWD ALONG THE WARM FRONT...FROM ERN IA/MO TO IND THROUGH LATE EVENING. DESPITE WEAKENING INSTABILITY WITH EWD EXTENT...A PLUME OF STRONGER INSTABILITY MAY STREAM INTO THESE AREAS FROM THE LOWER OH VALLEY. THREAT FOR DAMAGING WINDS AND POSSIBLY SOME LATE NIGHT TORNADOES MAY ACCOMPANY AN MCS OR TWO EVOLVING OUT OF THE PLAINS CONVECTION AND SUPPORTED/MAINTAINED BY LARGER SCALE DYNAMICS. ..CARBIN.. 04/05/2006  From SwoDy2 at goshenarc.org Wed Apr 5 17:35:21 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 05 Apr 2006 13:35:21 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 051732 SWODY2 SPC AC 051731 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1231 PM CDT WED APR 05 2006 VALID 061200Z - 071200Z ...THERE IS A MDT RISK OF SVR TSTMS FROM PARTS OF THE SRN AND CNTRL PLAINS THROUGH THE LOWER AND MIDDLE MS VALLEY... ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE SRN AND CNTRL PLAINS THROUGH THE LOWER AND MIDDLE MS VALLEY AND INTO THE OH VALLEY... ...SYNOPSIS... LARGE SCALE PATTERN WILL REMAIN PROGRESSIVE THIS PERIOD. THE UPPER TROUGH NOW OVER THE WRN STATES WILL MOVE INTO THE CNTRL AND SRN HIGH PLAINS THURSDAY...REACHING THE MIDDLE AND LOWER MS VALLEY THURSDAY EVENING. LEE CYCLOGENESIS WILL COMMENCE OVER THE CNTRL HIGH PLAINS TONIGHT WITHIN ZONE OF HEIGHT FALLS ACCOMPANYING THE UPPER TROUGH. SYNOPTIC WARM FRONT WILL DEVELOP AND EXTEND EWD FROM THE LOW THROUGH NEB AND INTO THE MID MS VALLEY BY EARLY THURSDAY. THE LEE CYCLONE WILL CONTINUE EAST THROUGH NEB THURSDAY WITH TRAILING PACIFIC FRONT EXTENDING SWD THROUGH THE CNTRL AND SRN PLAINS. THIS BOUNDARY IS FORECAST TO ADVANCE INTO THE MIDDLE MS VALLEY THURSDAY NIGHT...WHILE THE SURFACE LOW OCCLUDES OVER ERN NEB. ...CNTRL AND ERN NEB...IA THROUGH NERN KS AND NRN MO... PARTIALLY MODIFIED GULF AIR WITH DEWPOINTS IN THE LOW 60S IS ADVANCING NWD THROUGH THE SRN PLAINS AS FAR NORTH AS SRN OK. HOWEVER...12Z RAOB DATA FROM DFW...CRP...AND BRO SHOW THE DEPTH OF THE MOIST BOUNDARY LAYER IS SHALLOW...GENERALLY AOB 950 MB. THIS IMPLIES THAT AFTERNOON MIXING MAY LOWER THE DEWPOINTS AND SLOW THE NWD ADVANCE OF THE RICHER LOW LEVEL MOISTURE. THE STRONG SLY LOW LEVEL JET TONIGHT INTO THURSDAY WILL CONTINUE TO ADVECT PARTIALLY MODIFIED GULF AIR NWD INTO THE CNTRL PLAINS WITH SURFACE DEWPOINTS AROUND 60 INTO ERN NEB AND IA DURING THE DAY. PLUME OF STEEP MID LEVEL LAPSE RATES AND COOL MID LEVEL TEMPERATURE PROFILES WILL FURTHER CONTRIBUTE TO DESTABILIZATION WITH MODERATE MLCAPE EXPECTED BY MID DAY FROM ERN NEB...WRN IA SWD INTO NERN KS AND WRN MO. ELEVATED STORMS WILL LIKELY BE ONGOING WITHIN ZONE OF WARM ADVECTION AND ASCENT N OF WARM FRONT FROM THE CNTRL/NRN PLAINS SEWD INTO PARTS OF THE MID/UPPER MS VALLEY. ADDITIONAL STORMS ARE EXPECTED TO DEVELOP OVER ERN NEB NEAR TRIPLE POINT WITHIN ZONE OF ASCENT ASSOCIATED WITH THE CYCLONICALLY CURVED JET EXIT REGION. THIS ACTIVITY WILL LIKELY BUILD SEWD INTO NERN KS AND NWRN MO ALONG AND AHEAD OF PACIFIC FRONT. STRONG DEEP LAYER SHEAR PROFILES WILL SUPPORT SUPERCELL STRUCTURES. STRONGEST EFFECTIVE LOW LEVEL SHEAR IS EXPECTED EAST AND SE OF TRIPLE POINT WHERE THE LOW LEVEL FLOW WILL REMAIN BACKED TO ESELY IN VICINITY OF THE WARM FRONT FROM ERN NEB INTO PARTS OF WRN/SRN IA AND NRN MO. ...CNTRL AND SRN MO THROUGH NRN AND CNTRL AR...ERN OK AND NE TX... POTENTIAL FOR A STRONGER CAP WILL EXIST IN THIS REGION AS THE EML IS ADVECTED EWD THROUGH THE WARM SECTOR. ELEVATED CONVECTION MAY BE ONGOING EARLY THURSDAY ACROSS PARTS OF THE LOWER MS VALLEY WITHIN ZONE OF WARM ADVECTION ALONG THE LOW LEVEL JET. THIS ACTIVITY WILL LIKELY SPREAD NEWD DURING THE DAY. THE ATMOSPHERE WILL LIKELY DESTABILIZE IN WAKE OF EARLY STORMS FROM PARTS OF MO...WRN AR...ERN OK...NERN TX DURING THE DAY ALONG MOIST AXIS WITH MLCAPE FROM 2000 TO 2500 J/KG LIKELY. STRONGER CAP WILL LIKELY LIMIT THE POTENTIAL FOR SURFACE BASED DEVELOPMENT MOST OF THE DAY. HOWEVER...MODELS SUGGEST A STRONG VORT LOBE WILL ROUND THE BASE OF THE TROUGH DURING THE LATE AFTERNOON AND EVENING. INCREASING LARGE SCALE ASCENT AND BOUNDARY LAYER WARMING MAY WEAKEN THE CAP SUFFICIENTLY FOR SURFACE BASED DEVELOPMENT ALONG EWD ADVANCING PACIFIC FRONT FROM PARTS OF SRN MO THROUGH ERN OK AND NERN TX. ACTIVITY WILL LIKELY SPREAD EWD THROUGH THE LOWER MS VALLEY DURING THE EVENING. SUPERCELLS WITH LARGE HAIL AND A FEW TORNADOES WILL BE POSSIBLE. ...WRN/CNTRL TN THROUGH OH VALLEY AREAS... STORMS WILL HAVE CONSOLIDATED INTO ONE OR MORE MCSS AS THEY SPREAD EWD INTO THE OH VALLEY OVERNIGHT. INSTABILITY WILL BE MORE LIMITED WITH ERN EXTENT INTO THIS AREA. HOWEVER...SOME DESTABILIZATION IS EXPECTED ALONG THE STRONG SWLY LOW LEVEL JET. VERTICAL SHEAR PROFILES WILL BE SUFFICIENT FOR ORGANIZED SEVERE STORM STRUCTURES WITHIN THE MCS. PRIMARY THREAT IS EXPECTED TO TRANSITION TO DAMAGING WIND. HOWEVER...ISOLATED TORNADOES WILL REMAIN POSSIBLE. ..DIAL.. 04/05/2006  From SwoDy2 at goshenarc.org Thu Apr 6 06:21:46 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Thu, 06 Apr 2006 02:21:46 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 060618 SWODY2 SPC AC 060618 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0118 AM CDT THU APR 06 2006 VALID 071200Z - 081200Z ...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF EASTERN ARKANSAS...NORTHEAST LOUISIANA...MUCH OF TENNESSEE... MISSISSIPI...NORTHERN ALABAMA...AND NORTHERN GEORGIA...EXTREME SOUTHWEST NORTH CAROLINA... ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK FROM LA/AR/MO...ACROSS THE MIDWEST/OH VALLEY...EAST TO WV...WRN VA/NC/SC...AND NWRN GA..AND THE FL PANHANDLE... ...WIDESPREAD AND POSSIBLY SIGNIFICANT SEVERE WEATHER EPISODE APPEARS INCREASINGLY LIKELY ACROSS PARTS OF THE LOWER MS VALLEY AND TN VALLEY DURING FRIDAY.... ...SYNOPSIS... AN ACTIVE SPRINGTIME SEVERE WEATHER PATTERN WILL LIKELY CONTINUE INTO DAY 2/FRIDAY AS POTENT TROUGH AND BELT OF 80-90KT MID LEVEL FLOW SPREAD EAST FROM THE PLAINS TO THE MS AND TN VALLEYS. THE FORECAST PERIOD WILL BEGIN WITH A DEEP OCCLUDED CYCLONE OVER THE PLAINS...AND A MORE PROGRESSIVE NRN STREAM TROUGH DIGGING SEWD TOWARD THE NRN GREAT LAKES. A BROAD RIDGE WILL COVER THE MUCH OF THE INTERMOUNTAIN WEST...WHILE ANOTHER PACIFIC DISTURBANCE APPROACHES THE WEST COAST. NRN STREAM HEIGHT FALLS AND AMPLIFYING WRN RIDGE WILL INDUCE THE LOW OVER THE PLAINS TO OPEN UP AND REDEVELOP EWD/SEWD ACROSS THE MS VALLEY AS A FRONTAL WAVE/LOW. THIS WILL OCCUR AS THE LARGER SCALE POSITIVE TILT TROUGH AXIS...AND ASSOCIATED DEEP LAYER BAROCLINIC ZONE...SPREAD SEWD FROM THE GREAT LAKES/OH VALLEY...AND ANOTHER FRONTAL SURFACE WAVE TRACKS EWD FROM OH TO NEW ENGLAND. GREAT LAKES AND TN VALLEY SHORT WAVES WILL BEGIN TO PHASE BY SATURDAY WITH RESULTING/ASSOCIATED COLD FRONT MOVING TOWARD THE ATLANTIC SEABOARD. ...ERN AR/LA ACROSS THE TN VALLEY... GFS AND NAM APPEAR QUITE CONSISTENT WITH SYNOPTIC SCALE FEATURES THAT SHOULD RESULT IN WIDESPREAD SEVERE WEATHER ACROSS THE SOUTH ON FRIDAY. GFS HAS SHOWN A SLIGHT TREND TOWARD A SLOWER AND MORE AMPLIFIED MID LEVEL TROUGH. THIS APPEARS REASONABLE AND ALLOWS FOR THE DEVELOPMENT OF GREATER INSTABILITY ACROSS THE LOWER MS VALLEY PRIOR TO ARRIVAL OF STRONGER FORCING. GUIDANCE IS ALSO INDICATING THAT A POSSIBLE MCS WILL MOVE ACROSS PARTS OF THE TN VALLEY THROUGH EARLY FRIDAY MORNING. THIS WOULD BE WHAT REMAINS FROM PLAINS CONVECTION DURING DAY 1...SPREADING EAST AND BEING SUSTAINED BY ISENTROPIC LIFT ON THE NOSE OF THE LOW LEVEL JET. LOW LEVEL SSWLY FLOW IN THE WAKE OF THIS POTENTIAL MORNING CONVECTION WILL TRANSPORT HIGHER THETAE AIRMASS FROM THE GULF INLAND ACROSS LA/ERN AR/MS/AL AND TN. IT SEEMS REASONABLE TO EXPECT AT LEAST MID 60S DEWPOINTS SPREADING NEWD ACROSS THESE AREAS BENEATH A PLUME OF INCREASING STEEP LAPSE RATES AND STRENGTHENING MID LEVEL FLOW. FORCING ALONG POSSIBLE RESIDUAL MCS OUTFLOW BOUNDARY ACROSS THE TN VALLEY...AND INCREASING LARGE SCALE ASCENT ASSOCIATED WITH THE EJECTING UPPER TROUGH AND SURFACE WAVE ACROSS AR/LA...WILL CONTRIBUTE TO STORM INITIATION FROM LATE MORNING INTO THE AFTERNOON. MODERATE INSTABILITY...ESPECIALLY ACROSS THE LOWER MS VALLEY...WILL FUEL ROBUST STORM UPDRAFTS AS SHEAR AND FORCING CONTINUE TO STRENGTHEN ACROSS THE REGION INTO THE EVENING. EXPECT VERY STRONG...PRIMARILY UNIDIRECTIONAL...DEEP LAYER FLOW TO RESULT IN A NUMBER OF FAST MOVING BANDS...OR LINES...OF STORMS. SUPERCELLS APPEAR LIKELY AND ACTIVITY NEAR THE SURFACE LOW...AND TRACKING NEAR/ALONG ANY RESIDUAL OUTFLOW BOUNDARIES...COULD POSE A GREATER RISK OF TORNADOES. WIDESPREAD DAMAGING WINDS...VERY LARGE HAIL...AND POSSIBLY A COUPLE OF STRONGER FAST-MOVING TORNADOES COULD OCCUR. SPECIFIC SEVERE PROBABILITIES FOR PARTS OF THE AREA MAY NEED TO BE INCREASED IN LATER OUTLOOKS. ...MIDWEST/OH VALLEY... EXPECT AIRMASS TO RECOVER ALONG THE OH RIVER VALLEY IN THE WAKE OF MORNING CONVECTION...OR CONVECTIVE DEBRIS. GUIDANCE SUGGESTS THE POSSIBILITY OF MODEST INSTABILITY FORMING AHEAD OF THE STRENGTHENING COLD FRONT FORECAST TO MOVE INTO THE AREA AHEAD OF STRONG NRN STREAM TROUGH. STORMS SHOULD INCREASE IN COVERAGE AND INTENSITY INTO THE LATE AFTERNOON/EARLY EVENING AS FRONTAL CIRCULATION MOVES INTO THE INSTABILITY AXIS FROM IL TO OH. LARGE HAIL AND DAMAGING WINDS APPEAR TO BE PRIMARY THREATS. ...ERN PLAINS/MO... A FEW LOW-TOPPED STORMS WITH HAIL COULD DEVELOP NEAR/WITHIN THE MID LEVEL COLD POOL AS IT MOVES ESEWD ACROSS THE OZARKS THROUGH THE LATE AFTERNOON. GENERALLY WEAK SHEAR AND INSTABILITY SHOULD LIMIT STORM INTENSITY/DURATION. ..CARBIN.. 04/06/2006  From SwoDy2 at goshenarc.org Thu Apr 6 17:21:41 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Thu, 06 Apr 2006 13:21:41 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 061717 SWODY2 SPC AC 061716 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1216 PM CDT THU APR 06 2006 VALID 071200Z - 081200Z ...THERE IS A HIGH RISK OF SVR TSTMS ACROSS NE MS...NRN AL...SCNTRL TN AND FAR NW GA... ...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF MS...AL...TN...GA...LA...ERN AR...WRN NC AND FAR WRN SC... ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE LOWER MS VALLEY...OH VALLEY...SRN AND CNTRL APPALACHIANS AND IMMEDIATE GULF COAST... A POTENT UPPER-LEVEL TROUGH OVER THE PLAINS STATES WILL SHIFT SEWD INTO THE OZARKS FRIDAY AHEAD OF A MOIST AND VERY UNSTABLE WARM SECTOR ACROSS THE TN VALLEY. THE SHEAR ENVIRONMENT WILL BE VERY FAVORABLE FOR TORNADOES AND A SIGNIFICANT TORNADO OUTBREAK IS EXPECTED FRIDAY AFTERNOON AND EVENING ACROSS NRN AL...NE MS...SCNTRL TN AND FAR NW GA. ...TN VALLEY... SEVERAL MESOSCALE CONVECTIVE SYSTEMS ONGOING AT THE BEGINNING OF THE PERIOD IN THE MID-MS VALLEY WILL DRIFT QUICKLY NEWD AS A 90-100 KT MID-LEVEL JET EJECTS NEWD OUT OF THE CNTRL PLAINS TROUGH. THIS WILL INCREASE MOISTURE ADVECTION STRENGTHENING A 40-50 KT LOW-LEVEL JET TRANSPORTING MID TO UPPER 60S F SFC DEWPOINTS NNEWD ACROSS THE TN VALLEY. THE MODELS ARE IN GOOD AGREEMENT SHUNTING MORNING CONVECTION AWAY FROM THE HIGH RISK AREA DURING THE MORNING LEAVING THE AIRMASS UNDISTURBED MIDDAY FRIDAY ACROSS MS...AL...TN AND NRN GA. AS STORMS INITIATE FRIDAY AFTERNOON...SUPERCELLS WILL BE LIKELY DUE TO THE STRONG VERTICAL SHEAR ASSOCIATED WITH THE MID-LEVEL JET. NAMKF FORECAST SOUNDINGS FOR TUPELO MS...FLORENCE ALABAMA AND HUNTSVILLE ALABAMA FRIDAY AFTERNOON SEEM REASONABLE WITH MODERATE TO STRONG INSTABILITY (MLCAPE VALUES 2500-3000 J/KG)...0-6 KM SHEAR VALUES AT/ABV 60 KT AND IMPRESSIVE LOW-LEVEL SHEAR PROFILES (0-3 KM SRH AT/ABV 350 M2/S2). IN THIS ENVIRONMENT...STORMS SHOULD REMAIN DISCRETE FOR THE LATE AFTERNOON AND EARLY EVENING HOURS. IN ADDITION...LCL HEIGHTS ARE FORECAST TO REMAIN LOW WHICH COMBINED WITH THE INSTABILITY AND STRONG LOW-LEVEL SHEAR WILL BE VERY FAVORABLE FOR TORNADOES. LONG-TRACK STRONG OR EVEN VIOLENT TORNADOES WILL BE POSSIBLE ESPECIALLY WITH SUPERCELLS THAT TRACK ALONG ANY PRE-EXISTING BOUNDARIES OR CONVERGENCE ZONES. THE INSTABILITY...SHEAR AND STEEP MID-LEVEL LAPSE RATES NEAR 8.0 C/KM SHOWN ON THE FORECAST SOUNDINGS WILL ALSO BE FAVORABLE FOR LARGE HAIL AND WIND DAMAGE WITH THE SUPERCELLS. VERY LARGE HAIL WILL ALSO BE POSSIBLE WITH THE STRONGER SUPERCELLS. STORM COVERAGE WILL LIKELY EXPAND DURING THE EVENING AS THE UPPER-TROUGH APPROACHES FROM THE NORTHWEST. ALTHOUGH CONVECTION MAY GRADUALLY ORGANIZE INTO A LINEAR ORIENTATION BY LATE EVENING...THE WIND SHEAR ENVIRONMENT SHOULD REMAIN SUPPORTIVE OF DISCRETE SUPERCELLS AS THE LOW-LEVEL JET INCREASES AND EXPANDS NWD ACROSS THE HIGH RISK AREA. THE WIND DAMAGE POTENTIAL WILL LIKELY BE ENHANCED WITH SUPERCELLS AND/OR BOW ECHOES THAT DEVELOP DURING THE LATE EVENING. THE SEVERE THREAT ACROSS THE TN VALLEY SHOULD BEGIN TO DROP OFF AFTER MIDNIGHT AS INSTABILITY DECREASES AND A COLD FRONT ADVANCES EWD ACROSS THE REGION. ...OH VALLEY... VERY STRONG LARGE-SCALE ASCENT WILL SPREAD EWD ACROSS THE OH VALLEY FRIDAY MORNING AS A LARGE AREA OF CONVECTION SPREADS NEWD ACROSS THE REGION. THIS WILL LIKELY DELAY DESTABILIZATION ACROSS MUCH OF THE OH VALLEY AND UNCERTAINTY REMAINS CONCERNING THE DEVELOPMENT OF INSTABILITY IN THE AFTERNOON HOURS. THE NAM AND GFS INITIATE POST-FRONTAL CONVECTION IN THE EARLY IN THE AFTERNOON NORTH OF A FRONTAL BOUNDARY EXTENDING WSWD TO ENEWD ACROSS THE OH VALLEY. FORECAST SOUNDINGS FOR THIS AREA FRIDAY AFTERNOON SHOW SUFFICIENT INSTABILITY/SHEAR PROFILES AND STEEP LAPSE RATES THAT SHOULD BE FAVORABLE FOR SUPERCELLS WITH LARGE HAIL. FURTHER SOUTH ACROSS KY...SFC DEWPOINTS IN THE UPPER 50S TO NEAR 60 F SHOULD BE ALLOW MODERATE INSTABILITY TO DEVELOP. ALTHOUGH CONVECTIVE INITIATION MAY HOLD OFF UNTIL LATER IN THE AFTERNOON...SFC-BASED STORMS APPEAR LIKELY TO DEVELOP ALONG AND SOUTH OF THE BOUNDARY DURING THE LATE AFTERNOON AND EVENING HOURS. STEEP LOW-LEVEL LAPSE RATES...GREATER MOISTURE AND STRONG LOW-LEVEL SHEAR WILL FAVOR LARGE HAIL...WIND DAMAGE AND A FEW TORNADOES WITH SUPERCELLS THAT TRACK ENEWD ACROSS THE REGION. THE SEVERE THREAT SHOULD CONTINUE INTO THE EVENING HOURS WITH THE THREAT GRADUALLY BECOMING MARGINAL FORWARD MIDNIGHT AS INSTABILITY DECREASES. ..BROYLES.. 04/06/2006  From SwoDy2 at goshenarc.org Thu Apr 6 17:39:36 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Thu, 06 Apr 2006 13:39:36 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 061737 SWODY2 SPC AC 061735 DAY 2 CONVECTIVE OUTLOOK CORR 1 NWS STORM PREDICTION CENTER NORMAN OK 1235 PM CDT THU APR 06 2006 VALID 071200Z - 081200Z ...THERE IS A HIGH RISK OF SVR TSTMS ACROSS NE MS...NRN AL...SCNTRL TN AND FAR NW GA... ...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF MS...AL...TN...GA...LA...ERN AR...WRN NC AND FAR WRN SC... ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE LOWER MS VALLEY...OH VALLEY...SRN AND CNTRL APPALACHIANS AND IMMEDIATE GULF COAST... CORRECTED FOR WORDING LAST PARAGRAPH A POTENT UPPER-LEVEL TROUGH OVER THE PLAINS STATES WILL SHIFT SEWD INTO THE OZARKS FRIDAY AHEAD OF A MOIST AND VERY UNSTABLE WARM SECTOR ACROSS THE TN VALLEY. THE SHEAR ENVIRONMENT WILL BE VERY FAVORABLE FOR TORNADOES AND A SIGNIFICANT TORNADO OUTBREAK IS EXPECTED FRIDAY AFTERNOON AND EVENING ACROSS NRN AL...NE MS...SCNTRL TN AND FAR NW GA. ...TN VALLEY... SEVERAL MESOSCALE CONVECTIVE SYSTEMS ONGOING AT THE BEGINNING OF THE PERIOD IN THE MID-MS VALLEY WILL DRIFT QUICKLY NEWD AS A 90-100 KT MID-LEVEL JET EJECTS NEWD OUT OF THE CNTRL PLAINS TROUGH. THIS WILL INCREASE MOISTURE ADVECTION STRENGTHENING A 40-50 KT LOW-LEVEL JET TRANSPORTING MID TO UPPER 60S F SFC DEWPOINTS NNEWD ACROSS THE TN VALLEY. THE MODELS ARE IN GOOD AGREEMENT SHUNTING MORNING CONVECTION AWAY FROM THE HIGH RISK AREA DURING THE MORNING LEAVING THE AIRMASS UNDISTURBED MIDDAY FRIDAY ACROSS MS...AL...TN AND NRN GA. AS STORMS INITIATE FRIDAY AFTERNOON...SUPERCELLS WILL BE LIKELY DUE TO THE STRONG VERTICAL SHEAR ASSOCIATED WITH THE MID-LEVEL JET. NAMKF FORECAST SOUNDINGS FOR TUPELO MS...FLORENCE ALABAMA AND HUNTSVILLE ALABAMA FRIDAY AFTERNOON SEEM REASONABLE WITH MODERATE TO STRONG INSTABILITY (MLCAPE VALUES 2500-3000 J/KG)...0-6 KM SHEAR VALUES AT/ABV 60 KT AND IMPRESSIVE LOW-LEVEL SHEAR PROFILES (0-3 KM SRH AT/ABV 350 M2/S2). IN THIS ENVIRONMENT...STORMS SHOULD REMAIN DISCRETE FOR THE LATE AFTERNOON AND EARLY EVENING HOURS. IN ADDITION...LCL HEIGHTS ARE FORECAST TO REMAIN LOW WHICH COMBINED WITH THE INSTABILITY AND STRONG LOW-LEVEL SHEAR WILL BE VERY FAVORABLE FOR TORNADOES. LONG-TRACK STRONG OR EVEN VIOLENT TORNADOES WILL BE POSSIBLE ESPECIALLY WITH SUPERCELLS THAT TRACK ALONG ANY PRE-EXISTING BOUNDARIES OR CONVERGENCE ZONES. THE INSTABILITY...SHEAR AND STEEP MID-LEVEL LAPSE RATES NEAR 8.0 C/KM SHOWN ON THE FORECAST SOUNDINGS WILL ALSO BE FAVORABLE FOR LARGE HAIL AND WIND DAMAGE WITH THE SUPERCELLS. VERY LARGE HAIL WILL ALSO BE POSSIBLE WITH THE STRONGER SUPERCELLS. STORM COVERAGE WILL LIKELY EXPAND DURING THE EVENING AS THE UPPER-TROUGH APPROACHES FROM THE NORTHWEST. ALTHOUGH CONVECTION MAY GRADUALLY ORGANIZE INTO A LINEAR ORIENTATION BY LATE EVENING...THE WIND SHEAR ENVIRONMENT SHOULD REMAIN SUPPORTIVE OF DISCRETE SUPERCELLS AS THE LOW-LEVEL JET INCREASES AND EXPANDS NWD ACROSS THE HIGH RISK AREA. THE WIND DAMAGE POTENTIAL WILL LIKELY BE ENHANCED WITH SUPERCELLS AND/OR BOW ECHOES THAT DEVELOP DURING THE LATE EVENING. THE SEVERE THREAT ACROSS THE TN VALLEY SHOULD BEGIN TO DROP OFF AFTER MIDNIGHT AS INSTABILITY DECREASES AND A COLD FRONT ADVANCES EWD ACROSS THE REGION. ...OH VALLEY... VERY STRONG LARGE-SCALE ASCENT WILL SPREAD EWD ACROSS THE OH VALLEY FRIDAY MORNING AS A LARGE AREA OF CONVECTION SPREADS NEWD ACROSS THE REGION. THIS WILL LIKELY DELAY DESTABILIZATION ACROSS MUCH OF THE OH VALLEY AND UNCERTAINTY REMAINS CONCERNING THE DEVELOPMENT OF INSTABILITY IN THE AFTERNOON HOURS. THE NAM AND GFS INITIATE POST-FRONTAL CONVECTION EARLY IN THE AFTERNOON NORTH OF A FRONTAL BOUNDARY EXTENDING WSWD TO ENEWD ACROSS THE OH VALLEY. FORECAST SOUNDINGS FOR THIS AREA FRIDAY AFTERNOON SHOW SUFFICIENT INSTABILITY/SHEAR PROFILES AND STEEP LAPSE RATES THAT SHOULD BE FAVORABLE FOR SUPERCELLS WITH LARGE HAIL. FURTHER SOUTH ACROSS KY...SFC DEWPOINTS IN THE UPPER 50S TO NEAR 60 F SHOULD ALLOW MODERATE INSTABILITY TO DEVELOP. ALTHOUGH CONVECTIVE INITIATION MAY HOLD OFF UNTIL LATER IN THE AFTERNOON...SFC-BASED STORMS APPEAR LIKELY TO DEVELOP ALONG AND SOUTH OF THE BOUNDARY DURING THE LATE AFTERNOON AND EVENING HOURS. STEEP LOW-LEVEL LAPSE RATES...GREATER MOISTURE AND STRONG LOW-LEVEL SHEAR WILL FAVOR LARGE HAIL...WIND DAMAGE AND A FEW TORNADOES WITH SUPERCELLS THAT TRACK ENEWD ACROSS THE REGION. THE SEVERE THREAT SHOULD CONTINUE INTO THE EVENING HOURS WITH THE THREAT GRADUALLY BECOMING MARGINAL TOWARD MIDNIGHT AS INSTABILITY DECREASES. ..BROYLES.. 04/06/2006  From SwoDy2 at goshenarc.org Fri Apr 7 05:24:27 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Fri, 07 Apr 2006 01:24:27 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 070522 SWODY2 SPC AC 070521 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1221 AM CDT FRI APR 07 2006 VALID 081200Z - 091200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE GULF COAST AND SERN U.S.... ...SERN U.S... CENTRAL PLAINS SHORTWAVE TROUGH WILL BE ABSORBED WITHIN LONG WAVE TROUGH AXIS AND SHIFT EAST ACROSS THE CNTRL/ERN GULF STATES LATER IN THE DAY2 PERIOD. THIS FEATURE WILL BE RESPONSIBLE FOR INDUCING SEVERAL WEAK ELONGATED LOW PRESSURE AREAS ALONG ADVANCING COLD FRONT FROM NRN AL INTO SERN VA. MORE CONCENTRATED CYCLOGENESIS/CONVERGENCE WILL OCCUR ACROSS THE MIDDLE ATLANTIC INTO NC WHERE VEERED LLJ WILL FOCUS ASCENT WITH RETREATING WEAK WARM ADVECTION ZONE. IT APPEARS CONSIDERABLE AMOUNT OF LATE DAY1 CONVECTION WILL BE ONGOING AT THE BEGINNING OF THE PERIOD ALONG A GOOD PORTION OF THE FRONTAL ZONE. THIS WILL AID SWD FRONTAL SURGE DURING THE DAYTIME HOURS IN THE WAKE OF TROUGH PASSAGE. FORECAST SOUNDINGS ACROSS THE WARM SECTOR SUGGEST MORE THAN ADEQUATE DEEP SWLY SHEAR FOR SUSTAINING ANY UPDRAFTS THAT MANAGE TO DEVELOP WITHIN MODEST CAPE ENVIRONMENT. AT THIS TIME IT SEEMS REASONABLE THAT AN UPWARD EVOLVING SQUALL LINE WILL EMERGE BY MID DAY ALONG WIND SHIFT AS IT DROPS SWD ACROSS AL/GA/COASTAL CAROLINAS. THERE IS SOME REASON TO BELIEVE THAT SUFFICIENT HEATING MAY ALLOW ISOLATED DEEP CONVECTION TO DEVELOP AHEAD OF SQUALL LINE ACROSS PORTIONS OF THE NRN FL PENINSULA AND PANHANDLE...IF SO SUPERCELL STRUCTURES ARE POSSIBLE. DAMAGING WIND APPEARS THE MOST LIKELY SEVERE THREAT WITH ORGANIZED SQUALL LINE...WHILE LARGE HAIL MAY ACCOMPANY MORE DISCRETE STRUCTURES THAT ROTATE. ...NWRN U.S./NRN ROCKIES... MID LEVEL THERMAL TROUGH WILL ROTATE NWD ACROSS THE NWRN U.S./NRN ROCKIES DURING THE DAY AS UPPER TROUGH AND STRONG SPEED MAX SHIFT INTO NRN CA. STEEP LAPSE RATE ENVIRONMENT WITH INCREASING SUN ANGLE WILL ENHANCE CONVECTIVE UPDRAFT POTENTIAL MAINLY DURING THE AFTERNOON HOURS. AS A RESULT...ISOLATED THUNDERSTORMS ARE POSSIBLE ACROSS THIS REGION WITH THE POSSIBILITY FOR A CONCENTRATED AREA OF CONVECTION MOVING INTO CNTRL MT ALONG SFC WIND SHIFT AROUND 00Z. ..DARROW.. 04/07/2006  From SwoDy2 at goshenarc.org Fri Apr 7 17:16:14 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Fri, 07 Apr 2006 13:16:14 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 071712 SWODY2 SPC AC 071711 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1211 PM CDT FRI APR 07 2006 VALID 081200Z - 091200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SERN GULF COAST STATES AND CAROLINAS... ...NERN GULF COAST STATES... A LARGE MCS WILL LIKELY BE ONGOING ACROSS THE SRN APPALACHIAN MTNS AT THE BEGINNING OF THE PERIOD AHEAD OF AN UPPER-LEVEL TROUGH APPROACHING FROM THE WEST. STRONG LARGE-SCALE ASCENT AHEAD OF THE TROUGH AND DESTABILIZATION AROUND MID-DAY SHOULD SUPPORT ADDITIONAL THUNDERSTORM DEVELOPMENT FURTHER SOUTH ACROSS SRN/ERN AL...CNTRL/SRN GA AND NRN FL. STORMS WILL MOST LIKELY DEVELOP AHEAD OF A COLD FRONT AND SFC LOW MOVING SEWD ACROSS THE REGION DURING THE AFTERNOON. FORECAST SOUNDINGS IN THIS AREA FOR SATURDAY AFTERNOON SHOW MOIST PROFILES WITH STRONG VERTICAL SHEAR AND MODERATE INSTABILITY. IN ADDITION...AS THE TROUGH DIGS SEWD...TEMPS ALOFT WILL COOL AS THE CORE OF THE UPPER-TROUGH PASSES. THIS WILL STEEPEN LAPSE RATES FROM NW TO SE ACROSS THE REGION WHICH COMBINED WITH THE INSTABILITY AND STRONG SHEAR SUGGESTS DISCRETE SUPERCELLS WILL HAVE A POTENTIAL FOR LARGE HAIL. IF STORMS ORGANIZE INTO A LINEAR ORIENTATION DURING THE AFTERNOON AS SOME OF THE MODELS SUGGEST...THEN ISOLATED WIND DAMAGE WOULD ALSO BE LIKELY DUE TO ABUNDANT MOISTURE AND STEEP LAPSE RATES AT LOW-LEVELS. IF THE CELLS TEND TO REMAIN DISCRETE THROUGH EARLY EVENING AN ISOLATED TORNADO THREAT MAY ALSO DEVELOP ACROSS SRN AND CNTRL GA TO THE WEST OF THE LOW-LEVEL JET. THE SEVERE THREAT SHOULD TRANSITION EWD INTO NRN FL AS A COLD FRONT MOVES SEWD ACROSS THE REGION WITH THE THREAT SLOWLY DECREASING DURING THE EVENING HOURS DUE TO WEAKENING INSTABILITY. ...CAROLINAS... A POSITIVELY-TILTED UPPER-LEVEL LOW/TROUGH OVER THE OZARKS TONIGHT WILL OPEN AND DIG SEWD INTO THE GULF COAST STATES. WIDESPREAD LARGE-SCALE ASCENT AHEAD OF THE TROUGH WILL SPREAD EWD INTO THE SRN APPALACHIAN MTNS AND CNTRL CAROLINAS DURING THE DAY. THUNDERSTORMS WILL LIKELY BE ONGOING AT THE BEGINNING OF THE PERIOD ALONG A FRONTAL BOUNDARY EXTENDING SWWD FROM A SFC LOW IN VA ACROSS THE WRN CAROLINAS. WARMING SFC TEMPS AND DEWPOINTS IN THE 60S F MAY RESULT IN POCKETS OF MODERATE INSTABILITY ACROSS THE ERN CAROLINAS BY AFTERNOON. THIS COMBINED WITH VERY STRONG VERTICAL SHEAR PROFILES (0-6 KM SHEAR 55-65 KT) WILL BE FAVORABLE FOR SEVERE STORMS. IF MODERATE INSTABILITY DEVELOPS SATURDAY AFTERNOON IN ERN NC/ERN SC AS SUGGESTED BY NAM FORECAST SOUNDINGS...SHEAR PROFILES WILL BE SUFFICIENT FOR SUPERCELLS WITH LARGE HAIL. DAMAGING WIND GUSTS WILL ALSO BE POSSIBLE WITH THE STRONGER STORMS ESPECIALLY WITH SHORT-LINES AND BOW ECHOES THAT DEVELOP IN THE LATE AFTERNOON AND EARLY EVENING WHEN LOW-LEVEL LAPSE RATES SHOULD BE STEEPEST. AS THE UPPER-TROUGH APPROACHES FROM THE WEST...THE ACTIVITY SHOULD MOVE EWD INTO THE ATLANTIC DURING THE EVENING HOURS ALLOWING THE SEVERE THREAT TO DECREASE FROM WEST TO EAST ACROSS THE REGION. ..BROYLES.. 04/07/2006  From SwoDy2 at goshenarc.org Sat Apr 8 05:18:04 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 08 Apr 2006 01:18:04 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 080516 SWODY2 SPC AC 080515 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1215 AM CDT SAT APR 08 2006 VALID 091200Z - 101200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF CENTRAL/SOUTHERN FL... ...CENTRAL/SOUTHERN FL PENINSULA... CONVECTIVELY-ACTIVE COLD FRONT WILL BE FORCED SWD ACROSS THE CNTRL FL PENINSULA EARLY IN THE DAY2 PERIOD. THIS BOUNDARY WILL CONTINUE ITS SWD MOVEMENT DURING THE DAY AS STRONG UPPER SHORTWAVE IS ABSORBED WITHIN LONG WAVE TROUGH...THEN SHEARS SW-NE ACROSS THE SRN PENINSULA. IT APPEARS BOUNDARY LAYER WILL HEAT RAPIDLY SOUTH OF THE WIND SHIFT AND ASSOCIATED CONVECTIVE CLUSTERS ALONG IT. THIS WILL AID DESTABILIZATION FORCING MLCAPE VALUES AOA 2000 J/KG. WITH DEEP SWLY SHEAR VECTORS ON THE ORDER OF 30-35KT...IT APPEARS SUPERCELL DEVELOPMENT IS POSSIBLE. NUMEROUS THUNDERSTORMS ARE LIKELY ALONG/SOUTH OF ADVANCING COLD FRONT WITHIN AN ENVIRONMENT SEEMINGLY FAVORABLE FOR AT LEAST LARGE HAIL AND DAMAGING WINDS. OF COURSE...ANY SEA BREEZE INTERACTIONS WOULD AID LOW LEVEL SHEAR AND ENHANCE STORM ROTATION FOR POSSIBLE ISOLATED TORNADOES. ACTIVITY SHOULD SPREAD OFF THE SRN TIP OF FL BY EARLY EVENING. ...NWRN U.S... ANOTHER IN A SERIES OF UPPER TROUGHS WILL MOVE INTO THE GREAT BASIN SUNDAY. COLD MID LEVEL TEMPERATURES AND STEEPENING LAPSE RATES WILL AID SCATTERED CONVECTIVE POTENTIAL...MAINLY INLAND DURING THE AFTERNOON HOURS. ..DARROW.. 04/08/2006  From SwoDy2 at goshenarc.org Sat Apr 8 17:10:13 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 08 Apr 2006 13:10:13 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 081707 SWODY2 SPC AC 081706 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1206 PM CDT SAT APR 08 2006 VALID 091200Z - 101200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF CENTRAL/ SOUTHERN FL... ...CENTRAL/SRN FL PENINSULA... STRONG GULF COAST STATES SHORT WAVE TROUGH WILL CONTINUE TO BECOME ABSORBED BY NRN STREAM TROUGH ACROSS/EAST OF THE MID ATLANTIC STATES FIRST HALF OF DAY 2 PERIOD...WITH SRN EXTENT SHEARING SW-NE ACROSS THE SRN FL PENINSULA. ASSOCIATED SURFACE COLD FRONT WILL MOVE SWD ACROSS THE CENTRAL/SRN FL PENINSULA SUNDAY. GIVEN THE POTENTIAL FOR WEAK UPPER FORCING AND VEERED LOW-LEVEL FLOW S OF COLD FRONT LIMITING BETTER CONVERGENCE...SURFACE HEATING WITHIN A MOIST BOUNDARY LAYER BENEATH MODEST LAPSE RATES IS EXPECTED TO PROVIDE THE MAIN IMPETUS FOR WARM SECTOR THUNDERSTORMS. IN ADDITION...THUNDERSTORMS WILL BE POSSIBLE ALONG THE COLD FRONT AS IT MOVES SWD INTO THE MODERATELY UNSTABLE AIR MASS /MUCAPE UP TO 2000 J/KG/. 30-35 KT OF SFC-6 KM SHEAR SUGGESTS SUPERCELLS WILL BE POSSIBLE WITH THE PRIMARY THREATS BEING HAIL AND STRONG WIND GUSTS. HOWEVER...ISOLATED TORNADOES CAN NOT BE RULED OUT...ESPECIALLY WITH ANY STORMS THAT DEVELOP AND/OR INTERACT WITH SEA/LAKE BREEZE BOUNDARIES WHERE LOW-LEVEL SHEAR WILL BE ENHANCED. SEVERE THREAT SHOULD DIMINISH SUNDAY EVENING AS THE COLD FRONT MOVES OFFSHORE SRN FL. ...WRN STATES... ANOTHER IN A SERIES OF UPPER TROUGHS...CURRENTLY ORIENTED WSW-ENE FROM THE ERN PACIFIC TO THE PAC NW...IS EXPECTED TO ROTATE INLAND ACROSS THE WRN STATES SUNDAY. A SHORT WAVE TROUGH NOW MOVING AROUND THE WRN/SWRN PERIPHERY OF THIS TROUGH NEAR 33N 142W IS EXPECTED TO MOVE INLAND ACROSS SRN CA AND THEN TOWARD THE GREAT BASIN/FOUR CORNERS REGION SUNDAY NIGHT. MODELS SUGGEST A FORCED LINE OF CONVECTION IS POSSIBLE LATE SUNDAY AFTERNOON/EVENING ACROSS NV/SRN ID INTO UT AS A PACIFIC COLD FRONT ASSOCIATED WITH THE MID-LEVEL IMPULSE SPREADS EWD ACROSS THIS REGION. LIMITED INSTABILITY SHOULD PRECLUDE A SEVERE WEATHER THREAT WITH THIS ACTIVITY. ELSEWHERE ACROSS THE WEST...COLD MID LEVEL TEMPERATURES AND STEEPENING LAPSE RATES WILL AID SCATTERED CONVECTIVE POTENTIAL...MAINLY INLAND DURING THE AFTERNOON HOURS. ..PETERS.. 04/08/2006  From SwoDy2 at goshenarc.org Sun Apr 9 05:58:10 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 09 Apr 2006 01:58:10 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 090555 SWODY2 SPC AC 090555 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1255 AM CDT SUN APR 09 2006 VALID 101200Z - 111200Z ...NO SVR TSTM AREAS FORECAST... ...NRN PLAINS... LATE EVENING MODEL GUIDANCE CONTINUES TO SUGGEST A STRONG SPEED MAX WILL EJECT FROM BASE OF LONG WAVE TROUGH ACROSS THE SRN/CNTRL ROCKIES BY THE END OF THE PERIOD. A MINOR SHORTWAVE TROUGH WILL ADVECT AHEAD OF THIS FEATURE ACROSS WY INTO THE DAKOTAS BY EARLY EVENING ENHANCING ASCENT AHEAD OF WEAK SFC LOW WITHIN WARM ADVECTION ZONE. FORECAST SOUNDINGS SUGGEST BOUNDARY LAYER HEATING WILL BE EFFICIENT WITH STEEP LAPSE RATE ENVIRONMENT EXPECTED TO AID POTENTIAL CONVECTIVE DEVELOPMENT ALONG LEE TROUGH FROM WRN SD INTO PORTIONS OF NWRN NEB. IT APPEARS THUNDERSTORMS SHOULD EVOLVE ACROSS THIS REGION AROUND 00Z WITH AN UPWARD EXPANSION POSSIBLE ACROSS THE DAKOTAS AS LLJ INCREASES IN RESPONSE TO UPPER SHORTWAVE. MEAGER MOISTURE RETURN ACROSS THE PLAINS WILL LIMIT INSTABILITY AND THIS SHOULD REDUCE THE OVERALL SEVERE THREAT ACROSS THE NRN PLAINS TO ISOLATED ACTIVITY. HAIL MAY ACCOMPANY THE STRONGEST STORMS WITHIN ELEVATED CONVECTIVE MODE NORTH OF WARM FRONT...AND PERHAPS GUSTY WINDS FOR ANY STORMS THAT FORM NEAR THE WARM SECTOR WHERE CONVECTION WILL BE NEAR-SFC BASED. THUNDERSTORMS WILL SPREAD ACROSS THE DAKOTAS INTO NWRN PORTIONS OF MN BY THE END OF THE PERIOD TUESDAY MORNING. ..DARROW.. 04/09/2006  From SwoDy2 at goshenarc.org Sun Apr 9 17:21:00 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 09 Apr 2006 13:21:00 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 091718 SWODY2 SPC AC 091717 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1217 PM CDT SUN APR 09 2006 VALID 101200Z - 111200Z ...NO SVR TSTM AREAS FORECAST... ...NRN PLAINS... LEAD SHORT WAVE TROUGH IN BASE OF WEST COAST TROUGH EXPECTED TO TRACK NEWD ACROSS SRN CA SUNDAY EVENING IS PROGGED TO DE-AMPLIFY AS IT MOVES FARTHER INLAND...REACHING THE NRN HIGH PLAINS BY LATE MONDAY AFTERNOON /TOWARD 11/00Z/. WSWLY MID-UPPER LEVEL FLOW ACROSS THE ROCKIES WILL MAINTAIN LEE-SIDE TROUGH...WITH SURFACE CYCLOGENESIS EXPECTED IN SERN MT/ERN WY BY MONDAY AFTERNOON IN RESPONSE TO HEIGHT FALLS WITH APPROACH OF LEAD IMPULSE. PLUME OF STEEP LAPSE RATES ACROSS THE NRN/CENTRAL PLAINS ATOP MEAGER MOISTURE RETURN WILL RESULT IN A CAPPED AIR MASS FOR MUCH OF THE AFTERNOON ACROSS THE CENTRAL/NRN PLAINS. HOWEVER...SURFACE HEATING IS EXPECTED TO PROVE EFFICIENT FOR THUNDERSTORM DEVELOPMENT NEAR/ JUST AFTER PEAK HEATING IN THE VICINITY OF SURFACE LOW/HIGHER TERRAIN OF SERN MT/ERN WY/WRN PARTS OF SD/NEB. THE WEAK MOISTURE RETURN WILL ALSO LIMIT THE DEVELOPMENT OF A MORE UNSTABLE AIR MASS...REDUCING THE OVERALL SEVERE THREAT TO ISOLATED ACTIVITY. NAMKF/NAM FORECAST SOUNDINGS DO SUGGEST THE POTENTIAL FOR A NARROW AXIS OF STRONGER STORMS ALONG THE LEE TROUGH FROM MT/WRN ND SWD TO WRN NEB...GIVEN THE FAVORABLE DEEP LAYER SHEAR AND STEEP LAPSE RATE ENVIRONMENT. HOWEVER...SMALL TIME/SPACE ASPECTS OF THIS THREAT WILL PRECLUDE INTRODUCTION OF HIGHER SEVERE PROBABILITIES/CATEGORICAL RISK AT THIS TIME. STRENGTHENING SLY LLJ ALONG THE PLAINS MONDAY NIGHT IS EXPECTED TO SUPPORT INCREASING COVERAGE OF CONVECTIVE ACTIVITY ENEWD ACROSS THE DAKOTAS...REACHING NRN/WRN MN BY 12Z TUESDAY. ISOLATED HAIL/STRONG WIND GUSTS WILL BE POSSIBLE WITH THE INITIAL THUNDERSTORMS LATE MONDAY AFTERNOON/EARLY EVENING...WHILE HAIL WILL BE POSSIBLE WITH A FEW OF THE STRONGER CORES OVERNIGHT. ..PETERS.. 04/09/2006  From SwoDy2 at goshenarc.org Mon Apr 10 07:37:49 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 10 Apr 2006 03:37:49 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 100734 SWODY2 SPC AC 100734 DAY 2 CONVECTIVE OUTLOOK RESENT 1 NWS STORM PREDICTION CENTER NORMAN OK 0234 AM CDT MON APR 10 2006 VALID 111200Z - 121200Z ...NO SVR TSTM AREAS FORECAST... ...NERN KS TO WI... NRN PLAINS SHORTWAVE TROUGH WILL TOP CNTRL U.S. RIDGE FORCING COLD FRONT ACROSS THE NRN/CNTRL PLAINS INTO THE MID/UPPER MS VALLEY REGION BY EARLY EVENING. THIS BOUNDARY WILL LIKELY SERVE AS A FOCUS FOR DEEP CONVECTION DURING THE AFTERNOON HOURS...ESPECIALLY GIVEN THE LARGE SCALE ASCENT AHEAD OF SHORTWAVE TROUGH. BOUNDARY LAYER AIRMASS ACROSS THE WRN GULF OF MEXICO WILL BE SLOW TO MODIFY OVER THE NEXT FEW DAYS AS SFC RIDGING AND LARGE SCALE SUBSIDENCE WILL NOT PROVE FAVORABLE FOR MEANINGFUL RETURN FLOW. RESULTANT LOW LEVEL MOISTURE WILL THUS BE LIMITED ALONG/AHEAD OF ADVANCING COLD FRONT FROM MN INTO CNTRL KS. IT APPEARS STEEP LAPSE RATE ENVIRONMENT DUE TO STRONG HEATING WILL BE INSTRUMENTAL IN LATE AFTERNOON THUNDERSTORM DEVELOPMENT. FORECAST SOUNDINGS SUGGEST SCATTERED CONVECTION WILL EVOLVE WITH A FEW STRONG STORMS POSSIBLE...ESPECIALLY FROM NERN KS INTO CNTRL IA. LIMITED MOISTURE APPEARS TO BE THE MAIN IMPEDIMENT FOR ORGANIZED SEVERE THUNDERSTORMS ACROSS THIS REGION. FOR THIS REASON...LOW PROBABILITIES WILL BE MAINTAINED FOR THE POSSIBILITY FOR SOME HAIL OR GUSTY WINDS. ..DARROW.. 04/10/2006  From SwoDy2 at goshenarc.org Mon Apr 10 17:35:25 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 10 Apr 2006 13:35:25 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 101732 SWODY2 SPC AC 101730 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1230 PM CDT MON APR 10 2006 VALID 111200Z - 121200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF NE KS...SERN NEB...SWRN IA AND NWRN MO... ...SYNOPSIS... LEAD SHORTWAVE TROUGH NOW OVER THE NRN ROCKIES WILL CONTINUE NEWD INTO SRN CANADA BY EARLY TUESDAY. IN WAKE OF THIS FEATURE A COLD FRONT WILL MOVE SEWD THROUGH THE NRN PLAINS AND INTO THE UPPER MS VALLEY BY THE START OF THIS PERIOD. BY LATE TUESDAY AFTERNOON THE FRONT SHOULD EXTEND FROM PARTS OF MN SWWD THROUGH WRN IA...SERN NEB INTO NERN KS. A STRONGER UPSTREAM SHORTWAVE TROUGH NOW APPROACHING CA WILL EJECT NEWD INTO THE CNTRL PLAINS TUESDAY AFTERNOON. IN RESPONSE TO THIS FEATURE...A WEAK WAVE WILL DEVELOP ALONG THE SWRN PORTIONS OF THE FRONT AND LIFT NEWD INTO N CNTRL OR NERN KS BY LATE AFTERNOON. ...NERN KS...SERN NEB...SWRN IA AND NWRN MO... MOISTURE OVER THE GULF REMAINS LIMITED WITH ELY TRAJECTORIES EMANATING FROM HIGH PRESSURE OVER THE ERN STATES MAINTAINING AN INFLUX OF CP AIR. DEWPOINTS CURRENTLY RANGE FROM THE UPPER 50S OVER THE WRN GULF TO AROUND 50 NWD OVER CNTRL TX. A STRONG LOW LEVEL JET THAT WILL PERSIST TONIGHT INTO EARLY TUESDAY OVER THE PLAINS WILL CONTRIBUTE TO ADVECTION OF MODEST LOW LEVEL MOISTURE NWD. DEWPOINTS FROM 50 TO 55 WILL BE POSSIBLE INTO PORTIONS OF THE CNTRL PLAINS AND MIDDLE MS VALLEY TUESDAY. IN ADVANCE OF SWRN U.S. UPPER TROUGH...A PLUME OF STEEP MID LEVEL LAPSE RATES ASSOCIATED WITH THE ELEVATED MIXED LAYER WILL SPREAD EWD ABOVE THE MODEST MOIST AXIS AND CONTRIBUTE TO DESTABILIZATION DURING THE AFTERNOON. DESPITE LIMITED MOISTURE...COLD MID LEVEL TEMPERATURES AND SURFACE HEATING SHOULD SUPPORT MLCAPE FROM 500-1000 J/KG BY LATE AFTERNOON FROM PARTS OF NERN KS INTO SERN NEB AND SWRN IA. THE EML WILL LIKELY CONTRIBUTE TO A CAP MOST OF THE DAY IN THIS REGION. SOME ELEVATED STORMS MAY BE POSSIBLE EARLIER IN THE PERIOD IN WARM ADVECTION REGIME OVER PARTS OF THE UPPER MS VALLEY. STRONGER STORMS ARE EXPECTED TO DEVELOP BY LATE AFTERNOON ALONG AND AHEAD OF THE FRONT FROM NERN KS INTO SERN NEB AS LARGE SCALE AS ASCENT INCREASES DOWNSTREAM FROM APPROACHING SHORTWAVE TROUGH. VERTICAL SHEAR PROFILES WILL BE SUFFICIENT FOR UPDRAFTS TO ROTATE WITH ISOLATED HAIL AND STRONG WIND GUSTS THE PRIMARY THREATS. STORMS MAY EVOLVE INTO LINE SEGMENTS AND CLUSTERS AS THEY SPREAD EWD THROUGH THE MIDDLE MS VALLEY WITH A DIMINISHING SEVERE THREAT BY MID EVENING. ..DIAL.. 04/10/2006  From SwoDy2 at goshenarc.org Tue Apr 11 05:05:54 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 11 Apr 2006 01:05:54 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 110502 SWODY2 SPC AC 110501 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1201 AM CDT TUE APR 11 2006 VALID 121200Z - 131200Z ...NO SVR TSTM AREAS FORECAST... ...OH VALLEY... WEAK HEIGHT FALLS WILL PRECEED UPPER SHORTWAVE TROUGH OVER PORTIONS OF THE OH VALLEY EARLY IN THE DAY2 PERIOD. THIS FEATURE WILL FORCE ASSOCIATED SFC FRONT ACROSS IL INTO IND MID DAY...WITH TRAILING PORTIONS OF THIS BOUNDARY EXPECTED TO STALL OVER NRN AR LATE IN THE DAY. UPPER RIDGING OVER THE GULF OF MEXICO WILL MAINTAIN WEAK SUBSIDENT ENVIRONMENT THAT IS NOT PARTICULARLY FAVORABLE FOR SIGNIFICANT BOUNDARY LAYER MODIFICATION/ADAPTATION OF GULF ENVIRONMENT. RESULTANT DOWNSTREAM LOW LEVEL MOISTENING ACROSS THE SRN PLAINS INTO THE OH VALLEY WILL BE SUPPRESSED WITH 50S SFC DEW POINTS POSSIBLE AHEAD OF ADVANCING COLD FRONT. FORECAST SOUNDINGS DO HOWEVER SUGGEST CONVECTION SHOULD EVOLVE ALONG COLD FRONT BY EARLY AFTERNOON...ESPECIALLY IMMEDIATELY AHEAD OF UPPER VORT WHERE ASCENT WILL BE MAXIMIZED. THUNDERSTORMS SHOULD DEVELOP SWWD ACROSS ERN IL/IND ALONG THE OH RIVER VALLEY TOWARD THE BOOTHEEL OF MO WHERE WEAKENING CONVERGENCE AND UPPER RIDGING WILL SUPPRESS CONVECTIVE DEVELOPMENT. STRONGEST STORMS MAY PRODUCE ISOLATED HAIL OR GUSTY WINDS...HOWEVER MEAGER MOISTURE/INSTABILITY APPEAR TOO LOW TO WARRANT A RISK OF ORGANIZED SEVERE THUNDERSTORMS THIS PERIOD. ..DARROW.. 04/11/2006  From SwoDy2 at goshenarc.org Tue Apr 11 17:17:13 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 11 Apr 2006 13:17:13 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 111714 SWODY2 SPC AC 111713 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1213 PM CDT TUE APR 11 2006 VALID 121200Z - 131200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... UPPER FLOW REGIME WILL BECOME MORE AMPLIFIED THROUGH MID-WEEK AS THE UPPER LOW OVER THE EPAC DIGS SWD AND FORCES A LARGE SCALE RIDGE DOWNSTREAM OVER THE CNTRL/SRN PARTS OF NOAM. AS A RESULT...THE STRONG SHORTWAVE TROUGH NOW CROSSING THE CNTRL PLAINS WILL EJECT ENEWD ACROSS THE OH VLY/GRTLKS REGION ON WED. A REINFORCING SHORTWAVE TROUGH...NOW OVER THE NRN GRT BASIN...WILL QUICKLY FOLLOW THE LEAD DISTURBANCE...REACHING THE MIDWEST BY WED AFTN. AT THE SFC...PRIMARY LOW WILL DEVELOP NEWD FROM THE UPPER MIDWEST INTO QUE THROUGH EARLY THU. A TRAILING COLD FRONT...ACCOMPANYING THE SECONDARY UPPER TROUGH...WILL SETTLE SEWD THROUGH THE GRTLKS AND OH VLY BY WED EVENING. WRN PORTION OF THIS FRONT WILL STALL OVER THE SRN PLAINS AND OZARKS AS IT ENCOUNTERS THE PERSISTENT RIDGE OF HIGH PRESSURE SITUATED ACROSS THE GULF OF MEXICO. ...OH VLY... BOUNDARY LAYER MODIFICATION ACROSS THE GULF OF MEXICO WILL BE LIMITED THROUGH MID-WEEK OWING TO SUBSIDENCE BENEATH THE GULF OF MEXICO RIDGE. THUS...LOW-LEVEL MOISTURE TRANSPORT ACROSS THE SRN PLAINS TO THE OH VLY WILL BE WEAK WITH MAINLY 50S SFC DEW POINTS EXPECTED AHEAD OF THE APPROACHING COLD FRONT...LIMITING OVERALL INSTABILITY. THERE WILL LIKELY BE BANDS OF CONVECTION TIED TO THE LEAD SHORTWAVE TROUGH AND WITHIN THE WARM CONVEYOR ACROSS THE CNTRL GRTLKS AND OH VLY REGION EARLY WED. IN WAKE OF MORNING CLOUDS/PCPN...BOUNDARY LAYER SHOULD HEAT ALONG THE LWR OH VLY NWD INTO WRN/CNTRL OH. AS THE SECONDARY IMPULSE TRANSLATES SEWD...TSTMS ARE EXPECTED TO DEVELOP ALONG/AHEAD OF THE ASSOCIATED FRONT IN ERN IND/WRN OH BY MID-AFTN...THEN DEVELOP SWWD ALONG THE OH RVR DURING THE EVE. MAIN LIMITING FACTOR FOR ORGANIZED SEVERE TSTMS WILL BE THE LOW INSTABILITY...DESPITE THE SUPERCELL WIND PROFILES. ATTM...IT APPEARS THAT ONLY ISOLD TSTMS MAY GROW STRONG ENOUGH TO PRODUCE HAIL/GUSTY WINDS. BUT...LATER OTLKS WILL NEED TO ASSESS MOISTURE TRANSPORT CLOSELY AND A SLGT RISK MAY BE JUSTIFIED CLOSER TO THE EVENT. ..RACY.. 04/11/2006  From SwoDy2 at goshenarc.org Wed Apr 12 05:44:29 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 12 Apr 2006 01:44:29 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 120541 SWODY2 SPC AC 120540 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1240 AM CDT WED APR 12 2006 VALID 131200Z - 141200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM SERN MN INTO WRN IND... ...MID-UPPER MS VALLEY/OH VALLEY... WEAK HEIGHT FALLS WILL SPREAD ACROSS THE NRN PLAINS LATE IN THE PERIOD AS SHORTWAVE TROUGH FLATTENS UPPER RIDGE AND DIGS SEWD TOWARD THE UPPER GREAT LAKES REGION. THIS FEATURE WILL INDUCE SFC CYCLOGENESIS ALONG PSEUDO WARM FRONT OVER ERN SD...WHICH WILL THEN TRACK SEWD ACROSS SRN PORTIONS OF LAKE MI INTO NRN OH LATE IN THE PERIOD. WARM ADVECTION AND ASCENT AHEAD OF SHORTWAVE WILL BE CONFINED TO AREAS NORTH OF THIS BOUNDARY...WHILE VEERED BOUNDARY LAYER FLOW AND WEAK CONVERGENCE WILL DOMINATE THE WARM SECTOR. LATEST ETA MODEL GUIDANCE APPEARS TOO AGGRESSIVE IN MOISTURE RETURN WHICH ERRONEOUSLY GENERATES SBCAPE VALUES IN EXCESS OF 3500J/KG ACROSS PORTIONS OF IA. NO DOUBT STEEP LAPSE RATE ENVIRONMENT AND STRONGLY SHEARED PROFILES WILL FAVOR POTENTIAL SUPERCELL DEVELOPMENT WITHIN WARM ADVECTION ZONE...HOWEVER INSTABILITY WILL LIKELY FALL WITHIN 1000-1500 J/KG RANGE ALONG/NORTH OF FRONTAL BOUNDARY AS WARM SECTOR MOISTURE SHOULD BE GREATLY REDUCED. IT APPEARS SLIGHTLY ELEVATED THUNDERSTORMS WILL EVOLVE JUST NORTH OF BOUNDARY DURING THE LATE AFTERNOON HOURS WHERE WSWLY LLJ WILL BE FOCUSED OVER SERN MN/WCNTRL WI. THIS ACTIVITY...POTENTIALLY SUPERCELLULAR...SHOULD SPREAD SEWD ACROSS SRN WI/NRN IL INTO WRN IND DURING THE EVENING HOURS. FORECAST SOUNDINGS SUGGEST THERE IS SOME POTENTIAL FOR WARM SECTOR DEVELOPMENT AROUND 00Z WITHIN AXIS OF STRONGEST HEAT FROM ERN IA INTO NRN MO. GIVEN WEAK CONVERGENCE ANY CONVECTION THAT EVOLVES WITHIN THIS ZONE SHOULD BE SHORT LIVED AND DISSIPATE AFTER DARK. MORE CONCENTRATED ACTIVITY WILL SPREAD/DEVELOP SEWD INTO PORTIONS OF THE OH VALLEY WHERE ASCENT SHOULD AID CONVECTION WELL INTO THE OVERNIGHT HOURS. AT THIS TIME HAIL APPEARS TO BE THE PRIMARY CONCERN...ESPECIALLY IF PARCELS ARE FORCED TO CONVECT NORTH OF FRONTAL ZONE. ..DARROW.. 04/12/2006  From SwoDy2 at goshenarc.org Wed Apr 12 17:21:38 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 12 Apr 2006 13:21:38 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 121718 SWODY2 SPC AC 121717 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1217 PM CDT WED APR 12 2006 VALID 131200Z - 141200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE UPPER MS VALLEY INTO THE GREAT LAKES...... ...SYNOPSIS... BROAD UPPER RIDGE SLOWLY BUILDING OVER THE ROCKIES IS FORECAST TO PROGRESS EWD ACROSS THE PLAINS...AS DOWNSTREAM UPPER TROUGH CURRENTLY OVER THE GREAT LAKES MOVES INTO THE NERN STATES TONIGHT. WEAK SHORT WAVE TROUGH CURRENTLY OVER BRITISH COLUMBIA IS EXPECTED TO MOVE ESEWD AS A LOW AMPLITUDE SYSTEM ACROSS THE NRN PARTS OF THE ROCKIES AND PLAINS...WITH WNWLY UPPER FLOW DEVELOPING ACROSS THE UPPER MS VALLEY TOMORROW NIGHT. AT THE SURFACE...LOW PRESSURE OVER NRN/CENTRAL PLAINS WILL GRADUALLY SPREAD EWD TOWARD THE UPPER MS VALLEY...AS A WARM FRONT ACROSS THE OH VALLEY WWD INTO KS AT THE START OF THE PERIOD LIFTS NWD INTO THE UPPER MS VALLEY/SRN GREAT LAKES BY EVENING. THE LOW IS EXPECTED TO CONTINUE EWD INTO THE GREAT LAKES REGION OVERNIGHT. ...UPPER MS VALLEY INTO GREAT LAKES... LOW LEVEL MOISTURE IS EXPECTED TO SPREAD RAPIDLY NWD TOWARD THE UPPER MS VALLEY DURING THE DAY AS WARM FRONT LIFTS NWD INTO THE REGION...WITH SURFACE DEW POINTS OF 55-60F MOVING INTO PARTS OF SERN MN/WRN WI BY 00Z. STEEPER MID LEVEL LAPSE RATES OF 7.0-7.5 C/KM ARE FORECAST TO SPREAD EWD ACROSS THE MIDDLE AND UPPER MS VALLEY TOWARD THE WRN GREAT LAKES IN ASSOCIATION WITH STRONG WESTERLY MID LEVEL WINDS FROM THE NRN ROCKIES INTO THE GREAT LAKES. AIR MASS WILL DESTABILIZE NWD AS LOW LEVEL MOISTURE SPREADS NWD BENEATH THE STEEPER LAPSE RATES...WITH ELEVATED CAPE OF 1000-1500 J/KG DEVELOPING NORTH OF THE WARM FRONT AND MLCAPE OF 2000-2500 J/KG WITH WARM SECTOR. PRIMARY CONVECTIVE DEVELOPMENT IS EXPECTED TO BEGIN DURING THE LATE AFTERNOON OR EVENING OVER PARTS OF MN AND WI ALONG/NORTH OF THE WARM FRONT AS THE SWLY LOW LEVEL JET PROVIDES INCREASING WARM ADVECTION LIFT. THIS ACTIVITY IS EXPECTED TO SPREAD EWD/ESEWD DURING THE OVERNIGHT HOURS AS THE LOW LEVEL JET VEERS WITH TIME AND WARM ADVECTION ZONE SHIFTS TOWARD LOWER MI. FORECAST WIND PROFILES EXHIBIT STRONG VEERING WITH HEIGHT...WITH SUFFICIENT VERTICAL SHEAR WITHIN THE CLOUD LAYER TO SUPPORT ELEVATED SUPERCELLS. LARGE HAIL WILL BE POSSIBLE WITH STRONGER CELLS...WITH ADDITIONAL THREAT FOR STRONG WIND GUSTS WITH NEAR SURFACE-BASED STORMS CLOSE TO THE WARM FRONT. THIS ACTIVITY IS LIKELY TO PERSIST THROUGH THE NIGHT AS IT SPREADS ESEWD ACROSS THE LOWER GREAT LAKES AREA. THERE IS ALSO A POSSIBILITY OF ISOLATED THUNDERSTORMS FORMING DURING THE AFTERNOON IN THE WARM SECTOR...HOWEVER THE PRESENCE OF A WEAK CAP IS LIKELY TO LIMIT THE OVERALL COVERAGE OF DEEP CONVECTION. SINCE THE STRONGER VERTICAL SHEAR EXTENDS SWD INTO PARTS OF MO AND SRN IL...THERE IS A LOW CONDITIONAL PROBABILITY OF SEVERE WITH ANY STORM THAT DEVELOPS. THE CONVECTIVE POTENTIAL SOUTH OF THE WARM FRONT SHOULD DIMINISH AFTER SUNSET. ..WEISS.. 04/12/2006  From SwoDy2 at goshenarc.org Thu Apr 13 17:34:11 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Thu, 13 Apr 2006 13:34:11 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 131731 SWODY2 SPC AC 131730 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1230 PM CDT THU APR 13 2006 VALID 141200Z - 151200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE OH VALLEY AND CNTRL APPALACHIAN MTNS... ...CNTRL APPALACHIAN MTNS... A WEST TO NORTHWEST FLOW PATTERN WILL REMAIN IN PLACE ACROSS THE NERN U.S FRIDAY AS SEVERAL EMBEDDED SHORTWAVE TROUGHS MOVE QUICKLY ESEWD ACROSS REGION. THE FIRST SHORTWAVE TROUGH IS FORECAST TO MOVE ACROSS THE OH VALLEY TONIGHT WITH A SEVERE LINEAR MCS DEVELOPING AND REACHING OH BY DAYBREAK FRIDAY. ALTHOUGH THIS CONVECTIVE COMPLEX MAY BE IN A WEAKENING STAGE JUST AFTER DAYBREAK...REINTENSIFICATION BY MID-DAY WILL BE POSSIBLE AS DESTABILIZATION OCCURS ACROSS WV..SWRN PA...WRN MD AND WRN VIRGINIA. OTHER STORMS SHOULD REDEVELOP IN THE CNTRL APPALACHIAN MTNS BEHIND THE FIRST LINEAR MCS AIDED BY INCREASING LARGE-SCALE ASCENT AHEAD OF AN APPROACHING MID-LEVEL JET. FORECAST SOUNDINGS ACROSS THE CNTRL APPALACHIANS QUICKLY DEVELOP MODERATE INSTABILITY BY LATE FRIDAY MORNING WITH VERY STRONG VERTICAL SHEAR PROFILES IN PLACE AS THE NOSE OF THE MID-LEVEL JET MOVES ACROSS THE REGION. THIS SHOULD BE SUFFICIENT FOR A WIND DAMAGE/HAIL THREAT AS THE FIRST LINE MOVES ACROSS DURING THE MORNING. AS MODERATE INSTABILITY DEVELOPS BY MID-DAY...LITTLE OR NO CAPPING...INCREASING ASCENT FROM THE WEST AND THE STRONGLY SHEARED ENVIRONMENT SHOULD BE FAVORABLE FOR SUPERCELLS IN THE AFTERNOON. ALTHOUGH SUPERCELLS MAY INITIALLY HAVE A TORNADO THREAT...LARGE HAIL AND WIND DAMAGE SHOULD BECOME THE FAVORED THREAT BY MID TO LATE AFTERNOON AS LOW-LEVEL WINDS VEER AND BECOME MORE UNDIRECTIONAL. THE SEVERE THREAT SHOULD DROP-OFF BY EVENING AS INSTABILITY DECREASES ACROSS THE REGION. ...OH VALLEY... A WEST TO NORTHWEST FLOW PATTERN WILL CONTINUE IN PLACE ACROSS THE OH VALLEY FRIDAY AS AN EMBEDDED SHORTWAVE TROUGH APPROACHES THE REGION FROM THE WEST. ALTHOUGH A CAPPING INVERSION MAY BE IN PLACE ACROSS MUCH OF THE REGION THROUGH MID-DAY...STRENGTHENING INSTABILITY AND INCREASING LOW-LEVEL CONVERGENCE SHOULD ALLOW STORMS TO INITIATE IN IL...IND...ERN IA AND KY SOUTH OF A FRONTAL BOUNDARY DURING THE MID AFTERNOON HOURS. STORM COVERAGE SHOULD INCREASE WITH AN MCS DEVELOPING DURING THE EVENING AS A SHORTWAVE TROUGH DRIFTS ESEWD ACROSS THE OH VALLEY. FORECAST SOUNDINGS ACROSS IL AND SRN IND BY 22Z FRIDAY SHOW SBCAPES OF 2500-3500 J/KG WITH MODERATE VERTICAL SHEAR AND VERY STEEP MID-LEVEL LAPSE RATES SUGGESTING THE ENVIRONMENT WILL BE FAVORABLE FOR SUPERCELLS WITH LARGE HAIL. IN ADDITION...A 50 KT LOW-LEVEL JET IS FORECAST TO STRENGTHEN BY EARLY EVENING FEEDING THE DEVELOPING STORM COMPLEX. ALTHOUGH SFC WINDS WILL LIKELY BE VEERED...FORECAST SOUNDINGS SHOW SUFFICIENT DIRECTIONAL SHEAR BELOW 700 MB SUGGESTING A FEW TORNADOES WILL BE POSSIBLE WITH THE STRONGER SUPERCELLS. AS AN MCS EXPANDS AND DRIFTS ESEWD ACROSS OH AND KY INTO THE WRN APPALACHIAN FOOTHILLS FRIDAY EVENING...A LARGE HAIL AND WIND DAMAGE THREAT SHOULD CONTINUE WITH THE STRONGER STORMS. AS THE INSTABILITY DECREASES OVERNIGHT...THE SEVERE THREAT SHOULD GRADUALLY DIMINISH. ..BROYLES.. 04/13/2006  From SwoDy2 at goshenarc.org Sat Apr 15 04:51:52 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 15 Apr 2006 00:51:52 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 150448 SWODY2 SPC AC 150447 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1147 PM CDT FRI APR 14 2006 VALID 161200Z - 171200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM PORTIONS OF IA/MO ESEWD THROUGH THE OH VALLEY TO THE VA/NC COASTS... ...SYNOPSIS... AMPLIFIED LARGE-SCALE PATTERN IS FORECAST DURING THE DAY TWO PERIOD...CHARACTERIZED BY INTENSIFYING TROUGH OVER THE INTERMOUNTAIN W...RIDGING FROM THE WRN GREAT LAKES INTO HUDSON BAY...AND CLOSED MID-LEVEL LOW WHICH WILL PERSIST OFF THE COAST OF NOVA SCOTIA. WITHIN THIS LARGER-SCALE CIRCULATION...CLOSED LOW INITIALLY OVER THE MID MO VALLEY SUNDAY MORNING WILL WEAKEN AS IT UNDERCUTS WRN GREAT LAKES RIDGE...AND IS EVENTUALLY ENTRAINED INTO BROADER BELT OF CYCLONIC FLOW ASSOCIATED WITH WRN ATLANTIC UPPER LOW. IN THE LOW-LEVELS...SURFACE LOW COINCIDENT WITH MID MO VALLEY UPPER LOW WILL SLOWLY FILL AS IT DEVELOPS ESEWD ALONG ATTENDANT BAROCLINIC ZONE THROUGH THE OH VALLEY. ...MIDWEST EWD THROUGH THE OH VALLEY TO THE VA/NC COASTS... MOIST BOUNDARY-LAYER CONDITIONS /I.E. DEWPOINTS IN THE UPPER 50S TO LOWER 60S/ COUPLED WITH REMNANT PLUME OF STEEP MID-LEVEL LAPSE RATES ARE EXPECTED TO CONTRIBUTE TO A MODERATELY UNSTABLE AIR MASS ALONG AND S OF LOW-LEVEL BAROCLINIC ZONE WITH MLCAPES OF 1500-2000 J/KG DEVELOPING OVER PORTIONS OF ERN MO/IL/IND...AND GENERALLY 500-1500 J/KG ESEWD THROUGH THE REMAINDER OF THE OH VALLEY INTO VA/NC. DAYTIME HEATING COUPLED WITH FORCING FOR ASCENT AHEAD OF OPENING MID-LEVEL WAVE ARE EXPECTED TO RESULT IN VIGOROUS TSTM DEVELOPMENT BY EARLY TO MID AFTERNOON FROM VICINITY OF SURFACE LOW EWD ALONG BAROCLINIC ZONE OVER ERN IA/NERN MO INTO IL/IND. GIVEN THE MODERATE INSTABILITY AND VERTICAL WIND PROFILES EXHIBITING PRONOUNCED LOW-LEVEL VEERING AND 35-45 KTS OF DEEP-LAYER SHEAR...POTENTIAL WILL EXIST FOR SUPERCELLS CAPABLE OF LARGE HAIL /SOME SIGNIFICANT/...DAMAGING WINDS AND ISOLATED TORNADOES. ADDITIONAL CLUSTERS OF STRONG TO SEVERE STORMS WILL ALSO BE POSSIBLE FARTHER DOWNSTREAM OVER THE OH VALLEY...CNTRL APPALACHIANS AND EWD TO THE VA/NC COASTAL PLAIN OWING TO PERSISTENT LOW-LEVEL WARM/MOIST ADVECTION ALONG/N OF SURFACE BOUNDARY. HERE TOO...DEEP-LAYER VERTICAL SHEAR WILL BE SUPPORTIVE OF SUPERCELLS AND BOWING STRUCTURES CAPABLE OF LARGE HAIL...DAMAGING WINDS AND A COUPLE OF TORNADOES. OVERALL LARGE-SCALE PATTERN APPEARS TO SUPPORT UPSCALE GROWTH INTO ONE OR MORE FORWARD-PROPAGATING MCS/S LATE SUNDAY AFTERNOON INTO SUNDAY NIGHT WITH AN INCREASED POTENTIAL FOR CORRIDORS OF DAMAGING WINDS. ...ERN MT... BOUNDARY-LAYER MOISTURE WILL REMAIN QUITE LIMITED AHEAD OF PACIFIC COLD FRONT MOVING OUT OF THE NRN ROCKIES. HOWEVER...DIABATIC HEATING COUPLED WITH HEIGHT FALLS AHEAD OF MID-LEVEL TROUGH DEVELOPING EWD THROUGH THE INTERMOUNTAIN W WILL RESULT IN STEEP LOW TO MID-LEVEL LAPSE RATES AND RESULTANT WEAK INSTABILITY. THE POTENTIAL FOR A FEW HIGH-BASED STORMS WILL EXIST LATE SUNDAY AFTERNOON INTO SUNDAY EVENING AS SURFACE FRONT PUSHES EWD THROUGH REGION. ISOLATED SEVERE HAIL AND LOCALLY STRONG WIND GUSTS WILL BE POSSIBLE WITH THE MOST INTENSE STORMS OWING TO THE STEEP LAPSE RATES AND DEEP...RELATIVELY DRY SUB-CLOUD LAYER. ..MEAD.. 04/15/2006  From SwoDy2 at goshenarc.org Sat Apr 15 17:32:52 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 15 Apr 2006 13:32:52 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 151729 SWODY2 SPC AC 151728 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1228 PM CDT SAT APR 15 2006 VALID 161200Z - 171200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE OH VALLEY...CNTRL APPALACHIANS AND ATLANTIC COASTAL PLAINS... ...OH VALLEY/CNTRL APPALACHIANS/ATLANTIC COASTAL PLAINS... A NEGATIVELY-TILTED UPPER-LOW OVER THE PLAINS STATES WILL SLOWLY FILL AND DRIFT EWD TOWARD THE OH VALLEY SUNDAY. LARGE-SCALE ASCENT AHEAD OF THE SYSTEM WILL SUPPORT THE DEVELOPMENT OF SCATTERED TO NUMEROUS THUNDERSTORMS ACROSS THE REGION SUNDAY AND SUNDAY NIGHT. A LARGE MCS WILL LIKELY BE ONGOING AT THE BEGINNING OF THE PERIOD ACROSS WI...IL AND IND DURING THE MORNING AHEAD OF THE APPROACHING UPPER-TROUGH. SFC DEWPOINTS SHOULD BE IN THE LOWER 60S ACROSS MUCH OF THE OH VALLEY ALLOWING MODERATE INSTABILITY TO DEVELOP BY SUNDAY AFTERNOON SOUTH OF THE MCS WHERE THE AIRMASS SHOULD REMAIN UNDISTURBED. SUBSTANTIAL DESTABILIZATION ALSO APPEARS LIKELY WEST OF THE EXITING MCS ACROSS IA AND NRN IL NEAR A SFC LOW ASSOCIATED WITH THE UPPER SYSTEM. THIS WOULD BE THE MOST LIKELY AREA FOR STRONG CONVECTIVE INITIATION EARLY SUNDAY AFTERNOON WITH STORMS EXPANDING IN COVERAGE DURING THE AFTERNOON ALONG A STATIONARY FRONTAL BOUNDARY EXTENDING ESEWD FROM THE SFC LOW. MCS DEVELOPMENT WITH THIS CONVECTIVE COMPLEX APPEARS LIKELY LATE SATURDAY AFTERNOON WITH STORMS MOVING ACROSS NCNTRL IL INTO IND...NRN KY AND SRN OH DURING THE EVENING HOURS. FORECAST SOUNDINGS LATE SUNDAY AFTERNOON ACROSS THE REGION SHOW MODERATE INSTABILITY WITH 40 TO 50 KT OF VERTICAL SHEAR AND STEEP MID-LEVEL LAPSE RATES SUGGESTING SUPERCELLS WITH LARGE HAIL AND WIND DAMAGE WILL BE LIKELY. DUE TO THE MODERATE INSTABILITY AND COLDER AIR ALOFT WITH THE UPPER-TROUGH...VERY LARGE HAIL APPEARS POSSIBLE WITH THE STRONGER SUPERCELLS IN THE LATE AFTERNOON AND EARLY EVENING. A POTENTIAL FOR TORNADOES WILL ALSO EXIST AS SUPERCELLS INCREASE IN COVERAGE AND A LARGE MCS DEVELOPS IN THE EVENING. DUE TO THE UNSTABLE AIRMASS AND MODERATE VERTICAL SHEAR...THE MCS SHOULD CONTINUE TO DRIFT ESEWD OVERNIGHT WITH A LOW-END SEVERE THREAT POSSIBLE INTO THE CNTRL APPALACHIAN MTNS AND ATLANTIC COASTAL PLAINS LATE IN THE PERIOD. ...ERN MT/FAR WRN ND... A BROAD BAND OF SOUTHWEST FLOW ACROSS THE NWRN U.S. WILL REMAIN IN PLACE SUNDAY. SEVERAL SHORTWAVE TROUGHS EMBEDDED IN THE FLOW WILL DRIFT NEWD ACROSS THE NRN PLAINS SUNDAY AND SUNDAY NIGHT. ALTHOUGH FORECAST SOUNDINGS LATE SUNDAY AFTERNOON ACROSS THE REGION SHOW WEAK INSTABILITY IN PLACE...STEEPENING LAPSE RATES AND LARGE-SCALE ASCENT AHEAD OF ANY SHORTWAVE WOULD MAKE MARGINALLY SEVERE HAIL STORMS POSSIBLE. ANY MARGINAL SEVERE THREAT WOULD LIKELY BE TIED CLOSELY TO SFC HEATING. ..BROYLES.. 04/15/2006  From SwoDy2 at goshenarc.org Sun Apr 16 05:27:58 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 16 Apr 2006 01:27:58 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 160525 SWODY2 SPC AC 160523 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1223 AM CDT SUN APR 16 2006 VALID 171200Z - 181200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER MUCH OF THE CAROLINAS... ...THERE IS A SLGT RISK OF SVR TSTMS OVER WRN PARTS OF SD AND NEB... ...SYNOPSIS... AMPLIFIED LONG WAVE PATTERN IS FORECAST THROUGH THE DAY TWO PERIOD...CHARACTERIZED BY UPPER LOWS OVER THE GULF OF AK AND OVER THE CANADIAN MARITIMES...AND EVOLVING UPPER LOW OVER THE NRN HIGH PLAINS. BETWEEN THESE FEATURES...HIGH AMPLITUDE RIDGE WILL EXIST FROM HUDSON BAY/WRN QUEBEC SWWD INTO THE GREAT LAKES...AND A WEAKER UPSTREAM RIDGE FROM THE CANADIAN ROCKIES INTO THE PACIFIC NW. IN THE LOW-LEVELS...SURFACE LOW ASSOCIATED WITH A WEAKENING MID-LEVEL VORTICITY MAXIMUM WILL DEVELOP SEWD FROM ERN KY INTO SC BY AFTERNOON WITH ASSOCIATED COLD FRONT PUSHING SWD THROUGH THE PIEDMONT AND COASTAL PLAIN. OVER THE PLAINS...SURFACE PATTERN BECOMES MORE COMPLEX. PACIFIC COLD FRONT WILL PUSH EWD OUT OF THE NRN AND CNTRL ROCKIES INTO THE HIGH PLAINS WITH LEE CYCLONE EVOLVING ALONG THIS BOUNDARY OVER SERN WY MONDAY AFTERNOON. A DRY LINE OR LEE TROUGH WILL EXTEND SWD FROM THIS LOW INTO WRN PORTIONS OF KS AND TX...WITH ATTENDANT WARM FRONT SLOWLY LIFTING NWD THROUGH KS AND NEB. ...CAROLINAS... CLUSTERS OF TSTMS ARE EXPECTED TO BE ONGOING AT THE ONSET OF THE FORECAST MONDAY MORNING INVOF SURFACE LOW AND MID-LEVEL DISTURBANCE OVER PORTIONS OF THE OH VALLEY INTO CNTRL APPALACHIANS. THIS ACTIVITY WILL LIKELY INTENSIFY BY AFTERNOON AS IT CRESTS HIGHER TERRAIN AND MOVES INTO AN ENVIRONMENT CHARACTERIZED BY STEEP LOW-LEVEL LAPSE RATES...MOIST BOUNDARY-LAYER CONDITIONS AND RESULTANT WEAK TO MODERATE INSTABILITY. FORECAST SOUNDINGS WITHIN PRE-FRONTAL AIR MASS OVER THE PIEDMONT AND COASTAL PLAIN INDICATE LARGELY UNIDIRECTIONAL WLY OR WSWLY WINDS THROUGH THE DEPTH OF THE BUOYANCY LAYER WITH SUFFICIENT DEEP-LAYER SPEED SHEAR /40-45 KTS/ TO SUPPORT ORGANIZED SEVERE STORMS. THE MODEST MID-LEVEL LAPSE RATES WILL LIMIT A MORE SUBSTANTIAL HAIL THREAT WITH DAMAGING WINDS LIKELY WITH THE MOST INTENSE STORMS. ...SD / NEB... BOUNDARY-LAYER IS EXPECTED TO REMAIN RELATIVELY DRY AHEAD OF PACIFIC COLD FRONT EMERGING FROM THE ROCKIES WITH DEWPOINTS REMAINING LARGELY IN THE 30S AND 40S. MODEL GUIDANCE SUGGESTS THAT PRIMARY LOW-LEVEL MOISTURE AXIS WILL BE FOCUSED ALONG RETREATING WARM FRONT WITH 50-55 F DEWPOINTS ADVECTING NWWD INTO CNTRL NEB BY MONDAY NIGHT. FRONTAL CONVERGENCE COUPLED WITH INCREASED LARGE-SCALE FORCING AHEAD OF APPROACHING MID-LEVEL TROUGH ARE EXPECTED TO CONTRIBUTE TO TSTM DEVELOPMENT BY AFTERNOON INTO EVENING ALONG COLD FRONT FROM THE WRN DAKOTAS INTO SERN WY AND NWRN NEB WITHIN WEAKLY UNSTABLE ENVIRONMENT. DESPITE THE MARGINAL INSTABILITY...THE STEEP LAPSE RATES AND RELATIVELY STRONG VERTICAL SHEAR PROFILES SUGGEST THE POTENTIAL FOR A FEW ORGANIZED/ROTATING STORMS CAPABLE OF DAMAGING WINDS AND LARGE HAIL. THIS ACTIVITY WILL LIKELY MOVE/DEVELOP EWD ACROSS WRN SD AND NWRN/N-CNTRL NEB MONDAY NIGHT /PERHAPS BECOMING MORE ELEVATED WITH EWD EXTENT/ WITH A CONTINUING THREAT OF MAINLY SEVERE HAIL. ..MEAD.. 04/16/2006  From SwoDy2 at goshenarc.org Sun Apr 16 17:27:41 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 16 Apr 2006 13:27:41 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 161723 SWODY2 SPC AC 161723 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1223 PM CDT SUN APR 16 2006 VALID 171200Z - 181200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE CAROLINAS... ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE NRN AND CNTRL PLAINS... ...CAROLINAS... THE UPPER-LEVEL LOW OVER THE NRN MS VALLEY WILL SLIDE ESEWD ACROSS THE OH VALLEY TONIGHT INTO THE CNTRL APPALACHIAN MTNS MONDAY MORNING. IN RESPONSE...LARGE-SCALE ASCENT WILL INCREASE ACROSS THE ATLANTIC COASTAL PLAIN MONDAY AND SCATTERED THUNDERSTORMS SHOULD INITIATE IN THE CAROLINAS MONDAY AFTERNOON. IN RESPONSE TO THE UPPER-LEVEL TROUGH...A COLD FRONT IS FORECAST TO MOVE SWD ACROSS THE REGION MONDAY. AHEAD OF THE FRONT SFC DEWPOINTS IN THE 55-60 F RANGE MAY BE SUPPORTIVE OF LOWER-END MODERATE INSTABILITY AND STORMS SHOULD INITIATE ALONG AND SOUTH OF THE BOUNDARY DURING THE EARLY AFTERNOON. THE INSTABILITY COMBINED WITH STRONG VERTICAL SHEAR PROFILES ENHANCED BY A MID-LEVEL JET SHOULD BE SUFFICIENT FOR SUPERCELLS. HAIL AND ISOLATED WIND DAMAGE WILL BE POSSIBLE AS STORM COVERAGE INCREASES AND AN MCS GRADUALLY DEVELOPS. ALTHOUGH A SEVERE THREAT SHOULD CONTINUE WITH THE MCS INTO THE EVENING HOURS...ANY THREAT ACROSS THE ERN CAROLINAS SHOULD DECREASE FROM WEST TO EAST AS THE MCS MOVES ESEWD INTO THE ATLANTIC IN THE EARLY EVENING. ...NEB/SD... AN UPPER-LEVEL TROUGH OVER THE PACIFIC NORTHWEST IS FORECAST TO GRADUALLY FILL AND MOVE EWD INTO THE NRN ROCKIES MONDAY. LARGE-SCALE ASCENT WILL SPREAD EWD ACROSS THE HIGH PLAINS AS THE TROUGH APPROACHES MAKING THUNDERSTORM DEVELOPMENT LIKELY IN THE LATE AFTERNOON AND EVENING. FORECAST SOUNDINGS ACROSS NRN NEB MONDAY AFTERNOON DEVELOP LOWER-END MODERATE INSTABILITY WITH MLCAPE VALUES INCREASING TO AROUND 1500 J/KG RANGE BY EARLY EVENING. IN ADDITION...SWLY MID-LEVEL FLOW WILL INCREASE AS A MID-LEVEL JET DRIFTS EWD INTO THE REGION. THIS WILL CREATE VERTICAL SHEAR PROFILES FAVORABLE FOR SUPERCELLS. LARGE HAIL AND ISOLATED WIND DAMAGE WILL BE LIKELY WITH THE STRONGER SUPERCELLS AS LAPSE RATES STEEPEN AND STORMS MATURE IN THE EARLY EVENING. MCS DEVELOPMENT WILL BE POSSIBLE BUT THE SEVERE THREAT SHOULD GRADUALLY DECREASE AS INSTABILITY WEAKENS DURING THE EVENING. ..BROYLES.. 04/16/2006  From SwoDy2 at goshenarc.org Mon Apr 17 05:52:55 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 17 Apr 2006 01:52:55 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 170549 SWODY2 SPC AC 170548 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1248 AM CDT MON APR 17 2006 VALID 181200Z - 191200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE MID / LOWER MO VALLEY SEWD INTO THE TN VALLEY... ...SYNOPSIS... HIGH AMPLITUDE LARGE-SCALE PATTERN WILL CONTINUE ACROSS THE CONUS THROUGH THE DAY TWO PERIOD...CHARACTERIZED BY OMEGA BLOCK FROM THE WRN ATLANTIC WWD INTO THE PLAINS. WRN PART OF THIS BLOCK IS MID-LEVEL TROUGH WHICH WILL INTENSIFY AND FORM A CLOSED LOW OVER THE NRN PLAINS. IN THE LOW-LEVELS...OCCLUSION OF NRN-MOST SURFACE LOW WILL OCCUR TUESDAY MORNING OVER THE ERN DAKOTAS AS STRONG COLD FRONT OVERTAKES NRN EXTENSION OF WARM OR QUASI-STATIONARY BOUNDARY STRETCHING FROM THE MID MO VALLEY SEWD INTO THE TN VALLEY AND SERN STATES. A SECONDARY SURFACE LOW IS EXPECTED TO DEVELOP AT THE PROGRESSIVE COLD FRONTAL OCCLUSION POINT SEWD FROM NWRN MO TUESDAY AFTERNOON INTO THE WRN TN VALLEY LATE MONDAY NIGHT. ...MID AND LOWER MO VALLEY INTO THE TN VALLEY... 17/00Z SOUNDINGS FROM CRP/LCH INDICATE THAT LOW-LEVEL MOISTURE PROFILES ARE SLOWLY IMPROVING ACROSS THE NWRN GULF COAST WITH LOWEST MEAN MIXING RATIOS OF 13-15 G/KG. WHILE THIS RICH A BOUNDARY-LAYER AIR MASS WILL NOT LIKELY BE ADVECTED NWD INTO THE CNTRL LOW PLAINS...IT DOES APPEAR THAT 60-65 F DEWPOINTS WILL BE POSSIBLE INTO MO BY TUESDAY AFTERNOON...CONTRIBUTING TO MLCAPES OF 2000-2500 J/KG. STRONG DEEP-LAYER FORCING FOR ASCENT AHEAD OF EVOLVING UPPER LOW WILL LIKELY SUPPORT AN INCREASE IN ELEVATED TSTMS DURING THE DAY NEAR AND E OF OCCLUDED FRONT FROM PORTIONS OF ERN SD/SWRN MN SWD INTO ERN NEB AND WRN IA. RATHER STEEP MID-LEVEL LAPSE RATES AND STRONG LOW-LEVEL WARM ADVECTION WILL CONTRIBUTE TO POCKETS OF MODERATE INSTABILITY FOR ELEVATED PARCELS WITH STRONGEST STORMS CAPABLE OF MAINLY SEVERE HAIL. SURFACE-BASED STORM DEVELOPMENT IS EXPECTED BY MID TO LATE AFTERNOON NEAR SECONDARY SURFACE LOW AND OCCLUSION POINT OVER NWRN MO. DESPITE THE STRONGEST MID AND HIGH-LEVEL WIND FIELDS REMAINING FARTHER TO THE NW IN CLOSER PROXIMITY OF UPPER SYNOPTIC SYSTEM...VERTICAL SHEAR PROFILES WILL BE SUPPORTIVE OF SEVERE STORMS INCLUDING SUPERCELLS. THE WARM SECTOR IS EXPECTED TO BE RATHER NARROW AT THIS INITIATION POINT WITH ANY STORMS QUICKLY MOVING EWD ACROSS NW-SE ORIENTED STATIONARY OR WARM FRONT INTO A MUCH MORE STABLE ENVIRONMENT. ADDITIONAL STORMS MAY ALSO DEVELOP BY LATE AFTERNOON/EARLY EVENING SWD ALONG COLD FRONT OR PRE-FRONTAL TROUGH/DRY LINE OVER FAR E-CNTRL/SERN KS INTO SWRN MO. HERE...WARM SECTOR WILL BE WIDER THOUGH MARGINAL DEEP-LAYER SHEAR AND STRONG LINEAR FORCING ALONG COLD FRONT MAY PROMOTE A RAPID TRANSITION TO OUTFLOW-DOMINANT MCS WITH THE MAIN THREATS BEING LARGE HAIL AND DAMAGING WINDS. THE THREAT OF PRIMARILY DAMAGING WINDS AND SEVERE HAIL IS EXPECTED TO DEVELOP SEWD INTO THE WRN TN VALLEY OVERNIGHT IN ASSOCIATION WITH WEAKENING MIGRATORY SURFACE LOW. ...NRN FL INTO SWRN GA... MOIST BOUNDARY-LAYER CONDITIONS ARE EXPECTED TO CONTRIBUTE TO A MODERATELY UNSTABLE AIR MASS TUESDAY AFTERNOON ALONG WEAK BACK DOOR FRONT SLOWLY SAGGING SWWD. WHILE MID-LEVEL LAPSE RATES ARE NOT EXPECTED TO BE PARTICULARLY STEEP...MODERATELY STRONG UNIDIRECTIONAL VERTICAL SHEAR MAY SUPPORT A FEW ORGANIZED STORMS CAPABLE OF ISOLATED DAMAGING WINDS AND PERHAPS A BRIEF TORNADO. ..MEAD.. 04/17/2006  From SwoDy2 at goshenarc.org Tue Apr 18 05:25:03 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 18 Apr 2006 01:25:03 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 180521 SWODY2 SPC AC 180520 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1220 AM CDT TUE APR 18 2006 VALID 191200Z - 201200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM PARTS OF THE SRN OH AND TN VALLEYS INTO AL AND GA... ...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE TX HILL COUNTRY AND EDWARDS PLATEAU... ...SYNOPSIS... OMEGA BLOCK FROM THE NRN PLAINS INTO THE WRN ATLANTIC WILL GRADUALLY SHIFT EWD THROUGH THE DAY TWO PERIOD WITH MORE OF A REX BLOCK PATTERN BECOMING BETTER DEFINED FROM THE NRN PLAINS/UPPER MS VALLEY INTO HUDSON BAY. A SLIGHTLY MORE PROGRESSIVE SRN BRANCH OF WESTERLIES WILL PERSIST FROM THE SWRN DESERTS EWD THROUGH THE GULF COAST STATES WITH A VORTICITY MAXIMUM TRANSLATING FROM THE SRN CA COAST EWD INTO AZ. IN THE LOW-LEVELS...LOW PRESSURE OVER WRN TN WILL SLOWLY DEVELOP EWD THROUGH THE TN VALLEY BEFORE WEAKENING WITH COLD FRONTAL SURGE ALSO SLOWING OVER THE TN VALLEY SWWD THROUGH THE LOWER MS VALLEY INTO CNTRL TX. MEANWHILE...WEAK BACK DOOR FRONT INITIALLY FROM ERN KY/TN SEWD TO OFF THE NERN FL COAST WILL SLOWLY RETREAT EWD THROUGH THE PERIOD. ...OH AND TN VALLEYS INTO THE SERN STATES... CLUSTERS OF TSTMS ARE EXPECTED TO BE ONGOING AT THE ONSET OF THE FORECAST PERIOD OVER THE TN AND SRN OH VALLEYS WEDNESDAY MORNING DRIVEN LARGELY BY WAA ALONG WSWLY LLJ AXIS. THIS ACTIVITY WILL LIKELY CONTINUE EWD OR SEWD WEDNESDAY WITH SOME THREAT OF MARGINALLY SEVERE HAIL INTO THE CNTRL/SRN APPALACHIANS. A MODERATELY UNSTABLE AIR MASS /MLCAPES OF 1000-2000 J/KG/ IS EXPECTED TO DEVELOP BY AFTERNOON IN THE WAKE OF THIS ACTIVITY AHEAD OF COLD FRONT OWING TO MOIST BOUNDARY-LAYER CONDITIONS AND DIABATIC HEATING. WHILE LARGE-SCALE FORCING IS FORECAST TO REMAIN LARGELY NEUTRAL ACROSS REGION...A RELATIVELY WEAK CAP AND SUSTAINED FRONTAL CONVERGENCE SHOULD BE SUFFICIENT TO INITIATE MORE VIGOROUS SURFACE-BASED DEVELOPMENT BY AFTERNOON OVER MIDDLE TN AND SRN KY. ADDITIONAL STORMS WILL ALSO BE POSSIBLE SEWD ALONG RETREATING BOUNDARY OVER GA. 30-40 KTS OF WLY DEEP-LAYER SHEAR COUPLED WITH THE MODERATE INSTABILITY SHOULD SUPPORT SEVERE STORMS CAPABLE OF LARGE HAIL..DAMAGING WINDS AND PERHAPS A COUPLE OF TORNADOES. ...TX HILL COUNTRY AND EDWARDS PLATEAU... ENVIRONMENT IS EXPECTED TO BECOME INCREASINGLY SUPPORTIVE OF FEW DIURNAL SEVERE STORMS ALONG WRN EXTENSION OF STALLED FRONTAL BOUNDARY. HERE...DIABATIC HEATING AND MODEST BOUNDARY-LAYER MOISTURE WILL CONTRIBUTE TO A MODERATELY UNSTABLE AIR MASS WITH MLCAPES OF 1000-1500 J/KG. THE STRONG DAYTIME HEATING ALONG WITH FRONTAL CONVERGENCE AND PERHAPS SOME WEAK OROGRAPHIC FORCING SHOULD BE SUFFICIENT TO INITIATE DEEP MOIST CONVECTION BY LATE AFTERNOON OR EARLY EVENING. LARGELY UNIDIRECTIONAL 30-40 KT DEEP-LAYER SHEAR SUGGESTS THE POTENTIAL FOR ROTATING STORMS CAPABLE OF LARGE HAIL AND LOCALLY DAMAGING WINDS. MORE ELEVATED TSTM DEVELOPMENT WILL BECOME INCREASINGLY LIKELY N OF SURFACE FRONT WEDNESDAY NIGHT OVER THE CONCHO VALLEY/ERN PERMIAN BASIN EWD INTO CNTRL TX AS WAA AND ISENTROPIC ASCENT INCREASE ALONG STRENGTHENING SLY LLJ. SOME MARGINALLY SEVERE HAIL WILL BE POSSIBLE WITH THE STRONGEST STORMS. ...MS INTO ERN TX... DEWPOINTS IN THE 60S AND DAYTIME HEATING WILL SUPPORT MODERATE INSTABILITY S OF FRONT WEDNESDAY AFTERNOON WITH MLCAPES OF 1000-2000 J/KG. WEAK CAPPING AND FRONTAL CONVERGENCE SHOULD SUPPORT SCATTERED TSTM DEVELOPMENT BY MID AFTERNOON WITH SOME POTENTIAL FOR ISOLATED STRONG WIND GUSTS AND MARGINAL HAIL. THE PRIMARY FACTOR LIMITING A MORE ORGANIZED SEVERE THREAT APPEARS TO BE THE RATHER WEAK VERTICAL SHEAR. ..MEAD.. 04/18/2006  From SwoDy2 at goshenarc.org Tue Apr 18 17:38:10 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 18 Apr 2006 13:38:10 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 181734 SWODY2 SPC AC 181733 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1233 PM CDT TUE APR 18 2006 VALID 191200Z - 201200Z ...THERE IS A SLGT RISK OF SVR TSTMS WED/WED NIGHT ACROSS A LARGE PORTION OF THE GULF STATES INTO THE TENNESSEE VALLEY.... A ZONAL BELT OF WESTERLIES PERSISTS ACROSS THE FAR SOUTHERN TIER OF THE U.S...WHILE A BLOCK DEVELOPS IN A BRANCH OF THE POLAR WESTERLIES FROM THE NORTH CENTRAL U.S. INTO THE WESTERN ATLANTIC. A STRENGTHENING UPPER RIDGE IS EVIDENT IN LATEST WATER VAPOR IMAGERY NEAR JAMES BAY...WITH CLOSED LOWS DEVELOPING OFF THE NORTH ATLANTIC COAST...AND ACROSS THE NORTH CENTRAL PLAINS. MODELS SUGGEST LITTLE CHANGE TO THE LARGE-SCALE PATTERN WILL OCCUR THROUGH THIS FORECAST PERIOD...BUT THE RIDGE MAY BEGIN TO WEAKEN AS NORTHERN PLAINS CLOSED LOW SHIFTS TOWARD THE UPPER MISSISSIPPI VALLEY. THIS SEEMS LIKELY TO OCCUR MAINLY IN RESPONSE TO A SIGNIFICANT IMPULSE ROTATING AROUND THE SOUTHERN/EASTERN PERIPHERY OF THE CYCLONIC CIRCULATION. AMPLIFICATION OF AN UPPER TROUGH IS FORECAST UPSTREAM...OVER THE EASTERN PACIFIC...LATE WEDNESDAY INTO EARLY THURSDAY. THIS IS PROGGED TO FORCE A SOUTHERN BRANCH CLOSED LOW INLAND ACROSS THE LOWER COLORADO VALLEY/SOUTHERN PLATEAU BY 12Z THURSDAY...PERHAPS IN PHASE WITH AN IMPULSE IN THE WEAKER SUBTROPICAL STREAM. ...TEXAS THROUGH EASTERN GULF STATES/TENNESSEE VALLEY... A CLUSTER OF THUNDERSTORM ACTIVITY APPEARS LIKELY TO BE SPREADING INTO PARTS OF THE TENNESSEE VALLEY EARLY WEDNESDAY IN ASSOCIATION WITH AN EVOLVING ZONE OF STRONGER LOW-LEVEL WARM ADVECTION. THIS FORCING MAY BE ENHANCED BY A WEAK LOWER/MID TROPOSPHERIC IMPULSE EMBEDDED WITHIN BELT OF FLOW UNDERCUTTING BLOCK. MODELS SUGGEST THIS FEATURE WILL EVENTUALLY TURN SOUTHEASTWARD ACROSS THE SOUTHERN APPALACHIANS/SOUTH ATLANTIC COAST STATES...MERGING INTO CYCLONIC REGIME SOUTH OF NORTH ATLANTIC CLOSED LOW. WHILE A BROADER AREA OF CONVECTION SEEMS LIKELY TO SPREAD ABOVE LINGERING SURFACE RIDGING ACROSS PARTS OF THE SOUTH ATLANTIC COAST STATE...FORCING FOR ADDITIONAL ACTIVITY AHEAD OF STALLING UPSTREAM FRONT ACROSS THE LOWER MISSISSIPPI VALLEY IS MORE UNCERTAIN. HOWEVER...INHIBITION ACROSS PARTS OF THE TENNESSEE VALLEY AND NORTHERN GULF STATES MAY BECOME WEAKENED ENOUGH TO SUPPORT DEVELOPMENT OF THUNDERSTORMS BY WEDNESDAY AFTERNOON IN RESPONSE TO DAYTIME HEATING. MIXED BOUNDARY LAYER WITH MID/UPPER 60S DEW POINTS IS EXPECTED TO BECOME MODERATELY UNSTABLE...WITH CAPE IN EXCESS OF 2000 J/KG BY PEAK HEATING. THIS SHOULD BE SUFFICIENT FOR SCATTERED SEVERE STORMS. ISOLATED SUPERCELLS APPEAR POSSIBLE WHERE SHEAR PROFILES WILL BE MORE SUPPORTIVE NEAR 30 KT WESTERLY LOW-LEVEL JET AXIS...ACROSS PARTS OF FAR SOUTHERN TENNESSEE/NORTHERN ALABAMA INTO NORTHWEST GEORGIA. A TORNADO OR TWO IS POSSIBLE...BUT DAMAGING WIND GUSTS AND LARGE HAIL SEEM TO BE PRIMARY SEVERE THREATS. WIDELY SCATTERED STRONG/SEVERE THUNDERSTORMS APPEAR POSSIBLE FARTHER UPSTREAM...ALONG STALLED FRONT ACROSS SOUTHEAST TEXAS INTO THE HILL COUNTRY AND BIG BEND REGION. SOUTHEASTERLY SURFACE FLOW ACROSS AREAS TO THE EAST/SOUTHEAST OF DEL RIO WILL CONTRIBUTE TO ISOLATED SUPERCELL POTENTIAL BENEATH MODERATELY STRONG WESTERLY MID-LEVEL FLOW. THIS ACTIVITY SHOULD DIMINISH DURING THE EVENING...BUT ADDITIONAL...PERHAPS MORE WIDESPREAD...CONVECTIVE DEVELOPMENT IS EXPECTED WEDNESDAY NIGHT WITH APPROACH OF UPSTREAM SOUTHERN BRANCH TROUGH. THIS IS EXPECTED TO OCCUR IN ZONE OF STRONGER WARM ADVECTION...NORTH OF RETREATING SURFACE FRONT ACROSS CENTRAL TEXAS. CAPE OF 1000 TO 2000 J/KG FOR PARCELS BASED IN MOIST LAYER ABOVE FRONTAL INVERSION IS EXPECTED TO SUPPORT VIGOROUS UPDRAFTS WITH RISK OF LARGE HAIL. ..KERR.. 04/18/2006  From SwoDy2 at goshenarc.org Wed Apr 19 05:46:46 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 19 Apr 2006 01:46:46 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 190543 SWODY2 SPC AC 190542 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1242 AM CDT WED APR 19 2006 VALID 201200Z - 211200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM WRN TX EWD INTO THE SRN TN VALLEY AND CNTRL GULF COAST STATES... ...SYNOPSIS... AMPLIFIED LARGE-SCALE PATTERN WILL CONTINUE THROUGH THE DAY TWO PERIOD. MID AND UPPER-LEVEL LOW OVER THE UPPER MS VALLEY WILL SLOWLY TRANSLATE EWD INTO THE WRN GREAT LAKES...WHILE A MORE PROGRESSIVE SRN STREAM IS MAINTAINED ACROSS THE SRN TIER OF STATES. IN ADDITION TO VORTICITY MAXIMUM SHIFTING EWD FROM AZ/NM INTO TX/OK...OTHER MORE SUBTLE PERTURBATIONS MAY EXIST WITH WSWLY FLOW FROM THE ARKLATEX INTO THE TN VALLEY AND CNTRL GULF STATES. IN THE LOW-LEVELS...WEAK LOW PRESSURE IS FORECAST TO DEVELOP NEWD FROM THE LOWER MS VALLEY INTO THE UPPER OH VALLEY /LIKELY ASSOCIATED WITH A LEAD UPPER DISTURBANCE/ WITH TRAILING FRONTAL BOUNDARY STRETCHING SWWD THROUGH THE WRN TN VALLEY INTO WRN TX. THE WRN EXTENSION OF THIS BOUNDARY MAY ATTEMPT TO RETREAT SLIGHTLY NWD WITH APPROACH OF AZ/NM SHORT WAVE TROUGH...BEFORE PUSHING MORE SWD WITH THE PASSAGE OF THIS WAVE LATE WEDNESDAY NIGHT. ...TX INTO SRN OK... SLY LLJ...MAINTAINED BY DIRECT THERMAL CIRCULATION ASSOCIATED WITH ENTRANCE REGION OF UPPER JET STREAK OVER THE LOWER MO VALLEY...WILL LIKELY BE SUPPORTING CLUSTERS OF ELEVATED TSTMS WEDNESDAY MORNING OVER PORTIONS OF WRN AND NRN TX. THESE STORMS MAY PERSIST THROUGH THE DAY N OF SURFACE FRONT WITH SOME THREAT OF HAIL. MORE INTENSE SURFACE-BASED DEVELOPMENT IS ANTICIPATED BY AFTERNOON FROM THE CONCHO VALLEY AND PERMIAN BASIN INTO THE BIG COUNTRY WHERE DEWPOINTS IN THE 50S...COUPLED WITH STEEPENING LAPSE RATES WILL CONTRIBUTE TO MLCAPES OF 1000-1500 J/KG. IT APPEARS THAT THE SYNOPTIC FRONT...SHARPENING DRY LINE OVER SWRN TX AND RESIDUAL OUTFLOW BOUNDARIES WILL PROVIDE THE FOCUS FOR THIS MORE VIGOROUS STORM DEVELOPMENT. FORECAST SOUNDINGS INDICATE STRONGLY VEERING WIND PROFILES WITH 40-45 KTS OF SWLY DEEP-LAYER SHEAR WHICH SHOULD SUPPORT THE DEVELOPMENT OF A FEW SUPERCELLS CAPABLE OF MAINLY LARGE HAIL /SOME IT POSSIBLY SIGNIFICANT/. GIVEN THE EXPECTED W-E OR WSW-ENE ORIENTATION OF THE SYNOPTIC BOUNDARY...POTENTIAL WILL EXIST FOR A FEW TORNADOES WITH ANY MORE DISCRETE STORMS THAT CAN PROPAGATE ALONG THIS FEATURE WHERE LOW-LEVEL SHEAR WILL BE MAXIMIZED. SURFACE-BASED STORMS WITH A THREAT OF MAINLY HAIL AND HIGH WINDS ARE EXPECTED TO SPREAD INTO PORTIONS OF CNTRL AND NRN TX WEDNESDAY NIGHT. STRENGTHENING LLJ WILL ALSO SUPPORT A FEW SEVERE ELEVATED STORMS N OF FRONT INTO SRN OK WHERE LARGE HAIL WILL BE POSSIBLE. ...AR/LA EWD INTO TN VALLEY AND CNTRL GULF STATES... A MOIST LOW-LEVEL AIR MASS /DEWPOINTS IN THE 60S/ WILL LARGELY CONTRIBUTE TO THE DEVELOPMENT OF MODERATE AFTERNOON INSTABILITY FROM THE LOWER MS VALLEY EWD ACROSS THE GULF COAST INTO THE TN VALLEY /S OF WEAK FRONT/ WITH MLCAPES OF 1000-1500 J/KG. WHILE THE MAIN FOCUS FOR CONVECTIVE INITIATION IS SOMEWHAT UNCERTAIN...THERE IS SOME SUGGESTION THAT A LEAD IMPULSE MAY EXIST NEAR THE ARKLATEX WEDNESDAY MORNING...WHICH WILL MOVE NEWD INTO THE TN VALLEY BY AFTERNOON. SHOULD THIS SCENARIO OCCUR...A THREAT OF DAMAGING WINDS AND LARGE HAIL WILL EXIST WITH ANY ORGANIZED CLUSTER OR MCS THAT CAN DEVELOP AHEAD OF THIS IMPULSE. FARTHER S ACROSS CNTRL MS INTO CNTRL AL...THE ABSENCE OF ANY DISCERNABLE BOUNDARY MAKE THE INITIATION OF DEEP MOIST CONVECTION EVEN MORE UNCERTAIN. HOWEVER...FORECAST SOUNDINGS INDICATE THAT WEAK CAP SHOULD ERODE SUFFICIENTLY BY AFTERNOON SUCH THAT STORMS SHOULD DEVELOP ON ANY SMALL-SCALE BOUNDARIES PRESENT IN BROADER WARM SECTOR. GIVEN THE INITIATION AND MAINTENENCE OF STORMS...THE MODERATE INSTABILITY IN CONJUNCTION WITH A BELT OF 40-50 KT WLY MID-LEVEL FLOW DEVELOPING EWD ACROSS THE AREA WILL SUPPORT ORGANIZED/ROTATING STORMS WITH A THREAT OF LARGE HAIL AND DAMAGING WINDS. ..MEAD.. 04/19/2006  From SwoDy2 at goshenarc.org Wed Apr 19 06:01:05 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 19 Apr 2006 02:01:05 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 190557 SWODY2 SPC AC 190556 DAY 2 CONVECTIVE OUTLOOK CORR 1 NWS STORM PREDICTION CENTER NORMAN OK 1256 AM CDT WED APR 19 2006 VALID 201200Z - 211200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM WRN TX EWD INTO THE SRN TN VALLEY AND CNTRL GULF COAST STATES... CORRECTED FOR INCORRECT DAY REFERENCE ...SYNOPSIS... AMPLIFIED LARGE-SCALE PATTERN WILL CONTINUE THROUGH THE DAY TWO PERIOD. MID AND UPPER-LEVEL LOW OVER THE UPPER MS VALLEY WILL SLOWLY TRANSLATE EWD INTO THE WRN GREAT LAKES...WHILE A MORE PROGRESSIVE SRN STREAM IS MAINTAINED ACROSS THE SRN TIER OF STATES. IN ADDITION TO VORTICITY MAXIMUM SHIFTING EWD FROM AZ/NM INTO TX/OK...OTHER MORE SUBTLE PERTURBATIONS MAY EXIST WITH WSWLY FLOW FROM THE ARKLATEX INTO THE TN VALLEY AND CNTRL GULF STATES. IN THE LOW-LEVELS...WEAK LOW PRESSURE IS FORECAST TO DEVELOP NEWD FROM THE LOWER MS VALLEY INTO THE UPPER OH VALLEY /LIKELY ASSOCIATED WITH A LEAD UPPER DISTURBANCE/ WITH TRAILING FRONTAL BOUNDARY STRETCHING SWWD THROUGH THE WRN TN VALLEY INTO WRN TX. THE WRN EXTENSION OF THIS BOUNDARY MAY ATTEMPT TO RETREAT SLIGHTLY NWD WITH APPROACH OF AZ/NM SHORT WAVE TROUGH...BEFORE PUSHING MORE SWD WITH THE PASSAGE OF THIS WAVE LATE THURSDAY NIGHT. ...TX INTO SRN OK... SLY LLJ...MAINTAINED BY DIRECT THERMAL CIRCULATION ASSOCIATED WITH ENTRANCE REGION OF UPPER JET STREAK OVER THE LOWER MO VALLEY...WILL LIKELY BE SUPPORTING CLUSTERS OF ELEVATED TSTMS THURSDAY MORNING OVER PORTIONS OF WRN AND NRN TX. THESE STORMS MAY PERSIST THROUGH THE DAY N OF SURFACE FRONT WITH SOME THREAT OF HAIL. MORE INTENSE SURFACE-BASED DEVELOPMENT IS ANTICIPATED BY AFTERNOON FROM THE CONCHO VALLEY AND PERMIAN BASIN INTO THE BIG COUNTRY WHERE DEWPOINTS IN THE 50S...COUPLED WITH STEEPENING LAPSE RATES WILL CONTRIBUTE TO MLCAPES OF 1000-1500 J/KG. IT APPEARS THAT THE SYNOPTIC FRONT...SHARPENING DRY LINE OVER SWRN TX AND RESIDUAL OUTFLOW BOUNDARIES WILL PROVIDE THE FOCUS FOR THIS MORE VIGOROUS STORM DEVELOPMENT. FORECAST SOUNDINGS INDICATE STRONGLY VEERING WIND PROFILES WITH 40-45 KTS OF SWLY DEEP-LAYER SHEAR WHICH SHOULD SUPPORT THE DEVELOPMENT OF A FEW SUPERCELLS CAPABLE OF MAINLY LARGE HAIL /SOME IT POSSIBLY SIGNIFICANT/. GIVEN THE EXPECTED W-E OR WSW-ENE ORIENTATION OF THE SYNOPTIC BOUNDARY...POTENTIAL WILL EXIST FOR A FEW TORNADOES WITH ANY MORE DISCRETE STORMS THAT CAN PROPAGATE ALONG THIS FEATURE WHERE LOW-LEVEL SHEAR WILL BE MAXIMIZED. SURFACE-BASED STORMS WITH A THREAT OF MAINLY HAIL AND HIGH WINDS ARE EXPECTED TO SPREAD INTO PORTIONS OF CNTRL AND NRN TX THURSDAY NIGHT. STRENGTHENING LLJ WILL ALSO SUPPORT A FEW SEVERE ELEVATED STORMS N OF FRONT INTO SRN OK WHERE LARGE HAIL WILL BE POSSIBLE. ...AR/LA EWD INTO TN VALLEY AND CNTRL GULF STATES... A MOIST LOW-LEVEL AIR MASS /DEWPOINTS IN THE 60S/ WILL LARGELY CONTRIBUTE TO THE DEVELOPMENT OF MODERATE AFTERNOON INSTABILITY FROM THE LOWER MS VALLEY EWD ACROSS THE GULF COAST INTO THE TN VALLEY /S OF WEAK FRONT/ WITH MLCAPES OF 1000-1500 J/KG. WHILE THE MAIN FOCUS FOR CONVECTIVE INITIATION IS SOMEWHAT UNCERTAIN...THERE IS SOME SUGGESTION THAT A LEAD IMPULSE MAY EXIST NEAR THE ARKLATEX THURSDAY MORNING...WHICH WILL MOVE NEWD INTO THE TN VALLEY BY AFTERNOON. SHOULD THIS SCENARIO OCCUR...A THREAT OF DAMAGING WINDS AND LARGE HAIL WILL EXIST WITH ANY ORGANIZED CLUSTER OR MCS THAT CAN DEVELOP AHEAD OF THIS IMPULSE. FARTHER S ACROSS CNTRL MS INTO CNTRL AL...THE ABSENCE OF ANY DISCERNABLE BOUNDARY MAKE THE INITIATION OF DEEP MOIST CONVECTION EVEN MORE UNCERTAIN. HOWEVER...FORECAST SOUNDINGS INDICATE THAT WEAK CAP SHOULD ERODE SUFFICIENTLY BY AFTERNOON SUCH THAT STORMS SHOULD DEVELOP ON ANY SMALL-SCALE BOUNDARIES PRESENT IN BROADER WARM SECTOR. GIVEN THE INITIATION AND MAINTENENCE OF STORMS...THE MODERATE INSTABILITY IN CONJUNCTION WITH A BELT OF 40-50 KT WLY MID-LEVEL FLOW DEVELOPING EWD ACROSS THE AREA WILL SUPPORT ORGANIZED/ROTATING STORMS WITH A THREAT OF LARGE HAIL AND DAMAGING WINDS. ..MEAD.. 04/19/2006  From SwoDy2 at goshenarc.org Thu Apr 20 05:30:54 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Thu, 20 Apr 2006 01:30:54 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 200527 SWODY2 SPC AC 200526 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1226 AM CDT THU APR 20 2006 VALID 211200Z - 221200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM SE TX INTO THE CNTRL AND SRN APPALACHIANS...EWD INTO CENTRAL PARTS OF VA...NC AND SC... ...SYNOPSIS... SRN STREAM SHORT WAVE TROUGH OVER THE ARKLATEX FRIDAY MORNING WILL PHASE WITH UPPER LOW OVER THE GREAT LAKES...WITH FULL LATITUDE TROUGH EVOLVING E OF THE MS VALLEY DURING THE LATTER HALF OF THE FORECAST PERIOD. IN THE LOW-LEVELS...SURFACE LOW ASSOCIATED WITH THE SRN STREAM WAVE INITIALLY OVER AR WILL DEVELOP RAPIDLY NEWD ALONG BAROCLINIC ZONE INTO THE UPPER OH VALLEY BY FRIDAY EVENING. TRAILING COLD FRONT WILL PUSH EWD THROUGH THE LOWER MS AND TN VALLEYS AND CNTRL GULF COAST...WITH NAM AND ENSEMBLE MEAN FORECASTS INDICATING THE DEVELOPMENT A SECONDARY SURFACE LOW WHICH WILL TRACK MORE EWD ACROSS NRN MS/AL INTO NRN GA OR ERN TN BY FRIDAY NIGHT. ...SERN TX EWD TO THE CNTRL / SRN APPALACHIANS... CONSIDERABLE TSTM ACTIVITY IS EXPECTED TO BE ONGOING AT THE ONSET OF THE PERIOD FROM VICINITY OF SURFACE LOW OVER AR ENEWD WITHIN WAA REGIME INTO THE TN VALLEY...AS WELL AS ALONG TRAILING COLD FRONT INTO ERN TX. CONSIDERABLE CLOUDINESS ACROSS WARM SECTOR WILL TEND TO LIMIT DAYTIME HEATING...THOUGH BOUNDARY-LAYER SHOULD REMAIN MOIST WITH DEWPOINTS IN THE 60S...WHICH WILL LARGELY CONTRIBUTE TO POCKETS OF MODERATE INSTABILITY WITH MLCAPES APPROACHING 1000-1500 J/KG. SEVERE THREAT SHOULD INCREASE FROM LATE MORNING THROUGH THE AFTERNOON AS HEIGHT FALLS ASSOCIATED WITH INTENSIFYING TROUGH BEGIN TO OVERSPREAD DESTABILIZING WARM SECTOR ACROSS THE LOWER MS INTO TN VALLEYS. STRONGEST STORMS WILL LIKELY OCCUR NEAR INITIAL SURFACE LOW DEVELOPING NEWD ALONG BAROCLINIC ZONE...AS WELL AS ALONG SECONDARY LOW TRACK OVER MS/AL WHERE STRONGER INSTABILITY IS FORECAST. LOCALLY STRONGER LOW-LEVEL SHEAR NEAR THESE SURFACE LOWS WILL ENHANCE THE POTENTIAL FOR SUPERCELLS CAPABLE OF TORNADOES...DAMAGING WINDS AND PERHAPS SOME HAIL. OTHERWISE...MAIN SEVERE THREAT SHOULD BE ASSOCIATED WITH BOWS AND OTHER EMBEDDED MORE INTENSE LINE SEGMENTS. THIS SEVERE THREAT SHOULD DIMINISH LATE FRIDAY EVENING OVER THE CNTRL APPALACHIANS INTO UPPER OH VALLEY AS AIR MASS COOLS AND STABILIZES. FARTHER S...SEVERE THREAT MAY CONTINUE OVERNIGHT INTO GA AND THE WRN FL PNHDL. ...VA / NC / SC... RETREAT OF WARM FRONT NWD INTO THE MIDDLE ATLANTIC STATES WILL ALLOW AIR MASS TO DESTABILIZE IN THE LEE OF THE APPALACHIANS WITH DEWPOINTS INCREASING INTO THE 60S...SUPPORTING MLCAPES OF AROUND 1000 J/KG. INCREASING LOW-LEVEL WAA AHEAD OF EVOLVING MID-LEVEL TROUGH COUPLED WITH BROAD LOW-LEVEL CONFLUENCE AND PERHAPS OROGRAPHIC FORCING SHOULD ALL CONTRIBUTE TO AN INCREASE IN TSTM COVERAGE THROUGH THE DAY. ISALLOBARIC RESPONSE TO DEEPENING SURFACE LOW W OF THE MOUNTAINS WILL EFFECTIVELY BACK LOW-LEVEL SURFACE WINDS...RESULTING IN VERTICAL SHEAR PROFILES EXHIBITING STRONG VEERING WITH HEIGHT. INITIALLY...MID AND HIGH-LEVEL WIND FIELDS WILL BE MARGINALLY STRONG FOR ORGANIZED...SEVERE STORMS...THOUGH THEY ARE FORECAST TO INCREASE THROUGH THE AFTERNOON INTO EVENING. THREAT WILL EXIST FOR A COUPLE BRIEF TORNADOES IN ADDITION TO DAMAGING WINDS AND PERHAPS SOME HAIL. ..MEAD.. 04/20/2006  From SwoDy2 at goshenarc.org Thu Apr 20 17:20:09 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Thu, 20 Apr 2006 13:20:09 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 201716 SWODY2 SPC AC 201715 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1215 PM CDT THU APR 20 2006 VALID 211200Z - 221200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE WRN GULF STATES INTO THE SRN APPALACHIANS... ...WRN GULF COAST TO SRN APPALACHIANS... SRN ROCKIES SHORTWAVE TROUGH WILL SHIFT EAST ACROSS TX MAINTAINING SIGNIFICANT SEPARATION WITH UPPER LOW OVER THE GREAT LAKES REGION. THIS FEATURE WILL UNDOUBTEDLY AID UPWARD ASCENT ALONG SW-NE ORIENTED FRONTAL ZONE FROM THE UPPER TX COAST INTO THE SRN APPALACHIANS. EARLY IN THE PERIOD...IT APPEARS ONE OR MORE CONCENTRATED CLUSTERS OF THUNDERSTORMS WILL BE ONGOING FROM LATE DAY1 ACTIVITY IMMEDIATELY AHEAD OF SHORTWAVE TROUGH FROM THE MIDDLE TX COAST INTO THE ARKLATEX REGION. BOUNDARY LAYER HEATING AHEAD OF CONVECTIVE OUTFLOW/SFC FRONT SHOULD ENHANCE INSTABILITY FOR RENEWED THUNDERSTORM DEVELOPMENT/INTENSIFICATION DURING THE MID DAY HOURS. STORM MODE SHOULD BE MODULATED SIGNIFICANTLY BY CONVECTIVE OUTFLOW AND MODEST SHEAR...SEEMINGLY SUPPORTIVE OF LINE SEGMENT-TYPE BANDS. AS A RESULT...CONSIDERABLE AMOUNT OF CONVECTION SHOULD SPREAD ACROSS PORTIONS OF THE WRN GULF STATES INTO ERN TN DURING THE AFTERNOON HOURS WITH DAMAGING WINDS AND LARGE HAIL THE MOST LIKELY SEVERE THREATS. ..DARROW.. 04/20/2006  From SwoDy2 at goshenarc.org Fri Apr 21 06:25:02 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Fri, 21 Apr 2006 02:25:02 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 210621 SWODY2 SPC AC 210620 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0120 AM CDT FRI APR 21 2006 VALID 221200Z - 231200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE MIDDLE AND SRN ATLANTIC STATES... ...MID-SRN ATLANTIC STATES... SRN HIGH PLAINS SHORT WAVE TROUGH MOVING EWD DAY 1 PERIOD SHOULD BE LOCATED ACROSS THE CENTRAL GULF COAST STATES AT 12Z SATURDAY. THIS TROUGH IS THEN EXPECTED TO BECOME SLIGHTLY NEGATIVELY TILTED AS IT TRACKS NEWD IN LEE OF THE SRN/CENTRAL APPALACHIANS... REACHING THE DELMARVA REGION BY 12Z SUNDAY. SURFACE LOW ASSOCIATED WITH THIS SRN STREAM TROUGH SHOULD BE LOCATED OVER THE UPPER TN VALLEY AT THE START OF THE PERIOD...AND THEN TRACK NEWD ACROSS WRN NC/WRN VA SATURDAY AFTERNOON...REACHING ERN VA TO DEL LATE IN THE PERIOD. COLD FRONT TRAILING SWD ACROSS WRN GA TO THE FL PANHANDLE AND THEN OFFSHORE WILL MOVE ENEWD ACROSS THE SERN AND MID-ATLANTIC STATES... AND SHOULD EXTEND FROM SERN VA/ERN NC SWWD TO THE CENTRAL FL PENINSULA BY THE BEGINNING OF DAY 3. THUNDERSTORMS...SOME POTENTIALLY SEVERE...ARE EXPECTED TO BE ONGOING EARLY SATURDAY SWD FROM THE SURFACE LOW ALONG THE COLD FRONT. EXTENSIVE CLOUDINESS DOWNSTREAM ACROSS THE WARM SECTOR MAY LIMIT SURFACE HEATING. HOWEVER...LOW-LEVEL MOISTURE ADVECTION ACROSS ERN GA/CAROLINAS INTO SRN VA WITH SURFACE DEWPOINTS IN THE MID 60S BENEATH MODEST LAPSE RATES SHOULD CONTRIBUTE TO MUCAPES AROUND AT LEAST 1000 J/KG...WITH POCKETS OF HIGHER INSTABILITY POSSIBLE. ONGOING ACTIVITY SHOULD INCREASE IN INTENSITY/COVERAGE AS THE COLD FRONT SPREADS ENE INTO THE GREATER INSTABILITY ACROSS THE PIEDMONT AND COASTAL PLAINS OF SC/NC/VA BY SATURDAY AFTERNOON. SSWLY UNI-DIRECTIONAL WIND PROFILES WITH SHEAR VECTORS ORIENTED NEARLY PARALLEL TO THE SURFACE FRONT SUGGEST A LINEAR MODE WITH BOWING SEGMENTS. BACKED LOW-LEVEL FLOW ALONG THE TRACK OF THE SURFACE LOW SHOULD RESULT IN STRONGER DEEP LAYER SHEAR VALUES FOR SUPERCELLS. THUS...A FEW TORNADOES...DAMAGING WINDS...AND HAIL WILL BE POSSIBLE. FARTHER S ACROSS SERN GA/FL PENINSULA...DESPITE LOW-LEVEL FLOW VEERING IN ADVANCE OF THE FRONT IN GA/NRN FL...STRONG INSTABILITY AND MODERATE DEEP LAYER SHEAR SHOULD SUPPORT MULTICELLS WITH A THREAT FOR HAIL/DAMAGING WINDS. SEA BREEZE BOUNDARY IS EXPECTED TO BE THE FOCUS FOR THUNDERSTORMS SATURDAY AFTERNOON ACROSS THE NRN/CENTRAL FL PENINSULA WITH SIMILAR CAPE/SHEAR VALUES SUPPORTING A THREAT FOR HAIL/DAMAGING WINDS. ...SRN HIGH PLAINS... MODELS DIFFER WITH THE AMOUNT OF MOISTURE RETURN INTO SWRN-WRN TX/ SERN NM SATURDAY AFTERNOON. GFS INDICATED THE STRONGEST SIGNAL SUPPORTING AN AXIS OF MODERATE INSTABILITY ACROSS THIS REGION. DESPITE THE UNCERTAINTY IN MOISTURE RETURN...THIS OUTLOOK WILL MAINTAIN LOW SEVERE PROBABILITIES SINCE INCREASING SWLY MID-LEVEL FLOW ATOP A STRENGTHENING SSELY LLJ BY EARLY EVENING WOULD RESULT SUFFICIENT DEEP LAYER SHEAR FOR ORGANIZED STORMS WITH ANY ACTIVITY THAT CAN DEVELOP. FURTHER STRENGTHENING OF THE LLJ WITH ACCOMPANYING MOISTURE ADVECTION MAY SUPPORT WIDELY SCATTERED THUNDERSTORMS SATURDAY NIGHT ACROSS PARTS OF THE SRN PLAINS... POTENTIALLY REACHING SRN MO. ..PETERS.. 04/21/2006  From SwoDy2 at goshenarc.org Fri Apr 21 17:32:37 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Fri, 21 Apr 2006 13:32:37 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 211728 SWODY2 SPC AC 211727 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1227 PM CDT FRI APR 21 2006 VALID 221200Z - 231200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE MIDDLE AND SRN ATLANTIC COASTAL STATES... ...SYNOPSIS... LARGE MID/UPPER TROUGH WILL PROGRESS SLOWLY EWD ACROSS THE WRN U.S. THIS PERIOD...WHILE SECOND TROUGH -- COMPRISED OF A DEEP UPPER LOW OVER THE GREAT LAKES REGION AND A MORE PROGRESSIVE SRN STREAM SHORT-WAVE TROUGH OVER THE SOUTHEAST -- ALSO MOVES EWD THROUGH THE PERIOD. THOUGH SCATTERED THUNDERSTORMS ARE EXPECTED ACROSS THE WRN U.S. AHEAD OF UPPER TROUGH...MAIN SEVERE THREAT THIS PERIOD SHOULD EXIST OVER THE ATLANTIC COASTAL STATES AHEAD OF ERN TROUGH/COLD FRONT. ...SRN AND MIDDLE ATLANTIC COASTAL REGION... WIDESPREAD PRECIPITATION/THUNDERSTORMS WILL LIKELY BE ONGOING AT THE START OF THE PERIOD ALONG AND E OF THE APPALACHIANS...AHEAD OF EWD-MOVING COLD FRONT AND ASSOCIATED SHORT-WAVE TROUGH CROSSING THE CENTRAL AND SRN APPALACHIANS REGION EARLY IN THE PERIOD. WIDESPREAD CLOUDS/PRECIPITATION SHOULD LIMIT HEATING/DESTABILIZATION E OF THE MOUNTAINS TO A GREAT DEGREE...THOUGH AT LEAST MARGINAL INSTABILITY /500 TO 1000 J/KG MEAN-LAYER CAPE/ IS EXPECTED BY EARLY AFTERNOON...SUPPORTED BY MOIST BOUNDARY LAYER. THIS SHOULD RESULT IN AN INCREASE/INTENSIFICATION OF STORMS AHEAD OF BOUNDARY FROM MIDDAY THROUGH THE AFTERNOON AS CONVECTION SPREADS EWD TOWARD THE ATLANTIC COAST. THOUGH FORECAST TO BE FAIRLY UNIDIRECTIONAL/MERIDIONAL...DEEP-LAYER WIND FIELD WILL BE MODERATELY STRONG/SUFFICIENT FOR ORGANIZED CONVECTION. WHERE POCKETS OF GREATER INSTABILITY CAN DEVELOP...EXPECT STORMS TO BECOME SEVERE...WITH HAIL AND LOCALLY DAMAGING WINDS POSSIBLE -- AND PERHAPS A TORNADO. THREAT MAY CONTINUE INTO THE EVENING -- PARTICULARLY ACROSS THE ERN CAROLINAS...BEFORE STORMS DIURNALLY WEAKEN/MOVE OFFSHORE. ...FL... STORMS ARE FORECAST TO DEVELOP ACROSS ERN FL -- MAINLY OVER COASTAL AREAS AS WLY/SWLY LOW-LEVEL FLOW OVER THE PENINSULA AHEAD OF FRONT SUGGESTS THAT MAIN ZONE OF LOW-LEVEL CONVERGENCE WILL EVOLVE IN ASSOCIATION WITH E COAST SEA BREEZE BOUNDARIES. SUFFICIENT SHEAR AND INSTABILITY WILL EXIST FOR STRONG/LOCALLY SEVERE STORMS...ALONG WITH ACCOMPANYING THREAT FOR MARGINAL HAIL/LOCALLY DAMAGING WINDS...AND POSSIBLY AN ISOLATED TORNADO NEAR SURFACE BOUNDARIES. ..GOSS.. 04/21/2006  From SwoDy2 at goshenarc.org Sat Apr 22 06:17:52 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 22 Apr 2006 02:17:52 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 220612 SWODY2 SPC AC 220611 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0111 AM CDT SAT APR 22 2006 VALID 231200Z - 241200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS CENTRAL PLAINS TO LOWER OH/TN VALLEYS... ...SYNOPSIS... UPPER TROUGH/CLOSED LOW MOVING INLAND OVER CA AT THIS TIME PER WATER VAPOR IMAGERY WILL CONTINUE TO UNDERGO FURTHER WEAKENING ON SUNDAY AS IT MOVES SLOWLY NEWD ACROSS THE GREAT BASIN AND NRN INTERMOUNTAIN REGION. MEANWHILE...SRN PART OF TROUGH OVER CENTRAL CANADA WILL MOVE INTO THE DAKOTAS/UPPER MS VALLEY...WITH DOWNSTREAM CLOSED LOW MOVING SLOWLY NEWD ACROSS THE LOWER GREAT LAKES/CENTRAL APPALACHIANS. IN THE LOW-LEVELS...WEAK SURFACE LOW ASSOCIATED WITH GREAT LAKES CLOSED LOW WILL TRACK SLOWLY NEWD...WITH TRAILING SURFACE FRONT MOVING EWD ACROSS NY/PA/CENTRAL APPALACHIANS ON SUNDAY. THE REMAINING PORTION OF THIS BOUNDARY EXTENDING FROM THE OH VALLEY WWD THROUGH CENTRAL MO TO CENTRAL KS...AND THEN WNWWD INTO HIGH PLAINS OF NERN CO/SERN WY EXPECTED TO REMAIN QUASI-STATIONARY THROUGH THE PERIOD. DRY LINE IS EXPECTED TO MIX EWD AND SHOULD EXTEND FROM SWRN KS INTO FAR WRN OK TO PARTS OF WRN TX. ...CENTRAL PLAINS INTO MO... ELEVATED THUNDERSTORMS SHOULD BE ONGOING AT THE START OF THE PERIOD FROM ERN KS ESEWD INTO CENTRAL/SRN MO TO LOWER OH VALLEY WITHIN WAA REGIME ALONG NOSE OF STRONG W/SWLY LLJ. THIS ACTIVITY SHOULD GRADUALLY WEAKEN SUNDAY MORNING AS STRENGTH OF LLJ DECREASES... THOUGH WAA N OF SURFACE BOUNDARY MAY REMAIN SUFFICIENT FOR ELEVATED THUNDERSTORMS SUNDAY MORNING/AFTERNOON FROM PARTS OF NRN HIGH PLAINS SEWD INTO NEB. WEAK INSTABILITY WITH THIS LATTER ACTIVITY SHOULD LIMIT THE SEVERE THREAT. MEANWHILE...MOISTURE RETURN WILL CONTINUE ACROSS THE SRN/CENTRAL PLAINS WITH SURFACE DEWPOINTS IN THE LOWER-MID 60S ALONG/S OF SURFACE BOUNDARY FROM FAR SWRN NEB SEWD TO CENTRAL MO AND WRN KY/TN. ELEVATED MIXED LAYER /STEEP MID-LEVEL LAPSE RATES 7.5+ C/KM/ SPREADING EWD ACROSS MUCH OF THE CENTRAL/SRN PLAINS TO LOWER TN/MS VALLEYS DAY 1 WILL REMAIN IN PLACE DAY 2. IN ADDITION TO CONTRIBUTING TO A MODERATE-VERY UNSTABLE WARM SECTOR...THIS EML SHOULD EFFECTIVELY CAP THE WARM SECTOR INTO THE MID-LATE AFTERNOON...ESPECIALLY SWD ALONG DRY LINE. WEAK MID-LEVEL IMPULSES EMANATING FROM WRN STATES TROUGH ARE EXPECTED TO MOVE EWD ACROSS THE PLAINS TOWARD THE MID MS VALLEY. LARGE SCALE ASCENT WITH THESE FEATURES AND HEIGHT FALLS ACROSS THE NRN/CENTRAL PLAINS IN ADVANCE OF CANADIAN TROUGH ARE EXPECTED TO SUPPORT THUNDERSTORM DEVELOPMENT BY MID-LATE AFTERNOON ALONG THE SURFACE BOUNDARY FROM SERN WY INTO CENTRAL KS. INCREASING WLY MID-LEVEL WINDS ATOP STRENGTHENING CENTRAL/SRN PLAINS SLY LLJ BY LATE SUNDAY AFTERNOON WILL RESULT IN STRONG DEEP LAYER SHEAR SUPPORTING SUPERCELLS CAPABLE OF PRODUCING TORNADOES...LARGE HAIL...AND DAMAGING WINDS. FURTHER STRENGTHENING AND EVENTUAL VEERING OF LLJ EXPECTED TO RESULT IN UPSCALE GROWTH OF AFTERNOON/EVENING STORMS INTO AN MCS MOVING EWD INTO ERN KS/MO SUNDAY NIGHT WITH CONTINUED THREAT FOR DAMAGING WINDS/HAIL. ...OH/TN VALLEYS... DESPITE RATHER WEAK CONVERGENCE ALONG THE SURFACE BOUNDARY...THE COMBINATION OF INCREASING MOISTURE/INSTABILITY AND STRONG DEEP LAYER SHEAR GIVEN NWLY MID-LEVEL FLOW ATOP WLY LLJ EXPECTED TO SUPPORT WIDELY SCATTERED STRONG TO SEVERE STORMS. PRIMARY THREATS SHOULD BE DAMAGING WINDS AND HAIL WITH THE STRONGEST ACTIVITY. THESE STORMS ARE EXPECTED TO WEAKEN SUNDAY EVENING AS THE BOUNDARY LAYER STABILIZES WITH THE LOSS OF DAYTIME HEATING. ...PARTS OF NY/PA/WV/VA/MD... COLD MID-LEVEL TEMPERATURES -20 TO -26 C AT 500 MB WITH THE CLOSED LOW WILL STEEPEN LAPSE RATES CONTRIBUTING TO WEAK INSTABILITY IN ADVANCE OF THE SURFACE TROUGH MOVING EWD ACROSS THIS REGION SUNDAY. LARGE SCALE ASCENT WITHIN EXIT REGION OF 60-70 KT JET ROUNDING BASE OF UPPER SYSTEM WILL SUPPORT THUNDERSTORM DEVELOPMENT ALONG EXTENT OF SURFACE BOUNDARY. STRONG DEEP LAYER SHEAR SUGGESTS STORMS WILL BE ORGANIZED...BUT WEAK INSTABILITY SHOULD LIMIT SEVERE COVERAGE. ..PETERS.. 04/22/2006  From SwoDy2 at goshenarc.org Sat Apr 22 17:40:20 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 22 Apr 2006 13:40:20 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 221736 SWODY2 SPC AC 221735 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1235 PM CDT SAT APR 22 2006 VALID 231200Z - 241200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE CNTRL HIGH PLAINS TO THE TN VLY... ...SYNOPSIS... COMPLEX UPPER FLOW REGIME WILL CONTINUE ON SUNDAY WITH CLOSED LOWS MOVING SLOWLY ACROSS THE NERN STATES AND THE DESERT SW AND A WEAKER NRN STREAM TROUGH SKIRTING THE NRN PLAINS. AT THE SURFACE...AN OCCLUDED LOW OVER THE LWR GRTLKS WILL TRACK NEWD WITH ITS TRAILING FRONT MOVING SEWD ACROSS THE MID-ATLANTIC REGION. WRN EXTENT OF THIS BOUNDARY WILL STALL ACROSS THE TN VLY...OZARKS AND CNTRL PLAINS THROUGH SUNDAY EVENING. A LEE-LOW OVER ERN CO WILL STRENGTHEN AND MOVE ALONG THE FRONT INTO SWRN KS BY LATE SUNDAY AFTN WITH A DRYLINE EXTENDING SWD INTO THE ERN TX PNHDL AND SWRN TX. ...CNTRL PLAINS TO THE TN VLY... LOW-LEVEL MSTR WILL CONTINUE TO ADVECT NWD BENEATH THE ELEVATED MIXED LAYER THROUGH THE SRN/CNTRL PLAINS THROUGH SUNDAY EVENING. THIS WILL CONTRIBUTE TO A VERY UNSTABLE AIR MASS ACROSS CNTRL KS ALONG/S OF THE BAROCLINIC ZONE AND AHEAD OF THE TRIPLE POINT LOW. HEATING...LOW-LEVEL CONVERGENCE AND WEAK LARGE SCALE HEIGHT FALLS IN ADVANCE OF THE SWRN STATES CYCLONE WILL AID IN WEAKENING CINH. TSTM INITIATION IS LIKELY VCNTY THE TRIPLE POINT DURING THE LATE AFTN. VERTICAL SHEAR...THOUGH SOMEWHAT WEAK EARLY IN THE DAY...WILL INCREASE DURING THE EVENING AND BE SUFFICIENT FOR SUPERCELLS WITH VERY LARGE HAIL. TORNADOES WILL BE POSSIBLE... ESPECIALLY ACROSS CNTRL KS ALONG THE BAROCLINIC ZONE WHERE LOW-LEVEL TURNING WILL BE THE STRONGEST. ACTIVITY SHOULD GROW UPSCALE INTO A FORWARD PROPAGATING MCS DURING THE EVENING AND MOVE ESEWD ACROSS ECNTRL/SERN KS INTO SRN MO WITH DAMAGING WINDS BECOMING THE PRIMARY SEVERE THREAT OVERNIGHT. ISOLD TSTMS MAY DEVELOP SWD THE LENGTH OF THE DRYLINE INTO W TX SUNDAY EVENING...THOUGH THE CAP SHOULD REMAIN STRONG. THE SW TX MOUNTAINS AND AREAS FROM ERN TX PNHDL INTO SCNTRL KS APPEAR TO BE THE MOST FAVORABLE AREAS FOR POSSIBLE ISOLD DEVELOPMENT. SUPERCELLS WILL BE POSSIBLE WITH LARGE HAIL THE PRIMARY THREAT. ...CNTRL HIGH PLAINS... AS THE PLAINS SFC LOW DEEPENS...NELY UPSLOPE FLOW WILL INCREASE SUNDAY EVENING ACROSS THE CNTRL HIGH PLAINS BENEATH INCREASING SWLY FLOW ALOFT. SUFFICIENT LOW-LEVEL MOISTURE SHOULD EXIST TO BOOST CAPE VALUES AND SUPPORT A FEW TSTMS ALONG THE FRONT RANGE AND ADJACENT PLAINS. VERTICAL SHEAR WILL SUPPORT ORGANIZED STORMS WITH PERHAPS LARGE HAIL. ...MID-ATLANTIC REGION... BAND OF MODEST H5 FLOW ALONG SRN PERIPHERY OF THE LWR GRTLKS UPPER LOW AND FAVORABLY COLD MID-LEVEL TEMPERATURES MAY BE SUFFICIENT FOR A BAND OR TWO OF STRONG THUNDERSTORMS ACROSS THE MID-ATLANTIC REGION SUNDAY. ISOLD DAMAGING WINDS/HAIL MAY ACCOMPANY THE STRONGER STORMS. ...OH/TN VLYS... E-W ORIENTED SFC BOUNDARY WILL LIKELY BE THE FOCUS FOR SPORADIC CLUSTERS OF TSTMS DESPITE THE OVERALL WEAK MASS CONVERGENCE. BUT...SUSTAINED SSWLY MOIST INFLOW AND MODEST FLOW ALOFT WILL LIKELY SUPPORT SCATTERED STRONG-SEVERE TSTMS...MAINLY ALONG WRN PORTIONS OF THE FRONT VCNTY STEEPER MID-LEVEL LAPSE RATES. LARGE HAIL AND DAMAGING WIND WILL BE THE PRIMARY SEVERE THREATS...WITH THE SEVERE THREATS DIMINISHING OVERNIGHT. ..RACY.. 04/22/2006  From SwoDy2 at goshenarc.org Sun Apr 23 06:19:36 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 23 Apr 2006 02:19:36 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 230615 SWODY2 SPC AC 230614 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0114 AM CDT SUN APR 23 2006 VALID 241200Z - 251200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE SRN PLAINS TO THE LOWER OH VALLEY... ...SYNOPSIS... LARGE WRN STATES UPPER TROUGH...THOUGH WEAKENING WITH TIME...WILL MOVE NE TOWARD ROCKIES/HIGH PLAINS...WITH SHORT WAVE TROUGH WITHIN BASE OF THIS SYSTEM APPROACHING CENTRAL/SRN HIGH PLAINS BY 12Z TUESDAY. HEIGHT FALLS WITH APPROACH OF WRN TROUGH AND ALSO WITH STRONGER UPPER TROUGH DIGGING SEWD ACROSS THE GREAT LAKES AND MID MS/OH VALLEYS EXPECTED TO EFFECTIVELY BREAK DOWN RIDGE OVER CENTRAL/SRN PLAINS. BAND OF 40-50 KT WSWLY FLOW SHOULD EXTEND FROM SWRN STATES ACROSS THE SRN PLAINS TO OH/TN VALLEY AND MID-ATLANTIC STATES. MID/UPPER LEVEL CONFLUENT FLOW REGIME TRANSLATING SEWD ALONG MID/ LOWER MO VALLEY WILL ALLOW LARGE SURFACE ANTICYCLONE TO BUILD S/SEWD ACROSS THE PLAINS/MS VALLEY IN WAKE OF STRONG/PROGRESSIVE COLD FRONT ASSOCIATED WITH NRN STREAM SYSTEM. BY LATE MONDAY AFTERNOON...COLD FRONT EXPECTED TO EXTEND FROM CENTRAL GREAT LAKES SWWD ACROSS LOWER MO VALLEY TO CENTRAL OK...AND THEN WSWWD THROUGH NWRN TX-NERN NM. A SURFACE LOW SHOULD TRACK NEWD THROUGH THE OH VALLEY MONDAY NIGHT AS NRN EXTENT OF COLD FRONT SPREADS EWD TOWARD THE LOWER GREAT LAKES/CENTRAL APPALACHIANS. ANOTHER SURFACE WAVE/TRIPLE POINT IS EXPECTED TO EVOLVE OVER CENTRAL OK BY MONDAY AFTERNOON...AS A DRY LINE MIXES EWD AND THE COLD FRONT CONTINUES ITS TREK SSEWD THROUGH THE SRN PLAINS. ...SRN PLAINS ENE TO OZARKS/LOWER MO VALLEY... LOW-LEVEL MOISTURE WILL CONTINUE TO ADVECT NWD DAY 1 INTO DAY 2 ACROSS THE SRN PLAINS BENEATH ELEVATED MIXED LAYER...WITH SOMEWHAT MORE SUBSTANTIAL WARM SECTOR MOISTENING EXPECTED MONDAY THAN HAS BEEN OBSERVED ACROSS THIS REGION PAST SEVERAL DAYS. THIS WILL CONTRIBUTE TO A VERY UNSTABLE AIR MASS /MLCAPE 2500+ J/KG/ ACROSS NRN TX TO SERN KS/SWRN MO ALONG/S OF COLD FRONT AND EAST OF TRIPLE POINT AND TRAILING DRY LINE. ONE OR TWO MCS/S SHOULD BE ONGOING 12Z MONDAY ACROSS LOWER MO VALLEY TO OZARKS REGION ALONG/N OF QUASI-STATIONARY BOUNDARY WHICH SHOULD REMAIN LOCATED FROM ERN KS/SRN MO TO TN VALLEY PRIOR TO COLD FRONTAL PASSAGE. THIS ACTIVITY WILL BE ASSOCIATED WITH WAA REGIME ALONG NOSE OF STRONG NOCTURNAL SWLY LLJ. THIS ACTIVITY SHOULD TEND TO WEAKEN MONDAY MORNING WITH EWD EXTENT AS LLJ WITHIN WARM SECTOR BACKS TO SLY IN ADVANCE OF APPROACHING SRN STREAM SHORT WAVE TROUGH. EML IS EXPECTED TO CAP WARM SECTOR THROUGH MID AFTERNOON...WITH NEW THUNDERSTORM DEVELOPMENT LIKELY BY LATE AFTERNOON ACROSS SWRN MO/SERN KS INTO NRN OK BY MID AFTERNOON AS STRONG SURFACE HEATING...INCREASING LOW-LEVEL CONVERGENCE...AND WEAK HEIGHT FALLS AID IN WEAKENING CINH. STRONG DEEP LAYER SHEAR ORIENTED NORMAL TO DRY LINE SHOULD RESULT IN POTENTIAL FOR DISCRETE SUPERCELLS WITH INITIAL ACTIVITY CAPABLE OF PRODUCING TORNADOES...VERY LARGE HAIL...AND DAMAGING WINDS. ACTIVITY SHOULD EVOLVE INTO A LINEAR STRUCTURE AS THE COLD FRONT PROGRESSES S/SEWD INTO THE LOWER OH VALLEY AND OZARKS TO NRN TX MONDAY NIGHT. ...OH/TN VALLEYS TO NC... MOISTURE RETURN IS EXPECTED INTO THE OH VALLEY ALONG NWRN PERIPHERY OF SERN STATES SURFACE HIGH. SURFACE HEATING WITHIN THIS MOISTENING AIR MASS EXPECTED TO RESULT IN SUFFICIENT INSTABILITY ACROSS THE LOWER OH VALLEY IN ADVANCE OF EARLY MORNING MCS OVER SRN MO. THIS MAY ALLOW FOR SOME INCREASE IN STORM INTENSITY AND/OR SPORADIC STORM DEVELOPMENT ALONG BAROCLINIC ZONE ACROSS PARTS OF KY/TN TO WRN NC WHERE WEAK-MODERATE INSTABILITY AND STRONG DEEP LAYER SHEAR WOULD SUPPORT ISOLATED SEVERE STORMS. GREATER STORM COVERAGE AND OVERALL SEVERE THREAT IS EXPECTED MONDAY EVENING/NIGHT AS AFTERNOON STORMS ACROSS MO GROW UPSCALE INTO A FORWARD PROPAGATING MCS THROUGH THE OH VALLEY. STRONG WSWLY LLJ DEVELOPING ALONG OH VALLEY AFTER 25/00Z IN RESPONSE TO STRONG HEIGHT FALLS MAY INCREASE THE THREAT FOR DAMAGING WINDS... WITH GREATEST THREAT INTO THE LOWER OH VALLEY WHERE INSTABILITY WILL BE THE GREATEST. ..PETERS.. 04/23/2006  From SwoDy2 at goshenarc.org Sun Apr 23 17:32:41 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 23 Apr 2006 13:32:41 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 231728 SWODY2 SPC AC 231727 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1227 PM CDT SUN APR 23 2006 VALID 241200Z - 251200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE CNTRL/SRN PLAINS EWD TO THE TN VLY... ...SYNOPSIS... SRN PARTS OF THE UPPER LOW OVER THE WRN STATES IS EXPECTED TO DEAMPLIFY WHILE TRANSLATING NEWD ACROSS THE CNTRL/SRN HIGH PLAINS ON MON. THIS IN COMBINATION WITH A PROGRESSIVE NRN STREAM IMPULSE DIGGING INTO THE GRTLKS REGION MON AFTN WILL FLATTEN THE BROAD RIDGE ACROSS SRN NOAM. BUILDING SFC HIGH PRESSURE IN WAKE OF THE NRN STREAM SYSTEM WILL FORCE A COLD FRONT RAPIDLY SWD ACROSS THE HIGH PLAINS. THE SAME FRONT WILL MOVE MORE SLOWLY SEWD ACROSS THE GRTLKS AND THE LOWER PLAINS. A TRIPLE POINT WILL DEVELOP OVER NWRN OK MON AFTN WITH A DRYLINE MIXING EWD INTO WRN/CNTRL OK AND CNTRL TX. THE LOW WILL DEVELOP SWD ALONG THE DRYLINE AS THE COLD FRONT SURGES SWD MON EVE. ...CNTRL/SRN PLAINS... SHORT TERM MODEL SUITE IS QUITE VARIED WITH THE HANDLING OF THE SURGING HIGH PLAINS COLD FRONT AND CONFIDENCE IN THE OVERALL SEVERE SCENARIO IS LOW. CURRENT LOW-LEVEL MOISTURE PROFILES SHOULD BE MAINTAINED THROUGH MON EVENING ACROSS THE CNTRL/SRN PLAINS WITH UPPER 50S TO LOWER 60S BOUNDARY LAYER DEW POINTS COMMON ALONG/S OF THE APPROACHING COLD FRONT AND EAST OF THE DRYLINE. GIVEN MID-LEVEL LAPSE RATES OF 7-8 DEG C PER KM AND HEATING...AIR MASS WILL BECOME POTENTIALLY VERY UNSTABLE. ELEVATED TSTM CLUSTERS SHOULD BE ONGOING EARLY MON MORNING ACROSS ERN KS EWD INTO THE OZARKS ALONG THE EDGE OF THE STRONGER CAP AND NOSE OF THE LLJ. AIR MASS SHOULD RECOVER SOMEWHAT ALONG SWRN EDGE OF THIS COLD DOME AND AHEAD OF THE APPROACHING COLD FRONT ACROSS NCNTRL OK AND CNTRL/ERN KS MON AFTN. GIVEN GRADUAL LARGE SCALE HEIGHT FALLS...HEATING AND CONVERGENCE ALONG THE TRIPLE POINT...TSTMS SHOULD INITIATE AS CINH WEAKENS. STORMS WILL TEND TO EXPAND NEWD ALONG THE COLD FRONT INTO ERN KS AND SWWD ALONG THE DRYLINE INTO CNTRL OK/TX DURING THE EVENING. STRONGER VERTICAL SHEAR WILL EXIST N OF THE RED RIVER WHERE 40-50 KTS WILL BE SUPPORTIVE OF SUPERCELL STRUCTURES WITH VERY LARGE HAIL. SURFACE FLOW MAY REMAINED BACK ACROSS SERN KS AND ERN OK...BOTH DUE TO DEVELOPING SFC LOW IN NWRN OK AND THE RESIDUAL CONVECTIVE BOUNDARIES. THIS MAY AUGMENT THE TORNADO THREAT OVER THESE AREAS. BUT...AS THE COLD FRONT BEGINS TO SURGE SWD DURING THE MID-EVENING HOURS...TSTMS WILL TEND TO BECOME UNDERCUT AND DEVELOP INTO A LINEAR MCS. AT THAT TIME...DAMAGING WIND POTENTIAL WILL BECOME MORE OF A THREAT ANYWHERE FROM SRN MO INTO WRN AR OVERNIGHT. ...LWR OH AND TN VLYS... PERSISTENT MOIST LOW-LEVEL INFLOW ALONG/S OF AN OLD E-W ORIENTED FRONT ACROSS THE LWR OH/TN VLYS MAY PROVE SUFFICIENT FOR TSTM CLUSTERS MON AFTN. REGION WILL REMAIN ALONG SRN PERIPHERY OF STRONGER FLOW ALOFT AND A FEW STRONGER STORMS MAY DEVELOP WITH THE THREAT FOR LARGE HAIL/HIGH WINDS. HIGHER SEVERE PROBABILITIES SHOULD EXIST UPSTREAM OVER WRN KY/TN WHERE LAPSE RATES WILL BE STEEPER. ..RACY.. 04/23/2006  From SwoDy2 at goshenarc.org Mon Apr 24 06:12:37 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 24 Apr 2006 02:12:37 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 240604 SWODY2 SPC AC 240603 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0103 AM CDT MON APR 24 2006 VALID 251200Z - 261200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS SRN TX TO THE LOWER MS AND TN VALLEYS... ...SYNOPSIS... FLAT UPPER RIDGE EXTENDING FROM THE SOUTH CENTRAL-SERN STATES IS EXPECTED TO BREAK DOWN WITH STRONGER WLY MID-LEVEL FLOW DEVELOPING ACROSS THIS REGION...AS A SHORT WAVE TROUGH MOVES EWD TOWARD THE MID MS-LOWER OH/TN VALLEYS AND AN UPPER TROUGH AMPLIFIES ACROSS ERN CANADA/NERN STATES. IN THE LOW-LEVELS...A COLD FRONT ASSOCIATED WITH NRN STREAM SYSTEM IS EXPECTED TO EXTEND SWWD THROUGH THE LOWER GREAT LAKES/OH VALLEY TO THE OZARKS REGION INTO CENTRAL TX AT 12Z TUESDAY. THIS BOUNDARY WILL REMAIN PROGRESSIVE DAY 2 AS BUILDING SURFACE HIGH PRESSURE IN THE WAKE OF NRN STREAM TROUGH FORCES THE FRONT E/SE. A TRIPLE POINT LOW SHOULD BE LOCATED OVER ERN OK BY LATE DAY 1/EARLY DAY 2...WITH THIS FEATURE DEVELOPING SSEWD INTO THE LOWER MS VALLEY. A SECOND SURFACE WAVE ASSOCIATED WITH A WEAK LEAD IMPULSE AND/OR ONGOING MCS MAY BE LOCATED OVER SERN MO OR INTO LOWER OH VALLEY. ...TN/LOWER MS VALLEYS INTO SRN TX... THUNDERSTORMS ARE EXPECTED TUESDAY ALONG/S OF PROGRESSIVE COLD FRONT FROM THE CENTRAL APPALACHIANS/MID-ATLANTIC REGION SWWD THROUGH THE TN/LOWER MS VALLEYS TO TX. HOWEVER...STRONGEST AVAILABLE MOISTURE...STEEPER LAPSE RATES...AND RESULTANT GREATER INSTABILITY ARE EXPECTED TO EXTEND FROM SRN TX THROUGH THE LOWER MS VALLEY TO CENTRAL GULF COAST STATES AND TN VALLEY REGION. THUS...GREATER POTENTIAL FOR SEVERE STORMS SHOULD BE ACROSS THESE AREAS. AN MCS IS EXPECTED TO BE ONGOING START OF DAY 2 ACROSS PARTS OF ERN KS/ERN OK THROUGH MO/OZARKS REGION INTO LOWER OH VALLEY. SURFACE HEATING EAST OF THIS COMPLEX INTO KY/TN AND ALSO SWWD INTO LOWER MS VALLEY TO S TX AHEAD OF COLD FRONT EXPECTED TO RESULT IN A MODERATELY UNSTABLE AIR MASS BY EARLY TUESDAY AFTERNOON. A FEW WEAKLY SHEARED STORMS PER NAM ARE POSSIBLE ALONG A PRE-FRONTAL TROUGH FROM SERN TX/LA INTO CENTRAL GULF COAST STATES BY LATE TUESDAY MORNING. GREATER SEVERE THREAT IS EXPECTED TO DEVELOP BY TUESDAY AFTERNOON FROM TN SWWD INTO AR...WHERE STRONGER MID-LEVEL FLOW WILL RESULT IN SUFFICIENT VERTICAL SHEAR FOR STORM ORGANIZATION. STRONGER DEEP LAYER SHEAR WILL ALSO BE FOUND FARTHER S OVER SRN TX SUPPORTING ORGANIZED STORMS...DUE TO BACKED LOW-LEVEL WINDS BENEATH MODERATE WLY MID-LEVEL FLOW. SEVERE STORMS EXPECTED TO SPREAD SWD TOWARD THE WRN-CENTRAL GULF COAST REGION TUESDAY NIGHT AS EFFECTIVE DEEP LAYER SHEAR/INSTABILITY SHOULD REMAIN SUFFICIENT FOR CONTINUED THREAT. ...PARTS OF CENTRAL/SRN APPALACHIANS TO MID-ATLANTIC STATES. ALTHOUGH INSTABILITY IS EXPECTED TO BE WEAKER EAST OF THE TN VALLEY...MODERATE-STRONG WLY MID-LEVEL WINDS WILL LIKELY SUPPORT STRONG DEEP LAYER SHEAR FOR A FEW ORGANIZED SEVERE STORMS. THIS THREAT SHOULD DIMINISH TUESDAY EVENING AS INSTABILITY DECREASES WITH THE ONSET OF BOUNDARY LAYER COOLING. ..PETERS.. 04/24/2006  From SwoDy2 at goshenarc.org Mon Apr 24 17:03:04 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 24 Apr 2006 13:03:04 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 241658 SWODY2 SPC AC 241657 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1157 AM CDT MON APR 24 2006 VALID 251200Z - 261200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM SERN TX AND THE LOWER MS VALLEY NEWD TO PORTIONS OF THE DELMARVA AND NC... ...SYNOPSIS... AMPLIFIED...SPLIT FLOW PATTERN WILL CONTINUE THROUGH THE DAY TWO PERIOD WITH DEEP UPPER LOW EVOLVING OVER THE ERN CANADA AND SRN STREAM LOW SHIFTING SEWD ALONG THE SRN CA COAST. SHORT WAVE TROUGH EJECTING EWD INTO THE CNTRL AND SRN PLAINS DURING THE DAY ONE PERIOD IS FORECAST TO WEAKEN AS IT MOVES INTO PROGRESSIVELY CONFLUENT MID-LEVEL FLOW REGIME FROM THE SRN OH VALLEY TO MIDDLE ATLANTIC COAST. IN THE LOW-LEVELS...PRIMARY SURFACE LOW ASSOCIATED WITH PLAINS SHORT WAVE TROUGH /INITIALLY OVER THE MID MS VALLEY/ WILL DEVELOP RAPIDLY EWD ALONG BAROCLINIC ZONE TO NEAR CHESAPEAKE BAY BY TUESDAY EVENING. MEANWHILE...TRAILING COLD FRONT WILL PUSH SEWD THROUGH THE REMAINDER OF TX AND THE LOWER MS VALLEY BY WEDNESDAY MORNING. ...SERN TX/LOWER MS VALLEY EWD INTO THE CNTRL AND SRN APPALACHIANS... CURRENT SURFACE OBSERVATIONS AND 24/12Z SOUNDING DATA INDICATE A MOIST LOW-LEVEL AIR MASS IN PLACE ACROSS THE SRN PLAINS INTO WRN PORTIONS OF THE LOWER MS VALLEY WITH DEWPOINTS IN THE 60S TO LOWER 70S. INCREASING SWLY LOW-LEVEL FLOW AHEAD OF SURFACE FRONT WILL ALLOW FOR EWD/NEWD ADVECTION OF THIS MOISTURE ACROSS THE GULF COAST INTO TN VALLEY...SUPPORTING MODERATE AFTERNOON INSTABILITY WITH MLCAPES INCREASING TO 1000-2000 J/KG. THIS INSTABILITY WILL WEAKEN WITH NEWD EXTENT OVER THE APPALACHIANS WHERE MLCAPES OF 500-1000 J/KG APPEAR MORE LIKELY. CLUSTERS OF TSTMS OR A COUPLE OF MCS/S WILL LIKELY BE ONGOING TUESDAY MORNING FROM VICINITY OF SURFACE LOW SWWD ALONG COLD FRONT FROM THE LOWER OH VALLEY INTO AR. SOME DIURNAL WEAKENING MAY OCCUR THROUGH THE MORNING...WITH STORMS EXPECTED TO INCREASE IN COVERAGE AND INTENSITY BY AFTERNOON AS INFLOW AIR MASS DESTABILIZES. GIVEN THE ANTICIPATED MODERATE INSTABILITY...DEEP-LAYER SPEED SHEAR OF 35-40 KTS SHOULD BE SUFFICIENT TO SUPPORT ORGANIZED STORM CLUSTERS AND/OR LINE SEGMENTS CAPABLE OF MAINLY DAMAGING WINDS AND LARGE HAIL. ...DELMARVA INTO NC... CURRENT SURFACE OBSERVATIONS AND MODEL GUIDANCE SUGGEST THAT BOUNDARY-LAYER WILL LIKELY NOT BE AS MOIST AS LOCATIONS FARTHER TO THE W...THOUGH DEWPOINTS SHOULD INCREASE THROUGH THE 50S AS SLY LOW-LEVEL WINDS INCREASE AHEAD OF APPROACHING SURFACE LOW. WHILE FORECAST SOUNDINGS INDICATE THAT INSTABILITY WILL REMAIN SOMEWHAT MARGINAL /MLCAPES OF 500-800 J/KG/...VERTICAL SHEAR PROFILES WILL BE QUITE FAVORABLE FOR SEVERE STORMS WITH 40-50 KTS OF DEEP-LAYER SHEAR AND MORE STRONGLY CURVED LOW-LEVEL HODOGRAPHS OWING TO BACKED WINDS AHEAD OF SURFACE LOW. THEREFORE...SHOULD STORMS DEVELOP AND BECOME SUSTAINED NEAR SURFACE LOW...POTENTIAL WILL EXIST FOR DAMAGING WINDS...LARGE HAIL AND PERHAPS A TORNADO OR TWO FROM MID TO LATE AFTERNOON INTO THE EARLY EVENING HOURS. ..MEAD.. 04/24/2006  From SwoDy2 at goshenarc.org Tue Apr 25 05:38:06 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 25 Apr 2006 01:38:06 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 250534 SWODY2 SPC AC 250533 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1233 AM CDT TUE APR 25 2006 VALID 261200Z - 271200Z ...NO SVR TSTM AREAS FORECAST... ...SERN STATES... SHORT WAVE TROUGH EXPECTED TO BE LOCATED OVER THE LOWER MO VALLEY/ OZARKS REGION BEGINNING OF DAY 2 WILL AMPLIFY SOME AS IT TRACKS SEWD REACHING THE SRN APPALACHIANS BY 12Z THURSDAY. BAND OF 40-50 KT WLY MID-LEVEL WINDS ACCOMPANYING THIS TROUGH WILL SPREAD ACROSS THE CENTRAL GULF COAST/SERN STATES THIS FORECAST PERIOD. SURFACE COLD FRONT SHOULD INITIALLY EXTEND WWD FROM THE CAROLINAS TO AN AREA OF LOW PRESSURE OVER THE SRN APPALACHIANS...AND THEN SWWD THROUGH THE LOWER MS VALLEY. SURFACE LOW EXPECTED TO TRACK EWD INTO SC ALONG WEDGE FRONT BY WEDNESDAY AFTERNOON WITH TRAILING COLD FRONT SETTLING SOUTH TOWARD THE GULF COAST. COLD FRONT SHOULD THEN SURGE SWD INTO CENTRAL FL WEDNESDAY NIGHT AS LOW MOVES OFFSHORE IN RESPONSE TO STRONGER HEIGHT FALLS WITH APPROACH OF AMPLIFYING MID-LEVEL TROUGH. SWLY LOW-LEVEL WINDS S OF FRONT EXPECTED TO ADVECT SURFACE DEWPOINTS IN THE MID 60S ACROSS THE WARM SECTOR. SHOWERS AND EMBEDDED THUNDERSTORMS ARE PROGGED TO BE ONGOING ALONG AND S OF THE COLD FRONT WITH ASSOCIATED CLOUDINESS LIKELY LIMITING SURFACE HEATING ACROSS MUCH OF THE WARM SECTOR. IN ADDITION...WEAK LAPSE RATES SHOULD MINIMIZE DESTABILIZATION...WITH AFTERNOON MLCAPE VALUES GENERALLY RANGING FROM 500-1000 J/KG. GIVEN THE STRENGTHENING MID-LEVEL WINDS...VERTICAL SHEAR SHOULD BECOME SUFFICIENT TO SUPPORT STORM ORGANIZATION...WITH SHEAR VECTORS ORIENTED LARGELY PARALLEL TO THE SURFACE BOUNDARY PROMOTING MAINLY A LINEAR MODE. HOWEVER... OVERALL SEVERE THREAT/COVERAGE IS EXPECTED TO BE LIMITED BY THE WEAK INSTABILITY...THUS CONTINUING THE OUTLOOK OF LOW SEVERE PROBABILITIES. ..PETERS.. 04/25/2006  From swody2 at goshenarc.org Tue Apr 25 17:26:20 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 25 Apr 2006 13:26:20 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 251722 SWODY2 SPC AC 251721 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1221 PM CDT TUE APR 25 2006 VALID 261200Z - 271200Z ...NO SVR TSTM AREAS FORECAST... ...SERN AL...CNTRL AND SRN GA...SRN SC AND NRN FL... THE SHORTWAVE TROUGH NOW OVER THE CNTRL PLAINS IS FORECAST TO CONTINUE SEWD AND MAY UNDERGO SOME AMPLIFICATION AS IT MOVES THROUGH THE TN VALLEY. EARLY WEDNESDAY A COLD FRONT SHOULD EXTEND FROM SWRN LA NEWD THROUGH NERN AL AND INTO NRN GA...THEN SEWD AS A BACK DOOR FRONT ACROSS SC. THE FRONT WILL MOVE SEWD DURING THE DAY. LOW LEVEL DEWPOINTS IN THE UPPER 60S WILL RESIDE IN THE WARM SECTOR S OF THESE BOUNDARIES. SOME DESTABILIZATION SHOULD OCCUR DURING THE DAY. HOWEVER...MODEST LAPSE RATES...AREAS OF ONGOING CONVECTION AND WIDESPREAD CLOUDS WILL LIKELY LIMIT OVERALL DEGREE OF INSTABILITY WITH MLCAPE GENERALLY AOB 1000 J/KG EXPECTED. STORMS ARE EXPECTED TO INCREASE IN COVERAGE ALONG AND AHEAD OF THE FRONT WITHIN THE WEAKLY CAPPED ENVIRONMENT AND SPREAD EWD THROUGH THE WARM SECTOR BY LATE MORNING INTO THE AFTERNOON. SIGNIFICANT MODEL DIFFERENCES EXIST BETWEEN THE NAM...GFS AND ECMWF. THE GFS AND ECMWF DEVELOP MUCH STRONGER KINEMATIC FIELDS BETWEEN 850 AND 550 MB ACROSS PARTS OF SRN GA...SC AND NRN FL AS THE UPPER TROUGH AMPLIFIES SEWD...WHILE THE NAM IS MUCH WEAKER. THE GFS AND ECMWF SOLUTIONS WOULD SUPPORT A GREATER POTENTIAL FOR ORGANIZED SEVERE/DAMAGING WIND EVENTS IF SUFFICIENT DESTABILIZATION COULD OCCUR. GIVEN THE MODEL DIFFERENCES AND POTENTIAL FOR WIDESPREAD CLOUDS TO LIMIT DESTABILIZATION...WILL MAINTAIN 5% SEVERE PROBABILITIES AT THIS TIME. HOWEVER...IF IT BEGINS TO APPEAR THAT WIND FIELDS AND INSTABILITY WILL BE GREATER THAN CURRENTLY ANTICIPATED...AN UPGRADE TO SLIGHT RISK MIGHT BE NECESSARY IN LATER OUTLOOKS. ..DIAL.. 04/25/2006  From swody2 at goshenarc.org Wed Apr 26 06:06:52 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 26 Apr 2006 02:06:52 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 260602 SWODY2 SPC AC 260601 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0101 AM CDT WED APR 26 2006 VALID 271200Z - 281200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN HIGH PLAINS THURSDAY AFTERNOON/EVENING... ...SRN HIGH PLAINS... ALTHOUGH MODELS DIFFER WITH EWD MOVEMENT OF LARGE CLOSED UPPER LOW THROUGH THE SWRN STATES ON THURSDAY...WITH THE GFS/NAM FASTER THAN THE ECMWF/UKMET...EACH MODEL SUGGESTS STRENGTHENING MID/UPPER LEVEL SWLY WINDS ACROSS THE SRN HIGH PLAINS. SELY LOW-LEVEL WINDS DEVELOPING ALONG THE RIO GRANDE VALLEY/TRANS PECOS REGION DAY 1 WILL CONTINUE DAY 2...WITH NWWD MOISTURE ADVECTION. ELEVATED MIXED LAYER WITH MID-LEVEL LAPSE RATES EXCEEDING 7.5-8 C/KM IS EXPECTED TO SPREAD EWD ATOP THE NARROW AXIS OF MOISTURE RETURN...RESULTING IN MUCAPE VALUES AROUND 1000 J/KG ALONG TRANS PECOS REGION TO SERN NM. THE EML SHOULD CAP MUCH OF THE AIR MASS THROUGH THE AFTERNOON...WITH INITIAL THUNDERSTORM DEVELOPMENT LIKELY CONFINED TO THE HIGHER TERRAIN OF SW TX AND NM. EFFECTIVE DEEP LAYER SHEAR VALUES INCREASING TO 40-50 KT WILL BE SUFFICIENT FOR PERSISTENT ROTATING UPDRAFTS...WITH HAIL AND DAMAGING WIND GUSTS THE PRIMARY THREATS AS STORMS MOVE NEWD OFF THE HIGHER TERRAIN INTO THE INSTABILITY AXIS. LLJ STRENGTHENING/VEERING TO SLY THURSDAY NIGHT SHOULD ALLOW STORMS TO PERSIST OVERNIGHT WITHIN LOW-LEVEL WAA REGIME ACROSS WRN TX...WITH AT LEAST A LOW PROBABILITY FOR ISOLATED SEVERE HAIL. ...PARTS OF CENTRAL/NRN PLAINS... SHORT WAVE TROUGH...CURRENTLY APPROACHING BC COAST...IS EXPECTED TO MOVE SEWD INTO THE NRN PLAINS DAY 2. DESPITE MEAGER MOISTURE RETURN THIS FAR NORTH...WEAK INSTABILITY MAY DEVELOP DUE TO COMBINATION OF NRN EXTENT OF EML SPREADING INTO CENTRAL PLAINS AND COLD MID-LEVEL TEMPERATURES /-18 TO -22 C/ WITH TROUGH STEEPENING MID-LEVEL LAPSE RATES. THERMODYNAMIC PROFILES SHOULD SUPPORT THUNDERSTORMS ALONG A SURFACE BOUNDARY MOVING EWD ACROSS THE NRN/CENTRAL PLAINS. DESPITE DEEP LAYER SHEAR BECOMING SUFFICIENT FOR ORGANIZED STORMS ACROSS NEB...WEAK INSTABILITY EXPECTED TO LIMIT THE POTENTIAL FOR SEVERE STORMS. THUS...WILL NOT INTRODUCE ANY SEVERE PROBABILITIES AT THIS TIME. ..PETERS.. 04/26/2006  From swody2 at goshenarc.org Wed Apr 26 17:33:04 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 26 Apr 2006 13:33:04 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 261728 SWODY2 SPC AC 261727 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1227 PM CDT WED APR 26 2006 VALID 271200Z - 281200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER THE SRN HIGH PLAINS... ...SRN HIGH PLAINS... UPPER LOW OFF THE CA COAST IS FORECAST TO MOVE EWD INTO THE SRN ROCKIES BY THURSDAY EVENING...WHILE A NRN STREAM SHORTWAVE TROUGH AMPLIFIES SEWD INTO THE NRN HIGH PLAINS. A COLD FRONT WILL SETTLE SWD INTO WRN KS AND SERN CO TUESDAY AFTERNOON. A LEE TROUGH WILL BECOME ESTABLISHED OVER THE SRN HIGH PLAINS IN ADVANCE OF THE SRN STREAM UPPER LOW. LOW LEVEL MOISTURE WITH DEWPOINTS IN THE LOW TO MID 60S WILL ADVECT NWWD THROUGH SWRN AND WRN TX THURSDAY AFTERNOON AND EVENING AS THE BOUNDARY LAYER FLOW RETURNS TO SLY AND THE LOW LEVEL JET STRENGTHENS E OF DEVELOPING LEE TROUGH. PLUME OF STEEP LAPSE RATES WILL EXIST ABOVE THE RETURNING LOW LEVEL MOISTURE AND CONTRIBUTE TO MODERATE INSTABILITY DURING THE AFTERNOON. THE ATMOSPHERE WILL LIKELY REMAINED CAPPED MUCH OF THE DAY. HOWEVER... STORMS SHOULD DEVELOP BY LATE AFTERNOON OVER THE HIGHER TERRAIN OF NM AND SWRN TX WITHIN ZONE OF SURFACE HEATING...OROGRAPHIC FORCING AND INCREASING UPPER DIVERGENCE ASSOCIATED WITH EWD ADVANCING UPPER TROUGH. THERMODYNAMIC AND DEEP LAYER SHEAR PROFILES WILL BECOME INCREASINGLY FAVORABLE FOR SUPERCELLS CAPABLE OF PRODUCING VERY LARGE HAIL FROM ERN NM INTO PARTS OF WRN TX WITH SELY BOUNDARY LAYER FLOW VEERING TO SWLY AND STRENGTHENING THROUGH 8 KM. A FEW STORMS MAY ALSO DEVELOP FARTHER NWD INTO SWRN KS AND SERN CO IN VICINITY OF THE COLD FRONT DURING THE AFTERNOON. VERTICAL SHEAR AND INSTABILITY WILL BE WEAKER IN THIS AREA...BUT INVERTED-V THERMODYNAMIC PROFILES AND STEEP MID LEVEL LAPSE RATES MAY SUPPORT A THREAT FOR HAIL AND STRONG GUSTY WINDS. STRENGTHENING LOW LEVEL JET MAY SUPPORT STORMS CONTINUING SOME DISTANCE EWD INTO THE HIGH PLAINS DURING THE EVENING WHERE THE CAP WILL BE STRONGER. OTHER STORMS WILL LIKELY DEVELOP FARTHER N INTO OK AND SRN KS WITHIN ZONE OF INCREASING WARM ADVECTION OVERNIGHT. SOME OF THESE STORMS MAY ALSO BE CAPABLE OF PRODUCING LARGE HAIL. ..DIAL.. 04/26/2006  From SwoDy2 at goshenarc.org Fri Apr 28 05:57:56 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Fri, 28 Apr 2006 01:57:56 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 280556 SWODY2 SPC AC 280555 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1255 AM CDT FRI APR 28 2006 VALID 291200Z - 301200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN AND CNTRL PLAINS AND OZARK PLATEAU... ...EAST TX/AR... A LARGE LINEAR MCS SHOULD BE ONGOING AT THE BEGINNING OF THE PERIOD SOUTH OF A DEEPENING UPPER-LOW. MODEL FORECASTS AGREE WITH THIS SCENARIO WITH A SQUALL-LINE EXTENDING FROM OK SWD ACROSS EAST AND CNTRL TX. AS THE UPPER-SYSTEM TRANSITIONS NEWD DURING THE DAY...STRONG LARGE-SCALE ASCENT SHOULD HELP SUSTAIN THE LINEAR MCS WHICH SHOULD AFFECT AREAS OF FAR EAST TX...LA...ERN OK AND THE OZARKS BY AFTERNOON. AT LOW-LEVELS...MOISTURE ADVECTION SHOULD CONTINUE TONIGHT INTO SATURDAY ACROSS THE SABINE RIVER VALLEY WITH SFC DEWPOINTS LIKELY INCREASING INTO THE LOWER TO MID 60S F AS FAR NORTH AS THE SRN OZARKS. THIS MAY ALLOW POCKETS OF MODERATE INSTABILITY TO DEVELOP BY SATURDAY AFTERNOON ACROSS THE REGION WHICH WOULD LIKELY RESULT IN INTENSIFICATION OF THE LINEAR MCS. FORECAST SOUNDINGS SATURDAY AFTERNOON IN LA AND SRN AR SHOW STRONG VERTICAL SHEAR PROFILES WITH LOW-LEVEL FLOW INCREASING DURING THE DAY. THIS WOULD AID THE WIND DAMAGE POTENTIAL WITH THE STRONGER STORMS IN THE LINE. ALTHOUGH LAPSE RATES ARE NOT FORECAST TO BE THAT STEEP...LARGE HAIL WILL ALSO BE POSSIBLE ESPECIALLY IF MODERATE INSTABILITY DEVELOPS AHEAD OF THE LINE. ADDITIONAL STORMS MAY INITIATE TO THE WEST ACROSS ERN OK AND NE TX WHERE MODERATE INSTABILITY MAY ALSO DEVELOP IN A DRY SLOT WRAPPING AROUND THE SOUTHEAST SIDE OF THE UPPER-LOW. STORMS MAY REMAIN MORE DISCRETE IN THIS AREA AND SUPERCELLS WILL BE POSSIBLE ESPECIALLY IF MODERATE INSTABILITY DEVELOPS SATURDAY AFTERNOON. LARGE HAIL AND WIND DAMAGE WOULD BE POSSIBLE WITH THE STRONGER CELLS BEFORE THE SEVERE THREAT GRADUALLY DIMINISHES IN THE EVENING HOURS. ...KS/WRN MO... AN UPPER-LOW IS FORECAST TO DEEPEN AND MOVE NEWD ACROSS THE SRN AND CNTRL PLAINS SATURDAY. LOW-LEVEL MOISTURE WILL WRAP NORTH AND WWD AROUND THE UPPER-LOW AND SFC DEWPOINTS IN THE 50S F SHOULD BE IN PLACE ACROSS WRN MO AND ACROSS THE ERN HALF KS. SFC HEATING AND THE STEEP LAPSE RATES ASSOCIATED WITH THE UPPER-LOW SHOULD ALLOW DISCRETE STORMS TO INITIATE BY THE AFTERNOON AND MOVE SLOWLY NWD ACROSS THE REGION. FORECAST SOUNDINGS SATURDAY AFTERNOON IN KS AND WRN MO SHOW MODERATE VERTICAL SHEAR PROFILES WHICH WILL LIKELY BE SUFFICIENT FOR ISOLATED STORMS CAPABLE OF PRODUCING LARGE HAIL. ANY SEVERE THREAT THAT DEVELOPS SHOULD BE CONCENTRATED NEAR PEAK HEATING. ..BROYLES.. 04/28/2006  From SwoDy2 at goshenarc.org Fri Apr 28 17:31:49 2006 From: SwoDy2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Fri, 28 Apr 2006 13:31:49 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 281729 SWODY2 SPC AC 281728 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1228 PM CDT FRI APR 28 2006 VALID 291200Z - 301200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM SRN IA SWD TO THE TX/LA GULF COAST... ...SYNOPSIS... UPPER LOW/TROUGH OVER THE CENTRAL CONUS -- ACCOMPANIED BY STRONG DEEP-LAYER WIND FIELD -- WILL DEEPEN AND TAKE ON A MORE NEGATIVE TILT WITH TIME WHILE MOVING SLOWLY EWD THROUGH THE PERIOD. MEANWHILE...SURFACE LOW INITIALLY EXPECTED OVER NERN TX/ERN OK/ERN KS SHOULD DEEPEN AND SHIFT NWD ACROSS THE MIDDLE MO VALLEY. COLD FRONT ASSOCIATED WITH THIS LOW WILL MOVE ACROSS ERN OK/ERN KS INTO MO/AR...WHILE MOVING MORE SLOWLY SEWD ACROSS NRN LA/SERN TX THROUGH THE END OF THE PERIOD. ...ERN PORTIONS OF THE PLAINS TO THE MIDDLE/LOWER MS VALLEY... LARGE/COMMA-SHAPED AREA OF PRECIPITATION IS FORECAST TO BE ONGOING AT THE START OF THE PERIOD ACROSS THE CENTRAL CONUS. THE MOST INTENSE CONVECTION WITHIN THIS LARGER PRECIPITATION AREA -- POSSIBLY IN THE FORM OF AN ORGANIZED SQUALL LINE ALONG/AHEAD OF THE COLD FRONT -- IS EXPECTED TO EXTEND FROM ERN OK SWD INTO ERN TX. WITH STRONG SWLY MID-LEVEL FLOW LIKELY BLOWING DENSE UPPER CLOUDINESS DOWNSTREAM FROM ONGOING STORMS...DAYTIME HEATING SHOULD BE LIMITED ACROSS MUCH OF THE SLIGHT RISK AREA. THUS...DESPITE MOIST BOUNDARY LAYER SPREADING NWD ACROSS TX/LA INTO AR...INSTABILITY SHOULD REMAIN LIMITED TO 500 TO 1000 J/KG MIXED-LAYER CAPE THROUGH THE AFTERNOON. DESPITE THIS...STRONG UPPER SYSTEM AND ADVANCING COLD FRONT SHOULD HELP SUSTAIN A VIGOROUS LINEAR-TYPE MCS THROUGH THE DAY...WITH ADDITIONAL/MORE CELLULAR CONVECTION POSSIBLE AHEAD OF LINE. STRENGTH OF DEEP-LAYER SHEAR /50 TO 60 KT FLOW FROM THE S AT LOW-LEVELS VEERING TO SSWLY AT 65 TO 70 KT AT MID-LEVELS/ SHOULD SUPPORT A SEVERE THREAT -- PARTICULARLY FROM ERN TX/LA NWD INTO SERN KS/SRN MO. WITH INSTABILITY LIMITED...PRIMARY SEVERE THREAT MAY BE IN THE FORM OF WIND...THOUGH SOME HAIL AND A COUPLE OF TORNADOES WILL BE POSSIBLE. A LESSER SEVERE THREAT MAY EXTEND AS FAR N AS IA...THOUGH DECREASING INSTABILITY WITH NWD EXTENT SHOULD TEMPER THE DEGREE OF THREAT. MAIN LINE OF STORMS SHOULD CROSS SERN MO/AR/NRN LA AND REACH THE MS VALLEY DURING THE LATE AFTERNOON/EVENING...THOUGH THREAT SHOULD DIMINISH OVERNIGHT WITH INSTABILITY FORECAST TO REMAIN LIMITED E OF THE MS VALLEY. ..GOSS.. 04/28/2006