From swody2 at goshenarc.org Tue Aug 1 05:24:30 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 01 Aug 2006 01:24:30 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 010525 SWODY2 SPC AC 010523 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1223 AM CDT TUE AUG 01 2006 VALID 021200Z - 031200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM PARTS OF THE CNTRL PLAINS THROUGH THE MIDDLE AND UPPER MS VALLEY...GREAT LAKES AND NERN STATES... ...SYNOPSIS... UPPER TROUGH NOW MOVING INTO THE W COAST WILL CONTINUE EWD INTO THE UPPER MS VALLEY AND GREAT LAKES WEDNESDAY. POTENTIAL WILL EXIST FOR WEAKER IMPULSES TO EJECT NEWD AHEAD OF THIS FEATURE. ONE SUCH FEATURE OVER NM IS FORECAST TO EJECT INTO THE GREAT LAKES. HEIGHT FALLS ACCOMPANYING THE UPPER TROUGH WILL RESULT IN DEAMPLIFICATION OF SERN U.S. UPPER RIDGE AND A MORE ZONAL PATTERN BECOMING ESTABLISHED OVER THE NRN THIRD OF THE COUNTRY. A COLD FRONT WILL SETTLE SWD AND BY EARLY WEDNESDAY SHOULD EXTEND FROM SERN CANADA SWWD THROUGH THE GREAT LAKES AND INTO THE CNTRL PLAINS. A WEAK SURFACE LOW ACCOMPANYING THE ENEWD ADVANCING SHORTWAVE TROUGH IS FORECAST TO DEVELOP ALONG THE FRONT AND TRACK EWD THROUGH THE GREAT LAKES DURING THE DAY. ...CNTRL PLAINS THROUGH MID MS VALLEY AND GREAT LAKES... SURFACE FRONT EXPECTED TO EXTEND FROM THE CNTRL PLAINS NEWD THROUGH THE GREAT LAKES WILL PROVIDE A FOCUS FOR THUNDERSTORMS THIS PERIOD. WARM MID LEVEL TEMPERATURES WITH -4C TO -6C AT 500 MB WILL PERSIST IN PRE-FRONTAL WARM SECTOR. HOWEVER...RICH LOW LEVEL MOISTURE WITH LOW 70S DEWPOINTS WILL RESULT IN MODERATE INSTABILITY AS THE BOUNDARY LAYER WARMS. STORMS MAY BE ONGOING EARLY WEDNESDAY WITHIN ZONE OF ISENTROPIC ASCENT N OF FRONT OVER PARTS OF THE PLAINS NEWD INTO THE GREAT LAKES...SUPPORTED BY AN EXPANSIVE SWLY LOW LEVEL JET. THE LOW LEVEL JET WILL LIFT NEWD INTO THE GREAT LAKES AHEAD OF EWD ADVANCING SURFACE LOW...RESULTING IN ENHANCED CONVERGENCE IN THAT REGION. ADDITIONAL STORMS ARE EXPECTED TO REDEVELOP ALONG FRONT AS THE BOUNDARY LAYER DESTABILIZES DURING THE AFTERNOON. STRONG WSWLY WIND PROFILES...WITH 50 KT BETWEEN 3 AND 6 KM ACCOMPANYING EWD ADVANCING SHORTWAVE TROUGH AND ATTENDANT LOW LEVEL JET...WILL EXIST OVER THE GREAT LAKES. POTENTIAL WILL EXIST FOR FAST MOVING CLUSTERS AND BOWING SEGMENTS WITH DAMAGING WIND THE PRIMARY THREAT. A FEW STORMS MAY ALSO DEVELOP SUPERCELL STRUCTURES. FARTHER SW ACROSS THE MID MS VALLEY INTO KS...WIND PROFILES WILL BE WEAKER...BUT A FEW STORMS WILL BE CAPABLE OF WET MICROBURSTS. PORTIONS OF THE GREAT LAKES MAY NEED TO BE UPGRADED TO MODERATE RISK IN LATER OUTLOOKS GIVEN THE POTENTIAL FOR SIGNIFICANT WIND DAMAGE. ...NERN STATES... QUASISTATIONARY FRONT WILL EXTEND FROM W-E ACROSS ME AND MAY LIFT SLOWLY NWD DURING THE DAY. THE ATMOSPHERE WILL BECOME MODERATELY UNSTABLE OVER THE NERN STATES IN WARM SECTOR S OF THIS BOUNDARY SUPPORTED BY LOW 70S DEWPOINTS. STORMS MAY INTENSIFY IN VICINITY OF THIS BOUNDARY AS WELL AS UPSTREAM ALONG COLD FRONT OVER SERN CANADA AND ALONG LAKE BREEZE BOUNDARIES. THESE STORMS WILL SPREAD ESEWD THROUGH PARTS OF THE NERN U.S. DURING THE DAY. THIS REGION WILL REMAIN UNDER MODERATE DEEP LAYER 40 KT WNWLY FLOW. THIS ENVIRONMENT WILL BE SUPPORTIVE OF STORMS EVOLVING INTO MULTICELL CLUSTERS AND BOWING SEGMENTS. DAMAGING WIND WILL BE THE PRIMARY THREAT. ..DIAL.. 08/01/2006  From swody2 at goshenarc.org Tue Aug 1 16:51:11 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 01 Aug 2006 12:51:11 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 011651 SWODY2 SPC AC 011650 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK ISSUED BY AFWA OFFUTT AIR FORCE BASE BELLEVUE NE 1150 AM CDT TUE AUG 01 2006 VALID 021200Z - 031200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE GREAT LAKES INTO KANSAS... ...THERE IS A SLGT RISK OF SVR TSTMS IN NEW YORK AND NEW ENGLAND... ...SYNOPSIS... SUBTROPICAL RIDGE CONTINUES TO BREAK DOWN WITH AN UPPER TROUGH PROGRESSING EASTWARD FROM THE ROCKIES INTO THE GREAT LAKES. THIS WILL LEAD TO A ZONAL FLOW PATTERN OVER THE NORTHERN CONUS...WITH THE RIDGE AXIS SUPPRESSED FROM TEXAS INTO NORTH CAROLINA. A FRONTAL BOUNDARY ASSOCIATED WITH THE UPPER TROUGH WILL CONTINUE A SLOW SOUTHWARD PROGRESSION FROM NEW ENGLAND INTO MICHIGAN AND WISCONSIN AND THEN SOUTHWESTWARD INTO KANSAS. ...GREAT LAKES INTO KANSAS... SURFACE FRONT WILL DROP SOUTHWARD THROUGH THIS AREA DURING THE FORECAST PERIOD. CONVECTION WILL BE ONGOING ALONG THIS FRONT IN SOME LOCATIONS IN THE MORNING...AND TEND TO DISSIPATE AS THE LOW LEVEL JET WEAKENS DIURNALLY. CLOUD DEBRIS AND PRECIPITATION FROM THESE WEAKENING STORMS WILL MAKE PINPOINTING FAVORED LOCATIONS FOR SURFACE BASED CONVECTION LATER IN THE AFTERNOON AND EVENING TRICKY. STRONG FLOW AROUND 50 KNOTS AT 500 HPA EXISTS ACROSS NORTHERN MICHIGAN, BUT THIS WILL BE NORTH OF THE FRONTAL BOUNDARY WHERE INSTABILITY WILL BE WEAKER WITH MUCAPE AROUND 1000 J/KG AND WHERE STORMS WILL TEND TO BE ELEVATED. SOUTH OF THE BOUNDARY FROM SOUTHERN MICHIGAN INTO NORTHERN MISSOURI FLOW AT 500 MB WILL BE WEAKER AROUND 25-35 KNOTS BUT MLCAPE WILL BE HIGHER AROUND 2500 J/KG WHERE STRONG INSOLATION CAN OCCUR. THIS WILL BE ENOUGH FOR MULTICELL THUNDERSTORM CLUSTERS AND GIVEN 850 MB FLOW AROUND 25 KNOTS, WIND DAMAGE WILL BE A THREAT. MID LEVEL LAPSE RATES WILL BE FAIRLY WEAK AROUND 6.0 K/KM SO MARGINALLY SEVERE HAIL IS EXPECTED AT MOST. FARTHER SOUTHWEST INTO KANSAS, THE WRF IS SHOWING A STRONG CONVECTIVE SIGNAL AND THIS SEEMS REASONABLE GIVEN THE SURFACE CONVERGENCE ALONG THE FRONT. 500 MB FLOW WILL ALSO BE AROUND 25-35 KNOTS SO THAT MULTICELL THUNDERSTORMS AND SOME SCATTERED DAMAGING MICROBURSTS ARE POSSIBLE. ...NEW ENGLAND... FRONTAL BOUNDARY WILL BE MOSTLY STATIONARY IN THIS REGION, AND WITH INSOLATION MLCAPES WILL RISE TO OVER 3000 J/KG WITH MINIMAL CAPPING BY 1800 UTC. THIS WILL LEAD TO SCATTERED THUNDERSTORM DEVELOPMENT WITH POSSIBLE WIND DAMAGE GIVEN THE INSTABILITY AND 40 KNOTS OF 500 MB FLOW. THIS IS PROGGED TO INCREASE TO AROUND 45-50 KNOTS IN THE EVENING...BUT INSTABILITY SHOULD BE WANING BY THAT TIME. AN ISOLATED TORNADO OR TWO COULD BE POSSIBLE IF ANY LOCAL BOUNDARIES INTERACT WITH THUNDERSTORMS BEFORE THE INSTABILITY DECREASES. ..AFWA.. 08/01/2006  From swody2 at goshenarc.org Wed Aug 2 05:51:12 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 02 Aug 2006 01:51:12 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 020550 SWODY2 SPC AC 020549 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1249 AM CDT WED AUG 02 2006 VALID 031200Z - 041200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE OH VALLEY INTO THE NERN U.S.... ...SYNOPSIS... ZONAL FLOW WILL CONTINUE OVER THE NRN THIRD OF THE COUNTRY WITH AN UPPER RIDGE PREVAILING OVER THE SRN TWO THIRDS. SERIES OF SHORTWAVE TROUGHS WILL ADVANCE EWD THROUGH THE FLOW. ONE SUCH IMPULSE NOW MOVING INTO THE PLAINS AREA IS PROGGED OVER THE NERN U.S. EARLY THURSDAY WITH ATTENDANT SURFACE LOW. THE GFS AND NAM ARE SIMILAR IN TIMING OF THIS FEATURE. A SURFACE FRONT WILL SETTLE SWD INTO THE OH VALLEY AND NERN STATES IN WAKE OF THIS IMPULSE. SWRN PORTIONS OF THIS BOUNDARY WILL EXTEND SWWD INTO THE SRN PLAINS AREA. ...NERN STATES THROUGH OH VALLEY... FRONTAL BOUNDARY SHOULD EXTEND FROM A SURFACE LOW OVER THE NERN STATES SWWD THROUGH THE OH VALLEY AND SRN PLAINS EARLY THURSDAY AND PROVIDE A FOCUS FOR THUNDERSTORMS. EXITING SHORTWAVE TROUGH SHOULD FORCE NERN PORTION OF FRONT SEWD DURING THE DAY. A STRONG WLY LOW-MID LEVEL JET WITH DEEP LAYER UNIDIRECTIONAL 40 TO 50 KT FLOW WILL ACCOMPANY THE SHORTWAVE TROUGH INTO THE NERN STATES EARLY THURSDAY. HOWEVER...WIND PROFILES WILL GRADUALLY WEAKEN DURING THE MORNING AS THIS FEATURES MOVES OFFSHORE. GIVEN TIME OF DAY MUCH OF THE EARLY STORMS OVER THE NERN STATES COULD BE ELEVATED WHICH COULD LIMIT OVERALL DAMAGING WIND POTENTIAL. HOWEVER...IT REMAINS POSSIBLE THAT SOME OF THIS ACTIVITY COULD BECOME SURFACE BASED LATER IN THE MORNING BEFORE THE STRONGER WIND PROFILES SUBSIDE. OTHERWISE...A FEW STORMS MAY DEVELOP FARTHER SW ALONG FRONT OVER REMAINING PORTIONS OF THE NERN STATES AS THE BOUNDARY LAYER DESTABILIZES. POTENTIAL FOR SUBSIDENCE IN WAKE OF LEAD SHORTWAVE TROUGH COULD POTENTIALLY LIMIT COVERAGE. DAMAGING WIND WILL BE THE PRIMARY THREAT WITH ANY STORMS THAT DEVELOP IN THIS REGION DURING THE DAY. OH VALLEY PORTION OF FRONT MAY REMAIN NEARLY STATIONARY AS UPSTREAM VORT MAX...POSSIBLY ENHANCED BY OVERNIGHT MCS...LIFTS ENEWD THROUGH THE MID MS VALLEY AND INTO THE OH VALLEY. RICH LOW LEVEL MOISTURE AND SURFACE HEATING WILL CONTRIBUTE TO MODERATE INSTABILITY ALONG AND S OF FRONT. STORMS FROM OVERNIGHT MCS MAY STILL BE ONGOING EARLY THURSDAY. OUTFLOW FROM THIS ACTIVITY MAY SERVE TO REINFORCE THE FRONT. OTHER STORMS SHOULD DEVELOP ALONG FRONT OR RESIDUAL OUTFLOW BOUNDARIES WITHIN ZONE OF ASCENT DOWNSTREAM FROM VORT MAX AS THE BOUNDARY LAYER DESTABILIZES. THIS REGION WILL REMAIN ON SRN FRINGE OF STRONGER WLYS WITH 30 TO 35 KT WLY FLOW EXPECTED IN THE 850 MB TO 500 MB LAYER...BUT WITH MODEST VERTICAL SHEAR SUPPORTIVE OF MULTICELLS. STORMS MAY EVOLVE INTO CLUSTERS AND LINE SEGMENTS AS THEY SPREAD EWD WITH DAMAGING WIND THE PRIMARY THREAT. ...SRN PLAINS AREA... OTHER STORMS MAY DEVELOP ALONG TRAILING PORTIONS OF THE FRONT OVER THE SRN PLAINS AS WELL AS OVER THE HIGHER TERRAIN OF NM. WEAK VERTICAL SHEAR SUGGESTS STORMS WILL NOT BE VERY ORGANIZED. HOWEVER...THE THERMODYNAMIC ENVIRONMENT COULD SUPPORT ISOLATED WET MICROBURSTS. ...CNTRL AND NRN HIGH PLAINS... STORMS MAY DEVELOP OVER THE HIGHER TERRAIN OF THE CNTRL ROCKIES FROM CO THROUGH WY WHERE STRONGER VERTICAL SHEAR WILL EXIST. SOME OF THIS ACTIVITY MAY SPREAD EWD INTO THE HIGH PLAINS. MODEST LOW LEVEL MOISTURE WILL LIMIT INSTABILITY. HOWEVER...STEEP LAPSE RATES AND LOW LEVEL INVERTED-V PROFILES WILL SUPPORT A THREAT OF ISOLATED HAIL AND STRONG WIND GUSTS. ..DIAL.. 08/02/2006  From swody2 at goshenarc.org Wed Aug 2 17:41:04 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 02 Aug 2006 13:41:04 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 021740 SWODY2 SPC AC 021739 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1239 PM CDT WED AUG 02 2006 VALID 031200Z - 041200Z ...THERE IS A SLGT RISK OF SVR TSTMS THROUGH EARLY THURSDAY NIGHT FROM SRN NEW ENGLAND INTO THE LOWER OHIO VALLEY.... ...SYNOPSIS... MAIN BAND OF WESTERLIES WILL CONTINUE TO RUN ALONG THE NRN TIER OF THE U.S. DURING THE PERIOD. MINOR RAPIDLY MOVG MID LEVEL SHORTWAVE TROUGH WILL MOVE EWD FROM THE UPR GREAT LAKES REGION INTO THE LWR GREAT LAKES BY 04/00Z INTO THE CENTRAL NORTHEAST U.S. BY THE END OF THE PERIOD. THIS WILL PUSH MAIN COLD FRONTAL BOUNDARY SEWD EXTENDING FROM LONG ISLAND/SERN NY STATE WSWWD THRU SWRN PA INTO E CENTRAL MO BY EVENING. MEANWHILE...LARGE MID/UPPER LEVEL RIDGE WILL PRETTY MUCH HOLD FROM THE CAROLINAS WWD THRU THE SRN PLAINS INTO THE SRN ROCKIES. ...SRN PARTS OF NEW ENGLAND INTO THE LOWER OHIO VALLEY... FRONTAL BOUNDARY/ASSOCIATED CONVECTIVE BOUNDARIES FROM PREVIOUS DAY CONVECTION WILL EXTEND FROM SRN NH/VT WSWWD ALONG SRN PARTS OF THE ERN GREAT LAKES AND CENTRAL IL INTO NWRN MO AT THE START OF THE PERIOD. NAM PUSHES SURFACE RIDGING INTO IA/IL DURING THE AFTN...BUT ALSO LAGS 850 MB COLD FRONT ALONG THE SRN GREAT LAKES DURING THE AFTN. MID/UPR LEVEL JET STREAK OF 50-60 KT AND 80-90 KT RESPECTIVELY WILL EXTEND FROM SERN ONTARIO ENEWD OVER NRN NEW ENGLAND PLACING MUCH OF THE UPR OHIO VALLEY AND LOWER GREAT LAKES IN FAVORABLE ENTRANCE REGION TO PROMOTE UPWARD ASCENT. AIR MASS WILL BE MOST UNSTABLE OVER SRN NEW ENGLAND INTO CENTRAL PA BY 03/18Z WHERE THERE WILL BE DAYTIME HEATING WITH SBCAPES BETWEEN 2500-3000 J/KG. NAM IS QUESTIONABLE WITH LOW/MID LEVEL LAPSE RATES IN THESE AREAS AND THAT COULD BE THAT 500 MB ARE AROUND -5C...BUT GIVEN THAT SFC-3KM LAPSE RATES ARE 8.5C/KM AND DCAPE ESTIMATES ARE AROUND 1000 J/KG...IT LOOKS LIKE THE MAIN THREAT FOR DAMAGING WINDS WILL BE WITH STORMS ALONG/AHEAD OF THE FRONT BY 03/18Z INTO THE 04/00Z TIME FRAME...THEN DURING THE AFTN/EVE FROM WRN PA INTO E CENTRAL MO. ...SRN HIGH PLAINS... STRONG DAYTIME HEATING IN VICINITY OF WEAKENING FRONTAL BOUNDARY WILL BE SUFFICIENT FOR HIGH BASED TYPE THUNDERSTORMS FROM W CENTRAL MO WSWWD INTO THE TX PANHANDLE. MODEL SOUNDINGS INDICATE INVERTED-V TYPE PROFILES ACROSS THESE AREAS WITH TEMP/DEW POINT DIFFERENCES 25-30 DEG F WITH LOW LEVEL LAPSE RATES NEAR 9C/KM. THUS...STRONG MICROBURSTS ARE EXPECTED WITH SCATTERED THUNDERSTORMS ACROSS THESE AREAS LATE IN THE AFTN AND EVENING. ...PARTS OF THE CENTRAL AND NRN HIGH PLAINS... MODELS WANT TO BRING SOME RETURN LOW LEVEL MOISTURE/UPSLOPE TYPE FLOW INTO NERN CO NWD INTO THE BLACK HILLS OF SD. EXPECT A FEW HIGH BASED TYPE THUNDERSTORMS HERE AS WELL WITH LAPSE RATES AROUND 9C/KM IN THE LOW LEVELS SUPPORTING THE POSSIBILITY OF DRY MICROBURSTS. ..MCCARTHY.. 08/02/2006  From swody2 at goshenarc.org Thu Aug 3 17:30:27 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Thu, 03 Aug 2006 13:30:27 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 031730 SWODY2 SPC AC 031729 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1229 PM CDT THU AUG 03 2006 VALID 041200Z - 051200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... LARGE SCALE RIDGE WILL SPREAD ACROSS THE SRN TWO-THIRDS OF THE U.S. DURING THE PERIOD. THIS WILL KEEP MAIN BAND OF WESTERLIES ACROSS SRN CANADA/NRN TIER OF STATES. ONE MINOR SHORTWAVE TROUGH WILL MOVE EWD ACROSS THE NRN GREAT LAKES DURING THE SECOND HALF OF THE PERIOD...WHILE SECOND STRONGER TROUGH/ASSOCIATED VORTICITY MAX MOVES SEWD ACROSS ALBERTA/SASKATCHEWAN. COLD FRONTAL BOUNDARY MOVING SWD/SEWD ACROSS THE LOWER GREAT LAKES AND NRN MID ATLANTIC REGION ON DAY 1 WILL WEAKEN UNDERNEATH DOMINATE RIDGE AS IT MOVES THRU VA AND KY. ...NRN PLAINS... NAM MODEL RATHER AGGRESSIVE COMPARED TO THE GFS OVER PARTS OF ERN ND INTO NRN MN. THIS IS IN ASSOCIATION WITH STRONG WARM ADVECTION ASSOCIATED WITH EXIT REGION OF 35-45 KT LOW LEVEL JET THAT EXTENDS FROM NEB INTO CENTRAL AND NERN MN. THE NAM GENERATES QUITE A BIT OF DEEP LAYER SHEAR ACROSS MN S OF A WEAK FRONT THAT MAKES ITS WAY SWD THRU THIS REGION FRIDAY NIGHT. BUT...MODEL SOUNDINGS INDICATE VERY STRONG CAPPING INVERSION THRU THE NRN PLAINS WHICH WILL INHIBIT CONVECTIVE DEVELOPMENT EXCEPT NEAR THE ND/CANADA BORDER WHERE 50 KT MID LEVEL FLOW IS FORECAST...THEN ESEWD ACROSS EXTREME NRN MN. SOME THUNDERSTORMS CAN MOVE EWD/SEWD ACROSS EXTREME NRN MN FRIDAY NIGHT...BUT GIVEN THE LIMITED EFFECTIVE INSTABILITY AND ELEVATED NATURE OF THE STORMS...WOULD EXPECT ACTIVITY TO MOSTLY BE BELOW SEVERE LEVELS. ...PARTS OF ERN VA/ERN NC... REMNANTS OF COLD FRONTAL BOUNDARY IS EXPECTED TO EXTEND FROM THE CENTRAL DELMARVA INTO THE TN VALLEY FRI AFTN. AIR MASS ALONG AND S OF THE BOUNDARY WILL BE MODERATELY UNSTABLE WITH SBCAPES FORECAST BETWEEN 2000 AND 3000 J/KG. SCATTERED THUNDERSTORMS ARE EXPECTED IN THE VICINITY OF THE BOUNDARY...BUT REMAIN BELOW SEVERE LEVELS DUE TO WEAK FLOW AND HIGHER GEOPOTENTIAL HEIGHTS FROM DOMINATING RIDGE. ACTIVITY COULD PRODUCE SOME STRONG WINDS GIVEN THE EXPECTED 20 DEG T/TD SPREADS...BUT GIVEN WEAK FLOW ALOFT AND LOW/MID LEVEL LAPSE RATES AROUND 6-6.5C/KM ACTIVITY SHOULD REMAIN BELOW SEVERE LEVELS. ..MCCARTHY.. 08/03/2006  From swody2 at goshenarc.org Fri Aug 4 06:15:34 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Fri, 04 Aug 2006 02:15:34 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 040615 SWODY2 SPC AC 040614 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0114 AM CDT FRI AUG 04 2006 VALID 051200Z - 061200Z ...THERE IS A SLGT RISK OF SVR TSTMS NERN PLAINS...UPPER MS VALLEY REGION... ...SYNOPSIS... MID-UPPER LEVEL...SYNOPTIC-SCALE RIDGING WILL DOMINATE PATTERN FROM 4-CORNERS REGION EWD ACROSS SRN PLAINS TO CAROLINAS. MEANWHILE PROGRESSIVE AND GENERALLY ZONAL PATTERN IS EXPECTED TO CHARACTERIZE NRN STREAM FLOW BELT...ACROSS ROUGHLY NRN 1/4 OF CONUS. SHORTWAVE TROUGH -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY OVER CENTRAL/NRN BC -- IS FCST TO AMPLIFY THROUGH BOTH DAY-1 AND DAY-2...AS IT MOVES ESEWD ACROSS SASK. CONSIDERABLE DISAGREEMENT REMAINS IN PROGS OVER WHETHER THIS SYSTEM WILL EVOLVE INTO CLOSED LOW ACROSS SASK/MANITOBA DURING PERIOD...GIVEN PROGRESSIVE NATURE OF PATTERN AND PRESENCE OF OPEN WAVE IN ROUGHLY HALF OF COMBINED SREF/OPERATIONAL 500 MB MODEL PROGS. MID/UPPER LEVEL LOW - NOW CUT OFF ACROSS TRANS-PECOS AND BIG BEND REGIONS OF SW TX -- IS EXPECTED TO DRIFT GENERALLY WWD AROUND MEAN RIDGE TOWARD AZ...CONTRIBUTING TO CLOUDS/PRECIP AND GEN THUNDER POTENTIAL OVER PORTIONS AZ/NM. AT SFC...STRONG FRONTOGENESIS LATE DAY-1 AND EARLY DAY-2 OVER NRN ROCKIES AND NRN HIGH PLAINS WILL LEAD TO COLD FRONT SWEEPING SEWD ACROSS UPPER MIDWEST AND CENTRAL HIGH PLAINS DURING THIS PERIOD...WHILE DEEPENING SFC LOW EJECTS FROM ND ENEWD TOWARD NWRN ONT. FARTHER S...WEAK COLD FRONTAL ZONE IS ANALYZED FROM ERN GREAT LAKES ACROSS OZARKS AND RED RIVER REGION...TO E-CENTRAL/SERN NM. WRN PORTION OF THIS FRONT SHOULD BECOME DIFFUSE ACROSS SRN PLAINS DURING DAY-2...AMIDST BROAD SLY/SELY FLOW FETCH THAT WILL DEVELOP IN RESPONSE TO NRN PLAINS CYCLOGENESIS. FRONT FARTHER E -- FROM MS/AL ACROSS GA/SC -- WILL BE MODIFIED/SHIFTED SPATIALLY ON MESOSCALE BY OUTFLOWS. ...NRN PLAINS TO UPPER MS VALLEY REGION... LOW LEVEL WAA/ISENTROPIC ASCENT...AND INCREASING MOISTURE ABOVE SFC...MAY SUPPORT STG-SVR TSTMS FROM NERN ND EWD TO LS EARLY IN PERIOD...CARRYING OVER THREAT FROM DAY-1. REF SPC DAY-1 OUTLOOK FOR MORE INFORMATION ON THIS REGIME. SECOND AND MORE ROBUST SVR THREAT WILL DEVELOP DURING AFTERNOON/EVENING ACROSS LARGER PORTION OF THIS REGION. AS INTENSE CANADIAN MID-UPPER LEVEL TROUGH APCHS...VERTICAL SHEAR IS FCST TO STRENGTHEN OVER INCREASINGLY MOIST/UNSTABLE WARM SECTOR AIR MASS. THIS WILL RESULT BOTH FROM STRENGTHENING MID-UPPER LEVEL GRADIENTS AND FROM LOW LEVEL ACCELERATIONS IN WARM SECTOR ASSOCIATED WITH ISALLOBARIC/ISALLOHYPSIC FORCING. LOW LEVEL HODOGRAPHS FROM MODEL SOUNDINGS ACROSS PORTIONS MN APPEAR QUITE LARGE AND FAVORABLE FOR ROTATING STORMS...WITH ATTENDANT THREAT OF HAIL/WIND AND PERHAPS TORNADOES. MEANWHILE...LARGE SCALE ASCENT OVER STRONGLY HEATED BOUNDARY LAYER WILL FAVORABLY STEEPEN DEEP-LAYER LAPSE RATES...COMBINING WITH EVAPOTRANSPIRATIVELY BOOSTED SFC DEW POINTS TO GENERATE MDT-STG BUOYANCY. BY MID-LATE AFTERNOON...SEVERE TSTMS SHOULD ERUPT INVOF FRONT...AS HEATING AND CONVERGENCE BREAK CAP. MCS MAY EVOLVE FROM AFTERNOON ACTIVITY AND MOVE ESEWD-SEWD ACROSS PORTIONS UPPER MS VALLEY TOWARD WI/IL. SPECIFIC DISTRIBUTION OF SVR THREATS WILL DEPEND LARGELY ON STORM MODE AND MESOSCALE PROCESSES NOT WELL-RESOLVED THIS FAR IN ADVANCE. OVERALL PATTERN...HOWEVER...SUGGESTS THAT SOME CONCENTRATION/SIGNIFICANCE OF SVR POTENTIAL SUFFICIENT TO WARRANT MDT CATEGORICAL OUTLOOK MAY BECOME MORE APPARENT FOR LATER OUTLOOKS. ...SERN CONUS... SCATTERED TO WIDELY SCATTERED TSTMS IN CLUSTERS ARE FCST ACROSS THIS REGION...PRIMARILY CONCENTRATED ALONG MESOSCALE FOCI SUCH AS OUTFLOW BOUNDARIES INVOF FRONTAL ZONE. STRONG HEATING AND MOISTURE ARE EXPECTED...BUT WITH WEAK VERTICAL SHEAR INVOF MID-UPPER LEVEL RIDGE. ACCORDINGLY...WILL INTRODUCE MRGL AND BROAD-BRUSHED SVR PROBABILITIES FOR PULSE/MULTICELLULAR ACTIVITY. ..EDWARDS.. 08/04/2006  From swody2 at goshenarc.org Fri Aug 4 17:37:57 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Fri, 04 Aug 2006 13:37:57 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 041735 SWODY2 SPC AC 041734 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1234 PM CDT FRI AUG 04 2006 VALID 051200Z - 061200Z ...THERE IS A SLGT RISK OF SVR TSTMS SATURDAY AFTERNOON AND EARLY SATURDAY NIGHT FROM THE ERN DAKOTAS INTO MINNESOTA.... ...SYNOPSIS... VIGOROUS MID/UPPER LEVEL LOW/ASSOCIATED SHORTWAVE TROUGH IS FORECAST TO MOVE FROM SRN SASKATCHEWAN INTO SWRN ONTARIO DURING THE PERIOD. MODELS STRENGTHEN THE AMPLITUDE OF THIS TROUGH SLIGHTLY AS IT MOVES THROUGH THE UPPER MS VALLEY REGION DURING THE AFTERNOON AND EVENING. MEANWHILE...STRONG MID/UPPER LEVEL RIDGING WILL REMAINED ANCHORED FROM THE CENTRAL/SRN ROCKIES EWD INTO THE CAROLINAS. ...NRN PLAINS INTO THE UPPER MS VALLEY... MODELS GENERATE STRONG DYNAMICS IN ASSOCIATION WITH THE MID/UPPER LEVEL LOW MOVING THRU SOUTH CENTRAL CANADA ON SATURDAY. BY 06/00Z...STRONG COLD FRONT WILL EXTEND SWD/SWWD THRU NWRN MN...SERN ND AND S CENTRAL SD INTO SERN WY. SSWLY LOW LEVEL JET OF 40-45 KT WILL EXTEND FROM NERN NEB THRU THE MN ARROWHEAD BY THIS TIME. THIS WILL BECOME COUPLED WITH WLY/NWLY MID LEVEL FLOW NEAR 70 KT OVER NRN ND INTO NWRN MN...AND 250 MB WINDS NEAR 100 KT OVER EXTREME SRN MANITOBA INTO SWRN ONTARIO. THIS WILL CREATE FAVORABLE VERTICAL SHEAR PROFILES TO SUPPORT ROTATING STORMS OVER PARTS OF NRN MN BY SATURDAY AFTN. IN ADDITION...STRONG 700 MB DRY AIR INTRUSION IS EXPECTED TO PUSH ITS WAY OVER ND INTO NWRN MN IN CONJUNCTION WITH UPPER LEVEL DIVERGENCE WHICH IS EXPECTED TO ENHANCE UVVS ALONG AND AHEAD OF THE COLD FRONT. AIR MASS IS FORECAST TO BE QUITE UNSTABLE WITH MODEL LIS BETWEEN -6 AND -10...AND MLCAPE FROM NERN SD INTO W CENTRAL MN BETWEEN 2000 AND 3000 J/KG. ANALYSIS OF POINT FORECAST SOUNDINGS ACROSS W CENTRAL MN INDICATE STRONG CAPPING INVERSION INTO THE AFTERNOON THAT WILL WEAKEN AS FRONTAL BOUNDARY/SQUALL LINE APPROACHES GOING INTO THE EVENING. STEEP MID LEVEL LAPSE RATES OF 8-8.5C/KM WILL BE SUPPORTIVE OF HAIL AND STRONG DAMAGING WINDS. THUS...STRONG/SEVERE THUNDERSTORMS/SQUALL LINE ARE EXPECTED TO DEVELOP AFTER MID AFTN ALONG/AHEAD OF THE COLD FRONTAL BOUNDARY. THIS ACTIVITY IS EXPECTED TO INTENSIFY GOING INTO THE LATE AFTERNOON AND EVENING AS IT MOVES INTO VERY UNSTABLE AIR MASS. OTHER THAN THE MAIN THREATS OF HAIL AND DAMAGING WINDS...DEEP LAYER SHEAR OF 40-50 KT SUGGESTS THE POSSIBILITY OF SUPERCELLS/TORNADOES ACROSS THE NRN THIRD OF MN. ...SERN STATES... MOIST...TROPICAL-LIKE AIR MASS WILL REMAIN IN PLACE ACROSS MUCH OF THE SERN QUARTER OF THE U.S. FLOW IS WEAK ACROSS THIS GENERAL AREA WITH POTENTIAL INSTABILITY BETWEEN 1500 AND 2500 J/KG DURING PERIOD OF PEAK HEATING. WIDESPREAD PULSE THUNDERSTORMS WILL BE EXPECTED AGAIN SATURDAY AFTN AND EARLY SATURDAY NIGHT. TWO MAIN BOUNDARIES ARE EVIDENT IN THE MODEL DATA...ONE ACROSS THE TN VALLEY INTO SRN NC...THE OTHER ALONG THE CENTRAL GULF COAST. MORE NUMEROUS...ORGANIZED STORMS ARE POSSIBLE IN THESE AREAS. MAIN THREAT WITH THIS ACTIVITY WILL BE WET MICROBURSTS. ..MCCARTHY.. 08/04/2006  From swody2 at goshenarc.org Sat Aug 5 06:08:08 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 05 Aug 2006 02:08:08 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 050604 SWODY2 SPC AC 050603 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0103 AM CDT SAT AUG 05 2006 VALID 061200Z - 071200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... SYNOPTIC UPPER AIR PATTERN SHOULD FEATURE SLOW NEWD EJECTION OF PRESENTLY CUT-OFF PACIFIC LOW ACROSS NRN CA/ORE...PROGRESSIVE NRN STREAM BELT ACROSS NRN 1/4 OF CONUS...AND WWD EXTENSION OF BERMUDA RIDGE ACROSS SERN/S-CENTRAL STATES. SRN CONUS RIDGE MAY BE REGIONALLY INTRUDED BY WEAK AND SLOW-MOVING PERTURBATIONS -- PERHAPS CONVECTIVELY GENERATED/ENHANCED. STRONG SHORTWAVE TROUGH IS BECOMING BETTER DEFINED IN MOISTURE CHANNEL IMAGERY AND IS ACCELERATING EWD ACROSS CENTRAL/SRN ALBERTA AS OF 5/530Z. OPERATIONAL/DETERMINISTIC MODELS AND MOST MEMBERS OF SREF GUIDANCE PACKAGES ARE IN GOOD AGREEMENT WITH DAY-2 TRACK OF THIS SYSTEM ENEWD ACROSS NRN ONT...AND ALSO NOW...WITH ITS CHARACTER AS INITIALLY CLOSED LOW EVOLVING INTO OPEN WAVE TROUGH. ASSOCIATED SFC CYCLONE SHOULD BE NEARLY VERTICALLY STACKED WITH MID/UPPER LOW BY 6/12Z. THIS CYCLONE SHOULD LIKEWISE EJECT ENEWD IN OCCLUDED FORM AND WEAKEN...WHILE TRAILING COLD FRONT MOVES EWD ACROSS GREAT LAKES REGION. FRONT SHOULD MOVE SEWD OVER IA/NRN MO...NRN KS AND PORTIONS WRN CO BY END OF PERIOD. BROAD AREAS OF CONDITIONAL AND/OR MRGL SVR POTENTIAL ARE APPARENT FOR DAY-2...HOWEVER ENOUGH UNCERTAINTIES EXIST FOR EACH AREA THAT PRECLUDE CATEGORICAL OUTLOOK THIS SOON. ...UPPER GREAT LAKES...EARLY-MID PERIOD... MCS WITH POTENTIAL FOR STG-SVR GUSTS AND HAIL MAY BE ONGOING EARLY IN PERIOD AHEAD OF SFC COLD FRONT...ACROSS PORTIONS LS...WI...LM AND UPPER MI. POTENTIAL WOULD CARRY OVER FROM DAY-1 PERIOD...REF SPC DAY-1 OUTLOOK FOR MORE DETAILS. SUCH ACTIVITY SHOULD DIMINISH THROUGH EARLY MORNING...AS LLJ DIMINISHES IN ASSOCIATION WITH RECOUPLING OF BOUNDARY LAYER. SOME REVITALIZATION OF CONVECTION IS POSSIBLE DURING LATE MORNING THROUGH EARLY AFTERNOON ACROSS LOWER MI...LH...SWWD OVER PORTIONS NERN IL...SRN LM...SRN WI AND INDIANA. WITH MID/UPPER TROUGH EJECTING AWAY FROM AREA...RELATED ISALLOBARIC FORCING SHOULD YIELD VEERED BOUNDARY LAYER FLOW AND WEAKENING CONVERGENCE. ALSO...CLOUD/CONVECTIVE DEBRIS FROM EARLY ACTIVITY MAY LIMIT PREFRONTAL SFC HEATING. DEEP-LAYER FLOW FIELDS SHOULD BE NEARLY UNIDIRECTIONAL. MAIN THREAT WITH ANY SUSTAINED ACTIVITY WOULD BE DAMAGING GUSTS. ...MID MS VALLEY REGION TO CENTRAL LOW PLAINS...AFTERNOON... CONDITIONAL SVR POTENTIAL EXISTS INVOF SFC FRONT ACROSS THIS REGION. STRONG CAPPING MAY PRECLUDE DIURNAL DEVELOPMENT ALTOGETHER...BUT ANY TSTMS THAT DO FORM WILL BE SUPPORTED BY FAVORABLE INSTABILITY. OVER IA/IL/NRN MO...EVAPOTRANSPIRATIVELY AIDED SFC MOISTURE WILL BE HIGH WITH DEW POINTS 70S TO LOW 80S F...AND STRONG SFC HEATING...CONTRIBUTING TO MLCAPES 2000-3000 J/KG...POTENTIALLY MORE. STRONGER HEATING BUT DEEPER MIXING AND WEAKER MOISTURE ARE EXPECTED WITH WWD EXTENT ACROSS KS. DEEP-LAYER SHEAR PROFILES ALSO SHOULD WEAKEN WITH SWWD EXTENT. ISOLATED DAMAGING GUSTS AND LARGE HAIL MAY DEVELOP...HOWEVER THREAT APPEARS TOO DIFFUSELY DISTRIBUTED ATTM TO APPLY MORE CONCENTRATED SVR PROBABILITIES. ...CENTRAL HIGH PLAINS...FOOTHILLS... NELY/POST-FRONTAL FLOW WILL ADVECT MOISTURE UPSLOPE INTO THIS REGION...AND ENHANCE VERTICAL DIRECTIONAL SHEAR. THIS SHOULD CONTRIBUTE TO POTENTIAL FOR TSTMS DEVELOPMENT BY MID-LATE AFTERNOON OVER TYPICALLY FAVORED TOPOGRAPHIC FEATURES...WITH HAIL OR ISOLATED WIND DAMAGE POSSIBLE FROM MOST INTENSE CELLS. CONCERNS PRECLUDING MORE ROBUST SVR THREAT INCLUDE WEAK MIDLEVEL LAPSE RATES -- ASSOCIATED WITH ABUNDANT/PRECURSORY CONVECTION AND CLOUD COVER UPSTREAM...AND SMALL VALUES OF DEEP-LAYER BULK SHEAR THAT ARE LIKELY. ...SERN CONUS... SCATTERED TSTMS ARE EXPECTED TO DEVELOP AGAIN THIS AFTERNOON IN BOTH PULSE AND MULTICELLULAR MODES. VERTICAL WIND AND SHEAR PROFILES WILL REMAIN WEAK OVER THIS REGION...AND ANY SVR POTENTIAL WILL BE STRONGLY DEPENDENT ON RELATIVELY TRANSIENT MESOSCALE PROCESSES YET TO BE RESOLVED IN PROGS. SOME MULTICELL CLUSTERS MAY BECOME PERSISTENT AND WELL-ORGANIZED ENOUGH TO DEVELOP COLD POOLS TO AID IN FORWARD PROPAGATION...GENERALLY WWD OR SWWD...PRODUCING CONCENTRATION OF DAMAGING WIND AND/OR MRGL SVR HAIL REPORTS. IN GENERAL...STRONG SFC HEATING AND DEW POINTS UPPER 60S TO MID 70S F WILL SUPPORT WEAKENING CAP DURING AFTERNOON...PARTICULARLY NEAR OUTFLOW BOUNDARIES FROM PRIOR AND ONGOING CONVECTION. ...ERN GREAT LAKES...LATE PERIOD... AHEAD OF SFC FRONT...MOIST ADVECTION ASSOCIATED WITH SWLY LLJ MAY SUPPORT DEVELOPMENT OF TSTMS ACROSS PORTIONS SRN ONT...LE...AND PERHAPS PORTIONS OH/WRN PA/WRN NY DURING LAST SEVERAL HOURS OF PERIOD. DAMAGING GUSTS WOULD BE PRIMARY CONCERN. STRONGEST DEEP-LAYER FORCING SHOULD REMAIN FARTHER N IN CANADA...BUT MOST FAVORABLE BUOYANCY COULD EXTEND SWD OVER ERN GREAT LAKES REGION. THIS POTENTIAL IS MORE STRONGLY INDICATED BY OPERATIONAL WRF THAN MOST OTHER MODELS. FCST SOUNDINGS SUGGEST SUFFICIENTLY STEEP MIDLEVEL LAPSE RATES AND MOISTURE JUST OFF SFC FOR MUCAPES ABOVE 1500 J/KG IN PROSPECTIVE INFLOW LAYER...AND SFC THETAE LARGE ENOUGH THAT EFFECTIVE PARCELS MAY BE BASED NEAR GROUND. ..EDWARDS.. 08/05/2006  From swody2 at goshenarc.org Sat Aug 5 17:30:53 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 05 Aug 2006 13:30:53 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 051730 SWODY2 SPC AC 051729 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1229 PM CDT SAT AUG 05 2006 VALID 061200Z - 071200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE MID MO AND LOWER OH VALLEYS... ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE UPPER OH VALLEY... ...MID MO VALLEY/OH VALLEY... A ZONAL FLOW PATTERN WILL REMAIN IN PLACE ACROSS THE NRN U.S. AS AN UPPER-LEVEL TROUGH DRIFTS EWD ACROSS SRN CANADA INTO THE UPPER MIDWEST SUNDAY. AT THE SFC...A COLD FRONT WILL MOVE SEWD ACROSS THE NRN MS VALLEY AND SHOULD BE POSITIONED FROM WI EXTENDING SWWD INTO NRN MO AND ERN KS BY SUNDAY AFTERNOON. SOUTH OF THE BOUNDARY...DEWPOINTS FROM 65 TO 75 F SHOULD BE PRESENT RESULTING IN AN AXIS OF MODERATE INSTABILITY. ALTHOUGH A CAPPING INVERSION WILL LIKELY EXIST THROUGH MUCH OF THE DAY...SFC HEATING AND LOW-LEVEL CONVERGENCE ALONG THE BOUNDARY SHOULD BE ENOUGH FOR THUNDERSTORM INITIATION BY MID-AFTERNOON. SCATTERED THUNDERSTORMS SHOULD INCREASE IN COVERAGE THROUGH LATE AFTERNOON WITH THE GREATEST COVERAGE OVER NRN MO AND NRN IL. ADDITIONAL THUNDERSTORM DEVELOPMENT WILL BE LIKELY ALONG A SECONDARY INSTABILITY AXIS EXTENDING NWD FROM THE CNTRL APPALACHIAN MTNS INTO OH AS SHOWN BY THE NAM AND GFS SOLUTIONS. FORECAST SOUNDINGS ALONG AND AHEAD OF THE BOUNDARY SUNDAY AFTERNOON SHOW 0-6 KM SHEAR VALUES FROM 25 TO 35 KT SUGGESTING INSTABILITY/SHEAR PROFILES WILL BE SUFFICIENT FOR SEVERE MULTICELL STORMS. LOW-LEVEL LAPSE RATES ARE FORECAST TO BE VERY STEEP ESPECIALLY ACROSS NE KS...NRN MO...NRN IL AND OH FAVORING ISOLATED WIND DAMAGE WITH THE STRONGER CELLS. WARM MID-LEVEL TEMPS SHOULD CONFINE HAIL POTENTIAL TO THE STRONGEST OF CONVECTION. ALTHOUGH THUNDERSTORMS SHOULD CONTINUE OVERNIGHT CO-LOCATED WITH BANDS OF LARGE-SCALE ASCENT ASSOCIATED WITH THE UPPER-TROUGH...DECREASING INSTABILITY SHOULD ALLOW THE SEVERE THREAT TO DIMINISH BY LATE EVENING. ...ERN CO... AN UPPER-LEVEL RIDGE IS FORECAST TO BUILD OVER THE WRN U.S. AS A COLD FRONT BECOMES NEARLY STATIONARY FROM ERN WY EXTENDING SEWD INTO SRN NEB SUNDAY. SOUTH OF THE BOUNDARY DEWPOINTS SHOULD BE IN THE 50S F ALLOWING FOR SOME DESTABILIZATION SUNDAY ALONG AN EAST TO WEST AXIS FROM NE CO THROUGH NRN KS. SFC HEATING SHOULD RESULT IN THUNDERSTORM INITIATION IN THE HIGHER TERRAIN OF CNTRL CO BY MIDDAY WITH STORMS INCREASING IN COVERAGE AND MOVING EWD INTO THE PLAINS. FORECAST SOUNDINGS ACROSS NE CO SUNDAY AFTERNOON SHOW VERY STEEP LAPSE RATES AND 0-6 KM SHEAR VALUES AROUND 20 KT WHICH MAY BE ENOUGH FOR AN ISOLATED SEVERE THREAT WITH THE STRONGER MULTICELL STORMS. HOWEVER...THE AMOUNT OF DESTABILIZATION STILL REMAINS UNCERTAIN AND LARGE-SCALE ASCENT SHOULD REMAIN WEAK. THESE FACTORS MAY KEEP THE SEVERE THREAT MARGINAL SUNDAY AFTERNOON. ...NRN CA/SRN ORE... AN UPPER-LEVEL RIDGE WILL BUILD ACROSS THE ROCKIES AS AN UPPER-LOW OVER THE ERN PACIFIC MOVES SLOWLY NEWD TOWARD NRN CA SUNDAY. IN THE LOWER ELEVATIONS OF NRN CA AND SRN ORE...DEWPOINTS WILL LIKELY REMAIN NEAR 50 F ALLOWING SOME DESTABILIZATION BY AFTERNOON. SCATTERED THUNDERSTORMS SHOULD DEVELOP AND MOVE NEWD ACROSS NRN CA AND SRN ORE AS LARGE-SCALE ASCENT INCREASES AHEAD OF APPROACHING SYSTEM. FORECAST SOUNDINGS IN NRN CA INCREASE VERTICAL SHEAR PROFILES BY LATE AFTERNOON AS THE EXIT REGION OF A MID-LEVEL JET MOVES NEWD ACROSS THE REGION. THIS COMBINED WITH VERY STEEP LAPSE RATES WILL BE FAVORABLE FOR AN ISOLATED SEVERE THREAT WITH THE STRONGER CELLS NEAR PEAK HEATING. HOWEVER...THE SEVERE THREAT MAY REMAIN MARGINAL DUE TO RELATIVELY WEAK DESTABILIZATION. ...EAST TX/LA... A WEAK FLOW REGIME IS FORECAST TO BE IN PLACE ACROSS THE SRN U.S. SUNDAY. AT THE SFC...DEWPOINTS IN THE 70S F SHOULD RESULT IN MODERATE INSTABILITY ALONG THE GULF COAST AREAS. THUNDERSTORMS WILL LIKELY DEVELOP DUE TO SFC HEATING AND LARGE-SCALE ASCENT ASSOCIATED WITH AN ELY MOVING WAVE IN THE NRN GULF OF MEXICO. THUNDERSTORMS SHOULD INITIATE BY EARLY AFTERNOON AND SPREAD WWD ACROSS LA AND EAST TX. FORECAST SOUNDINGS SHOW STEEP LOW-LEVEL LAPSE RATES WHICH MAY BE SUFFICIENT FOR A MARGINAL WIND DAMAGE THREAT WITH THE STRONGEST OF STORMS NEAR PEAK HEATING SUNDAY AFTERNOON. ..BROYLES.. 08/05/2006  From swody2 at goshenarc.org Sun Aug 6 06:10:39 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 06 Aug 2006 02:10:39 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 060609 SWODY2 SPC AC 060608 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0108 AM CDT SUN AUG 06 2006 VALID 071200Z - 081200Z ...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS MID-ATLANTIC AND NEW ENGLAND... ...SYNOPSIS... MID-UPPER LEVEL SYNOPTIC PATTERN IS FCST TO REMAIN PROGRESSIVE ACROSS NRN CONUS...AMIDST PREVAILING AMPLIFICATION OF MEAN RIDGE ACROSS ROCKIES AND TROUGH OVER QUE. MID/UPPER LEVEL LOW -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY OVER MB -- IS FCST TO DEAMPLIFY DAY-1 AND ACCELERATE EWD ACROSS NRN QUE DAY-2. SPEED MAX ALOFT -- ASSOCIATED WITH WEAKER PERTURBATION NOW OVER WRN ALBERTA -- IS FCST TO DIG SEWD THROUGH W SIDE OF MEAN TROUGH...AND ACROSS PORTIONS SRN QUE/NRN NY/NRN NEW ENGLAND DURING THIS PERIOD. AT SFC...COLD FRONT NOW ANALYZED FROM NRN MN TO CENTRAL HIGH PLAINS IS EXPECTED TO MOVE EWD ACROSS ERN GREAT LAKES...MID ATLANTIC AND NEW ENGLAND REGIONS THROUGH 8/12Z. FRONT WILL MOVE MORE SLOWLY SWD ACROSS OH VALLEY REGION...WHILE STALLING AND BECOMING MORE DIFFUSE ACROSS CENTRAL PLAINS. ...NERN CONUS TO MO... SCATTERED TSTMS ARE EXPECTED TO DEVELOP ALONG/AHEAD OF SFC COLD FRONT DURING DAYLIGHT HOURS...ORGANIZED LARGELY IN LINEAR/SEGMENTED FASHION. ACTIVITY SHOULD MOVE EWD ACROSS OUTLOOK AREA WITH LEWP/BOW FORMATIONS POSSIBLE...DAMAGING WIND BEING MAIN THREAT. PRIND STRONGEST ISALLOBARIC FORCING SHOULD REMAIN FARTHER N ACROSS QUE AND CANADIAN MARITIMES...HOWEVER ASSOCIATED SWLY FLOW IS EXPECTED TO ADVECT FAVORABLE BOUNDARY LAYER THETAE CLOSER TO ATLANTIC COAST AND KEEP MOST OF RELATIVELY STABLE MARINE AIR MASS SHUNTED FARTHER E ACROSS CAPE COD REGION AND DOWNEAST MAINE. IN COMBINATION WITH SFC DIABATIC HEATING...THIS SHOULD RESULT IN ENOUGH DIURNAL DESTABILIZATION TO SUPPORT CONVECTIVE DEVELOPMENT/MAINTENANCE. PASSAGE OF MID-UPPER LEVEL SPEED MAX OVER SFC COLD FRONT...AND ACROSS PREFRONTAL WARM/MOIST SECTOR...IS EXPECTED TO ENHANCE DEEP-LAYER SPEED SHEAR AND POTENTIAL ORGANIZATION OF TSTMS ACROSS THIS AREA. ALTHOUGH NEARLY UNIDIRECTIONAL VERTICAL WIND PROFILES ARE PROGGED...DEEP-LAYER BULK SHEAR MAY SUPPORT SUPERCELL STRUCTURE WITH ANY DISCRETE ACTIVITY THAT MAY DEVELOP. ORGANIZED SVR POTENTIAL SHOULD DIMINISH WITH SWWD EXTENT AHEAD OF FRONT...CORRESPONDING TO PROGRESSIVELY WEAKER DEEP-LAYER SHEAR AND WEAKER LARGE SCALE FORCING. HOWEVER...COMBINATION OF MESOSCALE FOCI...RICH LOW LEVEL MOISTURE...AND STRONG SFC HEATING MAY HELP TO CONCENTRATE LOCALIZED/CLUSTERED MULTICELL SVR POTENTIAL ALMOST ANYWHERE FROM MID/UPPER OH VALLEY WWD ACROSS MO/ERN KS. ...CENTRAL HIGH PLAINS... STEEP MIDLEVEL LAPSE RATES...STRONG SFC HEATING...AT LEAST MRGLLY FAVORABLE MOISTURE AND PRESENCE OF FRONTAL ZONE SHOULD CONTRIBUTE TO RELATIVE CONCENTRATION OF TSTMS WITH HAIL/GUSTS NEAR SVR LEVELS POSSIBLE...MAINLY AFTERNOON INTO EARLY EVENING. STRONG DIRECTIONAL SHEAR IS LIKELY ALONG AND N OF SFC FRONTAL ZONE...WHERE BOUNDARY LAYER MOIST AXIS WILL BE EXTENDED WWD AMIDST ELY FLOW COMPONENT. WITH LACK OF MORE ROBUST MIDLEVEL WINDS OR DEEP-LAYER SHEAR...MESOSCALE PROCESSES WILL DETERMINE RELATIVE CONCENTRATIONS OF SVR POTENTIAL. ...NWRN CONUS... DAMAGING GUSTS MAY OCCUR WITH MOST INTENSE CONVECTION ACROSS THIS REGION...MAINLY DURING MID-LATE AFTERNOON. MID-UPPER LEVEL CUT-OFF LOW NOW EVIDENT OFFSHORE CA IS FCST TO DEAMPLIFY AND EJECT NEWD ACROSS PORTIONS NRN CA AND ORE DURING THIS PERIOD. MODELS ARE COMING INTO CLOSER AGREEMENT ON TIMING OF THIS PROCESS...WITH ENHANCED DEEP-LAYER SHEAR SPREADING ACROSS PORTIONS INTERIOR ORE DURING PEAK AFTERNOON WARMING. MAIN CONCERN WILL BE MARGINALITY AND SPORADIC DISTRIBUTION OF LOW LEVEL MOISTURE. ...WRN GULF COASTAL PLAIN... RELATIVE CONCENTRATION OF DIURNAL CONVECTION IS EXPECTED ACROSS THIS REGION IN ASSOCIATION WITH MID-UPPER LEVEL TROUGH IN ELY FLOW ALOFT. STRONG SFC HEARING AND MESOSCALE BOUNDARIES -- MAINLY OUTFLOW RELATED -- MAY CONCENTRATE SVR POTENTIAL WITH A FEW MULTICELL CLUSTERS LIKELY TO HAVE BULK OF STG-SVR WIND POTENTIAL. ..EDWARDS.. 08/06/2006  From swody2 at goshenarc.org Sun Aug 6 17:18:26 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 06 Aug 2006 13:18:26 -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 SUN AUG 06 2006 VALID 071200Z - 081200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE NERN U.S.... ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE CNTRL PLAINS... ...NERN U.S... AN UPPER-LEVEL TROUGH OVER SERN CANADA IS FORECAST TO CONTINUE EWD TONIGHT AND DIG ESEWD TOWARD THE NERN U.S. MONDAY. IN RESPONSE...A COLD FRONT WILL MOVE SEWD INTO WRN NY MONDAY AFTERNOON. MOISTURE ADVECTION WILL CONTINUE AHEAD OF THE APPROACHING FRONT ALLOWING SFC DEWPOINTS TO RISE INTO THE 60S F ACROSS MUCH OF THE REGION. THIS SHOULD ALLOW MODERATE INSTABILITY TO DEVELOP BY MIDDAY FROM PARTS OF NEW ENGLAND EXTENDING SSWWD THROUGH NY...PA AND MD. INCREASING LARGE-SCALE ASCENT ACROSS THE REGION AHEAD OF THE APPROACHING UPPER-LEVEL TROUGH SHOULD SUPPORT THE DEVELOPMENT OF SCATTERED THUNDERSTORMS ALONG THE INSTABILITY AXIS DURING THE AFTERNOON. FORECAST SOUNDINGS ACROSS THE REGION MONDAY AFTERNOON SHOW 0-6 KM SHEAR VALUES IN THE 30 TO 45 KT RANGE SUGGESTING SUPERCELLS WILL BE POSSIBLE ESPECIALLY WHERE INSTABILITY IS LOCALLY MAXIMIZED. SEVERE MULTICELLS WILL ALSO BE POSSIBLE WITH HAIL AND WIND DAMAGE LIKELY WITH THE STRONGER STORMS AROUND PEAK HEATING. ALTHOUGH SEVERE STORMS WILL BE LIKELY ACROSS THE REGION MONDAY AFTERNOON...LAPSE RATES ESPECIALLY AT MID-LEVELS ARE NOT FORECAST TO BE PARTICULARLY STEEP SUGGESTING A MORE WIDESPREAD SEVERE WEATHER EVENT IS NOT LIKELY. ...CNTRL PLAINS... UPPER-LEVEL HIGH PRESSURE IS FORECAST TO REMAIN IN PLACE ACROSS THE SRN PLAINS AS A COLD FRONT MOVES SWD INTO SRN KS AND WRN MO. AHEAD OF THE BOUNDARY...SFC DEWPOINTS IN THE 60S F SHOULD RESULT IN AN AXIS OF MODERATE INSTABILITY. AS THE CAPPING INVERSION WEAKENS...SCATTERED THUNDERSTORMS SHOULD DEVELOP ALONG AND SOUTH OF THE BOUNDARY DURING THE AFTERNOON. FORECAST SOUNDINGS ACROSS THE REGION MONDAY AFTERNOON SHOW 0-6 KM SHEAR VALUES IN THE 30 TO 35 KT RANGE MOSTLY DUE TO DIRECTIONAL SHEAR. THIS SUGGESTS SEVERE MULTICELLS WILL BE POSSIBLE WITH THE GREATEST SEVERE THREAT LIKELY WITH THE LARGER THUNDERSTORM CLUSTERS. HAIL AND ISOLATED WIND DAMAGE SHOULD BE THE PRIMARY THREATS. ...NRN CA/ORE... AN UPPER-LEVEL TROUGH IS FORECAST TO MOVE INTO NRN CA MONDAY SPREADING STRONG LARGE-SCALE ASCENT NEWD ACROSS THE REGION. THIS SHOULD SUPPORT SCATTERED THUNDERSTORM DEVELOPMENT MONDAY AFTERNOON IN NRN CA AND ORE. FORECAST SOUNDINGS IN NRN CA AND ORE MONDAY AFTERNOON SHOW STEEP LAPSE RATES WITH ADEQUATE SHEAR PROFILES FOR SEVERE STORMS. HOWEVER...THE AMOUNT OF DESTABILIZATION THAT WILL OCCUR MONDAY REMAINS UNCERTAIN. IF ENOUGH INSTABILITY DEVELOPS BY AFTERNOON...HAIL AND ISOLATED WIND DAMAGE WOULD BE POSSIBLE WITH THE STRONGER CELLS. HOWEVER...WILL NOT UPGRADE TO SLIGHT RISK ATTM. A SLIGHT RISK MAY BECOME NECESSARY IN LATER OUTLOOKS ONCE CERTAINTY CONCERNING INSTABILITY INCREASES. ..BROYLES.. 08/06/2006  From swody2 at goshenarc.org Sat Aug 12 05:46:03 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 12 Aug 2006 01:46:03 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 120547 SWODY2 SPC AC 120545 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1245 AM CDT SAT AUG 12 2006 VALID 131200Z - 141200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE UPPER MS VALLEY/WRN GREAT LAKES SWWD ACROSS THE CNTRL PLAINS... ...SYNOPSIS... BROAD SUB-TROPICAL RIDGE AXIS WILL CONTINUE TO DOMINATE THE SRN HALF OF THE U.S. THIS PERIOD WITH GENERALLY PROGRESSIVE FLOW EXISTING ACROSS THE NRN STATES FROM COAST TO COAST. PRIMARY FEATURE AFFECTING ORGANIZED CONVECTIVE WEATHER WILL BE A PROGRESSIVE TROUGH...EMBEDDED WITHIN THE FASTER FLOW REGIME...MOVING FROM SCNTRL CANADA/NRN PLAINS AREA ESEWD TO THE UPPER MS VALLEY/WRN GREAT LAKES. COLD FRONT ACCOMPANYING THIS SHORT WAVE TROUGH WILL SPREAD SWD ACROSS THE NRN AND CNTRL HIGH PLAINS...SEWD ACROSS THE MO RIVER VALLEY...AND EWD ACROSS UPPER MS VALLEY TO THE NRN GREAT LAKES REGIONS FROM SUNDAY AND INTO EARLY MONDAY. THE EAST COAST WILL REMAIN UNDER THE INFLUENCE OF STABLE CONTINENTAL POLAR AIR MASS. THE LEADING EDGE OF THIS AIR MASS WILL CONTINUE TO BE DEFINED BY A QUASI-STATIONARY FRONTAL BAND...AND SCATTERED DEEP CONVECTION INCREASING DURING THE AFTERNOON...FROM THE NERN GULF AND FL WWD TO THE LOWER MS VALLEY. A SUBTROPICAL DISTURBANCE DRIFTING NWWD AROUND THE SRN PERIPHERY OF BROAD CNTRL/SRN U.S. UPPER RIDGE...COUPLED WITH MOIST LOW LEVEL UPSLOPE FLOW AND HIGH PW AIR...WILL RESULT IN NUMEROUS STORMS ACROSS THE SOUTHWEST AND UPPER RIO GRANDE VALLEY. ...NRN PLAINS ACROSS UPPER MS VALLEY... MODEL GUIDANCE HAS COME INTO BETTER AGREEMENT WITH THE MOTION OF THE FRONT ACROSS THESE AREAS. PRIMARY SHORT WAVE TROUGH TO AFFECT THE NRN PLAINS AREA ON SUNDAY WAS CURRENTLY ROUNDING THE BASE OF THE LARGER SCALE TROUGH OVER THE PACIFIC NORTHWEST. THIS FEATURE IS FORECAST TO MAINTAIN MODEST AMPLITUDE WHILE CROSSING THE ROCKIES THROUGH SATURDAY. A LEADING IMPULSE...CURRENTLY LIFTING INTO SCNTRL CANADA...WILL DRIVE A FRONT ACROSS MUCH OF ND AND NWRN SD THROUGH SATURDAY. THIS BOUNDARY SHOULD STRETCH FROM MN TO WY BY SUNDAY MORNING. ONGOING MORNING CONVECTION WITHIN WARM CONVEYOR AXIS AHEAD OF THE COLD FRONT MAY EXIST OVER ERN SD INTO MN. ANOTHER CLUSTER OF POST-FRONTAL STORMS MAY BE ONGOING AT THE START OF THE PERIOD ACROSS THE NRN HIGH PLAINS IN AREA OF ENHANCED ASCENT AHEAD OF THE APPROACHING SHORT WAVE TROUGH OVER MT. AIR MASS IN THE WAKE OF MN MCS AND AHEAD OF THE FRONT SHOULD BECOME INCREASINGLY UNSTABLE THROUGH THE AFTERNOON GIVEN RICH LOW LEVEL MOISTURE AND MODERATE HEATING. SREF GUIDANCE INDICATES MLCAPE VALUES OF 800-1500 J/KG WILL BE POSSIBLE AHEAD OF THE FRONT...FROM MN INTO NRN NEB. EXPECT CONVECTIVE INHIBITION IN THIS CORRIDOR TO BE EFFECTIVELY ERODED AS FRONTAL CIRCULATION DEVELOPS SEWD INTO THE AREA FROM AFTERNOON THROUGH EVENING. BOTH SHEAR AND FORCING APPEAR STRONGEST IMMEDIATELY BEHIND THE COLD FRONT AND EXPECT LINE SEGMENTS AND PERHAPS A FEW SUPERCELLS TO PRODUCE SEVERE HAIL AND WIND OVER NRN PORTIONS OF THE SLGT RISK AREA AS THE FRONT AND POSSIBLE SQUALL LINE ADVANCE EWD/SEWD. ...CNTRL PLAINS... WHILE GREATER WARM SECTOR SHEAR AND FORCING ARE FORECAST TO EXIST ACROSS THE NRN PLAINS AND UPPER MS VALLEY AREAS THROUGH THE AFTERNOON AND EVENING...STRONGER DESTABILIZATION IS FORECAST ACROSS PORTIONS OF THE MO RIVER VALLEY AND ADJACENT PLAINS WHERE AIR MASS IS LIKELY TO BE CAPPED. HEATING AND WEAK LARGE SCALE FORCING AHEAD OF THE FRONT SHOULD ACT TO LOCALLY OVERCOME THE CAP IN THESE AREAS BY AFTERNOON WITH ROBUST CONVECTIVE DEVELOPMENT EXPECTED THROUGH EVENING. EVEN THOUGH VERTICAL SHEAR DIMINISHES WITH SWD EXTENT ACROSS THE REGION...THIS MAY BE OFFSET BY MAGNITUDE OF INSTABILITY. EXPECT WEAKLY ORGANIZED MULTICELLULAR STORMS TO DEVELOP INTO LINEAR MCS AS THE FRONT SPREADS SEWD. HAIL AND HIGH WINDS MAY ACCOMPANY THIS ACTIVITY WITH THE CONVECTION DEVELOPING ACROSS SRN NEB/IA...AND INTO KS/MO AREAS THROUGH SUNDAY NIGHT. ..CARBIN.. 08/12/2006  From swody2 at goshenarc.org Sat Aug 12 16:48:48 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 12 Aug 2006 12:48:48 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 121649 SWODY2 SPC AC 121648 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1148 AM CDT SAT AUG 12 2006 VALID 131200Z - 141200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE CNTRL/NRN PLAINS AND UPPER MS VLY REGION... ...SYNOPSIS... ACTIVE NRN STREAM WILL CONTINUE INTO SUNDAY AS A POTENT UPPER TROUGH PROGRESSES EWD FROM THE NWRN STATES TODAY TO THE UPPER MS VLY BY SUNDAY NIGHT. ASSOCD COLD FRONT WILL REACH A MN...SD... NERN CO LINE BY 00Z MON AND TO AN UPPER GRTLKS TO SRN HI PLAINS LINE BY 12Z MON. ...NRN PLAINS TO UPPER MS VALLEY... SEVERAL AREAS OF CONVECTION SHOULD BE ONGOING ACROSS A LARGE PORTION OF NWRN MN...THE DAKS AND NEB EARLY SUNDAY MORNING. STRONGEST STORMS SHOULD EXIST ACROSS MN ALONG THE NOSE OF THE WARM SUB-TROPICAL CONVEYOR AHEAD OF THE APPROACHING MID-LEVEL TROUGH. THIS ACTIVITY SHOULD EITHER WEAKEN OR MOVE INTO NWRN ONT BY AFTN. AIR MASS IN WAKE OF THE MORNING ACTIVITY AND AHEAD OF THE PRIMARY COLD FRONT SHOULD BECOME INCREASINGLY UNSTABLE THROUGH SUNDAY AFTN GIVEN RICH LOW-LEVEL MOISTURE AND MODEST HEATING. BUT...SUB- TROPICAL CONVEYOR AND POTENTIAL FOR CLOUD SUGGEST THAT LAPSE RATES MAY SUFFER AND BE LOWER THAN RECENT DAYS. NONETHELESS...TSTMS SHOULD INTENSIFY/DEVELOP ALONG SERN EDGE OF MORNING CLOUD/TSTM CLUSTERS ACROSS PORTIONS OF MN AND IA BY MID-AFTN AS CINH IS WEAKENED VIA FRONTAL CIRCULATION AND LARGE SCALE HEIGHT FALLS. SHEAR AND FORCING WILL BE STRONGEST WEST OF THE FRONT AND GIVEN ORIENTATION OF THE DEEP LAYER SHEAR VECTORS...TSTMS WILL TEND TO EVOLVE QUICKLY INTO LINE SEGMENTS WITH PERHAPS EMBEDDED SUPERCELLS. DAMAGING WINDS WILL BE THE PRIMARY SEVERE THREAT...BUT HAIL AND AN ISOLD TORNADO CANNOT BE RULED OUT. BY EVE...A FAIRLY EXTENSIVE SQUALL LINE WILL LIKELY EXIST ACROSS THE UPPER MS VLY THAT WILL MOVE EWD AND WEAKEN OVERNIGHT. ...CNTRL PLAINS... THOUGH STRONGEST DEEP LAYER SHEAR AND ASCENT ARE EXPECTED ACROSS THE NRN PLAINS...AIR MASS IS FORECAST TO BE MUCH MORE UNSTABLE ACROSS PARTS OF THE MO VLY AND ADJACENT PLAINS. HERE...MID-LEVEL LAPSE RATES WILL BE STEEPER AND BOUNDARY LAYER CAPPED FOR MOST OF THE AFTN. RESULTANT STRONGER LOW-LEVEL HEATING SHOULD WEAKEN THE CAP AND GIVEN WEAK LARGE SCALE FORCING AHEAD OF THE SEWD MOVING COLD FRONT...TSTMS SHOULD DEVELOP LATE IN THE AFTN FROM SERN NEB SWWD INTO WRN KS. MAGNITUDE OF BUOYANCY MAY COMPENSATE FOR THE WEAKER VERTICAL SHEAR AND ORGANIZED MULTICELL STORMS WILL BE POSSIBLE. MORE VIGOROUS STORMS WILL PRODUCE DAMAGING WINDS AND HAIL. AN MCS OR TWO IS LIKELY TO EVOLVE OVERNIGHT ACROSS PARTS OF IA SWWD INTO KS...THOUGH THE SEVERE THREATS WILL LIKELY DIMINISH DURING SUNDAY EVE. ..RACY.. 08/12/2006  From swody2 at goshenarc.org Sun Aug 13 05:55:57 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 13 Aug 2006 01:55:57 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 130556 SWODY2 SPC AC 130556 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1256 AM CDT SUN AUG 13 2006 VALID 141200Z - 151200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF THE MIDWEST/OH VALLEY... ...SYNOPSIS... PROGRESSIVE UPPER TROUGH WILL CONTINUE TO DEVELOP EWD ACROSS ONTARIO AND THE GREAT LAKES REGION THROUGH MONDAY WITH ASSOCIATED COLD FRONT SPREADING ACROSS THE MIDWEST...AND TRAILING SWWD INTO THE SRN PLAINS/HIGH PLAINS THROUGH THE DAY AND EVENING. LOW LEVEL FRONTAL CIRCULATION WILL DEVELOP INTO VERY MOIST AIR MASS FROM THE OH VALLEY/MIDWEST AREAS SWWD TO THE PLAINS. MEANWHILE...STRONGER FLOW AND DYNAMICS WITH THE ASSOCIATED UPPER TROUGH WILL SPREAD QUICKLY EAST ATOP RELATIVELY COOLER AND DRIER AIR MASS FROM THE ERN GREAT LAKES THROUGH THE NORTHEAST. ...MIDWEST/OH VALLEY... SCATTERED AREAS OF CONVECTION MAY BE ONGOING NEAR THE COLD FRONT EARLY MONDAY FROM LOWER MI TO IL/MO. PROGRESSIVE NATURE OF THE UPPER TROUGH AND WEAK HEIGHT FALLS SHOULD PROMOTE THE EWD/SEWD MOTION OF THE FRONTAL ZONE INTO AN INCREASINGLY WARM AND MOIST AIR MASS DURING THE DAY. PREFRONTAL ENVIRONMENT WILL TRANSITION FROM LOW CAPE/HIGH SHEAR ACROSS THE UPPER MIDWEST/LOWER MI AREAS...TO HIGH CAPE AND WEAKER SHEAR ACROSS THE OH VALLEY. THUS...EXPECT A POSSIBLE TRANSITION IN CHARACTER OF CONVECTION...FROM FAST MOVING LOW-TOPPED LINE SEGMENTS NORTH...TO MORE MULTICELLULAR SLOWER MOVING STORMS SOUTH. ACTIVITY ACROSS THE OH VALLEY MAY BECOME MORE LINEAR AS THE FRONT MOVES DEVELOPS INTO THIS AREA THROUGH THE EVENING. AT THIS TIME...PRIMARY SEVERE WEATHER HAZARD APPEARS TO BE SCATTERED DAMAGING WINDS. ...SRN PLAINS/HIGH PLAINS... VERY WARM AND MOIST AIR MASS WILL EXIST AHEAD OF THE BOUNDARY FROM AR WWD TO NM. EXPECT THE FRONTAL BOUNDARY WILL PROVIDE A FOCUS FOR TSTM DEVELOPMENT AND PERSISTENCE. WITH GREATER FORCING ASSOCIATED WITH THIS FRONT WELL REMOVED FROM THE REGION...LARGE SCALE SUPPORT WILL BE LIMITED. BUT SOME LARGE SCALE SUPPORT FOR DEEPER LIFT MAY BE PROVIDED BY RESIDUAL MCVS...AS WELL AS WEAK SUBTROPICAL DISTURBANCE TRAVERSING PARTS OF THE SRN HIGH PLAINS. WEAKLY ORGANIZED AND DIURNALLY DRIVEN MULTICELLULAR CONVECTION SHOULD POSE SOME THREAT FOR ISOLATED DAMAGING WINDS AND PERHAPS MARGINALLY SEVERE HAIL. ...LOWER MS VALLEY TO FL... PRESENCE OF REMNANT BAROCLINIC ZONE...STRONG HEATING...AND TROPICAL MOISTURE WILL ALL CONTRIBUTE TO AFTERNOON TSTM DEVELOPMENT ACROSS THESE AREAS. WHILE DEEP LAYER FLOW AND LAPSE RATES WILL REMAIN MEAGER...BOUNDARY/CELL INTERACTIONS...AND PERHAPS SOME POTENTIAL FOR GREATER FORCING/SHEAR NEAR UPPER LOW OVER FL...COULD RESULT IN ISOLATED WET MICROBURSTS OR PERHAPS A BRIEF TORNADO/WATERSPOUT. ..CARBIN.. 08/13/2006  From swody2 at goshenarc.org Sun Aug 13 16:44:55 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 13 Aug 2006 12:44:55 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 131645 SWODY2 SPC AC 131644 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1144 AM CDT SUN AUG 13 2006 VALID 141200Z - 151200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE OH VLY... ...SYNOPSIS... A PROGRESSIVE UPPER TROUGH WILL MOVE FROM THE NRN PLAINS TODAY THEN EWD ACROSS ONTARIO AND THE GRTLKS THROUGH MON. ASSOCD COLD FRONT WILL SPREAD ACROSS THE MIDWEST AND TRAIL SWWD INTO THE SRN HIGH PLAINS BY MON EVE. THIS FRONT WILL BE THE FOCUS FOR PSBL SVR TSTMS MON AFTN-EVE. ...MIDWEST/OH VALLEY... SCT CONVECTION SHOULD BE ONGOING ACROSS THE GRTLKS REGION SWWD INTO THE UPPER MIDWEST EARLY ON MON VCNTY THE APPROACHING COLD FRONT. THIS FRONT WILL DEVELOP SEWD INTO AN INCREASINGLY WARM/MOIST AIR MASS DURING THE AFTN. STEEPER MID-LEVEL LAPSE RATES AND BOUNDARY LAYER HEATING WILL EXIST ALONG TRAILING PORTIONS OF THE FRONT WITH THE STRONGER FLOW LOCATED FARTHER N. THIS WILL LEAD TO A TRANSITION FROM LOW CAPE/MODEST SHEAR ACROSS THE GRTLKS AND UPPER OH VLY TO HIGH CAPE/WEAKER SHEAR OVER THE LWR OH VLY. AS A RESULT...THERE WILL BE A TRANSITION IN CHARACTER OF CONVECTION... FROM FAST MOVING LOW-TOPPED LINE SEGMENTS N...TO MORE MULTICELLULAR SLOWER MOVING STORMS S. THE PRIMARY SEVERE RISK WILL BE DAMAGING WINDS. ...OZARKS WWD TO SRN PLAINS/HIGH PLAINS... SUB-TROPICAL PLUME OF MSTR WILL STREAM NEWD ACROSS THE SRN PLAINS ON MON. HEATING AND FAVORABLY MOIST AIR MASS AHEAD OF THE SWD MOVING COLD FRONT WILL BE THE FOCUS FOR TSTM DEVELOPMENT FROM THE OZARKS WWD INTO THE SRN HIGH PLAINS. HIGHER CONCENTRATION OF STORMS SHOULD EXIST ACROSS SERN CO...NERN NM...AND THE TX/OK PNHDLS WHERE UPSLOPE FLOW CONTRIBUTES TO LARGE SCALE LIFT. WEAKLY ORGANIZED AND MOSTLY DIURNALLY DRIVEN MULTICELLULAR CONVECTION SHOULD POSE SOME THREAT FOR ISOLATED DAMAGING WINDS AND PERHAPS HAIL. BUT GIVEN THE HIGH PWAT AIR MASS...HEAVY RAINFALL APPEARS TO BE THE PRIMARY THREAT. ...LWR MS VALLEY TO FL... PERSISTENT REMNANT BAROCLINIC ZONE...HEATING AND AMPLY MOIST BOUNDARY LAYER WILL CONTRIBUTE TO DIURNAL TSTMS FROM THE LWR MS VLY TO FL. DEEP LAYER SHEAR AND MID-LEVEL LAPSE RATES WILL BE MEAGER. THUS...MAINLY MULTICELL PULSE-TYPE OF SEVERE CAN BE EXPECTED GIVING LOCAL DAMAGING WIND GUSTS OR A BRIEF TORNADO/WATERSPOUT. ..RACY.. 08/13/2006  From swody2 at goshenarc.org Mon Aug 14 05:49:22 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 14 Aug 2006 01:49:22 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 140550 SWODY2 SPC AC 140549 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1249 AM CDT MON AUG 14 2006 VALID 151200Z - 161200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... FASTER/PROGRESSIVE FLOW WILL REMAIN CONFINED TO THE NRN AREAS WHILE BROAD UPPER RIDGE PERSISTS ACROSS THE SOUTH...GENERALLY EAST OF THE ROCKIES. A COUPLE OF DIFFICULT TO FORECAST SUBTROPICAL DISTURBANCES CONTINUE TO BE SUGGESTED BY THE LATEST GUIDANCE ALONG THE SRN PERIPHERY OF THE UPPER RIDGE. ONE OF THESE DISTURBANCES MOVES CLOSE TO...OR OVER...FL AND THE ERN GULF. THE OTHER SYSTEM DEVELOPS SLOWLY NWD ACROSS PARTS OF THE UPPER RIO GRANDE VALLEY. THE COLD FRONT SPREADING ACROSS THE OH VALLEY AND NORTHEAST DURING THE DAY 1 PERIOD WILL SETTLE INTO THE MID ATLANTIC..CNTRL/SRN APPALACHIANS...AND TN VALLEY AREAS BY EARLY TUESDAY. THIS BOUNDARY WILL CONTINUE TO WEAKEN AS STRONGER LARGE SCALE SUPPORT FOR UPWARD MOTION MOVES OVER THE NEW ENGLAND COASTAL WATERS. WEAK CONVERGENCE ALONG THE TRAILING BOUNDARY WILL DEVELOP INTO VERY MOIST AND POTENTIALLY UNSTABLE AIR MASS SWWD/WWD FROM VA TO THE LOWER MS VALLEY. ...LOWER MS VALLEY TO SRN APPALACHIANS TO SRN VA... FRONTAL CIRCULATION WILL DEVELOP INTO MOIST AND UNSTABLE AIR MASS AND PROMOTE THE DEVELOPMENT OF TSTMS...POSSIBLY INCREASING IN COVERAGE AND INTENSITY DURING THE DAY. GENERALLY WEAK FLOW AND LAPSE RATES PRECLUDE A HIGHER SEVERE RISK AT THIS TIME. A FEW STORM CLUSTERS...CELL MERGERS...AND LOCALLY STRONGER LOW LEVEL SHEAR COULD RESULT IN BRIEFLY INTENSE ACTIVITY NEAR THE DECAYING FRONT AND ALONG RESIDUAL/GULF AND SEA BREEZE BOUNDARIES. ISOLATED WET MICROBURSTS APPEAR POSSIBLE. ...SOUTHWEST... LOW LEVEL UPSLOPE FLOW IN WAKE OF RECENT FRONTAL INTRUSION/WIND SHIFT MAY AID TSTM DEVELOPMENT ACROSS PARTS OF NM/AZ THROUGH THE AFTERNOON. SUBTROPICAL MOISTURE PLUME ACROSS THE AREA...AND POSSIBILITY OF WEAK DISTURBANCES CHANNELED BETWEEN ANTICYCLONE TO THE EAST AND TROUGHING ACROSS THE WEST...WILL FURTHER SUPPORT THE DEVELOPMENT OF DEEP CONVECTION OVER THE SRN MOGOLLON PLATEAU AND HIGHER ELEVATIONS OF NM. GENERALLY WEAK LOW LEVEL ELY FLOW TOPPED BY SLY MID LEVEL FLOW WILL RESULT IN ADEQUATE DIRECTIONAL SHEAR FOR A FEW LONGER-LIVED UPDRAFTS CAPABLE OF ISOLATED DOWNBURST WINDS AND MARGINALLY SEVERE HAIL. ...NRN PLAINS... FAST FLOW WITHIN BUILDING RIDGE ACROSS THE PLAINS WILL EXIST ATOP STRONGLY HEATED AND MARGINALLY MOIST AIR MASS. ALTHOUGH MOST OF THE AREA IS EXPECTED TO REMAIN CAPPED...ISOLATED CONVECTION COULD BREACH THE CAP BY LATE IN THE DAY FROM ERN MT INTO ND. PERSISTENT WARM AIR ADVECTION AND DESTABILIZATION ON THE NOSE OF LOW LEVEL JET...COUPLED WITH LOW AMPLITUDE IMPULSES EMANATING FROM DEVELOPING WRN U.S. TROUGH...COULD SUSTAIN A COUPLE OF SEVERE STORMS WITH HAIL AND WIND POTENTIAL OVER THE NRN PLAINS THROUGH EARLY WEDNESDAY MORNING. ..CARBIN.. 08/14/2006  From swody2 at goshenarc.org Mon Aug 14 17:07:46 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 14 Aug 2006 13:07:46 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 141707 SWODY2 SPC AC 141706 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1206 PM CDT MON AUG 14 2006 VALID 151200Z - 161200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... SYNOPTIC PATTERN WILL BE CHARACTERIZED BY PROGRESSIVE NRN STREAM FLOW BELT...AND MESSY RIDGING WITH SOME WEAK/EMBEDDED SHORTWAVE PERTURBATIONS OVER S-CENTRAL/SERN STATES. STRONG SHORTWAVE TROUGH -- CURRENTLY ANALYZED OVER ONT AND UPPER GREAT LAKES -- IS FCST TO MOVE EWD ACROSS SRN QUE...NY AND NEW ENGLAND DURING DAY-2. ASSOCIATED SFC COLD FRONT IS FCST TO MOVE OFFSHORE MOST OF NEW ENGLAND AND MID-ATLANTIC REGION DURING MORNING/EARLY AFTERNOON HOURS...TRAILING SWWD ACROSS TN/NRN GA AND BECOMING QUASISTATIONARY OVER OK. MEANWHILE...HEIGHTS ARE FCST TO FALL ACROSS MUCH OF W COAST AND GREAT BASIN REGIONS...AHEAD OF SHORTWAVE TROUGH NOW EVIDENT IN MOISTURE CHANNEL IMAGERY INVOF 49N147W. THIS FEATURE IS PROGGED TO STRENGTHEN AND DIG SEWD...MOVING ONSHORE NRN CA LATE DAY-2 OR EARLY DAY-3. SWLY FLOW ALOFT -- POSSIBLY WITH ONE OR TWO WEAK/EMBEDDED PERTURBATIONS -- SHOULD DEVELOP OVER NRN ROCKIES AND NRN HIGH PLAINS BY 16/00Z...WHILE MIDLEVEL RIDGING SHIFTS EWD OVER DAKOTAS. ASSOCIATED LEE-SIDE PRESSURE FALLS ARE FCST AT SFC ACROSS PORTIONS NRN WY AND ERN MT...WITH SFC FRONTOGENESIS OVER PORTIONS NRN MT AND SRN SASK. ...NRN PLAINS... ISOLATED TO WIDELY SCATTERED TSTMS ARE POSSIBLE DURING AFTERNOON INTO EVENING ACROSS ERN MT AND/OR WRN DAKOTAS...SHIFTING EWD DURING EVENING. SOME OF THIS ACTIVITY MAY LAST THROUGH EVENING HOURS AND OVERNIGHT ALONG NOSE OF 30-40 KT LLJ...MOVING EWD TO NEWD ACROSS PORTIONS DAKOTAS. OCCASIONAL HAIL/GUSTS NEAR SVR LEVELS ARE POSSIBLE. AS RIDGING ALOFT MOVES OVER AND THEN E OF THIS AREA...TIGHTENING HEIGHT GRADIENT ALOFT AND LEE-SIDE PRESSURE FALLS IN LOW LEVELS WILL RESULT IN STRENGTHENING OF DEEP-LAYER VERTICAL SHEAR. FCST HODOGRAPHS SUGGEST MRGL POTENTIAL FOR SUPERCELLS...AND ASSOCIATED RISK OF HAIL. LACK OF MORE ROBUST LOW LEVEL MOISTURE WILL LIMIT BUOYANCY AND OVERALL TSTM COVERAGE...DESPITE STEEP MIDLEVEL LAPSE RATES APCHG DRY ADIABATIC. HOWEVER...WELL-MIXED SUBCLOUD LAYERS DURING AFTERNOON INTO EARLY EVENING...BEFORE NEAR-SFC LAYER COOLS SUBSTANTIALLY...WILL SUPPORT HAIL/GUSTS NEAR SVR LIMITS WITH ANY ACTIVITY THAT DOES DEVELOP. ...SERN CONUS... SUFFICIENT BUOYANCY...MOISTURE...HEATING AND WEAK AFTERNOON CINH ARE EXPECTED FOR SCATTERED TO LOCALLY NUMEROUS TSTMS. RICH BOUNDARY LAYER MOISTURE -- CHARACTERIZED BY SFC DEW POINTS UPPER 60S TO MID 70S F -- WILL BE COMMON ALONG AND S OF FRONT. A FEW MULTICELL CLUSTERS ARE POSSIBLE WITH FRONT AND OUTFLOW BOUNDARIES BEING PRIMARY FOCI. ISOLATED DAMAGING GUSTS ARE POSSIBLE...PRIMARILY DURING AFTERNOON INTO EARLY EVENING. WEAKNESS OF DEEP-LAYER FLOW AND VERTICAL SHEAR APPEAR TO PRECLUDE WELL ORGANIZED SVR THREAT. CONVERGENCE ALONG CAROLINAS/GA PORTION OF FRONT MAY BE REDUCED BY ISALLOBARIC INFLUENCES ON SFC WIND FIELDS RELATED TO LOW LEVEL DISTURBANCE NOW OVER BAHAMAS. REF NHC OUTLOOKS UNDER ABNT20 KNHC FOR LATEST INFO ON TROPICAL DEVELOPMENT POTENTIAL. CONVECTIVE POTENTIAL ALONG WRN SEGMENT OF FRONT -- ARKLATEX REGION TO LOWER MS VALLEY -- MAY BE ENHANCED BY LARGE SCALE ASCENT ASSOCIATED WITH PORTION OF WEAK/SUBTROPICAL UPPER LOW DRIFTING NEWD FROM W-CENTRAL TX. ...SWRN CONUS... TSTMS SHOULD DEVELOP OVER MUCH OF SRN NM AND SERN AZ...AS WELL AS FAR W TX...DURING AFTERNOON AND EVENING. ISOLATED GUSTS NEAR SVR LEVELS ARE POSSIBLE FROM MOST INTENSE TSTMS...HOWEVER POTENTIAL APPEARS TOO CONDITIONAL/MRGL TO WARRANT CATEGORICAL OUTLOOK ATTM. RICH LOW LEVEL MOISTURE FOR THIS REGION WILL PERSIST THROUGH DAY-2...WITH SFC DEW POINTS COMMONLY 60S F LOWER ELEVATIONS...AND 50S IN MOUNTAINS. THIS WILL SUPPORT TSTMS WITH WEAK CINH AND HEATING OF HIGHER TERRAIN...IN RELATIVELY CLOUD-FREE AREAS. ONE SIGNIFICANT LIMITING FACTOR MAY BE BROAD AREA OF CLOUDS WITH SOME EMBEDDED PRECIP...LEFT BEHIND BY AFTERNOON/OVERNIGHT ACTIVITY DAY-1. THIS WOULD DELAY/RESTRICT SFC HEATING BUT ALSO FOCUS SOME POTENTIAL FOR DEVELOPMENT ALONG DIFFERENTIAL HEATING ZONES. ..EDWARDS.. 08/14/2006  From swody2 at goshenarc.org Tue Aug 15 06:08:25 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 15 Aug 2006 02:08:25 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 150604 SWODY2 SPC AC 150603 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0103 AM CDT TUE AUG 15 2006 VALID 161200Z - 171200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF ERN MT AND ND... ...SYNOPSIS... NWRN U.S. UPPER TROUGH SHOULD EDGE EAST OVER THE NRN GREAT BASIN AND NRN ROCKIES DURING WEDNESDAY. A BELT OF MODEST /30-40KT/ WSWLY MID LEVEL FLOW WILL EXTEND FROM THE BASE OF THE TROUGH...ACROSS THE NRN PLAINS...AND THEN THROUGH A SHORT WAVE RIDGE AXIS FROM THE UPPER MS VALLEY TO GREAT LAKES. LOWER-AMPLITUDE DISTURBANCES ARE FORECAST TO EMANATE FROM THE LARGER SCALE TROUGH WITH VERY WEAK HEIGHT FALLS SPREADING ACROSS THE NRN PLAINS THROUGH WEDNESDAY NIGHT. IT IS ALSO POSSIBLE THAT A MORE SUBTLE SHORT WAVE IMPULSE...PERHAPS CONVECTIVELY ENHANCED...MAY EMERGE FROM SUBTROPICAL STREAM ACROSS THE SRN PLAINS AND AID LARGE SCALE BACKGROUND ASCENT OVER THE SRN AND CNTRL HIGH PLAINS...EWD TO THE MO VALLEY. MODELS CONTINUE TO INDICATE SUBTROPICAL GYRE WILL DRIFT INTO THE GULF WHILE A SMALLER SCALE LOW FORMS NEAR THE SOUTHEAST U.S. COAST. BOTH THESE FEATURES WILL BE TO THE SOUTH AND EAST OF A DECAYING SYNOPTIC FRONTAL BOUNDARY SITUATED FROM THE CAROLINAS TO THE DEEP SOUTH. ...NRN PLAINS... LOW LEVEL SLY FLOW AND MOISTURE TRANSPORT WILL STRENGTHEN ACROSS THE CNTRL AND NRN PLAINS THIS PERIOD IN RESPONSE TO ISALLOBARIC AND DIABATIC FORCING RESULTING FROM APPROACH OF ROCKIES TROUGH AND DIURNAL HEATING. IT IS LIKELY THAT A STRONG EML/CAP WILL ACT TO INHIBIT CONVECTIVE DEVELOPMENT ACROSS MUCH OF THE WARM SECTOR BUT AIR MASS ACROSS THE REGION SHOULD BECOME MODERATELY UNSTABLE GIVEN DEWPOINTS IN THE 60S AND TEMPERATURES IN THE UPPER 80S AND LOWER 90S. GIVEN STRONG CAP AND ONLY MARGINAL LARGE SCALE SUPPORT FOR ASCENT FROM LOW AMPLITUDE MID LEVEL IMPULSE...LATE DAY STORM INITIATION APPEARS MOST LIKELY NEAR AND NORTH OF WSW-ENE ORIENTED DEEP-LAYER BAROCLINIC ZONE...FROM MT INTO NCNTRL ND. ADDITIONAL TSTM ACTIVITY...IN LOWER CAPE ENVIRONMENT...APPEARS LIKELY FROM ERN ORE ACROSS PARTS OF ID AND WRN MT...CLOSER TO THE STRONGER FORCING AND AIDED BY OROGRAPHIC FORCING. ISOLATED HIGH-BASED CONVECTION MAY ALSO FORM WHERE CAP CAN BE LOCALLY OVERCOME NEAR LEE/THERMAL TROUGH OR DRYLINE FROM WRN/CNTRL SD...SSWWD INTO NEB. OVER ERN MT AND ND...INSTABILITY FLOWING FROM CAPPED ENVIRONMENT INTO FRONTAL AND POST-FRONTAL CONVECTION WILL LIKELY FUEL A FEW INTENSE STORM UPDRAFTS WHERE DEEP LAYER SHEAR WILL BE MORE THAN SUFFICIENT FOR CELL ROTATION AND HAIL PRODUCTION. IT IS POSSIBLE THAT OUTFLOW FROM THIS ACTIVITY WILL ENHANCE MESOSCALE FORCING ALONG THE LOW LEVEL BOUNDARY TO PROMOTE ADDITIONAL SURFACE-BASED STORMS OVER SRN/ERN SECTIONS OF ND. HAIL AND WIND THREAT MAY EVOLVE FROM THIS CONVECTION AND SPREAD EAST TOWARD PARTS OF WRN MN DURING THE NIGHT. ...CNTRL PLAINS TO MO VALLEY... WEAK QG-FORCING ATOP LEE TROUGH AND/OR RESIDUAL FRONTAL BOUNDARY BISECTING KS SHOULD PROMOTE AFTERNOON AND EVENING TSTM DEVELOPMENT OVER THE PLAINS. GENERALLY WEAK DEEP-LAYER SHEAR AND LAPSE RATES IN WARM MOIST/MOIST ENVIRONMENT SUGGEST ONLY ISOLATED AND MARGINAL HAIL/WIND POTENTIAL. HOWEVER...LOCALLY ENHANCED LOW LEVEL SHEAR AND INSTABILITY NEAR THE RESIDUAL FRONT MIGHT SUPPORT A SUPERCELL OR TWO FROM CNTRL KS NWD TO SRN NEB. IT IS POSSIBLE THAT A FEW STRONG TSTMS MAY PERSIST IN WAA REGIME ACROSS KS/NEB INTO THE NIGHT. THIS ACTIVITY MAY CONGEAL INTO A SMALL MCS AND BE SUSTAINED ACROSS THE MO VALLEY AS NOCTURNAL LLJ INTENSIFIES OVERNIGHT. ..CARBIN.. 08/15/2006  From swody2 at goshenarc.org Tue Aug 15 17:30:08 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 15 Aug 2006 13:30:08 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 151730 SWODY2 SPC AC 151729 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1229 PM CDT TUE AUG 15 2006 VALID 161200Z - 171200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... PROGRESSIVE NRN STREAM SHORTWAVE PATTERN WILL CONTINUE THROUGH PERIOD IN MID/UPPER LEVELS...DOWNSTREAM FROM AMPLIFYING TROUGH OVER PACIFIC NW. BROAD FETCH OF SWLY FLOW ALOFT...FROM NRN GREAT BASIN ACROSS NRN ROCKIES AND NRN HIGH PLAINS...WILL CONTRIBUTE TO LEE-SIDE PRESSURE FALLS AND LOW LEVEL WAA ACROSS CENTRAL/NRN HIGH PLAINS. BY 17/00Z...QUASISTATIONARY FRONTAL ZONE IS EXPECTED FROM SRN MB SWWD INTO CENTRAL WY. SFC FRONTAL ZONE -- STRONGLY MODULATED BY CONVECTIVE OUTFLOWS -- SHOULD LINGER FROM VA/NC TIDEWATER REGION SWWD ACROSS MS...BECOMING DIFFUSE NWWD ACROSS CENTRAL PLAINS. FARTHER S...SHORTWAVE TROUGH -- EVIDENT IN MOISTURE CHANNEL IMAGERY OVER NWRN MEX -- MAY LIFT NEWD ACROSS PORTIONS SRN ROCKIES AND/OR SRN HIGH PLAINS DURING PERIOD. MEANWHILE...TROUGH NOW OVER NM SHOULD LIFT NEWD ACROSS PORTIONS NEB/IA. PROGS ARE VERY INCONSISTENT WITH SRN FEATURE...WHICH IS NOT SURPRISING GIVEN ITS ORIGIN IN RELATIVE VOID OF MEX UPPER AIR DATA. THEREFORE CONSIDERABLE UNCERTAINTY REMAINS WITH ITS POTENTIAL TRACK...AND BY EXTENSION...GEN THUNDER POTENTIAL WITHIN ASSOCIATED PLUME OF LARGE SCALE ASCENT. ...CENTRAL/NRN PLAINS... LOW LEVEL MOISTURE IS EXPECTED TO INCREASE WITH SWD EXTENT...REMAINING MRGL OVER NRN PLAINS WITH DEW POINTS UPPER 40S TO UPPER 50S F...BUT WITH 60S TO LOW 70S OVER PORTIONS KS. BY CONTRAST...MID/UPPER LEVEL LAPSE RATES AND DEEP-LAYER SHEAR GENERALLY SHOULD INCREASE WITH NWRN EXTENT. CAP MAY WEAKEN DURING MID-LATE AFTERNOON SUFFICIENTLY FOR TSTMS OVER PORTIONS CENTRAL/ERN MT...DAKOTAS...NEB AND WRN/NRN KS. BOUNDARY LAYER FORCING FOR SFC-BASED CONVECTION APPEARS RATHER ILL-DEFINED S OF FRONT AND AWAY FROM POSTFRONTAL OROGRAPHIC LIFT ZONE IN MT. CONVERGENCE IS NOT EXPECTED TO BE PARTICULARLY STRONG ALONG FRONT...WHILE MOISTURE WILL BE IN QUESTION OVER OROGRAPHIC LIFT REGION. GIVEN THESE OFFSETS IN MOST FAVORABLE INGREDIENTS FOR SVR POTENTIAL...AND CONVECTIVE SPATIAL/COVERAGE UNCERTAINTIES...WILL KEEP UNCONDITIONAL SVR PROBABILITIES BELOW CATEGORICAL OUTLOOK CRITERIA ATTM. ...SERN STATES... WIDELY SCATTERED TSTMS -- IN PULSE FORM AND IN MULTICELLULAR CLUSTERS -- ARE EXPECTED ACROSS MUCH OF REGION ALONG AND S OF FRONT. CONVECTIVE POTENTIAL ACROSS COASTAL PLAIN OF CAROLINAS MAY BE INFLUENCED BY POTENTIAL TROPICAL DEVELOPMENT ASSOCIATED WITH AREA OF LOW LEVEL LOW PRESSURE NOW EVIDENT OVER ATLANTIC SE OF SC COAST. SEE NHC OUTLOOKS UNDER WMO HEADER ABNT20 KNHC FOR MORE INFO. MORE ROBUST DIURNAL DESTABILIZATION IS FCST FROM GA SWWD ACROSS SRN PORTIONS MS/AL/LA...WHERE STRONG SFC HEATING AND DEW POINTS 70S F WILL YIELD MODERATE-STRONG BUOYANCY. LOCALIZED POTENTIAL FOR STG-SVR GUSTS MAY DEVELOP...ESPECIALLY WITH TSTMS DEVELOPING INVOF BOUNDARIES RELATED TO OUTFLOW...SEA BREEZE AND RESIDUAL SYNOPTIC FRONT. ...INTERIOR NWRN CONUS... STRONG LARGE SCALE ASCENT/COOLING WILL OCCUR AHEAD OF DIGGING MID/UPPER LEVEL TROUGH...RESULTING IN STEEPENED LOW/MIDDLE LEVEL LAPSE RATES...IN TANDEM WITH DAYTIME SFC HEATING. THIS SHOULD RESULT IN WEAK AFTERNOON CINH AND POTENTIAL FOR WIDELY SCATTERED TSTMS TO DEVELOP...IN ENVIRONMENT OF AT LEAST MRGL BOUNDARY LAYER MOISTURE. STRONGEST ACTIVITY MAY PRODUCE HAIL AND/OR GUSTS NEAR SEVERE LEVELS. ..EDWARDS.. 08/15/2006  From swody2 at goshenarc.org Wed Aug 16 06:07:25 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 16 Aug 2006 02:07:25 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 160605 SWODY2 SPC AC 160604 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0104 AM CDT WED AUG 16 2006 VALID 171200Z - 181200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE NRN PLAINS... ...SYNOPSIS... POSITIVE TILT UPPER TROUGH WILL MOVE OVER THE INTERIOR NORTHWEST AND NRN ROCKIES THIS PERIOD WITH ONE OR MORE SMALLER SCALE DISTURBANCES EMANATING FROM THIS FEATURE AND TRANSLATING DOWNSTREAM WITHIN BAND OF FAST WSWLY MID LEVEL FLOW FROM MT/WY TO THE DAKOTAS/MN. EXPANSIVE ANTICYCLONE WILL COVER MUCH OF THE SRN U.S FROM THE DESERT SOUTHWEST TO THE MID ATLANTIC COAST WITH SEVERAL SMALLER SCALE MID LEVEL VORTICES ROTATING AROUND THE EDGES OF THE MID/UPPER LEVEL HIGH. ONE OR TWO OF THESE WEAKER DISTURBANCES WILL DEVELOP NEWD ACROSS THE SRN/CNTRL PLAINS TO THE MO AND MID MS VALLEY AREAS THROUGH EARLY FRIDAY. ...NRN PLAINS... A WSW-ENE ORIENTED DEEP-LAYER BAROCLINIC ZONE IS FORECAST TO EXIST ACROSS THE DAKOTAS ON THE SRN EDGE OF FASTER WSWLY FLOW ALOFT. THIS BOUNDARY WILL PROVIDE A FOCUS FOR TSTM DEVELOPMENT THROUGH THE PERIOD AS SHORT WAVE TROUGHS TRAVERSE THE REGION AND ENHANCE SYNOPTIC/MESOSCALE FORCING FOR ASCENT. STRONG EML/CAP ACROSS THE WARM SECTOR SUGGESTS PRIMARY DEVELOPMENT MAY OCCUR ON AND NORTH OF THE BOUNDARY. INFLOW OF WARM AND UNSTABLE AIR FROM CAPPED AIR MASS INTO THE FRONTAL ZONE SHOULD FUEL ROBUST STORMS IN STRONGLY SHEARED FLOW. THIS ACTIVITY WILL BE CAPABLE OF PRODUCING HAIL AND HIGH WINDS AS IT DEVELOPS EWD/SEWD FROM ERN MT/WRN DAKOTAS TO THE ERN DAKOTAS THROUGH THURSDAY NIGHT. ...CNTRL PLAINS... RESIDUAL BOUNDARY ACROSS THE CNTRL PLAINS /NRN KS TO IA/ WILL ACT AS A WEAK WARM FRONT ACROSS THE REGION THROUGH THURSDAY. PARTS OF THE BOUNDARY MAY BE LOCALLY REINFORCED THROUGH CONVECTIVE OUTFLOW AND/OR DIFFERENTIAL HEATING. WARM AND UNSTABLE AIR MASS ACROSS THE REGION WILL FUEL STRONG TO ISOLATED SEVERE TSTM DEVELOPMENT WHERE CAP CAN BE OVERCOME BY HEATING AND SYNOPTIC/MESOSCALE FORCING NEAR THE BOUNDARY. SOME SUPPORT FOR LARGE SCALE LIFT MAY BE PROVIDED BY THE PASSAGE OF SUBTLE SHORT WAVE IMPULSES ROTATING AROUND AND OUT OF THE SUBTROPICAL RIDGE. A CONVECTIVE COMPLEX MAY EVOLVE FROM AREAS OF AFTERNOON AND EVENING CONVECTION. AS ACTIVITY COALESCES AND GROWS UPSCALE...INTENSIFYING LOW LEVEL JET WITHIN PLAINS WARM CONVEYOR BELT MAY SUSTAIN A STORM COMPLEX THROUGH THE NIGHT FROM THE MO VALLEY EWD TO THE MID/UPPER MS VALLEY. ..CARBIN.. 08/16/2006  From swody2 at goshenarc.org Wed Aug 16 17:32:03 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 16 Aug 2006 13:32:03 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 161731 SWODY2 SPC AC 161731 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1231 PM CDT WED AUG 16 2006 VALID 171200Z - 181200Z ...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS NRN PLAINS... ...SYNOPSIS... PRONOUNCED MID-UPPER LEVEL TROUGH -- NOW MOVING INLAND PACIFIC NW -- IS EXPECTED TO SHIFT FARTHER EWD ACROSS INTERIOR NW TO NRN ROCKIES DURING DAY2...AS ASSOCIATED SWLY FLOW ALOFT AND MIDLEVEL SPEED MAX SPREAD OVER NRN HIGH PLANS AND ND. MEANWHILE...WEAK SRN STREAM PERTURBATION -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY OVER NWRN MEX S OF SWRN NM -- IS FCST TO LIFT NEWD ACROSS SRN/CENTRAL HIGH PLAINS DURING THIS PERIOD. AT SFC...COLD FRONT IS EXPECTED TO MOVE SEWD FROM CANADIAN HIGH PLAINS AND MT...ACROSS DAKOTAS AND FAR NRN MN. FRONTAL-WAVE CYCLONE SHOULD FORM INVOF BLACK HILLS...IN ADVANCE OF APCHG MID-UPPER TROUGH. AS THIS OCCURS...COLD FRONT SHOULD DECELERATE ACROSS NRN SD/SRN ND AREA AND REMAIN QUASISTATIONARY UNTIL PASSAGE OF SFC LOW LATE DAY-2 AND EARLY DAY-3. MEANWHILE...WARM FRONTAL ZONE NOW OVER SRN PLAINS IS FCST TO SHIFT/REDEVELOP NNEWD TO LOWER MO VALLEY. ...NRN PLAINS... SCATTERED TSTMS ARE EXPECTED TO DEVELOP FROM MID-LATE AFTERNOON ONWARD...WITH EVOLUTION TO ORGANIZED MCS POSSIBLE AFTER DARK ACROSS PORTIONS DAKOTAS INTO WRN MN. DAMAGING GUSTS AND LARGE HAIL WILL BE POSSIBLE. TORNADO POTENTIAL IS MORE CONDITIONAL/MRGL...AND DEPENDENT ON MESOSCALE TO STORM-SCALE BOUNDARY RELATED PROCESSES. FORECAST SOUNDINGS ACROSS THIS REGION SUGGEST FAVORABLE VERTICAL SHEAR PROFILES ALONG AND N OF FRONT FOR SUPERCELLS...WITH STRONG DIRECTIONAL VEERING CONTRIBUTING TO EFFECTIVE SHEARS AOA 50 KT. THERMODYNAMICS SHOULD BECOME INCREASINGLY FAVORABLE THROUGH AFTERNOON ALSO...AS SFC DIABATIC HEATING AND FRONTAL LIFT REDUCE CINH IN FAVORABLY MOIST BOUNDARY LAYER ENVIRONMENT. MOIST ADVECTION AND EVAPOTRANSPIRATIVE EFFECTS SHOULD RESULT IN AXIS OF SFC DEW POINTS MID 60S ALONG OR JUST N OF FRONT...COMBINING WITH STEP MIDLEVEL LAPSE RATES TO SUPPORT MLCAPES OVER 2000 J/KG OVER CENTRAL/WRN DAKOTAS. ISOLATED STG-SVR STMS ALSO WILL BE POSSIBLE WWD ACROSS MUCH OF MT IN POST-FRONTAL ZONE OF BOUNDARY LAYER UPSLOPE FLOW...JUXTAPOSED WITH COOLING ALOFT AND AT LEAST MRGL MOISTURE. SVR POTENTIAL IS EXPECTED TO BE CONCENTRATED IN FAIRLY DENSE FASHION INVOF BOUNDARY LAYER MOIST AXIS FROM AFTERNOON THROUGH EVENING HOURS. MAIN UNCERTAINTY ATTM IS POSITIONING OF FRONT AND MOIST AXIS ON MESO BETA SCALE. PROBABILITIES THEREFORE MAY NEED TO BE BOOSTED WITHIN BROADER 15 PERCENT AREA...ONCE THOSE ELEMENTS BECOME MORE CERTAIN IN SUCCEEDING OUTLOOKS. ...CENTRAL PLAINS... VERTICAL SHEAR IS FCST TO DIMINISH WITH SWD EXTENT FROM DAKOTAS FRONTAL ZONE. HOWEVER...PLUME OF FAVORABLE LOW LEVEL MOISTURE WILL BE IN PLACE FROM SRN HIGH PLAINS NNEWD ACROSS MUCH OF CENTRAL PLAINS REGION...ALONG WITH WEAK AFTERNOON CINH IN RELATIVELY CLOUD-FREE AREAS. MULTICELL AND PULSE STORMS WILL PREDOMINATE...MOST INTENSE OF WHICH MAY PRODUCE GUSTS NEAR SEVERE LEVELS DURING LATE AFTERNOON/EARLY EVENING. ...IA/IL... SEVERAL DETERMINISTIC PROGS ARE CONSISTENT IN DEVELOPMENT OF TSTM CLUSTER ALONG OR N OF SFC WARM FRONT DURING EVENING...WHICH WOULD MOVE SLOWLY ESEWD ACROSS MS RIVER WITH SOME POTENTIAL FOR DAMAGING GUSTS AND MRGL HAIL. AIR MASS IN THIS REGION WILL BE CHARACTERIZED BY REGIONAL MOISTURE MAXIMUM...ASSOCIATED BOTH WITH PRIOR MOIST ADVECTION AND WITH EVAPOTRANSPIRATION AT SFC. THIS AREA ALSO WILL BE WITHIN WAA/MOISTURE TRANSPORT REGIME...NEAR NOSE OF 30 KT NOCTURNAL LLJ. THIS WILL SUPPORT PERSISTENCE OF ANY LATE AFTERNOON/EARLY EVENING DEVELOPMENT OVERNIGHT. RELATIVELY WEAK MIDLEVEL FLOW WILL LIMIT BULK SHEAR...AND THERE IS SOME CONCERN THAT CAP MAY NOT BREAK DIURNALLY INVOF WARM FRONT. THEREFORE SVR PROBABILITIES ARE KEPT MRGL ATTM. ..EDWARDS.. 08/16/2006  From swody2 at goshenarc.org Thu Aug 17 06:08:03 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Thu, 17 Aug 2006 02:08:03 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 170605 SWODY2 SPC AC 170604 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0104 AM CDT THU AUG 17 2006 VALID 181200Z - 191200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE DAKOTAS AND NERN NEB... ...SYNOPSIS... UPPER TROUGH CURRENTLY MOVING INTO THE INTERIOR NORTHWEST WILL BRING MODEST MID LEVEL HEIGHT FALLS FROM THE NRN PLAINS TO UPPER MS VALLEY THROUGH EARLY SATURDAY. THIS DISTURBANCE WILL CONTINUE TO DAMPEN THE NRN PERIPHERY OF THE LARGE UPPER HIGH BLANKETING MUCH OF THE CNTRL AND SRN U.S...AND WILL INDUCE FRONTAL WAVE DEVELOPMENT ACROSS SD FRIDAY AFTERNOON. COLD FRONT ACCOMPANYING UPPER TROUGH AND ASSOCIATED SURFACE WAVE WILL SPREAD SOUTH ACROSS THE CNTRL PLAINS THROUGH FRIDAY NIGHT AS UPPER TROUGH AND SURFACE LOW TRACK GENERALLY EAST TOWARD THE UPPER MS VALLEY. NAM-WRF AND GFS MODELS DIFFER SLIGHTLY ON THE TIMING OF THE NRN STREAM FEATURES WITH THE GFS INDICATING A FASTER EWD/SEWD MOVEMENT TO THE UPPER TROUGH AND COLD FRONT THROUGH EARLY SATURDAY. THIS OUTLOOK IS FURTHER COMPLICATED BY A SERIES OF MORE SUBTLE SUBTROPICAL SRN STREAM DISTURBANCES IN WEAKER FLOW AROUND THE NRN EDGE OF THE DEEP-LAYER ANTICYCLONE. A LEADING FEATURE IN THIS WAVE TRAIN WAS ALREADY AIDING MESOSCALE CONVECTIVE COMPLEX OVER THE MO VALLEY ATTM. ADDITIONAL IMPULSES ARE FORECAST TO EVOLVE AND EMANATE FROM HIGH PLAINS CONVECTION OVER THE NEXT DAY OR SO. THESE WEAK DISTURBANCES WILL SPREAD EAST AND ENHANCE ASCENT ATOP A QUASI-STATIONARY WARM FRONT FROM MO/IA...ACROSS THE MIDWEST...TO THE OH VALLEY THROUGH EARLY SATURDAY. ...DAKOTAS/NEB... STRONGER FORCING ASSOCIATED WITH UPPER TROUGH AND COLD FRONT WILL SPREAD ESEWD OVER THE NRN PLAINS DURING THE DAY AND ENHANCE LIFT ACROSS INCREASINGLY UNSTABLE AIR MASS. MODELS APPEAR TO BE OVERFORECASTING LOW LEVEL MOISTURE ACROSS THE AREA BUT MLCAPE VALUES TO 2000 J/KG APPEAR POSSIBLE OVER NEB/SD GIVEN MID TO UPPER 60S DEWPOINTS AND TEMPERATURES IN THE 80S TO 90S. SUFFICIENT SHEAR AND INSTABILITY ARE FORECAST ACROSS SERN ND AND SD FOR SUPERCELLS WITH HAIL. TORNADO POTENTIAL MAY INCREASE SHOULD THIS CONVECTION REMAIN DISCRETE AND PERSIST NEAR SURFACE WAVE. ACROSS NEB...SHEAR WILL INITIALLY BE WEAKER BUT POTENTIAL INSTABILITY IS FORECAST TO BE GREATER. HEATING AND LARGE SCALE LIFT WILL ACT TO OVERCOME THE CAP ACROSS THIS AREA AND SHOULD RESULT IN SCATTERED TSTM DEVELOPMENT THROUGH EVENING. ROBUST MULTICELL CONVECTION SHOULD POSE SOME THREAT OF LARGE HAIL AND LOCAL DOWNBURST WINDS BEFORE COLD FRONT MOVES ACROSS THE REGION OVERNIGHT. ...MO/IA EAST TO OH VALLEY... AN MCS OR TWO MAY BE ONGOING AT THE START OF THE PERIOD WITHIN PLAINS WARM CONVEYOR BELT FROM MO VALLEY EAST ACROSS THE MS VALLEY. CONVECTION MAY REGENERATE OR CONTINUE TO SPREAD EAST ACROSS THE MIDWEST THROUGH THE DAY SUSTAINED BY MCVS/SHORT WAVE TROUGHS AND PERSISTENT WARM AIR ADVECTION ON THE EDGE OF THE STRONGER CAP. POCKETS OF GREATER MID LEVEL FLOW ASSOCIATED WITH MCVS/SUBTLE SHORT WAVES...COUPLED WITH AREAS OF STRONGER DESTABILIZATION...COULD SUPPORT CLUSTERS OF SEVERE STORMS WITH WIND AND HAIL. UNCERTAINTIES WITH RESPECT TO TIMING AND AMPLITUDE OF MID LEVEL IMPULSES...CAP STRENGTH...LOCATION OF MCS OUTFLOW...AND STRENGTH OF SHEAR...ALL PLAY INTO KEEPING SEVERE PROBABILITIES LOW AT THIS TIME. ..CARBIN.. 08/17/2006  From swody2 at goshenarc.org Thu Aug 17 17:33:04 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Thu, 17 Aug 2006 13:33:04 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 171732 SWODY2 SPC AC 171731 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1231 PM CDT THU AUG 17 2006 VALID 181200Z - 191200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE MID MO VALLEY REGION EWD INTO THE MIDWEST/OH VALLEY... ...SYNOPSIS... LARGE UPPER RIDGE WILL PREVAIL ACROSS MUCH OF THE ERN 2/3 OF THE CONUS...WHILE MAIN SHORT-WAVE TROUGH MOVES EWD FROM THE NRN ROCKIES INTO THE NRN PLAINS ALONG NRN PERIPHERY OF RIDGE. ADDITIONALLY...SEVERAL SMALLER-SCALE VORTICITY MAXIMA ARE EXPECTED TO SHIFT EWD ACROSS THE PLAINS/MIDWEST...AHEAD OF MAIN SHORT-WAVE TROUGH. AT THE SURFACE...COLD FRONT INITIALLY FORECAST FROM THE UPPER GREAT LAKES INTO THE CENTRAL ROCKIES IS EXPECTED TO WEAKEN WITH TIME AS IT SHIFTS EWD/SEWD. RESULTING SURFACE PATTERN SHOULD BECOME INCREASINGLY ILL-DEFINED...EXTENDING FROM THE PLAINS EWD INTO THE MIDWEST/OH VALLEY REGION. ...MID MO/MID MS VALLEY REGIONS INTO THE OH VALLEY... LARGE AREA OF WEAK WARM ADVECTION IS FORECAST ACROSS THIS REGION...AS UPPER HEIGHTS FALL AHEAD OF ADVANCING SHORT-WAVE TROUGH. SEVERAL CLUSTERS OF CONVECTION SHOULD BE ONGOING AT THE START OF THE PERIOD...WHICH COMBINED WITH THE INCREASINGLY ILL-DEFINED SURFACE PATTERN SUGGEST A RATHER COMPLEX SEVERE WEATHER FORECAST. IN GENERAL...SUFFICIENT INSTABILITY AND MARGINAL SHEAR ARE ANTICIPATED INVOF BAROCLINIC ZONE...WHILE STRONGER SHEAR REMAINS N OF THE WARM SECTOR WITHIN THE COOLER AIR AND CAPPING INVERSION PREVAILS WITHIN WARM SECTOR AWAY FROM SURFACE BOUNDARIES. GREATEST THREAT APPEARS TO EXIST ACROSS THE MID MO VALLEY REGION...AS LOW-LEVEL CONVERGENCE INCREASES AHEAD OF APPROACHING SHORT-WAVE FEATURE DURING THE AFTERNOON. EXPECT STORMS TO DEVELOP INVOF WEAKENING SURFACE BOUNDARY -- AND PERHAPS ALONG REMNANT OUTFLOWS...WHERE SUFFICIENT INSTABILITY BUT MARGINAL SHEAR SUGGEST MULTICELL/WEAK SUPERCELL STORMS CAPABLE OF HAIL AND/OR LOCALLY-DAMAGING WINDS. LESSER SEVERE THREAT SHOULD EXTEND EWD INTO THE MIDWEST/OH VALLEY...WHERE WEAKER SHEAR IS FORECAST ALONG REMNANT WARM FRONT/BAROCLINIC ZONE. OVERNIGHT...MODEST SWLY LOW-LEVEL JET IS FORECAST TO DEVELOP ACROSS MO AND VICINITY...WHICH SHOULD SUPPORT A CONTINUATION OF CONVECTION -- LIKELY IN THE FORM OF ONE OR MORE MCS. OVERALL HOWEVER...DIURNALLY-STABILIZING AIRMASS SUGGESTS A SLOWLY DECREASING SEVERE THREAT THROUGH THE END OF THE PERIOD. ..GOSS.. 08/17/2006  From swody2 at goshenarc.org Fri Aug 18 05:54:13 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Fri, 18 Aug 2006 01:54:13 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 180554 SWODY2 SPC AC 180553 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1253 AM CDT FRI AUG 18 2006 VALID 191200Z - 201200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... DOMINANT UPPER RIDGE WILL BE SUPPRESSED INTO THE SRN U.S. SATURDAY AS SHORTWAVE TROUGH DIGS SEWD INTO THE GREAT LAKES REGION. IN THE WAKE OF THIS FEATURE...SFC PRESSURES WILL RISE MARKEDLY ACROSS THE CNTRL PLAINS/MS VALLEY FORCING A COLD FRONT SOUTH OF ANY MEANINGFUL FLOW ALOFT INTO THAT REGION MOSTLY DOMINATED BY LARGE SCALE UPPER RIDGING. ...OH VALLEY/TN VALLEY... WEAK HEIGHT FALLS WILL SPREAD ACROSS THE GREAT LAKES INTO PORTIONS OF THE OH VALLEY DURING THE DAY2 PERIOD...COINCIDENT WITH FRONTAL PASSAGE FROM UPSTATE NY...SWWD INTO SRN IL BY EARLY EVENING. TROPOSPHERIC MOISTURE IS EXPECTED TO REMAIN QUITE HIGH ALONG/AHEAD OF FRONTAL ZONE WHERE PRECIPITABLE WATER VALUES MAY EXCEED 2 INCHES. AS EXPECTED...FORECAST SOUNDINGS ACROSS THIS REGION SUGGEST WEAK LAPSE RATES AND MOIST PROFILES ALONG ADVANCING COLD FRONT. DUE TO MOIST PROFILES IT APPEARS ANY ASCENT AHEAD OF SHORTWAVE WILL PROVE EFFICIENT IN GENERATING CLOUDS AND THUNDERSTORMS. AIRMASS SHOULD BE MOST BUOYANT ALONG AN E-W AXIS SOUTH OF STRONGER HEIGHT FALLS ACROSS THE TN VALLEY REGION. AS A RESULT...IT APPEARS THUNDERSTORMS THAT DEVELOP ACROSS PORTIONS OF KY INTO NRN TN WILL EVOLVE WITHIN A MORE FAVORABLE THERMODYNAMIC ENVIRONMENT FOR LOCALLY STRONG WIND GUSTS. EVEN SO ORGANIZED SEVERE THREAT APPEARS LIMITED AT THIS TIME...DESPITE THE LIKELIHOOD THAT ORGANIZED CONVECTION AND WIDESPREAD THUNDERSTORMS SHOULD EVOLVE ALONG COLD FRONT. ...SRN HIGH PLAINS/SRN ROCKIES... NELY BOUNDARY LAYER FLOW WILL INCREASE ACROSS THE SRN HIGH PLAINS INTO ERN NM DURING THE PERIOD AS SFC RIDGE BUILDS SWWD ACROSS KS INTO THE TX PANHANDLE. CONVECTION WILL LIKELY DEVELOP WITHIN WEAK UPSLOPE ENVIRONMENT WHERE DEEP LAYER SHEAR WILL BE NEGLIGIBLE BENEATH UPPER RIDGE. GUSTY WINDS OR PERHAPS SMALL HAIL MAY ACCOMPANY STRONGER STORMS ACROSS THIS REGION. ADDITIONALLY...ISOLATED STORMS THAT DEVELOP WITHIN WEAKLY CONVERGENT FRONTAL ZONE INTO OK COULD GENERATE GUSTY WINDS AS WELL. THIS REGION WILL BE SOMEWHAT MORE SUPPORTIVE OF MICROBURSTS DUE TO STEEP LOW LEVEL LAPSE RATES AND DRY SUB CLOUD AIRMASS. ..DARROW.. 08/18/2006  From swody2 at goshenarc.org Tue Aug 22 17:31:40 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 22 Aug 2006 13:31:40 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 221730 SWODY2 SPC AC 221729 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1229 PM CDT TUE AUG 22 2006 VALID 231200Z - 241200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE UPPER MS VALLEY TO LAKE MI... ...SYNOPSIS... A SERIES OF SHORT WAVE TROUGHS WILL TRANSLATE THROUGH MEAN UPPER RIDGE ACROSS THE NRN HIGH PLAINS AND NRN PLAINS THIS PERIOD AND DRIVE EPISODES OF STRONG TO SEVERE TSTM DEVELOPMENT. THE LEADING FEATURE TO RESULT IN MCS DEVELOPMENT ACROSS ERN DAKOTAS/MN THROUGH THE DAY 1 PERIOD WAS CURRENTLY SPREADING ACROSS MT. THIS IMPULSE WILL CREST THE UPPER RIDGE ACROSS THE NRN PLAINS LATE THIS EVENING BEFORE SLIDING SEWD ACROSS THE UPPER MS VALLEY THROUGH EARLY WEDNESDAY. A STRONGER TROUGH IS FORECAST TO MOVE INLAND ACROSS THE PACIFIC NORTHWEST DURING DAY 2. THIS TROUGH WAS CURRENTLY MOVING TOWARD THE COAST OF NRN CA AND IS EXPECTED TO PRODUCE RELATIVELY STRONG HEIGHT FALLS ACROSS MT/WY AREA BY LATE IN THE DAY 2 PERIOD...EARLY THURSDAY. RIDGING...SURFACE AND ALOFT...IS EXPECTED TO KEEP MOSTLY TRANQUIL CONDITIONS ACROSS MUCH OF THE CENTER OF THE CONUS WHILE DEEP TROPICAL MOISTURE REMAINS SITUATED ACROSS THE SOUTHERN STATES FROM AZ TO FL. ...UPPER MS VALLEY TO LAKE MI... STRONG MCS EXPECTED TO BE ONGOING ACROSS MN/WRN WI WEDNESDAY MORNING BASED ON LATEST SHORT-RANGE DETERMINISTIC AND ENSEMBLE GUIDANCE. THIS SYSTEM WILL BE SUPPORTED BY STRONG LOW LEVEL WARM AIR AND MOISTURE ADVECTION ON THE NOSE OF SWLY LOW LEVEL JET. LEADING EDGE OF THIS DEEP CONVECTION WILL TRANSLATE INTO INCREASINGLY STABLE AIR MASS ACROSS NRN WI AND THE U.P. OF MI. HOWEVER...FLANKING PORTION OF THE MCS AND RESULTANT OUTFLOW WILL SETTLE INTO INCREASINGLY UNSTABLE AIR MASS ACROSS SRN MN AND SRN WI DURING THE AFTERNOON AND ACT TO REINFORCE THE QUASISTATIONARY WARM FRONT ACROSS THESE AREAS. MODELS INDICATE THAT LIFT AND DESTABILIZATION ALONG THE OUTFLOW BOUNDARY/WARM FRONT WILL BE SUFFICIENT FOR ADDITIONAL CONVECTIVE DEVELOPMENT DURING THE DAY. EXPECT SEVERE STORM POTENTIAL TO INCREASE AS THIS ACTIVITY TAPS STRENGTHENING INSTABILITY. PRESENCE OF STRONG VERTICAL SPEED AND DIRECTIONAL SHEAR ACROSS THE REGION WILL FURTHER SUPPORT ORGANIZED/PERSISTENT UPDRAFTS CAPABLE OF PRODUCING VERY LARGE HAIL AND HIGH WINDS. INITIAL ACTIVITY MAY BE ROOTED SLIGHTLY ABOVE CAPPED BOUNDARY LAYER WITH STRONG WARM SECTOR HEATING POSSIBLY PROMOTING MORE SURFACE-BASED DEVELOPMENT NEAR THE WARM FRONT BY AFTERNOON. IF THIS CAN OCCUR...MODEST LOW LEVEL DIRECTIONAL SHEAR/HELICITY COUPLED WITH MAGNITUDE OF FORECAST INSTABILITY MAY ENHANCE TORNADO POTENTIAL FOR ANY DISCRETE CELLS TRACKING SEWD NEAR THE FRONT. CURRENT INDICATIONS SUGGEST THAT THIS POTENTIAL MAY REMAIN ISOLATED/BRIEF GIVEN STRENGTH OF CAP AND LACK OF STRONGER FORCING. ...NRN HIGH PLAINS LATE... STRONG FORCING FOR ASCENT IS EXPECTED TO EMERGE ACROSS MT/WRN ND LATER IN THE PERIOD AS UPPER TROUGH AND HEIGHT FALLS DEVELOP ACROSS THE REGION. LINEAR CONVECTIVE DEVELOPMENT IN LOW-CAPE HIGH-SHEAR ENVIRONMENT ALONG ADVANCING COLD FRONT OVER WRN/CNTRL MT COULD SUPPORT SOME LATE NIGHT TSTMS WITH ISOLATED DAMAGING WINDS. FARTHER EAST...FROM ERN MT INTO ND...LOW LEVEL ELY FLOW NORTH OF DEVELOPING LEE-SIDE LOW MIGHT SUSTAIN MOIST UPSLOPE FLOW WITH POTENTIAL FOR MODEST INSTABILITY AND STRONG FORCING PROVIDING FOR A FEW SEVERE STORMS WITH HAIL/WIND INTO EARLY THURSDAY MORNING. ..CARBIN.. 08/22/2006  From swody2 at goshenarc.org Wed Aug 23 05:59:35 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 23 Aug 2006 01:59:35 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 230558 SWODY2 SPC AC 230557 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1257 AM CDT WED AUG 23 2006 VALID 241200Z - 251200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE NRN/CNTRL PLAINS TO THE UPPER GREAT LAKES... DEEP CONVECTION SHOULD READILY DEVELOP ACROSS MUCH OF THE NRN PLAINS INTO THE UPPER MS VALLEY REGION THURSDAY AHEAD OF SHORTWAVE TROUGH AND UPPER HEIGHT FALLS. WHILE MODELS REMAIN CONSISTENT IN EJECTING SHORTWAVE ACROSS THE DAKOTAS BY EARLY EVENING...LOW LEVEL WARM ADVECTION MAY PROVE AS MUCH RESPONSIBLE FOR EXPECTED THUNDERSTORM DEVELOPMENT FROM ND INTO CNTRL MN...TO THE NORTH OF THE WELL DEFINED WARM FRONTAL ZONE. LATEST THINKING IS THUNDERSTORM CLUSTERS MAY EVOLVE EARLY IN THE PERIOD ACROSS WRN ND...POSSIBLY AN EXTENSION OF OVERNIGHT ACTIVITY THAT SPREADS ACROSS MT AHEAD OF UPPER SHORTWAVE. AN MCS MAY EVOLVE WITHIN STRONG ZONE OF FORCING AND PROPAGATE EWD...WELL TO THE NORTH OF E-W WIND SHIFT. HAIL IS THE MOST LIKELY SEVERE THREAT WITH THIS ELEVATED CONVECTION. WITH TIME BOUNDARY LAYER INSTABILITY SHOULD INCREASE NEAR THE WARM FRONT ACROSS SERN SD INTO SRN MN/NRN IA...IMMEDIATELY AHEAD OF SFC LOW. THIS ZONE IS THE MOST LIKELY REGION FOR BOUNDARY LAYER SUPERCELL DEVELOPMENT DURING THE LATE AFTERNOON HOURS. FORECAST SOUNDINGS SUGGEST CAP WILL HOLD MUCH OF THE DAY ACROSS THE WARM SECTOR...WITH SUSTAINED ASCENT NEAR THE FRONT EXPECTED TO WEAKEN THE INHIBITION SUFFICIENTLY FOR NEAR SFC-BASED UPDRAFTS AFTER 21Z. IF STORMS CAN INDEED DEVELOP ALONG THE WARM FRONT IT APPEARS EWD STORM MOTIONS WOULD PROVE FAVORABLE FOR SUSTAINED HIGHER HELICITY INFLOW...WITH THE POSSIBILITY FOR A FEW TORNADOES. OTHERWISE...AN EXPANDING ZONE OF WARM ADVECTION...ELEVATED THUNDERSTORMS SHOULD EVOLVE ACROSS CNTRL MN INTO WI DURING THE OVERNIGHT HOURS. TRAILING COLD FRONT WILL LIKELY AID IN THE INITIATION OF HIGH BASED MULTI-CELL...POSSIBLY SUPERCELLULAR...THUNDERSTORMS FROM CNTRL NEB INTO NWRN KS BY 00Z. THIS ACTIVITY SHOULD PROPAGATE SWD THROUGH THE CENTRAL PLAINS ENHANCED BY INCREASING LLJ ACROSS KS DURING THE OVERNIGHT HOURS. WIND AND SOME HAIL SHOULD BE THE PRIMARY THREATS WITH THIS ACTIVITY. ..DARROW.. 08/23/2006  From swody2 at goshenarc.org Wed Aug 23 17:53:17 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 23 Aug 2006 13:53:17 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 231746 SWODY2 SPC AC 231745 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1245 PM CDT WED AUG 23 2006 VALID 241200Z - 251200Z ...THERE IS A SLGT RISK OF SVR TSTMS NRN PLAINS TO UPPER MS VALLEY... ...SYNOPSIS... STRONG SHORT WAVE TROUGH WAS CURRENTLY MOVING ACROSS THE PACIFIC NORTHWEST AND WILL TRACK EAST ACROSS THE NRN ROCKIES THROUGH TONIGHT. HEIGHT FALLS AND WIDESPREAD UPWARD VERTICAL MOTION ASSOCIATED WITH THIS SYSTEM ARE FORECAST TO EMERGE OVER THE NRN HIGH PLAINS THURSDAY MORNING BEFORE DEVELOPING EAST ACROSS THE NRN/CNTRL PLAINS AND UPPER MS VALLEY THROUGH THURSDAY NIGHT. AS PRIMARY RESULTING LEE-SIDE CYCLONE UNDERGOES OCCLUSION AND LIFTS NWD ACROSS ND...TRIPLE-POINT LOW WILL TRACK EWD ALONG STRONG WARM FRONT FROM SD INTO SRN MN AS COLD FRONT SPREADS SEWD INTO THE CNTRL PLAINS THROUGH THE EVENING. GIVEN MAGNITUDE OF FORCING AND ANTICIPATED SHEAR AND INSTABILITY ACROSS THE NRN PLAINS AREA...IT IS POSSIBLE THAT PARTS OF THE REGION MAY BE UPGRADED TO HIGHER SEVERE PROBABILITIES/MDT RISK IN LATER OUTLOOKS AS MESOSCALE DETAILS BECOME MORE CERTAIN. LOWER-AMPLITUDE IMPULSES WILL SPREAD ESEWD ATOP LOW-LEVEL BAROCLINIC ZONE FROM LOWER MI TO THE MID ATLANTIC SEABOARD AND SHOULD PROMOTE ACTIVE AREAS OF SHOWERS AND TSTMS ACROSS THESE AREAS THROUGH THURSDAY. ...NRN PLAINS TO UPPER MS VALLEY... MODELS ARE IN GENERALLY GOOD AGREEMENT THAT STRONG TO LOCALLY EXTREME INSTABILITY WILL DEVELOP ACROSS CAPPED WARM SECTOR THROUGH THE AFTERNOON. STRONG FORCING WITH UPPER TROUGH AND ASSOCIATED MID LEVEL SPEED MAX WILL ACT TO OVERCOME CONVECTIVE INHIBITION WITH POTENTIALLY EXPLOSIVE TSTM DEVELOPMENT OCCURRING NEAR AND NORTH OF SURFACE LOW AND WARM FRONT FROM LATE MORNING INTO THE AFTERNOON. INITIAL ACTIVITY...FROM ND TO SRN MN...MAY BE ROOTED ABOVE CAPPED BOUNDARY LAYER BUT WILL STILL POSE A THREAT VERY LARGE HAIL AND HIGH WINDS WITH TIME. STRENGTH OF SHEAR FORECAST ACROSS THE REGION...AND POTENTIAL FOR ENHANCED ASCENT WITHIN LEFT EXIT REGION OF INTENSIFYING MID LEVEL JET...SUGGEST WIDESPREAD SEVERE HAIL AND DAMAGING WIND COULD UNFOLD ACROSS PORTIONS OF SERN ND...ERN SD...AND SWRN MN THROUGH THE EVENING. TORNADO THREAT MAY BE MODULATED BY WEAKNESS IN LOWER LEVEL FLOW THAT RESULTS IN GENERALLY LIMITED SRH...IN ADDITION TO WARM SECTOR CAPPING AND POTENTIALLY HIGHER LFC. HOWEVER...IF SUPERCELLS CAN BECOME ROOTED IN THE BOUNDARY LAYER AND PERSIST NEAR THE WARM FRONT...A FEW TORNADOES APPEAR POSSIBLE. PARTS OF THE REGION MAY REQUIRE UPGRADE TO A MDT RISK IN LATER OUTLOOKS. ...MIDWEST TO NORTHEAST/MID ATLANTIC... HARD TO TIME LOW-AMPLITUDE SHORT WAVES WILL TRAVERSE LOW LEVEL FRONTAL ZONE AND ACT TO ENHANCE TSTM DEVELOPMENT AND ORGANIZATION FROM LOWER MI/OH EWD ACROSS PA/NJ AREAS DURING THE AFTERNOON. WHILE LAPSE RATES ACROSS THESE AREAS APPEAR SOMEWHAT MARGINAL FOR VIGOROUS STORM UPDRAFTS...IT IS POSSIBLE THAT MESOSCALE FORCING AND POCKETS OF STRONGER DESTABILIZATION COULD SUSTAIN STORMS IN AREAS WHERE SHEAR MAY ALSO SUPPORT SUPERCELLS. POTENTIAL FOR WEAK SURFACE DEVELOPMENT ACROSS ERN PA TO DELMARVA AREA BY LATER AFTERNOON COULD FURTHER AID STORM ORGANIZATION WITH A DAMAGING WIND/ISOLATED TORNADO EVENT POSSIBLE. PARTS OF THIS CORRIDOR MAY BE UPGRADED TO SLGT RISK IN LATER OUTLOOKS AS FORECAST DETAILS BECOME CLEARER. ..CARBIN.. 08/23/2006  From swody2 at goshenarc.org Thu Aug 24 05:37:45 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Thu, 24 Aug 2006 01:37:45 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 240538 SWODY2 SPC AC 240537 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1237 AM CDT THU AUG 24 2006 VALID 251200Z - 261200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS SERN WI TO SRN PORTIONS OF LAKE MI... NRN PLAINS SPEED MAX/SHORTWAVE TROUGH WILL MOVE QUICKLY ACROSS THE UPPER MS VALLEY INTO THE GREAT LAKES REGION EARLY IN THE DAY2 PERIOD. THIS FEATURE WILL UNDOUBTEDLY AID A BAND OF WARM ADVECTION/ELEVATED THUNDERSTORMS NORTH OF RETREATING FRONTAL ZONE FROM PORTIONS OF MN...SEWD INTO NRN LOWER MI EARLY IN THE PERIOD. LOW LEVEL TRAJECTORIES ACROSS THE LOWER GREAT LAKES INTO THIS REGION ARE NOT PARTICULARLY MOIST/BUOYANT THIS MORNING...AND SHOULD NOT MOISTEN SIGNIFICANTLY WITHIN THE COOL SECTOR PRIOR TO LARGE SCALE ASCENT/CONVECTIVE OVERTURNING. ALTHOUGH HAIL MAY ACCOMPANY STRONGER STORMS WITHIN THIS ZONE...IT APPEARS ELEVATED CAPE MAY BE TOO WEAK FOR MORE THAN MARGINALLY SEVERE HAIL. OF MORE CONCERN IS THE POSSIBILITY FOR WARM SECTOR THUNDERSTORM DEVELOPMENT BENEATH THE UPPER SHORTWAVE TROUGH...POSSIBLY AS EARLY AS 18Z. STRONGEST BOUNDARY LAYER HEATING SHOULD OCCUR ACROSS NRN IL INTO SERN WI...IMMEDIATELY AHEAD OF WEAK SFC LOW...ALLOWING A NARROW AXIS OF MODEST INSTABILITY TO DEVELOP...1500-2000 J/KG. FORECAST SOUNDINGS SUGGEST ORGANIZED MULTI-CELL UPDRAFTS...OR PERHAPS ISOLATED SUPERCELLS...SHOULD EVOLVE OVER SERN WI BY EARLY AFTERNOON...THEN SPREAD ESEWD TOWARD SRN LAKE MI. HAIL AND GUSTY WINDS ARE THE MAIN SEVERE THREATS. ...CNTRL PLAINS... TRAILING FRONTAL BOUNDARY WILL SAG INTO KS AND SERN CO FRIDAY AS MAIN BELT OF WLY FLOW ALOFT REMAINS WELL NORTH OF THIS REGION. MARGINAL VERTICAL SHEAR WILL NOT PROVE CONDUCIVE FOR MORE THAN WEAKLY ORGANIZED MULTI-CELL UPDRAFTS ALONG THIS WIND SHIFT. MODELS DIFFER ON SWD EXTENT OF THIS BOUNDARY ACROSS KS/OK...POSSIBLY DUE TO EXTENSIVE CONVECTION AND OUTFLOW PROCESSES. STRONGEST UPDRAFTS SHOULD OCCUR IN ZONE OF GREATEST BOUNDARY LAYER HEATING/INSTABILITY...RESULTING IN ISOLATED DAMAGING WIND GUSTS OR MARGINALLY SEVERE HAIL. ..DARROW.. 08/24/2006  From swody2 at goshenarc.org Thu Aug 24 17:27:16 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Thu, 24 Aug 2006 13:27:16 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 241727 SWODY2 SPC AC 241726 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1226 PM CDT THU AUG 24 2006 VALID 251200Z - 261200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF THE UPPER MIDWEST/GREAT LAKES REGION... ...THERE IS A SLGT RISK OF SVR TSTMS OVER KS INTO NRN OK... ...SYNOPSIS... STRONG SHORT WAVE TROUGH NOW MOVING INTO THE WRN DAKOTAS IS FORECAST TO WEAKEN DURING THE DAY TWO PERIOD AS IT TRANSLATES EWD THROUGH THE GREAT LAKES REGION...UNDERCUTTING AMPLIFIED RIDGE OVER ONTARIO. WEAKER DOWNSTREAM IMPULSES WILL SHIFT EWD ALONG SRN PERIPHERY OF ERN CANADA LONG WAVE TROUGH ACROSS THE LOWER GREAT LAKES AND CNTRL/SRN NEW ENGLAND. MEANWHILE TO THE W...UPSTREAM TROUGH WILL EVOLVE INTO A CUTOFF LOW OVER THE ERN GREAT BASIN. IN THE LOW-LEVELS...SURFACE LOW ASSOCIATED WITH THE GREAT LAKES SHORT WAVE TROUGH WILL DEVELOP EWD FROM SRN WI ACROSS LOWER MI INTO SWRN ONTARIO WITH TRAILING COLD FRONT PUSHING SWD THROUGH THE LOWER MO VALLEY AND CNTRL HIGH PLAINS. ATTENDANT WARM FRONT IS FORECAST TO LIFT NWD THROUGH LOWER MI WITH ERN EXTENSION OF THIS BOUNDARY REMAINING MORE QUASI-STATIONARY FROM THE LOWER GREAT LAKES SEWD TO THE MIDDLE ATLANTIC COAST. ...UPPER MIDWEST/GREAT LAKES REGION... WARM SECTOR AIR MASS IS FORECAST TO REMAIN QUITE MOIST FRIDAY AHEAD OF SURFACE LOW AND COLD FRONT WITH DEWPOINTS IN THE MID 60S TO LOWER 70S. WHILE MID-LEVEL LAPSE RATES ARE NOT FORECAST TO BE PARTICULARLY STEEP...DAYTIME HEATING COUPLED WITH THIS BOUNDARY-LAYER MOISTURE ARE EXPECTED TO CONTRIBUTE TO MODERATE AFTERNOON INSTABILITY WITH MLCAPES OF 1500-3000 J/KG DEVELOPING FROM SRN WI/NRN IL WWD INTO NRN MO. ELEVATED TSTMS CAPABLE OF MARGINALLY SEVERE HAIL WILL LIKELY PERSIST THROUGH THE DAY FRIDAY N OF WARM FRONT OVER NRN WI/THE UP/NRN LOWER MI...DRIVEN BY LOW-LEVEL WAA AHEAD OF WEAKENING SHORT WAVE TROUGH. POTENTIALLY MORE INTENSE...SURFACE-BASED STORM DEVELOPMENT WILL BECOME INCREASINGLY LIKELY BY AFTERNOON FROM VICINITY OF SURFACE LOW SWD ALONG COLD FRONT FROM CNTRL/SRN WI INTO NRN IL AS DIABATIC HEATING AND LARGE-SCALE FORCING FOR ASCENT EFFECTIVELY ERODE THE CAP. PRESENCE OF 70-80 KT UPPER JET STREAK ACCOMPANYING SHORT WAVE TROUGH WILL RESULT IN SUFFICIENT DEEP LAYER SHEAR FOR SUPERCELLS AND BOWING STRUCTURES CAPABLE OF MAINLY LARGE HAIL AND DAMAGING WINDS. APPEARS BEST POTENTIAL FOR A TORNADO OR TWO WILL BE WITH ANY STORMS DEVELOPING NEARER TO SURFACE LOW AND ATTENDANT WARM FRONT WHERE LOW-LEVEL SHEAR WILL BE ENHANCED FROM E-CNTRL WI EWD INTO CNTRL OR NRN LOWER MI. ...KS... THERE REMAINS SOME UNCERTAINTY AS TO THE POSITION OF TRUE SYNOPTIC FRONT AND ANY OUTFLOW BOUNDARIES REMNANT FROM CONVECTION DEVELOPING DURING THE LATTER HALF OF THE DAY ONE PERIOD. LATEST SHORT TERM MODEL GUIDANCE DOES SUGGEST THAT STEEP LOW/MID-LEVEL LAPSE AND MOIST BOUNDARY-LAYER CONDITIONS WILL BECOME CO-LOCATED ACROSS REGION NEAR OR JUST N OF SURFACE FRONT FRIDAY AFTERNOON...CONTRIBUTING TO MLCAPES OF 1500-2500 J/KG. IT APPEARS THAT DAYTIME HEATING...LOW-LEVEL CONVERGENCE ALONG PRE-EXISTING BOUNDARIES AND LARGER-SCALE FORCING IN RIGHT ENTRANCE REGION OF UPPER JET STREAK OVER THE NRN PLAINS WILL ALL CONTRIBUTE TO AN INCREASE IN SURFACE-BASED STORM ACTIVITY DURING THE AFTERNOON AND EVENING HOURS. WHILE ONLY 15-25 KT MID-LEVEL FLOW IS FORECAST...UPPER TROPOSPHERIC WIND FIELDS WILL REMAIN 50-60 KTS. WHEN COUPLED WITH ELY LOW-LEVEL WINDS N OF SURFACE FRONT...EFFECTIVE BULK SHEAR OF 30-40 KTS IS FORECAST...SUPPORTIVE OF ORGANIZED...ROTATING UPDRAFTS CAPABLE OF SEVERE HAIL AND LOCALLY DAMAGING WINDS. ...CNTRL HIGH PLAINS... VERTICAL SHEAR WILL REMAIN SUPPORTIVE OF UPDRAFT ROTATION NWWD INTO CNTRL WY WITHIN POST-FRONTAL UPSLOPE REGIME. HOWEVER...PRIMARY FACTOR LIMITING A MORE ORGANIZED SEVERE THREAT WILL BE LIMITED INSTABILITY. A FEW POCKETS OF AT LEAST WEAK INSTABILITY /MLCAPES OF 250-500 J/KG/ WILL LIKELY DEVELOP BY AFTERNOON AND IF STORMS CAN DEVELOP AND BECOME SUSTAINED...THEN POTENTIAL WOULD EXIST FOR SOME HAIL AND GUSTY WINDS. ...LOWER GREAT LAKES TO THE MID ATLANTIC COAST... CONSIDERABLE UNCERTAINTY EXISTS WITH REGARD TO CONVECTIVE EVOLUTION DOWNSTREAM FROM CNTRL GREAT LAKES LOW ALONG ATTENDANT WARM FRONT OR QUASI-STATIONARY BOUNDARY. AS MENTIONED ABOVE...IT APPEARS THAT SEVERAL WEAK IMPULSES WILL ROTATE THROUGH THE BASE OF ERN CANADA LONG WAVE TROUGH...THE TIMING OF WHICH REMAINS DIFFICULT. IN ADDITION...THE DEGREE OF AIR MASS DESTABILIZATION REMAINS IN QUESTION. VERTICAL SHEAR INVOF THE SURFACE FRONT WILL REMAIN QUITE FAVORABLE FOR SUPERCELLS THROUGH THE PERIOD GIVEN THE DEVELOPMENT AND MAINTENENCE OF MOIST DEEP CONVECTION. ONCE FINER SCALE DETAILS BECOME MORE CLEAR...PORTIONS OF REGION MAY NEED TO BE UPGRADED TO A SLIGHT RISK IN SUBSEQUENT DAY ONE OUTLOOKS. ..MEAD.. 08/24/2006  From swody2 at goshenarc.org Fri Aug 25 05:59:56 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Fri, 25 Aug 2006 01:59:56 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 250600 SWODY2 SPC AC 250559 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1259 AM CDT FRI AUG 25 2006 VALID 261200Z - 271200Z ...THERE IS A SLGT RISK OF SVR TSTMS SAT AFTN/SAT EVE ACROSS PARTS OF THE GREAT LAKES/UPR OH VLY.... ...THERE IS A SLGT RISK OF SVR TSTMS LATE SAT AFTN/SAT EVE ACROSS PARTS OF THE SRN PLAINS/OZARKS.... ...THERE IS A SLGT RISK OF SVR TSTMS LATE SAT AFTN/SAT EVE...EAST OF THE FRONT RANGE OF THE ROCKIES.... MODELS INDICATE THAT A SUBTLE WEAKENING OF THE CENTRAL/SOUTHERN U.S. SUBTROPICAL RIDGE...WHICH HAS BEEN UNDERWAY THE PAST WEEK OR SO...WILL CONTINUE THROUGH THIS FORECAST PERIOD...IN RESPONSE TO PROGRESSION OF SHORT WAVE TROUGHS WITHIN THE POLAR WESTERLIES. THE PRIMARY BELT WILL GENERALLY REMAIN JUST NORTH OF THE CANADIAN/U.S. BORDER...WITH A SIGNIFICANT EMBEDDED SHORT WAVE PROGGED EAST OF MANITOBA EARLY SATURDAY THROUGH MUCH OF ONTARIO BY 12Z SUNDAY. PHASING OF THIS FEATURE WITH AN IMPULSE IN A WEAKER SOUTHERN BELT IS FORECAST TO OCCUR LATE SATURDAY THROUGH SATURDAY EVENING ACROSS THE GREAT LAKES/OHIO VALLEY REGION. MEANWHILE...A MORE SIGNIFICANT SOUTHERN BRANCH TROUGH SEEMS LIKELY TO LAG TO THE WEST...BUT STILL CONTINUE TO SLOWLY DIG SOUTHEAST OF THE NORTHERN GREAT BASIN INTO THE CENTRAL ROCKIES. FORCING WITH THE LARGE-SCALE FEATURES...SEASONABLY MOIST LOW-LEVEL ENVIRONMENT AND AN INFLUX OF MOISTURE FROM THE LOWER LATITUDE EASTERN PACIFIC WILL PROBABLY ALL CONTRIBUTE TO A CONSIDERABLE AMOUNT OF CONVECTIVE ACTIVITY SATURDAY/SATURDAY NIGHT. WEAK FRONTAL SURGE INTO THE OHIO VALLEY AND SOUTHERN PLAINS WILL PROVIDE ONE FOCUS FOR ACTIVITY...AS WILL A BAROCLINIC ZONE ACROSS THE LOWER GREAT LAKES/NORTHERN MID ATLANTIC REGION...ASSOCIATED WITH A RETREATING SURFACE RIDGE. A WEAK IMPULSE MIGRATING AROUND THE SOUTHWESTERN PERIPHERY OF MID-LEVEL HIGH CENTER OVER THE MID ATLANTIC STATES WILL CONTRIBUTE TO SCATTERED AFTERNOON/EVENING STORMS ACROSS MUCH OF THE GULF STATES. AND...DIURNAL THUNDERSTORM ACTIVITY WILL BECOME FOCUSED PRIMARILY ACROSS THE HIGHER TERRAIN OF THE INTERMOUNTAIN WEST/ROCKIES. ...LOWER GREAT LAKES/OHIO VALLEY... LACK OF COLDER AIR ALOFT/STEEPER MID-LEVEL LAPSE RATES WILL BE THE PRIMARY LIMITING FACTOR TO SEVERE POTENTIAL SATURDAY. POTENTIAL CLOUD COVER IS ALSO A CONCERN...BUT CONSIDERABLE HEATING IS EXPECTED ACROSS MUCH OF INDIANA/OHIO INTO PARTS OF WESTERN PENNSYLVANIA...WHERE VEERING WINDS WITH HEIGHT BENEATH WEAK TO MODERATE WESTERLY MID-LEVEL FLOW WILL BE MARGINALLY SUFFICIENT FOR SUPERCELLS. SHEAR WILL BE STRONGER...BUT WITH WEAKER INSTABILITY...ACROSS LOWER MICHIGAN...WHERE STORMS COULD INITIATE BY EARLY SATURDAY AFTERNOON. THEN...AS LARGE-SCALE FORCING FOR UPWARD VERTICAL MOTION INCREASES LATE SATURDAY AFTERNOON INTO SATURDAY EVENING...STRONG/SEVERE STORMS ARE EXPECTED TO INCREASE ACROSS THE UPPER OHIO VALLEY. ISOLATED TORNADOES ARE POSSIBLE...BUT...AT THIS TIME...IT APPEARS LARGE HAIL/DAMAGING WIND GUSTS WILL BE PRIMARY THREATS BEFORE SEVERE POTENTIAL DIMINISHES ACROSS THE LOWER GREAT LAKES REGION LATE SATURDAY EVENING. ...SOUTHERN PLAINS/OZARK PLATEAU... STABILIZING INFLUENCE OF WEAKENING CONVECTIVE CLUSTER EXPECTED ALONG FRONT ACROSS THE EAST CENTRAL PLAINS/OZARK PLATEAU EARLY SATURDAY IS A CONCERN FOR SEVERE POTENTIAL. AT THE PRESENT TIME...IT APPEARS STRONGEST DESTABILIZATION WILL OCCUR SOUTH OF SURFACE BOUNDARY...IN THE WAKE OF THIS FEATURE...AS IT SHIFTS EASTWARD THROUGH THE MIDDLE MISSISSIPPI/LOWER OHIO VALLEY. LOW-LEVEL CONVERGENCE ALONG FRONT AND/OR WARM ADVECTION ALONG/NORTH OF PRE-FRONTAL THERMAL RIDGE WILL AID CONVECTIVE DEVELOPMENT LATE SATURDAY AFTERNOON/EVENING...FROM PARTS OF NORTH CENTRAL OKLAHOMA INTO THE OZARKS. VERTICAL SHEAR WILL BE WEAK...BUT VERY WARM DEEP MIXED BOUNDARY WITH CAPE AROUND 2000 J/KG WILL BE SUPPORTIVE OF VIGOROUS STORMS WITH POTENTIAL FOR STRONG DOWNBURSTS...AND POTENTIALLY DAMAGING SURFACE WINDS. ...GREAT BASIN/CENTRAL HIGH PLAINS... DRYING/WEAK INSTABILITY IS EXPECTED TO BE A LIMITING FACTOR FOR SEVERE POTENTIAL NEAR COLD CORE OF UPPER TROUGH...FROM PARTS OF NORTHERN UTAH INTO SOUTHWEST WYOMING/NORTHWEST COLORADO...EARLY SATURDAY. HOWEVER...DESTABILIZATION IN MOIST UPSLOPE FLOW REGIME ALONG AND TO THE LEE OF THE FRONT RANGE OF THE ROCKIES IS EXPECTED TO BE SUFFICIENT FOR VIGOROUS CONVECTIVE DEVELOPMENT LATE SATURDAY AFTERNOON AND EVENING. LOW/MID-LEVEL FLOW WILL BE WEAK...BUT VEERING WITH HEIGHT BENEATH STRONG SOUTHWESTERLY HIGH LEVEL FLOW WILL PROVIDE FAVORABLE HODOGRAPHS FOR SUPERCELLS...ENHANCING RISK FOR LARGE HAIL/DAMAGING WINDS...POSSIBLY A TORNADO OR TWO. ..KERR.. 08/25/2006  From swody2 at goshenarc.org Fri Aug 25 17:24:35 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Fri, 25 Aug 2006 13:24:35 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 251725 SWODY2 SPC AC 251724 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1224 PM CDT FRI AUG 25 2006 VALID 261200Z - 271200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM PORTIONS OF THE GREAT LAKES AND NRN OH VALLEY SEWD TO THE DELMARVA... ...THERE IS A SLGT RISK OF SVR TSTMS FROM PARTS OF THE CNTRL/SRN HIGH PLAINS EWD TO THE OZARK PLATEAU... ...SYNOPSIS... ACTIVE WAVE TRAIN WITHIN PRIMARY BELT OF POLAR WESTERLIES WILL EXIST ACROSS CANADA DURING THE DAY TWO PERIOD WITH A LOWER LATITUDE UPPER LOW EVOLVING INTO AN OPEN WAVE OVER THE GREAT BASIN INTO CNTRL ROCKIES. IN THE LOW-LEVELS...SURFACE LOW ASSOCIATED WITH A WEAK IMPULSE MOVING THROUGH THE GREAT LAKES WILL DEVELOP EWD FROM LAKE MI INTO SWRN ONTARIO WHILE TRAILING COLD FRONT SLOWLY SAGS SWD THROUGH THE MID MS VALLEY AND SRN HIGH PLAINS. TO THE E...QUASI-STATIONARY BOUNDARY...DELINEATING WRN EDGE OF ANTICYCLONE OVER ME INTO NEW BRUNSWICK...WILL EXTEND FROM THE GREAT LAKES LOW SEWD TO THE MID ATLANTIC COAST. ...GREAT LAKES/NRN OH VALLEY TO THE DELMARVA... SHORT WAVE TROUGH CURRENTLY OVER CNTRL WY IS FORECAST TO TRANSLATE NEWD THROUGH THE NRN PLAINS AND UPPER MS VALLEY DURING THE DAY ONE PERIOD...AND EVENTUALLY MORE EWD THROUGH LOWER MI INTO NY SATURDAY/SATURDAY NIGHT. FORCING FOR ASCENT ASSOCIATED WITH THIS FEATURE AND CONVERGENCE ALONG ABOVE MENTIONED LOW-LEVEL BOUNDARIES WILL PROVIDE THE FOCUS FOR STRONG TO SEVERE STORMS DURING THE AFTERNOON AND EVENING HOURS. IT APPEARS THAT CLOUDS/ONGOING PRECIPITATION MAY SLOW DESTABILIZATION PROCESS NEAR SURFACE FRONTAL SYSTEM SATURDAY. HOWEVER...COMPARABLY STRONGER DIABATIC HEATING AND MOIST BOUNDARY LAYER CONDITIONS WITHIN INFLOW AIR MASS FROM CNTRL MO/IL INTO NRN IND/SRN LOWER MI...AND FARTHER E OVER WV/MD/NRN VA WILL CONTRIBUTE TO MODERATE AFTERNOON INSTABILITY WITH MLCAPES OF 1000-2000 J/KG. AS THIS OCCURS...EXPECT A GRADUAL INCREASE IN STORM COVERAGE AND INTENSITY THROUGH THE AFTERNOON FROM VICINITY OF SURFACE LOW OVER CNTRL LOWER MI SWWD ALONG FRONT INTO NRN PARTS OF IND/IL...AND SEWD ALONG QUASI-STATIONARY BOUNDARY FROM WRN NY INTO PA/MD/NJ. STRONGEST VERTICAL SHEAR OWING TO ENHANCED LOW-LEVEL WAA/VEERING WIND PROFILES WILL EXIST FROM LOWER MI SURFACE LOW SEWD ALONG QUASI-STATIONARY BOUNDARY WHERE POTENTIAL WILL EXIST FOR ORGANIZED...ROTATING UPDRAFTS CAPABLE OF DAMAGING WINDS...SOME SEVERE HAIL AND PERHAPS A TORNADO OR TWO. ALONG COLD FRONT...VERTICAL SHEAR PROFILES ARE MUCH MORE UNIDIRECTIONAL...THOUGH 30-35 KTS OF VERTICAL SPEED SHEAR WILL BE SUPPORTIVE OF ORGANIZED STORMS CAPABLE OF SEVERE WINDS AND HAIL. ...CNTRL/SRN HIGH PLAINS INTO OZARK PLATEAU... RICHEST BOUNDARY LAYER MOISTURE AND RESULTANT DESTABILIZATION /MLCAPES OF 1500-3000 J/KG/ IS EXPECTED TO OCCUR ALONG W-E PORTION OF SYNOPTIC FRONT FROM OK/TX PNHDLS ENEWD INTO CNTRL/SRN MO. DESPITE THE ABSENCE OF ANY APPRECIABLE LARGE-SCALE FORCING FOR ASCENT...STRONG DIABATIC HEATING WITHIN PRE-FRONTAL AIR MASS WILL CONTRIBUTE TO AN INCREASE IN TSTM ACTIVITY THROUGH THE AFTERNOON AND EVENING HOURS ALONG LENGTH OF FRONTAL ZONE. DEEP LAYER BULK SHEAR WILL REMAIN MARGINAL /25-30 KTS/ FOR ORGANIZED SEVERE STORMS...THOUGH THE MODERATE INSTABILITY AND PRESENCE OF STEEP LOW LEVEL LAPSE RATES INDICATE THE POTENTIAL FOR DAMAGING WIND GUSTS AND PERHAPS SOME SEVERE HAIL. OVER THE HIGH PLAINS REGION FROM SERN WY INTO NERN NM...INSTABILITY WILL BE WEAKER /MLCAPES 500-1500 J/KG/ THAN POINTS TO THE SE OWING TO DRIER BOUNDARY LAYER CONDITIONS. HOWEVER...THE PRESENCE OF STEEP LOW TO MID LEVEL LAPSE RATES AND STRONGER VERTICAL SHEAR /30-40 KTS/ WILL SUPPORT SEVERE STORMS...INCLUDING THE POTENTIAL FOR A COUPLE SUPERCELLS CAPABLE OF LARGE HAIL AND LOCALLY STRONG WIND GUSTS. ..MEAD.. 08/25/2006  From swody2 at goshenarc.org Sat Aug 26 05:53:42 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 26 Aug 2006 01:53:42 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 260554 SWODY2 SPC AC 260553 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1253 AM CDT SAT AUG 26 2006 VALID 271200Z - 281200Z ...THERE IS A SLGT RISK OF SVR TSTMS SUN AFTN/EVE ACROSS THE UPPER OHIO VALLEY.... SHORT WAVE TROUGHS WITHIN SPLIT BELTS OF POLAR WESTERLIES WILL REMAIN PROGRESSIVE THROUGH THIS FORECAST PERIOD. MODELS SUGGEST PHASING OF A SIGNIFICANT NORTHERN STREAM TROUGH AND A WEAKER SOUTHERN STREAM IMPULSE WILL OCCUR LATE TODAY INTO EARLY SUNDAY ACROSS THE GREAT LAKES REGION. HOWEVER...THIS APPEARS LIKELY TO BE SHORT-LIVED...AS THE NORTHERN SYSTEM IS FORECAST TO LIFT THROUGH QUEBEC LATER SUNDAY INTO EARLY MONDAY. SOUTHERN IMPULSE IS PROGGED TO TURN SOUTHEAST OF THE LOWER GREAT LAKES AND CONTINUE ACROSS THE MID ATLANTIC COAST...AS UPSTREAM SHORT WAVE RIDGING BUILDS INTO THE GREAT LAKES. THIS WILL OCCUR AHEAD OF A MORE SIGNIFICANT SOUTHERN STREAM TROUGH SLOWLY ADVANCING EAST OF THE CENTRAL ROCKIES. MEANWHILE...A SUBTROPICAL RIDGE WILL GENERALLY HOLD FIRM FROM THE SOUTHEASTERN STATES INTO THE LOWER LATITUDE WESTERN ATLANTIC. AND...AN UPPER RIDGE WILL BUILD ACROSS THE INTERMOUNTAIN WEST... AHEAD OF ANOTHER VIGOROUS NORTHERN BRANCH TROUGH DIGGING ACROSS THE NORTHEAST PACIFIC. ...UPPER OHIO VALLEY/LOWER GREAT LAKES INTO THE NORTHEAST... IN THE WAKE OF A SIGNIFICANT UPPER TROUGH ALREADY EAST OF THE NORTH ATLANTIC COAST BY EARLY SUNDAY...SURFACE RIDGING WILL BE SLOW TO RETREAT EAST OF NORTHERN/MID ATLANTIC COASTAL AREAS. THIS WILL MAINTAIN COOLER SOUTHEASTERLY FLOW ALONG COASTAL AREAS...AND WARM ADVECTION CLOUDINESS LIKELY WILL MINIMIZE DESTABILIZATION AHEAD OF APPROACHING SOUTHERN BRANCH IMPULSE. HOWEVER...AHEAD OF A COLD FRONT ADVANCING INTO THE UPPER OHIO VALLEY...AT LEAST WEAK SURFACE HEATING OF VERY MOIST BOUNDARY LAYER...CHARACTERIZED BY SURFACE DEW POINTS NEAR 70F...IS EXPECTED TO CONTRIBUTE TO CAPE OF 1000 TO 1500. THOUGH ANTICIPATED INSTABILITY IS NOT PARTICULARLY STRONG...DEEP LAYER SHEAR BENEATH MODERATE WEST NORTHWESTERLY MID-LEVEL FLOW IS FORECAST TO BE MARGINALLY SUFFICIENT FOR UPDRAFT ROTATION. A FEW SEVERE STORMS ARE POSSIBLE...INCLUDING ISOLATED SUPERCELLS WITH ENHANCED RISK OF HAIL/DAMAGING WIND GUSTS...PERHAPS A TORNADO OR TWO. INITIATION OF STORMS APPEARS LIKELY BY EARLY SUNDAY AFTERNOON ACROSS PARTS OF NORTHERN OHIO/NORTHWESTERN PENNSYLVANIA...POSSIBLY PARTS OF WESTERN NEW YORK STATE...BEFORE DEVELOPING SOUTHEASTWARD INTO/ACROSS THE NORTH CENTRAL APPALACHIANS BY SUNDAY EVENING. ...CENTRAL ROCKIES INTO SOUTHERN PLAINS/OZARKS... CONSIDERABLE UNCERTAINTY EXISTS CONCERNING SEVERE POTENTIAL SUNDAY. WIDESPREAD CONVECTIVE DEVELOPMENT APPEARS POSSIBLE AIDED BY LARGE-SCALE FORCING ACCOMPANYING SOUTHERN BRANCH TROUGH. HOWEVER...STABILIZING INFLUENCE OF EARLY SUNDAY MORNING CONVECTION ALONG CONVECTIVELY GENERATED/ENHANCED BOUNDARY ADVANCING SOUTHWARD TOWARD THE RED RIVER VALLEY...AND THROUGH THE OZARKS...IS UNCERTAIN. AND...TENDENCY MAY BE FOR BOUNDARY TO ADVANCE SOUTH OF STRONGER MID/UPPER FLOW...MINIMIZING SHEAR IN AXIS OF STRONGER INSTABILITY. ..KERR.. 08/26/2006  From swody2 at goshenarc.org Sat Aug 26 17:14:12 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 26 Aug 2006 13:14:12 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 261714 SWODY2 SPC AC 261713 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1213 PM CDT SAT AUG 26 2006 VALID 271200Z - 281200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER THE UPPER OH VALLEY... ...THERE IS A SLGT RISK OF SVR TSTMS OVER SERN CO...SWRN KS...AND THE OK/NRN TX PNHDLS... ...SYNOPSIS... PROGRESSIVE WAVE TRAIN OF POLAR WESTERLIES WILL CONTINUE ACROSS CANADA THIS FORECAST PERIOD. A LOWER LATITUDE TROUGH OVER THE INTERMOUNTAIN W WILL GRADUALLY SHIFT EWD INTO THE CNTRL PLAINS IN RESPONSE TO THE APPROACH OF A STRONG UPSTREAM SYSTEM FROM THE GULF OF AK. IN THE LOW-LEVELS...SURFACE LOW PRESSURE OVER LOWER MI SUNDAY MORNING WILL DEVELOP EWD INTO N-CNTRL PA BY SUNDAY NIGHT WITH A TRAILING BAROCLINIC ZONE STRETCHING WWD THROUGH THE OH VALLEY TO SECONDARY LOW PRESSURE DEVELOPING NEWD FROM OK INTO SWRN MO. THE WRN EXTENSION OF THIS BOUNDARY WILL GRADUALLY SHIFT SWD THROUGH THE SRN HIGH PLAINS. ...UPPER OH VALLEY... AIR MASS DESTABILIZATION IS EXPECTED TO BE TEMPERED BY CONSIDERABLE CLOUDS AND PRECIPITATION SUNDAY IN ADVANCE OF SURFACE LOW AND ATTENDANT FRONT SHIFTING EWD THROUGH THE REGION. HOWEVER...THE PRESENCE OF A MOIST LOW-LEVEL AIR MASS CHARACTERIZED BY DEWPOINTS IN THE UPPER 60S TO LOW 70S COUPLED WITH SOME DIABATIC HEATING WILL LIKELY RESULT IN POCKETS OF MODERATE INSTABILITY WITH MLCAPES APPROACHING 1000-1500 J/KG. TSTMS ARE FORECAST TO INCREASE IN COVERAGE AND INTENSITY BY EARLY AFTERNOON FROM WRN PARTS OF NY/PA SWWD INTO CNTRL OH AS SURFACE FRONT ENCOUNTERS DESTABILIZING AIR MASS...AND DEEPER LAYER FORCING FOR ASCENT IS ENHANCED BY WEAK IMPULSES MOVING THROUGH THE OH VALLEY. MODEST LOW-LEVEL VEERING WIND PROFILES WITH 30-40 KTS OF WNWLY MID-LEVEL FLOW WILL RESULT IN SUFFICIENT VERTICAL SHEAR FOR A FEW ORGANIZED SEVERE STORMS INCLUDING SUPERCELLS CAPABLE OF SEVERE HAIL...DAMAGING WINDS AND PERHAPS A COUPLE OF TORNADOES. ERN EXTENT OF SEVERE THREAT WILL BE LIMITED BY STABLE LOW-LEVEL TRAJECTORIES ORIGINATING FROM SURFACE HIGH OVER THE CANADIAN MARITIMES. ...SERN CO/SWRN KS/OK AND TX PNHDLS... LOW-LEVEL AIR MASS IS NOT EXPECTED TO BECOME PARTICULARLY WARM OWING TO SOURCE REGION BEING CONVECTIVELY PROCESSED AIR ORIGINATING OVER OK AND THE ERN OK/TX PNHDLS. HOWEVER...DAYTIME HEATING COUPLED WITH HEIGHT FALLS/DYNAMIC COOLING AHEAD OF UPPER SYSTEM MOVING THROUGH THE CNTRL ROCKIES WILL CONTRIBUTE TO MODIFICATION VIA STEEPENING LOW TO MID LEVEL LAPSE RATES WITH RESULTANT MLCAPES APPROACHING 500-1500 J/KG. WEAK LEE CYCLOGENESIS OCCURRING OVER SERN CO WILL LIKELY RESULT IN SUFFICIENT LOW-LEVEL CONVERGENCE TO INITIATE TSTMS BY MID TO LATE AFTERNOON WITH ACTIVITY MOVING/DEVELOPING EWD OR SEWD INTO SWRN KS/OK AND TX PNHDLS SUNDAY NIGHT. DESPITE THE MODEST INSTABILITY...THE INCREASED LARGE-SCALE FORCING FOR ASCENT AND 40-50 KTS OF EFFECTIVE BULK SHEAR SHOULD SUPPORT ORGANIZED...ROTATING UPDRAFTS WITH THE PRIMARY THREAT BEING SEVERE HAIL. A TORNADO OR TWO ALSO WILL BE POSSIBLE IN ADDITION TO LOCALLY DAMAGING WINDS. ...OK/NRN TX INTO THE MID MS VALLEY... CONSIDERABLE UNCERTAINTY EXISTS WITH REGARD TO CONVECTIVE INITIATION AND EVOLUTION THROUGH THE FORECAST OWING TO COMPLICATING EFFECTS ANTECEDENT CONVECTION AND RESULTANT LOCATION OF SURFACE BOUNDARIES. AS SUCH...A HOT AND MOIST LOW-LEVEL AIR MASS WILL ONCE AGAIN DEVELOP ACROSS WARM SECTOR...SUPPORTING MLCAPES OF 2000-3000 J/KG. IT APPEARS THAT THE STRONGER VERTICAL SHEAR WILL LIKELY EXIST N OF PRIMARY LOW-LEVEL BAROCLINIC ZONE WITH GENERALLY 20-30 KTS OF DEEP LAYER SHEAR ANTICIPATED ACROSS AREA OF STRONGEST AIR MASS DESTABILIZATION. THIS ENVIRONMENT SHOULD SUPPORT ORGANIZED MULTICELL CLUSTERS CAPABLE OF SOME HAIL AND DAMAGING WINDS THROUGH THE AFTERNOON AND EVENING HOURS. ONCE FINER SCALE DETAILS BECOME MORE CLEAR...PARTS OF AREA MAY NEED TO BE UPGRADED TO A SLIGHT RISK. ..MEAD.. 08/26/2006  From swody2 at goshenarc.org Sun Aug 27 05:50:32 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 27 Aug 2006 01:50:32 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 270550 SWODY2 SPC AC 270549 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1249 AM CDT SUN AUG 27 2006 VALID 281200Z - 291200Z ...NO SVR TSTM AREAS FORECAST... SUBTROPICAL RIDGING WILL REMAIN PROMINENT ACROSS THE GULF AND SOUTH ATLANTIC COAST STATES THROUGH THIS FORECAST PERIOD. HOWEVER...MODELS SUGGEST AMPLIFICATION WILL OCCUR WITHIN THE POLAR WESTERLIES...WITH A SIGNIFICANT TROUGH DIGGING ALONG THE BRITISH COLUMBIA/NORTHERN PACIFIC COAST BY 12Z TUESDAY. DOWNSTREAM EVOLUTION IN THE SOUTHERN BRANCH OF SPLIT WESTERLIES REMAINS A BIT MORE UNCERTAIN...BUT IT APPEARS LIKELY THAT THE CENTRAL STATES TROUGH WILL MAINTAIN A POSITIVE TILT AND BECOME INCREASINGLY SHEARED...IN CONFLUENT REGIME BETWEEN SOUTHEASTERN RIDGE AND A NORTHERN BRANCH TROUGH ACROSS THE EASTERN CANADIAN PROVINCES. A SURFACE FRONTAL ZONE WILL BE SLOW TO PROGRESS THROUGH THE OHIO VALLEY MONDAY...BUT SOUTHWARD ADVANCEMENT INTO THE SOUTHERN PLAINS SHOULD OCCUR. MONSOONAL MOISTURE ADVECTING AROUND MID-LEVEL RIDGE WILL CONTRIBUTE TO WIDESPREAD CONVECTIVE DEVELOPMENT ALONG AND SOUTH OF THIS FRONT...AS THE SOUTHERN BRANCH TROUGH SHIFTS EASTWARD INTO THE CENTRAL PLAINS. IN THE WAKE OF UPPER SYSTEM...MOISTURE WILL REMAIN SUFFICIENT AND INHIBITION WEAK ENOUGH TO ALLOW FAIRLY WIDESPREAD THUNDERSTORM ACTIVITY ACROSS THE SOUTHERN AND CENTRAL ROCKIES AS WELL. ...CENTRAL/EASTERN STATES... SURFACE FRONTAL ZONE IS EXPECTED TO STALL FROM THE NORTHERN MID ATLANTIC COAST THROUGH THE VICINITY OF THE OHIO RIVER. WHILE THIS FEATURE...AND WEAK WAVES ALONG IT...WILL PROVIDE THE FOCUS FOR CONVECTIVE DEVELOPMENT MONDAY...DESTABILIZATION MAY BE LIMITED BY CONSIDERABLE CLOUD COVER AND MOIST MID-LEVEL ENVIRONMENT WITH WEAK LAPSE RATES. WITH FLOW FIELDS/DEEP LAYER SHEAR ASSOCIATED WITH THE SOUTHERN STREAM LIKELY ONLY MODERATE AT BEST...SEVERE POTENTIAL SEEMS SMALL. HOWEVER...HIGH PRECIPITABLE WATER CONTENT AROUND 2 INCHES OR BETTER MAY STILL CONTRIBUTE TO LOCALLY HEAVY DOWNPOURS...AND PERHAPS A FEW WET DOWNBURSTS. FARTHER WEST...IT APPEARS THAT A PRE-FRONTAL CONGLOMERATE OUTFLOW BOUNDARY WILL BECOME THE PRIMARY FOCUS FOR CONVECTIVE DEVELOPMENT BY MONDAY AFTERNOON...ACROSS CENTRAL ARKANSAS INTO NORTHEAST/NORTH CENTRAL TEXAS. THIS WILL BE WELL SOUTH OF BETTER MID-LEVEL FLOW/DEEP LAYER SHEAR...BUT STRONG SURFACE HEATING PROBABLY WILL CONTRIBUTE TO A HOT DEEP MIXED BOUNDARY LAYER...WHICH SHOULD BE FAVORABLE FOR LOCALIZED DOWNBURSTS NEAR HEAVIER PRECIPITATION CORES. THREAT IS EXPECTED TO DIMINISH EARLY MONDAY EVENING WITH ONSET OF RADIATIONAL COOLING. ..KERR.. 08/27/2006  From swody2 at goshenarc.org Sun Aug 27 17:02:29 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 27 Aug 2006 13:02:29 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 271702 SWODY2 SPC AC 271701 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1201 PM CDT SUN AUG 27 2006 VALID 281200Z - 291200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... STRONG TROUGH...ANCHORED BY UPPER LOW ALONG THE NWRN BRITISH COLUMBIA COAST...WILL DIG SEWD TOWARD THE PACIFIC NW COAST WITH RESULTANT AMPLIFICATION OF DOWNSTREAM RIDGING OVER THE N-CNTRL CONUS INTO CANADIAN PRAIRIES. AS THIS OCCURS UPPER LOW OVER THE CNTRL PLAINS WILL BECOME BLOCKED BETWEEN RIDGE OVER THE ROCKIES AND SUBTROPICAL RIDGE OFF THE SERN U.S. COAST...WITH SYSTEM GRADUALLY SHEARING INTO INCREASINGLY CONFLUENT FLOW OVER THE OH VALLEY AND LOWER GREAT LAKES. IN THE LOW-LEVELS...SURFACE LOW OVER THE MID MS VALLEY WILL DEVELOP ENEWD ALONG BAROCLINIC ZONE ACROSS THE OH VALLEY. THE ERN EXTENSION OF THIS BOUNDARY WILL STRETCH EWD TO THE MIDDLE ATLANTIC COAST...WHILE TRAILING PORTION EXTENDS SWWD TO THE SRN HIGH PLAINS. ...MID MS VALLEY EWD ACROSS THE OH VALLEY TO THE MID ATLANTIC COAST... A MOIST AND UNSTABLE LOW-LEVEL AIR MASS COUPLED WITH THE PRESENCE OF THE SURFACE BOUNDARY AND WEAK IMPULSES EMANATING FROM CNTRL PLAINS TROUGH WILL SUPPORT SCATTERED TSTM DEVELOPMENT ACROSS THE REGION MONDAY INTO MONDAY NIGHT. WHILE LAPSE RATES ARE FORECAST TO REMAIN POOR AND NEAR MOIST ADIABATIC...POCKETS OF STRONGER DIABATIC HEATING SHOULD SUPPORT LOCALLY STRONGER INSTABILITY WITH MLCAPES INCREASING TO 1000-1500 J/KG. ASIDE FROM THE POOR LAPSE RATES...IT APPEARS THAT ANY ORGANIZED SEVERE THREAT WILL BE LIMITED BY THE MARGINAL VERTICAL SHEAR AS THE STRONGER MID AND HIGH-LEVEL FLOW WILL REMAIN N OF THE PRIMARY BAROCLINIC ZONE. POTENTIAL WILL EXIST FOR ISOLATED...STRONG TO MARGINALLY SEVERE TSTM CLUSTERS WITH THE PRIMARY SEVERE THREAT BEING LOCALLY DAMAGING WINDS. ...ARKLATEX INTO CNTRL NM... COMPARATIVELY STRONGER BOUNDARY LAYER HEATING IS FORECAST ACROSS PORTIONS OF CNTRL/SRN TX MONDAY WITH TEMPERATURES WARMING INTO THE 90S AHEAD OF SURFACE FRONT AND ANY RESIDUAL OUTFLOW BOUNDARIES. WHEN COUPLED WITH DEWPOINTS IN THE 60S TO LOWER 70S...AIR MASS SHOULD BECOME MODERATELY UNSTABLE WITH MLCAPES OF 1500-2500 J/KG. RELATIVELY WEAK CAPPING SHOULD ALLOW TSTMS TO INCREASE IN COVERAGE AND INTENSITY THROUGH THE AFTERNOON FROM CNTRL/SRN AR SWWD INTO CNTRL TX. HERE TOO...VERTICAL SHEAR WILL REMAIN RELATIVELY WEAK...EFFECTIVELY LIMITING STORM ORGANIZATION. STILL...POTENTIAL WILL EXIST FOR MULTICELL CLUSTERS CAPABLE OF DAMAGING WINDS. FARTHER TO THE W...POST-FRONTAL UPSLOPE REGIME IS FORECAST TO BECOME ESTABLISHED IN THE LEE OF THE SRN ROCKIES WITH TSTMS EXPECTED BY AFTERNOON ALONG THE HIGHER TERRAIN OF CNTRL NM. DESPITE A DRIER LOW-LEVEL AIR MASS THAN POINTS TO THE E...THE DEVELOPMENT OF STEEP LOW TO MID-LEVEL LAPSE RATES WILL SUPPORT POCKETS OF MODERATE INSTABILITY WITH MLCAPES OF 500-1000 J/KG. WHILE RELATIVELY STRONG VEERING IS FORECAST IN THE LOWEST 3 KM AGL...WIND FIELDS AND RESULTANT SHEAR MAGNITUDE WILL REMAIN MARGINAL. A FEW ORGANIZED STORMS /PERHAPS EXHIBITING SOME MID-LEVEL ROTATION/ WILL BE POSSIBLE WITH THE PRIMARY SEVERE THREAT BEING SEVERE HAIL. ..MEAD.. 08/27/2006  From swody2 at goshenarc.org Mon Aug 28 05:50:40 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 28 Aug 2006 01:50:40 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 280550 SWODY2 SPC AC 280549 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1249 AM CDT MON AUG 28 2006 VALID 291200Z - 301200Z ...NO SVR TSTM AREAS FORECAST... MODELS CONTINUE TO INDICATE THAT A MORE AMPLIFIED AND LESS PROGRESSIVE UPPER FLOW PATTERN WILL DEVELOP ACROSS NORTH AMERICA LATER TODAY INTO TUESDAY. DISCREPANCIES EXIST...PERHAPS MOST NOTABLY CONCERNING THE EVOLUTION OF CENTRAL U.S. TROUGH WITHIN THE SOUTHERN BRANCH OF A SPLIT FLOW REGIME...DOWNSTREAM OF A SIGNIFICANT NORTHERN BRANCH TROUGH EVOLVING ACROSS WESTERN CANADA AND THE NORTHERN U.S. INTERMOUNTAIN REGION. THE IMPACT OF THESE FEATURES ON LINGERING SUBTROPICAL RIDGE ACROSS THE SOUTHERN TIER STATES IS ALSO UNCERTAIN...BUT MOST SUBSTANTIAL WEAKENING SEEMS LIKELY TO OCCUR ACROSS THE SOUTHERN PLATEAU. NCEP SREF AND BULK OF MODEL DATA SUGGEST RIDGING WILL BE SLOWEST TO WEAKEN OVER THE LOWER LATITUDE WESTERN ATLANTIC. AND ERNESTO...TRACKING AROUND SOUTHWESTERN PERIPHERY OF HIGH CENTER BEFORE LIFTING AHEAD OF WEAK SOUTHERN BRANCH TROUGH...SEEMS MOST LIKELY TO MIGRATE ACROSS THE LOWER KEYS INTO THE VICINITY OF THE SOUTHERN FLORIDA GULF COAST BY 12Z WEDNESDAY. ...MID ATLANTIC STATES... MODELS CONTINUE TO SUGGEST THAT A WEAK SURFACE LOW WILL DEVELOP TO THE LEE OF THE CENTRAL APPALACHIANS...ALONG OR SOUTH OF SURFACE FRONT ADVANCING SOUTHWARD INTO THE MID ATLANTIC REGION. THIS COULD PROVIDE THE FOCUS FOR AT LEAST SCATTERED CONVECTIVE DEVELOPMENT ACROSS PARTS OF EASTERN VIRGINIA...AND PERHAPS NORTHEASTERN NORTH CAROLINA...INTO THE DELMARVA PENINSULA...WHERE BOUNDARY LAYER IS EXPECTED TO BE QUITE MOIST WITH DEW POINTS AROUND 70F. WEAK MID-LEVEL LAPSE RATES WILL PROBABLY LIMIT CAPE TO WEAK TO MODERATE LEVELS AT OR ABOVE 1000 J/KG. HOWEVER...SHEAR PROFILES WILL BE MARGINALLY FAVORABLE FOR UPDRAFT ROTATION... BENEATH 30+ KT WESTERLY MID-LEVEL FLOW...IN CONFLUENT REGIME DOWNSTREAM OF SOUTHERN BRANCH TROUGH. AND...INSTABILITY MAY BE SUFFICIENT FOR AN ISOLATED SUPERCELL OR TWO...MAINLY DURING/ SHORTLY AFTER PEAK DAYTIME HEATING. IF THIS OCCURS...POTENTIAL EXISTS FOR A TORNADO...IN ADDITION TO DAMAGING WIND GUSTS...AND POSSIBLY SOME HAIL. ...FLORIDA... UNCERTAINTIES CONCERNING TRACK/STRENGTH OF ERNESTO...AND ASSOCIATED WIND FIELDS AND LOW-LEVEL SHEAR ARE STILL LARGE. HOWEVER...POTENTIAL FOR AT LEAST ISOLATED TORNADOES WILL PROBABLY INCREASE ACROSS THE FLORIDA KEYS INTO THE SOUTHERN PENINSULA LATE TUESDAY/TUESDAY NIGHT...NORTH/NORTHEAST OF APPROACHING CIRCULATION CENTER. ...NORTHWEST... LACK OF MOISTURE IN WARM PRE-FRONTAL ENVIRONMENT IS EXPECTED TO MINIMIZE CONVECTIVE POTENTIAL ASSOCIATED WITH VIGOROUS UPPER TROUGH DIGGING INTO THE NORTHERN INTERMOUNTAIN REGION. OROGRAPHY MAY AID DEVELOPMENT OF THUNDERSTORMS ACROSS THE MOUNTAINS OF NORTHERN IDAHO/WESTERN MONTANA...SOME OF WHICH COULD DEVELOP EAST OF THE HIGHER TERRAIN WITH POTENTIAL FOR ISOLATED MICROBURSTS IN DEEP MIXED BOUNDARY LAYER. ...SOUTHWEST... A NORTHWARD SURGE OF LOW-LEVEL MOISTURE THROUGH THE GULF OF CALIFORNIA INTO THE LOWER COLORADO VALLEY AND SOUTHERN PLATEAU APPEARS LIKELY TO OCCUR BY TUESDAY. FAIRLY STRONG DAYTIME HEATING AND WEAKENING INHIBITION ARE EXPECTED TO CONTRIBUTE TO INCREASING THUNDERSTORM ACTIVITY TUESDAY AFTERNOON. SHEAR WILL BE WEAK... BUT DEEP MIXED BOUNDARY LAYER WITH CAPE AS LARGE AS 1000 J/KG WILL PROBABLY BE SUFFICIENT FOR A FEW VIGOROUS STORMS...SOME OF WHICH MAY BE ACCOMPANIED BY LOCALIZED DOWNBURSTS...POSSIBLY SOME SMALL HAIL. ..KERR.. 08/28/2006  From swody2 at goshenarc.org Mon Aug 28 17:40:08 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 28 Aug 2006 13:40:08 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 281740 SWODY2 SPC AC 281739 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1239 PM CDT MON AUG 28 2006 VALID 291200Z - 301200Z ...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS DELMARVA/MID-ATLANTIC REGION... ...SYNOPSIS... SEASONALLY HIGH-AMPLITUDE AND PROGRESSIVE SYNOPTIC PATTERN WILL PERSIST OVER MUCH OF CONUS THROUGH PERIOD. HEIGHTS WILL FALL ACROSS PACIFIC NW IN ADVANCE OF TROUGH NOW EVIDENT IN MOISTURE CHANNEL IMAGERY OVER SERN GULF OF AK AND ADJACENT NERN PACIFIC. MID-UPPER LEVEL LOW NOW LOCATED INVOF YKN IS PROGGED TO MOVE ESEWD ACROSS IL/INDIANA THROUGH PERIOD. CONFIDENCE IN THIS TRACK IS GAINED FROM REASONABLY STRONG CONSENSUS AND LITTLE VARIATION AMONGST 28/12Z DETERMINISTIC SHORT-RANGE MODELS...REGARDING LOCATION AND POSITIVE TILT OF ASSOCIATED TROUGH. SOME DIFFERENCES ARE EVIDENT IN STRENGTH...NAMELY WHETHER TROUGH WILL CONTINUE HOLDING CLOSED LOW OR EVOLVE TO OPEN-WAVE STRUCTURE. ASSOCIATED SFC LOW -- NOW ANALYZED OVER MO/IA BORDER -- IS FCST TO MOVE GENERALLY EWD ALONG FRONTAL ZONE TO COASTAL DELMARVA/MID-ATLANTIC BY 30/00Z. TRAILING COLD FRONT WILL MOVE SEWD OVER OH VALLEY...SRN/CENTRAL APPALACHIANS...AND ALL BUT COASTAL PLAIN OF TX BY SAME TIME. AS OF THIS WRITING...TS ERNESTO IS MOVING NWWD ACROSS SERN CUBA. LATEST NHC TRACK FCST FOR ITS CENTER...AS WELL AS TRENDS IN THESE FCSTS...SUGGEST MOST FAVORABLE AREA FOR TORNADOES WILL REMAIN OFFSHORE OVER ATLANTIC. AS SUCH...NO PROBABILITIES ARE INCORPORATED ATTM...THOUGH ANY LEFTWARD DEVIATION FROM THIS TRACK MIGHT RESULT IN PERIPHERAL SUPERCELL POTENTIAL ALONG FL E COAST. ...MID-ATLANTIC/DELMARVA REGION... WIDELY SCATTERED TSTMS ARE EXPECTED TO DEVELOP IN ZONE OF MAXIMIZED LOW LEVEL ASCENT AND HEATING...SE THROUGH E OF SFC LOW...LATE MORNING THROUGH AFTERNOON. THERE IS SOME CONCERN THAT CLOUD COVER MAY LIMIT DIURNAL HEATING...HOWEVER WEAK CINH AND CONVERGENCE INVOF LOW SHOULD SUPPORT ENOUGH SUPERCELL POTENTIAL TO WARRANT CATEGORICAL SLGT RISK. MOST FAVORABLE ZONE FOR SVR SHOULD BE FROM LOW EWD INVOF FRONT...WHERE SUPERCELLS ARE MOST PROBABLE. PRIND THIS AREA WILL COMPRISE A NARROW CORRIDOR -- JUXTAPOSING NRN PERIPHERY OF MOST FAVORABLE BOUNDARY LAYER HEATING/MOISTURE...SRN PERIPHERY OF STRONGER MIDLEVEL FLOW...AND RELATIVELY BACKED LOW LEVEL WINDS IN ORDER TO MAXIMIZE DEEP-LAYER VERTICAL SHEAR. ACCORDINGLY...MODEL FCST SOUNDINGS INDICATE 35-35 KT EFFECTIVE SHEAR...AND 0-1 KM SRH 100-200 J/KG FOR EWD STORM MOTIONS. IN ENVIRONMENT OF RELATIVELY LOW LCL AND FAVORABLE KINEMATIC PROFILES NEAR WARM FRONT...A TORNADO OR TWO IS POSSIBLE. DAMAGING GUST THREAT MAINLY WOULD BE FROM AFTERNOON CONVECTION WHOSE SUBCLOUD LAYERS ARE OPTIMALLY MIXED BY HEATING. LOW-MIDLEVEL ABSOLUTE WARMTH AND LAPSE RATES NEAR MOIST-ADIABATIC ALOFT WILL LIMIT BOTH RATE OF CONVECTIVE DEVELOPMENT AND POTENTIAL FOR LARGE HAIL. ...MID-UPPER MS VALLEY REGION... ALTHOUGH BOUNDARY LAYER WILL BE POSTFRONTAL AND CHARACTERIZED BY AMBIENT CAA OVER THIS REGION...WIDELY SCATTERED TSTMS ARE POSSIBLE DURING AFTERNOON..BENEATH COLD CORE REGION OF MID/UPPER LOW. DIABATIC HEATING WILL OFFSET SFC CAA ENOUGH TO REMOVE CINH IN SOME AREAS...IN COMBINATION WITH RESIDUAL/EVAPOTRANSPIRATED MOISTURE. LAPSE RATES SHOULD BECOME STEEP ENOUGH TO SUPPORT MLCAPES LOCALLY EXCEEDING 1000 J/KG. STRONGEST CELLS MAY PRODUCE HAIL AND GUSTS NEAR SVR LEVELS. ...SRN AND PERHAPS CENTRAL AZ... STRONG SFC HEATING IS ANTICIPATED ACROSS MUCH OF THIS REGION CONCURRENT WITH INCREASE IN LOW LEVEL MOISTURE...SUPPORTING CONVECTIVE POTENTIAL DURING MID-LATE AFTERNOON OVER HIGHER ELEVATIONS AND LATE AFTERNOON INTO EVENING OVER LOWER DESERTS. DEEP/LOW-MIDLEVEL ELY FLOW COMPONENT -- PARTICULARLY OVER SRN AZ -- WOULD AID MOVEMENT OF CONVECTION OFF MOUNTAINS AND OVER HOT/DEEPLY MIXED DESERT BOUNDARY LAYERS...IN SUPPORT OF AT LEAST MRGL POTENTIAL FOR STG-SVR GUSTS. ..EDWARDS.. 08/28/2006  From swody2 at goshenarc.org Wed Aug 30 05:22:34 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 30 Aug 2006 01:22:34 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 300523 SWODY2 SPC AC 300522 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1222 AM CDT WED AUG 30 2006 VALID 311200Z - 011200Z ...THERE IS A SLGT RISK OF SVR TSTMS LATE THU AFTN AND EVE ACROSS PARTS OF THE CNTRL HIGH PLAINS.... VARIABILITY STILL EXISTS AMONG THE MODELS WITH REGARD TO THE SPECIFICS OF THE EVOLUTION OF THE LARGE-SCALE UPPER FLOW PATTERN DURING THIS FORECAST PERIOD. IN GENERAL...THOUGH...A MORE AMPLIFIED...AND LESS PROGRESSIVE/BLOCKED REGIME IS FORECAST TO CONTINUE TO DEVELOP. A WEAK CLOSED LOW IN THE SOUTHERN BRANCH OF THE POLAR WESTERLIES IS PROGGED TO BECOME CUT-OFF OVER THE LOWER OHIO VALLEY BY THURSDAY...WITH A PERTURBATION...EMANATING FROM THE TROPICS...LIFTING OUT OF THE NORTHWESTERN GULF OF MEXICO AROUND ITS SOUTHERN PERIPHERY. TO THE SOUTHEAST OF THE LOW...AN INCREASINGLY SHEARED ERNESTO IS PROGGED TO ACCELERATE FROM SOUTH ATLANTIC COASTAL AREAS THROUGH MUCH OF THE EASTERN CAROLINAS BY 12Z FRIDAY. UPSTREAM...MODELS SUGGEST A SUBTROPICAL HIGH CENTER WILL EXPAND ONCE AGAIN ACROSS THE NORTHERN MEXICAN PLATEAU. BUT...THIS WILL BE TEMPERED TO THE NORTH BY THE CONTINUING SLOW EASTWARD MIGRATION OF AN AMPLIFIED POLAR TROUGH...AND EMBEDDED SHORT WAVES...EASTWARD INTO/THROUGH THE CENTRAL CANADIAN PRAIRIES AND NORTHERN U.S. PLAINS. ...SOUTHEAST... CONSIDERABLE UNCERTAINTIES REMAIN CONCERNING TORNADO POTENTIAL WITH ERNESTO. LOW-LEVEL CIRCULATION CENTER MAY NOT MAKE LANDFALL ACROSS COASTAL EASTERN SOUTH CAROLINA UNTIL NEAR OR SHORTLY AFTER DARK THURSDAY EVENING. A BRIEF PERIOD OF SOMEWHAT ENHANCED RISK OF AN ISOLATED TORNADO OR TWO COULD EXIST IN FAVORABLE LOW-LEVEL CONVERGENCE AND SHEAR...MAINLY ALONG COASTAL AREAS TO ITS NORTHEAST. HOWEVER...SLIGHT BOUNDARY LAYER COOLING AFTER DARK... AS ERNESTO CONTINUES INLAND...MAY ULTIMATELY MITIGATE THREAT. ...CENTRAL HIGH PLAINS... ALTHOUGH A RETURN FLOW OF GULF MOISTURE IS NOT LIKELY...MODELS INDICATE MOISTENING WILL OCCUR IN LEE SURFACE TROUGH NEAR THE KANSAS/COLORADO BORDER. SURFACE DEW POINTS NEAR 60F APPEAR LIKELY...AND THIS SHOULD BE SUFFICIENT FOR MODERATE DESTABILIZATION AS LAPSE RATES STEEPEN WITH DAYTIME HEATING...ALONG WITH AT LEAST WEAK MID-LEVEL COOLING. BOUNDARY LAYER CAPE ON THE ORDER OF 2000 J/KG IS ANTICIPATED BY LATE THURSDAY AFTERNOON...WHEN FORCING NEAR INTERSECTION OF COLD FRONT AND SURFACE TROUGH/WEAK DRY LINE IS EXPECTED TO ELIMINATED CAPPING ASSOCIATED WITH ELEVATED MIXED LAYER. THIS SEEMS MOST PROBABLE ACROSS NORTHEAST COLORADO OR NORTHWEST KANSAS...WHERE WEAK BUT VEERING WINDS WITH HEIGHT FROM LOWER TO MID-LEVELS...BENEATH MODERATE WESTERLY HIGH LEVEL FLOW...SHOULD BY SUFFICIENT FOR ISOLATED SUPERCELLS. FORCING ASSOCIATED WITH DIFLUENT/DIVERGENT UPPER FLOW FIELD BETWEEN BASE OF POLAR TROUGH AND CREST OF SUBTROPICAL RIDGE SHOULD ENHANCE DEVELOPMENT. AND...ONE OR MORE SMALL CONVECTIVE CLUSTERS COULD EVOLVE THROUGH EARLY THURSDAY EVENING...PROPAGATING SOUTHWARD ACROSS THE CENTRAL HIGH PLAINS...ALONG INSTABILITY AXIS NEAR LEE SURFACE TROUGH. ..KERR.. 08/30/2006  From swody2 at goshenarc.org Wed Aug 30 17:26:50 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 30 Aug 2006 13:26:50 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 301727 SWODY2 SPC AC 301726 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1226 PM CDT WED AUG 30 2006 VALID 311200Z - 011200Z ...THERE IS A SLGT RISK OF SVR TSTMS ERN CAROLINAS... ...THERE IS A SLGT RISK OF SVR TSTMS CNTRL HIGH PLAINS... ...SYNOPSIS... COMPLEX INTERACTION AMONG A NUMBER OF MULTI-STREAM AND MULTI-SCALE PERTURBATIONS WILL COMMENCE BY LATE IN THE DAY 2 PERIOD AND CONTINUE INTO FRIDAY. ERNESTO/S DEEP-LAYER TROPICAL CIRCULATION IS FORECAST TO LIFT NNEWD ALONG THE SOUTHEAST U.S. COASTLINE AND MOVE ACROSS THE ERN CAROLINAS THROUGH FRIDAY MORNING. THIS DISTURBANCE MAY EVENTUALLY BECOME INCORPORATED INTO THE LARGER SCALE CYCLONIC CIRCULATION ASSOCIATED WITH THE CUT-OFF LOW MEANDERING OVER THE MIDWEST/OH VALLEY. MEANWHILE...LARGE AND PROGRESSIVE UPPER TROUGH WILL CONTINUE TO TRACK EAST FROM THE NRN ROCKIES TO THE NRN PLAINS THIS PERIOD. STRONGEST HEIGHT FALLS ASSOCIATED THIS SYSTEM WILL LIKELY OCCUR FROM THE NRN PLAINS TO MANITOBA. HOWEVER...PRONOUNCED HEIGHT RISES AND CORRESPONDING SURFACE PRESSURE RISES BEHIND THE TROUGH...SPREADING FROM THE INTERIOR NORTHWEST ACROSS THE NRN ROCKIES...WILL AID IN DRIVING A COLD FRONT SWD/SEWD ACROSS THE CNTRL HIGH PLAINS THROUGH LATE THURSDAY NIGHT. SUBTROPICAL RIDGE WILL PERSIST FROM THE RIO GRANDE VALLEY WNWWD ACROSS THE SOUTHWEST WITH MONSOON MOISTURE PERSISTING ACROSS PARTS OF AZ/NM. ...ERN CAROLINAS... THERE IS RELATIVELY GOOD AGREEMENT AMONG A VARIETY OF GUIDANCE THAT STRONG TO INTENSE LOW LEVEL SHEAR WILL STEADILY INCREASE ACROSS THE ERN CAROLINAS THROUGH THURSDAY NIGHT. VERY MOIST AIR MASS...LIFT ALONG RESIDUAL FRONT AND OUTFLOW BOUNDARIES...AND INCREASING FORCING ASSOCIATED WITH THE ADVANCING ERNESTO CIRCULATION...WILL ALL CONTRIBUTE TO THE POTENTIAL FOR WIDESPREAD DEEP CONVECTION. CONVECTIVE BANDS ROTATING AROUND THE TROPICAL LOW SHOULD TRANSLATE NWD/NWWD AND INLAND ACROSS THE COASTLINE FROM NERN SC TO THE OUTER BANKS OF NC THROUGH FRIDAY NIGHT. GIVEN A STEADY INCREASE IN LOW LEVEL ELY FLOW...AND CORRESPONDING STRENGTHENING OF SRH IN THE NERN QUADRANT OF TROPICAL LOW...A FEW ISOLATED/BRIEF TORNADOES APPEAR POSSIBLE. ...CNTRL HIGH PLAINS... WHILE STRONG MOISTURE RETURN DOES NOT APPEAR LIKELY ACROSS THE REGION...MODEST BOUNDARY LAYER MOISTENING WILL OCCUR NEAR LEE-TROUGH AND ADVANCING COLD FRONT FROM SWRN NEB SWD ALONG CO/KS BORDER. SURFACE DEWPOINTS AROUND 60F AND TEMPERATURES CLIMBING THROUGH THE 80S WILL CONTRIBUTE TO MODERATE DESTABILIZATION WITH LAPSE RATES STEEPENING WITH DAYTIME HEATING. MEAN LAYER CAPE ON THE ORDER OF 1500 J/KG IS ANTICIPATED BY AFTERNOON...WHEN FORCING NEAR INTERSECTION OF COLD FRONT AND SURFACE TROUGH/WEAK DRY LINE SHOULD LOCALLY ELIMINATE CAPPING ASSOCIATED WITH ELEVATED MIXED LAYER. WEAK BUT VEERING WINDS WITH HEIGHT FROM LOWER TO MID-LEVELS...BENEATH MODERATE WESTERLY HIGH LEVEL FLOW...SHOULD PROVE ADEQUATE FOR ISOLATED SUPERCELLS WITH HAIL AND HIGH WINDS. ADDITIONAL ACTIVITY WITH SEVERE HAIL POTENTIAL MAY ALSO OCCUR IN RELATIVELY MOIST POST-FRONTAL UPSLOPE FLOW REGIME FROM NEB PNHDL TO THE CO FRONT RANGE. DESPITE WEAK SYNOPTIC SCALE HEIGHT FALLS...DIFFLUENT MID AND UPPER LEVEL FLOW...AND FOCUSED LIFT ALONG THE FRONT/LEE TROUGH...ARE EXPECTED TO RESULT IN ONE OR MORE SMALL CONVECTIVE CLUSTERS EVOLVING ACROSS THE HIGH PLAINS AREA THROUGH THURSDAY EVENING. THIS ACTIVITY MAY MERGE AND GROW UPSCALE INTO AN MCS WITH ISOLATED SEVERE WEATHER POSSIBLY SPREADING SSEWD FROM WRN KS THROUGH LATE THURSDAY NIGHT. ..CARBIN.. 08/30/2006  From swody2 at goshenarc.org Thu Aug 31 05:24:05 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Thu, 31 Aug 2006 01:24:05 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 310524 SWODY2 SPC AC 310523 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1223 AM CDT THU AUG 31 2006 VALID 011200Z - 021200Z ...THERE IS A SLGT RISK OF SVR TSTMS FRI ACROSS PARTS OF THE MID ATLANTIC COAST STATES.... MODELS MAINTAIN THEIR DIFFERENCES CONCERNING THE DETAILS OF THE LARGE SCALE PATTERN EVOLUTION INTO THE EARLY PART OF THE WEEKEND. BUT...IN GENERAL TERMS...AN AMPLIFIED POLAR TROUGH STILL APPEARS LIKELY TO BEGIN SPLIT AS IT VERY SLOWLY PROGRESSES ACROSS THE CENTRAL CANADIAN PROVINCES AND THE NORTH CENTRAL U.S. FRIDAY INTO EARLY SATURDAY. AN EMBEDDED SHORT WAVE IN THE NORTHERN PORTION OF THE TROUGH IS PROGGED TO REMAIN A BIT MORE PROGRESSIVE WITHIN STRONGER BELT OF WESTERLIES...WELL NORTH OF THE CANADIAN/U.S. BORDER. A SHORT WAVE EMBEDDED WITHIN THE SOUTHERN PORTION OF THE TROUGH IS PROGGED TO DIG INTO THE WEAKER SOUTHERN STREAM...AND BEGIN TO EVOLVE INTO ANOTHER CLOSED LOW ACROSS THE NORTHERN PLAINS/UPPER MISSISSIPPI VALLEY. WHILE THIS OCCURS...DOWNSTREAM CLOSED LOW/TROUGH MAY BEGIN TO SHIFT OR REDEVELOP EASTWARD/NORTHEASTWARD THROUGH THE OHIO VALLEY...AS MID-LEVEL REMNANTS OF ERNESTO ROTATE AROUND ITS EASTERN AND NORTHEASTERN PERIPHERY. ...MID ATLANTIC COAST STATES... A WEAK SURFACE BOUNDARY IS EXPECTED TO LINGER TO THE LEE OF THE CENTRAL/SOUTHERN APPALACHIANS INTO THE DELMARVA PENINSULA THROUGH EARLY FRIDAY. AS REMNANT LOW-LEVEL CIRCULATION ASSOCIATED WITH ERNESTO INTERACTS WITH THIS FEATURE...TORNADIC POTENTIAL COULD BECOME ENHANCED ACROSS PARTS OF EASTERN VIRGINIA INTO THE DELMARVA REGION. LATER IN THE DAY...A BRIEF PERIOD OF SURFACE HEATING STILL APPEARS POSSIBLE IN VERY MOIST WARM SECTOR ACROSS THIS SAME REGION...IN THE WAKE OF THE MID-LEVEL IMPULSE. IF THIS OCCURS... LOW-LEVEL CONVERGENCE IN AN UNSTABLE BOUNDARY LAYER MAY SUPPORT ADDITIONAL SCATTERED CONVECTIVE DEVELOPMENT...AND LOW-LEVEL SHEAR/ AMBIENT VERTICAL VORTICITY IS EXPECTED TO REMAIN FAVORABLE FOR ISOLATED TORNADOES. ...CENTRAL STATES... MODELS STILL VARY SUBSTANTIALLY WITH THE TIMING OF INITIAL COOL SURGE INTO THE LEE OF THE CENTRAL ROCKIES. INFLUENCE OF WEAKENING MORNING CONVECTION AND LINGERING CLOUD COVER IS ALSO A CONCERN TO POTENTIAL FOR DESTABILIZATION IN MORE MOIST POST-FRONTAL/OUTFLOW REGIME ACROSS THE CENTRAL HIGH PAINS. IT APPEARS THE STRONGEST INSTABILITY WILL DEVELOP NEAR THE IMMEDIATE VICINITY OF BOUNDARY ...TO THE SOUTHEAST OF THE FRONT RANGE INTO THE TEXAS/OKLAHOMA PANHANDLE REGION. BUT...PEAK LATE AFTERNOON CAPE VALUES ON THE ORDER OF 1000 TO 1500 J/KG...IN ONLY WEAK TO MODERATE SHEAR BENEATH NORTHWESTERLY MID-LEVEL FLOW...SEEMS LIKELY TO MARGINALIZE SEVERE WEATHER POTENTIAL. ..KERR.. 08/31/2006  From swody2 at goshenarc.org Thu Aug 31 17:29:50 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Thu, 31 Aug 2006 13:29:50 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 311730 SWODY2 SPC AC 311729 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1229 PM CDT THU AUG 31 2006 VALID 011200Z - 021200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF ERN NC...ERN VA...SRN MD AND DE... ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF ERN CO AND FAR WRN KS... ...ERN SEABOARD... BASED ON THE HURRICANE CENTER FORECAST TRACK OF ERNESTO/SEE TPC FORECAST ADVISORY 28...TROPICAL STORM ERNESTO IS FORECAST TO CONTINUE A NWD MOVEMENT AND SHOULD BE LOCATED IN ECNTRL NC BY 12Z FRI. ALTHOUGH ERNESTO IS FORECAST TO REMAIN A TROPICAL STORM...SOME ORGANIZATION AND STRENGTHENING MAY OCCUR TONIGHT BEFORE ERNESTO MOVES INLAND NEAR WILMINGTON NC. STRONG ELY WINDS AHEAD OF THE STORM WILL INCREASE DEWPOINTS ACROSS NC FROM EAST TO WEST TONIGHT RESULTING IN A GRADUAL INCREASE OF INSTABILITY. IN ADDITION...FORECAST SOUNDINGS ACROSS THE REGION AT 12Z FRIDAY SHOW STRONG LOW-LEVEL SHEAR PROFILES ACROSS THE ENTIRE STATE OF NC WITH THE MOST FAVORABLE DEEP LAYER SHEAR ACROSS THE ERN HALF OF THE STATE. THIS SUGGESTS THE POTENTIAL FOR ROTATING STORMS WILL BE MOST LIKELY EAST OF THE CENTER WITH THE GREATEST THREAT IN THE COASTAL PLAINS EAST OF I-40 AND I-95. THE HIGH SFC DEWPOINTS AND STRONG LOW-LEVEL SHEAR PROFILES APPEAR FAVORABLE FOR TORNADOES. THE GREATEST THREAT FOR TORNADOES SHOULD OCCUR BETWEEN 12Z AND 18Z AS THE TROPICAL STORM MOVES FURTHER INLAND. FOR THIS REASON...HAVE ADJUSTED THE SLIGHT RISK AREA SWD ACROSS ERN NC TO ACCOUNT FOR A SLIGHTLY SLOWER FORWARD SPEED OF ERNESTO. THE TORNADO THREAT MAY ALSO CONTINUE NWD INTO ERN VA...MD AND DE AS INSTABILITY INCREASES FRIDAY AFTERNOON EAST OF THE CENTER OF ERNESTO. ...SRN PLAINS/CNTRL HIGH PLAINS... AN UPPER-LEVEL TROUGH OVER THE NRN ROCKIES/NRN HIGH PLAINS WILL CONTINUE MOVING SLOWLY EWD TONIGHT INTO THE NRN PLAINS. THE UPPER-TROUGH IS FORECAST TO BECOME MORE AMPLIFIED WITH TIME AND THE FAR SRN EXTENT OF THE TROUGH SHOULD AFFECT THE CNTRL HIGH PLAINS BY FRIDAY AFTERNOON. AT THE SFC...A MOIST AXIS SHOULD REMAIN IN PLACE EXTENDING NWD FROM THE TX PANHANDLE INTO ERN CO WHERE SFC DEWPOINTS SHOULD BE IN THE 55-65 F RANGE. AN AREA OF MODERATE INSTABILITY APPEARS MOST LIKELY TO DEVELOP NEAR THE PALMER DIVIDE AND ACROSS SE CO DURING THE DAY FRIDAY. MODEL FORECASTS ARE ALSO CONSISTENT WITH DEVELOPING A CLUSTER OF STRONG CONVECTION NEAR A BAND OF ENHANCED LOW-LEVEL CONVERGENCE ALONG A COLD FRONT IN ERN CO BY AFTERNOON. FORECAST SOUNDINGS ACROSS ERN CO FRIDAY AFTERNOON SHOW MODERATE TO STRONG SHEAR PROFILES WITH STEEP LOW-LEVEL LAPSE RATES SUGGESTING SUPERCELLS WITH LARGE HAIL WILL BE POSSIBLE. ISOLATED WIND DAMAGE MAY ALSO OCCUR AS AN MCS MOVES SWD ACROSS SERN CO BY EARLY EVENING. FOR THIS REASON...WILL UPGRADE THE AREA TO SLIGHT RISK. FURTHER SOUTH SOUTHEAST ACROSS THE TX PANHANDLE...MODERATE INSTABILITY MAY ALSO DEVELOP BY FRIDAY AFTERNOON. HOWEVER...THE UPPER-TROUGH IS NOT FORECAST TO AFFECT THE AREA AND DEEP LAYER SHEAR IS FORECAST TO BE WEAKER THAN AREAS FURTHER NORTH. FOR THIS REASON...ANY THREAT FOR HAIL AND DAMAGING WINDS IS EXPECTED TO MARGINAL AND ISOLATED. ..BROYLES.. 08/31/2006  From swody2 at goshenarc.org Tue Aug 1 05:24:30 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 01 Aug 2006 01:24:30 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 010525 SWODY2 SPC AC 010523 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1223 AM CDT TUE AUG 01 2006 VALID 021200Z - 031200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM PARTS OF THE CNTRL PLAINS THROUGH THE MIDDLE AND UPPER MS VALLEY...GREAT LAKES AND NERN STATES... ...SYNOPSIS... UPPER TROUGH NOW MOVING INTO THE W COAST WILL CONTINUE EWD INTO THE UPPER MS VALLEY AND GREAT LAKES WEDNESDAY. POTENTIAL WILL EXIST FOR WEAKER IMPULSES TO EJECT NEWD AHEAD OF THIS FEATURE. ONE SUCH FEATURE OVER NM IS FORECAST TO EJECT INTO THE GREAT LAKES. HEIGHT FALLS ACCOMPANYING THE UPPER TROUGH WILL RESULT IN DEAMPLIFICATION OF SERN U.S. UPPER RIDGE AND A MORE ZONAL PATTERN BECOMING ESTABLISHED OVER THE NRN THIRD OF THE COUNTRY. A COLD FRONT WILL SETTLE SWD AND BY EARLY WEDNESDAY SHOULD EXTEND FROM SERN CANADA SWWD THROUGH THE GREAT LAKES AND INTO THE CNTRL PLAINS. A WEAK SURFACE LOW ACCOMPANYING THE ENEWD ADVANCING SHORTWAVE TROUGH IS FORECAST TO DEVELOP ALONG THE FRONT AND TRACK EWD THROUGH THE GREAT LAKES DURING THE DAY. ...CNTRL PLAINS THROUGH MID MS VALLEY AND GREAT LAKES... SURFACE FRONT EXPECTED TO EXTEND FROM THE CNTRL PLAINS NEWD THROUGH THE GREAT LAKES WILL PROVIDE A FOCUS FOR THUNDERSTORMS THIS PERIOD. WARM MID LEVEL TEMPERATURES WITH -4C TO -6C AT 500 MB WILL PERSIST IN PRE-FRONTAL WARM SECTOR. HOWEVER...RICH LOW LEVEL MOISTURE WITH LOW 70S DEWPOINTS WILL RESULT IN MODERATE INSTABILITY AS THE BOUNDARY LAYER WARMS. STORMS MAY BE ONGOING EARLY WEDNESDAY WITHIN ZONE OF ISENTROPIC ASCENT N OF FRONT OVER PARTS OF THE PLAINS NEWD INTO THE GREAT LAKES...SUPPORTED BY AN EXPANSIVE SWLY LOW LEVEL JET. THE LOW LEVEL JET WILL LIFT NEWD INTO THE GREAT LAKES AHEAD OF EWD ADVANCING SURFACE LOW...RESULTING IN ENHANCED CONVERGENCE IN THAT REGION. ADDITIONAL STORMS ARE EXPECTED TO REDEVELOP ALONG FRONT AS THE BOUNDARY LAYER DESTABILIZES DURING THE AFTERNOON. STRONG WSWLY WIND PROFILES...WITH 50 KT BETWEEN 3 AND 6 KM ACCOMPANYING EWD ADVANCING SHORTWAVE TROUGH AND ATTENDANT LOW LEVEL JET...WILL EXIST OVER THE GREAT LAKES. POTENTIAL WILL EXIST FOR FAST MOVING CLUSTERS AND BOWING SEGMENTS WITH DAMAGING WIND THE PRIMARY THREAT. A FEW STORMS MAY ALSO DEVELOP SUPERCELL STRUCTURES. FARTHER SW ACROSS THE MID MS VALLEY INTO KS...WIND PROFILES WILL BE WEAKER...BUT A FEW STORMS WILL BE CAPABLE OF WET MICROBURSTS. PORTIONS OF THE GREAT LAKES MAY NEED TO BE UPGRADED TO MODERATE RISK IN LATER OUTLOOKS GIVEN THE POTENTIAL FOR SIGNIFICANT WIND DAMAGE. ...NERN STATES... QUASISTATIONARY FRONT WILL EXTEND FROM W-E ACROSS ME AND MAY LIFT SLOWLY NWD DURING THE DAY. THE ATMOSPHERE WILL BECOME MODERATELY UNSTABLE OVER THE NERN STATES IN WARM SECTOR S OF THIS BOUNDARY SUPPORTED BY LOW 70S DEWPOINTS. STORMS MAY INTENSIFY IN VICINITY OF THIS BOUNDARY AS WELL AS UPSTREAM ALONG COLD FRONT OVER SERN CANADA AND ALONG LAKE BREEZE BOUNDARIES. THESE STORMS WILL SPREAD ESEWD THROUGH PARTS OF THE NERN U.S. DURING THE DAY. THIS REGION WILL REMAIN UNDER MODERATE DEEP LAYER 40 KT WNWLY FLOW. THIS ENVIRONMENT WILL BE SUPPORTIVE OF STORMS EVOLVING INTO MULTICELL CLUSTERS AND BOWING SEGMENTS. DAMAGING WIND WILL BE THE PRIMARY THREAT. ..DIAL.. 08/01/2006  From swody2 at goshenarc.org Tue Aug 1 16:51:11 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 01 Aug 2006 12:51:11 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 011651 SWODY2 SPC AC 011650 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK ISSUED BY AFWA OFFUTT AIR FORCE BASE BELLEVUE NE 1150 AM CDT TUE AUG 01 2006 VALID 021200Z - 031200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE GREAT LAKES INTO KANSAS... ...THERE IS A SLGT RISK OF SVR TSTMS IN NEW YORK AND NEW ENGLAND... ...SYNOPSIS... SUBTROPICAL RIDGE CONTINUES TO BREAK DOWN WITH AN UPPER TROUGH PROGRESSING EASTWARD FROM THE ROCKIES INTO THE GREAT LAKES. THIS WILL LEAD TO A ZONAL FLOW PATTERN OVER THE NORTHERN CONUS...WITH THE RIDGE AXIS SUPPRESSED FROM TEXAS INTO NORTH CAROLINA. A FRONTAL BOUNDARY ASSOCIATED WITH THE UPPER TROUGH WILL CONTINUE A SLOW SOUTHWARD PROGRESSION FROM NEW ENGLAND INTO MICHIGAN AND WISCONSIN AND THEN SOUTHWESTWARD INTO KANSAS. ...GREAT LAKES INTO KANSAS... SURFACE FRONT WILL DROP SOUTHWARD THROUGH THIS AREA DURING THE FORECAST PERIOD. CONVECTION WILL BE ONGOING ALONG THIS FRONT IN SOME LOCATIONS IN THE MORNING...AND TEND TO DISSIPATE AS THE LOW LEVEL JET WEAKENS DIURNALLY. CLOUD DEBRIS AND PRECIPITATION FROM THESE WEAKENING STORMS WILL MAKE PINPOINTING FAVORED LOCATIONS FOR SURFACE BASED CONVECTION LATER IN THE AFTERNOON AND EVENING TRICKY. STRONG FLOW AROUND 50 KNOTS AT 500 HPA EXISTS ACROSS NORTHERN MICHIGAN, BUT THIS WILL BE NORTH OF THE FRONTAL BOUNDARY WHERE INSTABILITY WILL BE WEAKER WITH MUCAPE AROUND 1000 J/KG AND WHERE STORMS WILL TEND TO BE ELEVATED. SOUTH OF THE BOUNDARY FROM SOUTHERN MICHIGAN INTO NORTHERN MISSOURI FLOW AT 500 MB WILL BE WEAKER AROUND 25-35 KNOTS BUT MLCAPE WILL BE HIGHER AROUND 2500 J/KG WHERE STRONG INSOLATION CAN OCCUR. THIS WILL BE ENOUGH FOR MULTICELL THUNDERSTORM CLUSTERS AND GIVEN 850 MB FLOW AROUND 25 KNOTS, WIND DAMAGE WILL BE A THREAT. MID LEVEL LAPSE RATES WILL BE FAIRLY WEAK AROUND 6.0 K/KM SO MARGINALLY SEVERE HAIL IS EXPECTED AT MOST. FARTHER SOUTHWEST INTO KANSAS, THE WRF IS SHOWING A STRONG CONVECTIVE SIGNAL AND THIS SEEMS REASONABLE GIVEN THE SURFACE CONVERGENCE ALONG THE FRONT. 500 MB FLOW WILL ALSO BE AROUND 25-35 KNOTS SO THAT MULTICELL THUNDERSTORMS AND SOME SCATTERED DAMAGING MICROBURSTS ARE POSSIBLE. ...NEW ENGLAND... FRONTAL BOUNDARY WILL BE MOSTLY STATIONARY IN THIS REGION, AND WITH INSOLATION MLCAPES WILL RISE TO OVER 3000 J/KG WITH MINIMAL CAPPING BY 1800 UTC. THIS WILL LEAD TO SCATTERED THUNDERSTORM DEVELOPMENT WITH POSSIBLE WIND DAMAGE GIVEN THE INSTABILITY AND 40 KNOTS OF 500 MB FLOW. THIS IS PROGGED TO INCREASE TO AROUND 45-50 KNOTS IN THE EVENING...BUT INSTABILITY SHOULD BE WANING BY THAT TIME. AN ISOLATED TORNADO OR TWO COULD BE POSSIBLE IF ANY LOCAL BOUNDARIES INTERACT WITH THUNDERSTORMS BEFORE THE INSTABILITY DECREASES. ..AFWA.. 08/01/2006  From swody2 at goshenarc.org Wed Aug 2 05:51:12 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 02 Aug 2006 01:51:12 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 020550 SWODY2 SPC AC 020549 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1249 AM CDT WED AUG 02 2006 VALID 031200Z - 041200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE OH VALLEY INTO THE NERN U.S.... ...SYNOPSIS... ZONAL FLOW WILL CONTINUE OVER THE NRN THIRD OF THE COUNTRY WITH AN UPPER RIDGE PREVAILING OVER THE SRN TWO THIRDS. SERIES OF SHORTWAVE TROUGHS WILL ADVANCE EWD THROUGH THE FLOW. ONE SUCH IMPULSE NOW MOVING INTO THE PLAINS AREA IS PROGGED OVER THE NERN U.S. EARLY THURSDAY WITH ATTENDANT SURFACE LOW. THE GFS AND NAM ARE SIMILAR IN TIMING OF THIS FEATURE. A SURFACE FRONT WILL SETTLE SWD INTO THE OH VALLEY AND NERN STATES IN WAKE OF THIS IMPULSE. SWRN PORTIONS OF THIS BOUNDARY WILL EXTEND SWWD INTO THE SRN PLAINS AREA. ...NERN STATES THROUGH OH VALLEY... FRONTAL BOUNDARY SHOULD EXTEND FROM A SURFACE LOW OVER THE NERN STATES SWWD THROUGH THE OH VALLEY AND SRN PLAINS EARLY THURSDAY AND PROVIDE A FOCUS FOR THUNDERSTORMS. EXITING SHORTWAVE TROUGH SHOULD FORCE NERN PORTION OF FRONT SEWD DURING THE DAY. A STRONG WLY LOW-MID LEVEL JET WITH DEEP LAYER UNIDIRECTIONAL 40 TO 50 KT FLOW WILL ACCOMPANY THE SHORTWAVE TROUGH INTO THE NERN STATES EARLY THURSDAY. HOWEVER...WIND PROFILES WILL GRADUALLY WEAKEN DURING THE MORNING AS THIS FEATURES MOVES OFFSHORE. GIVEN TIME OF DAY MUCH OF THE EARLY STORMS OVER THE NERN STATES COULD BE ELEVATED WHICH COULD LIMIT OVERALL DAMAGING WIND POTENTIAL. HOWEVER...IT REMAINS POSSIBLE THAT SOME OF THIS ACTIVITY COULD BECOME SURFACE BASED LATER IN THE MORNING BEFORE THE STRONGER WIND PROFILES SUBSIDE. OTHERWISE...A FEW STORMS MAY DEVELOP FARTHER SW ALONG FRONT OVER REMAINING PORTIONS OF THE NERN STATES AS THE BOUNDARY LAYER DESTABILIZES. POTENTIAL FOR SUBSIDENCE IN WAKE OF LEAD SHORTWAVE TROUGH COULD POTENTIALLY LIMIT COVERAGE. DAMAGING WIND WILL BE THE PRIMARY THREAT WITH ANY STORMS THAT DEVELOP IN THIS REGION DURING THE DAY. OH VALLEY PORTION OF FRONT MAY REMAIN NEARLY STATIONARY AS UPSTREAM VORT MAX...POSSIBLY ENHANCED BY OVERNIGHT MCS...LIFTS ENEWD THROUGH THE MID MS VALLEY AND INTO THE OH VALLEY. RICH LOW LEVEL MOISTURE AND SURFACE HEATING WILL CONTRIBUTE TO MODERATE INSTABILITY ALONG AND S OF FRONT. STORMS FROM OVERNIGHT MCS MAY STILL BE ONGOING EARLY THURSDAY. OUTFLOW FROM THIS ACTIVITY MAY SERVE TO REINFORCE THE FRONT. OTHER STORMS SHOULD DEVELOP ALONG FRONT OR RESIDUAL OUTFLOW BOUNDARIES WITHIN ZONE OF ASCENT DOWNSTREAM FROM VORT MAX AS THE BOUNDARY LAYER DESTABILIZES. THIS REGION WILL REMAIN ON SRN FRINGE OF STRONGER WLYS WITH 30 TO 35 KT WLY FLOW EXPECTED IN THE 850 MB TO 500 MB LAYER...BUT WITH MODEST VERTICAL SHEAR SUPPORTIVE OF MULTICELLS. STORMS MAY EVOLVE INTO CLUSTERS AND LINE SEGMENTS AS THEY SPREAD EWD WITH DAMAGING WIND THE PRIMARY THREAT. ...SRN PLAINS AREA... OTHER STORMS MAY DEVELOP ALONG TRAILING PORTIONS OF THE FRONT OVER THE SRN PLAINS AS WELL AS OVER THE HIGHER TERRAIN OF NM. WEAK VERTICAL SHEAR SUGGESTS STORMS WILL NOT BE VERY ORGANIZED. HOWEVER...THE THERMODYNAMIC ENVIRONMENT COULD SUPPORT ISOLATED WET MICROBURSTS. ...CNTRL AND NRN HIGH PLAINS... STORMS MAY DEVELOP OVER THE HIGHER TERRAIN OF THE CNTRL ROCKIES FROM CO THROUGH WY WHERE STRONGER VERTICAL SHEAR WILL EXIST. SOME OF THIS ACTIVITY MAY SPREAD EWD INTO THE HIGH PLAINS. MODEST LOW LEVEL MOISTURE WILL LIMIT INSTABILITY. HOWEVER...STEEP LAPSE RATES AND LOW LEVEL INVERTED-V PROFILES WILL SUPPORT A THREAT OF ISOLATED HAIL AND STRONG WIND GUSTS. ..DIAL.. 08/02/2006  From swody2 at goshenarc.org Wed Aug 2 17:41:04 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 02 Aug 2006 13:41:04 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 021740 SWODY2 SPC AC 021739 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1239 PM CDT WED AUG 02 2006 VALID 031200Z - 041200Z ...THERE IS A SLGT RISK OF SVR TSTMS THROUGH EARLY THURSDAY NIGHT FROM SRN NEW ENGLAND INTO THE LOWER OHIO VALLEY.... ...SYNOPSIS... MAIN BAND OF WESTERLIES WILL CONTINUE TO RUN ALONG THE NRN TIER OF THE U.S. DURING THE PERIOD. MINOR RAPIDLY MOVG MID LEVEL SHORTWAVE TROUGH WILL MOVE EWD FROM THE UPR GREAT LAKES REGION INTO THE LWR GREAT LAKES BY 04/00Z INTO THE CENTRAL NORTHEAST U.S. BY THE END OF THE PERIOD. THIS WILL PUSH MAIN COLD FRONTAL BOUNDARY SEWD EXTENDING FROM LONG ISLAND/SERN NY STATE WSWWD THRU SWRN PA INTO E CENTRAL MO BY EVENING. MEANWHILE...LARGE MID/UPPER LEVEL RIDGE WILL PRETTY MUCH HOLD FROM THE CAROLINAS WWD THRU THE SRN PLAINS INTO THE SRN ROCKIES. ...SRN PARTS OF NEW ENGLAND INTO THE LOWER OHIO VALLEY... FRONTAL BOUNDARY/ASSOCIATED CONVECTIVE BOUNDARIES FROM PREVIOUS DAY CONVECTION WILL EXTEND FROM SRN NH/VT WSWWD ALONG SRN PARTS OF THE ERN GREAT LAKES AND CENTRAL IL INTO NWRN MO AT THE START OF THE PERIOD. NAM PUSHES SURFACE RIDGING INTO IA/IL DURING THE AFTN...BUT ALSO LAGS 850 MB COLD FRONT ALONG THE SRN GREAT LAKES DURING THE AFTN. MID/UPR LEVEL JET STREAK OF 50-60 KT AND 80-90 KT RESPECTIVELY WILL EXTEND FROM SERN ONTARIO ENEWD OVER NRN NEW ENGLAND PLACING MUCH OF THE UPR OHIO VALLEY AND LOWER GREAT LAKES IN FAVORABLE ENTRANCE REGION TO PROMOTE UPWARD ASCENT. AIR MASS WILL BE MOST UNSTABLE OVER SRN NEW ENGLAND INTO CENTRAL PA BY 03/18Z WHERE THERE WILL BE DAYTIME HEATING WITH SBCAPES BETWEEN 2500-3000 J/KG. NAM IS QUESTIONABLE WITH LOW/MID LEVEL LAPSE RATES IN THESE AREAS AND THAT COULD BE THAT 500 MB ARE AROUND -5C...BUT GIVEN THAT SFC-3KM LAPSE RATES ARE 8.5C/KM AND DCAPE ESTIMATES ARE AROUND 1000 J/KG...IT LOOKS LIKE THE MAIN THREAT FOR DAMAGING WINDS WILL BE WITH STORMS ALONG/AHEAD OF THE FRONT BY 03/18Z INTO THE 04/00Z TIME FRAME...THEN DURING THE AFTN/EVE FROM WRN PA INTO E CENTRAL MO. ...SRN HIGH PLAINS... STRONG DAYTIME HEATING IN VICINITY OF WEAKENING FRONTAL BOUNDARY WILL BE SUFFICIENT FOR HIGH BASED TYPE THUNDERSTORMS FROM W CENTRAL MO WSWWD INTO THE TX PANHANDLE. MODEL SOUNDINGS INDICATE INVERTED-V TYPE PROFILES ACROSS THESE AREAS WITH TEMP/DEW POINT DIFFERENCES 25-30 DEG F WITH LOW LEVEL LAPSE RATES NEAR 9C/KM. THUS...STRONG MICROBURSTS ARE EXPECTED WITH SCATTERED THUNDERSTORMS ACROSS THESE AREAS LATE IN THE AFTN AND EVENING. ...PARTS OF THE CENTRAL AND NRN HIGH PLAINS... MODELS WANT TO BRING SOME RETURN LOW LEVEL MOISTURE/UPSLOPE TYPE FLOW INTO NERN CO NWD INTO THE BLACK HILLS OF SD. EXPECT A FEW HIGH BASED TYPE THUNDERSTORMS HERE AS WELL WITH LAPSE RATES AROUND 9C/KM IN THE LOW LEVELS SUPPORTING THE POSSIBILITY OF DRY MICROBURSTS. ..MCCARTHY.. 08/02/2006  From swody2 at goshenarc.org Thu Aug 3 17:30:27 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Thu, 03 Aug 2006 13:30:27 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 031730 SWODY2 SPC AC 031729 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1229 PM CDT THU AUG 03 2006 VALID 041200Z - 051200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... LARGE SCALE RIDGE WILL SPREAD ACROSS THE SRN TWO-THIRDS OF THE U.S. DURING THE PERIOD. THIS WILL KEEP MAIN BAND OF WESTERLIES ACROSS SRN CANADA/NRN TIER OF STATES. ONE MINOR SHORTWAVE TROUGH WILL MOVE EWD ACROSS THE NRN GREAT LAKES DURING THE SECOND HALF OF THE PERIOD...WHILE SECOND STRONGER TROUGH/ASSOCIATED VORTICITY MAX MOVES SEWD ACROSS ALBERTA/SASKATCHEWAN. COLD FRONTAL BOUNDARY MOVING SWD/SEWD ACROSS THE LOWER GREAT LAKES AND NRN MID ATLANTIC REGION ON DAY 1 WILL WEAKEN UNDERNEATH DOMINATE RIDGE AS IT MOVES THRU VA AND KY. ...NRN PLAINS... NAM MODEL RATHER AGGRESSIVE COMPARED TO THE GFS OVER PARTS OF ERN ND INTO NRN MN. THIS IS IN ASSOCIATION WITH STRONG WARM ADVECTION ASSOCIATED WITH EXIT REGION OF 35-45 KT LOW LEVEL JET THAT EXTENDS FROM NEB INTO CENTRAL AND NERN MN. THE NAM GENERATES QUITE A BIT OF DEEP LAYER SHEAR ACROSS MN S OF A WEAK FRONT THAT MAKES ITS WAY SWD THRU THIS REGION FRIDAY NIGHT. BUT...MODEL SOUNDINGS INDICATE VERY STRONG CAPPING INVERSION THRU THE NRN PLAINS WHICH WILL INHIBIT CONVECTIVE DEVELOPMENT EXCEPT NEAR THE ND/CANADA BORDER WHERE 50 KT MID LEVEL FLOW IS FORECAST...THEN ESEWD ACROSS EXTREME NRN MN. SOME THUNDERSTORMS CAN MOVE EWD/SEWD ACROSS EXTREME NRN MN FRIDAY NIGHT...BUT GIVEN THE LIMITED EFFECTIVE INSTABILITY AND ELEVATED NATURE OF THE STORMS...WOULD EXPECT ACTIVITY TO MOSTLY BE BELOW SEVERE LEVELS. ...PARTS OF ERN VA/ERN NC... REMNANTS OF COLD FRONTAL BOUNDARY IS EXPECTED TO EXTEND FROM THE CENTRAL DELMARVA INTO THE TN VALLEY FRI AFTN. AIR MASS ALONG AND S OF THE BOUNDARY WILL BE MODERATELY UNSTABLE WITH SBCAPES FORECAST BETWEEN 2000 AND 3000 J/KG. SCATTERED THUNDERSTORMS ARE EXPECTED IN THE VICINITY OF THE BOUNDARY...BUT REMAIN BELOW SEVERE LEVELS DUE TO WEAK FLOW AND HIGHER GEOPOTENTIAL HEIGHTS FROM DOMINATING RIDGE. ACTIVITY COULD PRODUCE SOME STRONG WINDS GIVEN THE EXPECTED 20 DEG T/TD SPREADS...BUT GIVEN WEAK FLOW ALOFT AND LOW/MID LEVEL LAPSE RATES AROUND 6-6.5C/KM ACTIVITY SHOULD REMAIN BELOW SEVERE LEVELS. ..MCCARTHY.. 08/03/2006  From swody2 at goshenarc.org Fri Aug 4 06:15:34 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Fri, 04 Aug 2006 02:15:34 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 040615 SWODY2 SPC AC 040614 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0114 AM CDT FRI AUG 04 2006 VALID 051200Z - 061200Z ...THERE IS A SLGT RISK OF SVR TSTMS NERN PLAINS...UPPER MS VALLEY REGION... ...SYNOPSIS... MID-UPPER LEVEL...SYNOPTIC-SCALE RIDGING WILL DOMINATE PATTERN FROM 4-CORNERS REGION EWD ACROSS SRN PLAINS TO CAROLINAS. MEANWHILE PROGRESSIVE AND GENERALLY ZONAL PATTERN IS EXPECTED TO CHARACTERIZE NRN STREAM FLOW BELT...ACROSS ROUGHLY NRN 1/4 OF CONUS. SHORTWAVE TROUGH -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY OVER CENTRAL/NRN BC -- IS FCST TO AMPLIFY THROUGH BOTH DAY-1 AND DAY-2...AS IT MOVES ESEWD ACROSS SASK. CONSIDERABLE DISAGREEMENT REMAINS IN PROGS OVER WHETHER THIS SYSTEM WILL EVOLVE INTO CLOSED LOW ACROSS SASK/MANITOBA DURING PERIOD...GIVEN PROGRESSIVE NATURE OF PATTERN AND PRESENCE OF OPEN WAVE IN ROUGHLY HALF OF COMBINED SREF/OPERATIONAL 500 MB MODEL PROGS. MID/UPPER LEVEL LOW - NOW CUT OFF ACROSS TRANS-PECOS AND BIG BEND REGIONS OF SW TX -- IS EXPECTED TO DRIFT GENERALLY WWD AROUND MEAN RIDGE TOWARD AZ...CONTRIBUTING TO CLOUDS/PRECIP AND GEN THUNDER POTENTIAL OVER PORTIONS AZ/NM. AT SFC...STRONG FRONTOGENESIS LATE DAY-1 AND EARLY DAY-2 OVER NRN ROCKIES AND NRN HIGH PLAINS WILL LEAD TO COLD FRONT SWEEPING SEWD ACROSS UPPER MIDWEST AND CENTRAL HIGH PLAINS DURING THIS PERIOD...WHILE DEEPENING SFC LOW EJECTS FROM ND ENEWD TOWARD NWRN ONT. FARTHER S...WEAK COLD FRONTAL ZONE IS ANALYZED FROM ERN GREAT LAKES ACROSS OZARKS AND RED RIVER REGION...TO E-CENTRAL/SERN NM. WRN PORTION OF THIS FRONT SHOULD BECOME DIFFUSE ACROSS SRN PLAINS DURING DAY-2...AMIDST BROAD SLY/SELY FLOW FETCH THAT WILL DEVELOP IN RESPONSE TO NRN PLAINS CYCLOGENESIS. FRONT FARTHER E -- FROM MS/AL ACROSS GA/SC -- WILL BE MODIFIED/SHIFTED SPATIALLY ON MESOSCALE BY OUTFLOWS. ...NRN PLAINS TO UPPER MS VALLEY REGION... LOW LEVEL WAA/ISENTROPIC ASCENT...AND INCREASING MOISTURE ABOVE SFC...MAY SUPPORT STG-SVR TSTMS FROM NERN ND EWD TO LS EARLY IN PERIOD...CARRYING OVER THREAT FROM DAY-1. REF SPC DAY-1 OUTLOOK FOR MORE INFORMATION ON THIS REGIME. SECOND AND MORE ROBUST SVR THREAT WILL DEVELOP DURING AFTERNOON/EVENING ACROSS LARGER PORTION OF THIS REGION. AS INTENSE CANADIAN MID-UPPER LEVEL TROUGH APCHS...VERTICAL SHEAR IS FCST TO STRENGTHEN OVER INCREASINGLY MOIST/UNSTABLE WARM SECTOR AIR MASS. THIS WILL RESULT BOTH FROM STRENGTHENING MID-UPPER LEVEL GRADIENTS AND FROM LOW LEVEL ACCELERATIONS IN WARM SECTOR ASSOCIATED WITH ISALLOBARIC/ISALLOHYPSIC FORCING. LOW LEVEL HODOGRAPHS FROM MODEL SOUNDINGS ACROSS PORTIONS MN APPEAR QUITE LARGE AND FAVORABLE FOR ROTATING STORMS...WITH ATTENDANT THREAT OF HAIL/WIND AND PERHAPS TORNADOES. MEANWHILE...LARGE SCALE ASCENT OVER STRONGLY HEATED BOUNDARY LAYER WILL FAVORABLY STEEPEN DEEP-LAYER LAPSE RATES...COMBINING WITH EVAPOTRANSPIRATIVELY BOOSTED SFC DEW POINTS TO GENERATE MDT-STG BUOYANCY. BY MID-LATE AFTERNOON...SEVERE TSTMS SHOULD ERUPT INVOF FRONT...AS HEATING AND CONVERGENCE BREAK CAP. MCS MAY EVOLVE FROM AFTERNOON ACTIVITY AND MOVE ESEWD-SEWD ACROSS PORTIONS UPPER MS VALLEY TOWARD WI/IL. SPECIFIC DISTRIBUTION OF SVR THREATS WILL DEPEND LARGELY ON STORM MODE AND MESOSCALE PROCESSES NOT WELL-RESOLVED THIS FAR IN ADVANCE. OVERALL PATTERN...HOWEVER...SUGGESTS THAT SOME CONCENTRATION/SIGNIFICANCE OF SVR POTENTIAL SUFFICIENT TO WARRANT MDT CATEGORICAL OUTLOOK MAY BECOME MORE APPARENT FOR LATER OUTLOOKS. ...SERN CONUS... SCATTERED TO WIDELY SCATTERED TSTMS IN CLUSTERS ARE FCST ACROSS THIS REGION...PRIMARILY CONCENTRATED ALONG MESOSCALE FOCI SUCH AS OUTFLOW BOUNDARIES INVOF FRONTAL ZONE. STRONG HEATING AND MOISTURE ARE EXPECTED...BUT WITH WEAK VERTICAL SHEAR INVOF MID-UPPER LEVEL RIDGE. ACCORDINGLY...WILL INTRODUCE MRGL AND BROAD-BRUSHED SVR PROBABILITIES FOR PULSE/MULTICELLULAR ACTIVITY. ..EDWARDS.. 08/04/2006  From swody2 at goshenarc.org Fri Aug 4 17:37:57 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Fri, 04 Aug 2006 13:37:57 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 041735 SWODY2 SPC AC 041734 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1234 PM CDT FRI AUG 04 2006 VALID 051200Z - 061200Z ...THERE IS A SLGT RISK OF SVR TSTMS SATURDAY AFTERNOON AND EARLY SATURDAY NIGHT FROM THE ERN DAKOTAS INTO MINNESOTA.... ...SYNOPSIS... VIGOROUS MID/UPPER LEVEL LOW/ASSOCIATED SHORTWAVE TROUGH IS FORECAST TO MOVE FROM SRN SASKATCHEWAN INTO SWRN ONTARIO DURING THE PERIOD. MODELS STRENGTHEN THE AMPLITUDE OF THIS TROUGH SLIGHTLY AS IT MOVES THROUGH THE UPPER MS VALLEY REGION DURING THE AFTERNOON AND EVENING. MEANWHILE...STRONG MID/UPPER LEVEL RIDGING WILL REMAINED ANCHORED FROM THE CENTRAL/SRN ROCKIES EWD INTO THE CAROLINAS. ...NRN PLAINS INTO THE UPPER MS VALLEY... MODELS GENERATE STRONG DYNAMICS IN ASSOCIATION WITH THE MID/UPPER LEVEL LOW MOVING THRU SOUTH CENTRAL CANADA ON SATURDAY. BY 06/00Z...STRONG COLD FRONT WILL EXTEND SWD/SWWD THRU NWRN MN...SERN ND AND S CENTRAL SD INTO SERN WY. SSWLY LOW LEVEL JET OF 40-45 KT WILL EXTEND FROM NERN NEB THRU THE MN ARROWHEAD BY THIS TIME. THIS WILL BECOME COUPLED WITH WLY/NWLY MID LEVEL FLOW NEAR 70 KT OVER NRN ND INTO NWRN MN...AND 250 MB WINDS NEAR 100 KT OVER EXTREME SRN MANITOBA INTO SWRN ONTARIO. THIS WILL CREATE FAVORABLE VERTICAL SHEAR PROFILES TO SUPPORT ROTATING STORMS OVER PARTS OF NRN MN BY SATURDAY AFTN. IN ADDITION...STRONG 700 MB DRY AIR INTRUSION IS EXPECTED TO PUSH ITS WAY OVER ND INTO NWRN MN IN CONJUNCTION WITH UPPER LEVEL DIVERGENCE WHICH IS EXPECTED TO ENHANCE UVVS ALONG AND AHEAD OF THE COLD FRONT. AIR MASS IS FORECAST TO BE QUITE UNSTABLE WITH MODEL LIS BETWEEN -6 AND -10...AND MLCAPE FROM NERN SD INTO W CENTRAL MN BETWEEN 2000 AND 3000 J/KG. ANALYSIS OF POINT FORECAST SOUNDINGS ACROSS W CENTRAL MN INDICATE STRONG CAPPING INVERSION INTO THE AFTERNOON THAT WILL WEAKEN AS FRONTAL BOUNDARY/SQUALL LINE APPROACHES GOING INTO THE EVENING. STEEP MID LEVEL LAPSE RATES OF 8-8.5C/KM WILL BE SUPPORTIVE OF HAIL AND STRONG DAMAGING WINDS. THUS...STRONG/SEVERE THUNDERSTORMS/SQUALL LINE ARE EXPECTED TO DEVELOP AFTER MID AFTN ALONG/AHEAD OF THE COLD FRONTAL BOUNDARY. THIS ACTIVITY IS EXPECTED TO INTENSIFY GOING INTO THE LATE AFTERNOON AND EVENING AS IT MOVES INTO VERY UNSTABLE AIR MASS. OTHER THAN THE MAIN THREATS OF HAIL AND DAMAGING WINDS...DEEP LAYER SHEAR OF 40-50 KT SUGGESTS THE POSSIBILITY OF SUPERCELLS/TORNADOES ACROSS THE NRN THIRD OF MN. ...SERN STATES... MOIST...TROPICAL-LIKE AIR MASS WILL REMAIN IN PLACE ACROSS MUCH OF THE SERN QUARTER OF THE U.S. FLOW IS WEAK ACROSS THIS GENERAL AREA WITH POTENTIAL INSTABILITY BETWEEN 1500 AND 2500 J/KG DURING PERIOD OF PEAK HEATING. WIDESPREAD PULSE THUNDERSTORMS WILL BE EXPECTED AGAIN SATURDAY AFTN AND EARLY SATURDAY NIGHT. TWO MAIN BOUNDARIES ARE EVIDENT IN THE MODEL DATA...ONE ACROSS THE TN VALLEY INTO SRN NC...THE OTHER ALONG THE CENTRAL GULF COAST. MORE NUMEROUS...ORGANIZED STORMS ARE POSSIBLE IN THESE AREAS. MAIN THREAT WITH THIS ACTIVITY WILL BE WET MICROBURSTS. ..MCCARTHY.. 08/04/2006  From swody2 at goshenarc.org Sat Aug 5 06:08:08 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 05 Aug 2006 02:08:08 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 050604 SWODY2 SPC AC 050603 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0103 AM CDT SAT AUG 05 2006 VALID 061200Z - 071200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... SYNOPTIC UPPER AIR PATTERN SHOULD FEATURE SLOW NEWD EJECTION OF PRESENTLY CUT-OFF PACIFIC LOW ACROSS NRN CA/ORE...PROGRESSIVE NRN STREAM BELT ACROSS NRN 1/4 OF CONUS...AND WWD EXTENSION OF BERMUDA RIDGE ACROSS SERN/S-CENTRAL STATES. SRN CONUS RIDGE MAY BE REGIONALLY INTRUDED BY WEAK AND SLOW-MOVING PERTURBATIONS -- PERHAPS CONVECTIVELY GENERATED/ENHANCED. STRONG SHORTWAVE TROUGH IS BECOMING BETTER DEFINED IN MOISTURE CHANNEL IMAGERY AND IS ACCELERATING EWD ACROSS CENTRAL/SRN ALBERTA AS OF 5/530Z. OPERATIONAL/DETERMINISTIC MODELS AND MOST MEMBERS OF SREF GUIDANCE PACKAGES ARE IN GOOD AGREEMENT WITH DAY-2 TRACK OF THIS SYSTEM ENEWD ACROSS NRN ONT...AND ALSO NOW...WITH ITS CHARACTER AS INITIALLY CLOSED LOW EVOLVING INTO OPEN WAVE TROUGH. ASSOCIATED SFC CYCLONE SHOULD BE NEARLY VERTICALLY STACKED WITH MID/UPPER LOW BY 6/12Z. THIS CYCLONE SHOULD LIKEWISE EJECT ENEWD IN OCCLUDED FORM AND WEAKEN...WHILE TRAILING COLD FRONT MOVES EWD ACROSS GREAT LAKES REGION. FRONT SHOULD MOVE SEWD OVER IA/NRN MO...NRN KS AND PORTIONS WRN CO BY END OF PERIOD. BROAD AREAS OF CONDITIONAL AND/OR MRGL SVR POTENTIAL ARE APPARENT FOR DAY-2...HOWEVER ENOUGH UNCERTAINTIES EXIST FOR EACH AREA THAT PRECLUDE CATEGORICAL OUTLOOK THIS SOON. ...UPPER GREAT LAKES...EARLY-MID PERIOD... MCS WITH POTENTIAL FOR STG-SVR GUSTS AND HAIL MAY BE ONGOING EARLY IN PERIOD AHEAD OF SFC COLD FRONT...ACROSS PORTIONS LS...WI...LM AND UPPER MI. POTENTIAL WOULD CARRY OVER FROM DAY-1 PERIOD...REF SPC DAY-1 OUTLOOK FOR MORE DETAILS. SUCH ACTIVITY SHOULD DIMINISH THROUGH EARLY MORNING...AS LLJ DIMINISHES IN ASSOCIATION WITH RECOUPLING OF BOUNDARY LAYER. SOME REVITALIZATION OF CONVECTION IS POSSIBLE DURING LATE MORNING THROUGH EARLY AFTERNOON ACROSS LOWER MI...LH...SWWD OVER PORTIONS NERN IL...SRN LM...SRN WI AND INDIANA. WITH MID/UPPER TROUGH EJECTING AWAY FROM AREA...RELATED ISALLOBARIC FORCING SHOULD YIELD VEERED BOUNDARY LAYER FLOW AND WEAKENING CONVERGENCE. ALSO...CLOUD/CONVECTIVE DEBRIS FROM EARLY ACTIVITY MAY LIMIT PREFRONTAL SFC HEATING. DEEP-LAYER FLOW FIELDS SHOULD BE NEARLY UNIDIRECTIONAL. MAIN THREAT WITH ANY SUSTAINED ACTIVITY WOULD BE DAMAGING GUSTS. ...MID MS VALLEY REGION TO CENTRAL LOW PLAINS...AFTERNOON... CONDITIONAL SVR POTENTIAL EXISTS INVOF SFC FRONT ACROSS THIS REGION. STRONG CAPPING MAY PRECLUDE DIURNAL DEVELOPMENT ALTOGETHER...BUT ANY TSTMS THAT DO FORM WILL BE SUPPORTED BY FAVORABLE INSTABILITY. OVER IA/IL/NRN MO...EVAPOTRANSPIRATIVELY AIDED SFC MOISTURE WILL BE HIGH WITH DEW POINTS 70S TO LOW 80S F...AND STRONG SFC HEATING...CONTRIBUTING TO MLCAPES 2000-3000 J/KG...POTENTIALLY MORE. STRONGER HEATING BUT DEEPER MIXING AND WEAKER MOISTURE ARE EXPECTED WITH WWD EXTENT ACROSS KS. DEEP-LAYER SHEAR PROFILES ALSO SHOULD WEAKEN WITH SWWD EXTENT. ISOLATED DAMAGING GUSTS AND LARGE HAIL MAY DEVELOP...HOWEVER THREAT APPEARS TOO DIFFUSELY DISTRIBUTED ATTM TO APPLY MORE CONCENTRATED SVR PROBABILITIES. ...CENTRAL HIGH PLAINS...FOOTHILLS... NELY/POST-FRONTAL FLOW WILL ADVECT MOISTURE UPSLOPE INTO THIS REGION...AND ENHANCE VERTICAL DIRECTIONAL SHEAR. THIS SHOULD CONTRIBUTE TO POTENTIAL FOR TSTMS DEVELOPMENT BY MID-LATE AFTERNOON OVER TYPICALLY FAVORED TOPOGRAPHIC FEATURES...WITH HAIL OR ISOLATED WIND DAMAGE POSSIBLE FROM MOST INTENSE CELLS. CONCERNS PRECLUDING MORE ROBUST SVR THREAT INCLUDE WEAK MIDLEVEL LAPSE RATES -- ASSOCIATED WITH ABUNDANT/PRECURSORY CONVECTION AND CLOUD COVER UPSTREAM...AND SMALL VALUES OF DEEP-LAYER BULK SHEAR THAT ARE LIKELY. ...SERN CONUS... SCATTERED TSTMS ARE EXPECTED TO DEVELOP AGAIN THIS AFTERNOON IN BOTH PULSE AND MULTICELLULAR MODES. VERTICAL WIND AND SHEAR PROFILES WILL REMAIN WEAK OVER THIS REGION...AND ANY SVR POTENTIAL WILL BE STRONGLY DEPENDENT ON RELATIVELY TRANSIENT MESOSCALE PROCESSES YET TO BE RESOLVED IN PROGS. SOME MULTICELL CLUSTERS MAY BECOME PERSISTENT AND WELL-ORGANIZED ENOUGH TO DEVELOP COLD POOLS TO AID IN FORWARD PROPAGATION...GENERALLY WWD OR SWWD...PRODUCING CONCENTRATION OF DAMAGING WIND AND/OR MRGL SVR HAIL REPORTS. IN GENERAL...STRONG SFC HEATING AND DEW POINTS UPPER 60S TO MID 70S F WILL SUPPORT WEAKENING CAP DURING AFTERNOON...PARTICULARLY NEAR OUTFLOW BOUNDARIES FROM PRIOR AND ONGOING CONVECTION. ...ERN GREAT LAKES...LATE PERIOD... AHEAD OF SFC FRONT...MOIST ADVECTION ASSOCIATED WITH SWLY LLJ MAY SUPPORT DEVELOPMENT OF TSTMS ACROSS PORTIONS SRN ONT...LE...AND PERHAPS PORTIONS OH/WRN PA/WRN NY DURING LAST SEVERAL HOURS OF PERIOD. DAMAGING GUSTS WOULD BE PRIMARY CONCERN. STRONGEST DEEP-LAYER FORCING SHOULD REMAIN FARTHER N IN CANADA...BUT MOST FAVORABLE BUOYANCY COULD EXTEND SWD OVER ERN GREAT LAKES REGION. THIS POTENTIAL IS MORE STRONGLY INDICATED BY OPERATIONAL WRF THAN MOST OTHER MODELS. FCST SOUNDINGS SUGGEST SUFFICIENTLY STEEP MIDLEVEL LAPSE RATES AND MOISTURE JUST OFF SFC FOR MUCAPES ABOVE 1500 J/KG IN PROSPECTIVE INFLOW LAYER...AND SFC THETAE LARGE ENOUGH THAT EFFECTIVE PARCELS MAY BE BASED NEAR GROUND. ..EDWARDS.. 08/05/2006  From swody2 at goshenarc.org Sat Aug 5 17:30:53 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 05 Aug 2006 13:30:53 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 051730 SWODY2 SPC AC 051729 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1229 PM CDT SAT AUG 05 2006 VALID 061200Z - 071200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE MID MO AND LOWER OH VALLEYS... ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE UPPER OH VALLEY... ...MID MO VALLEY/OH VALLEY... A ZONAL FLOW PATTERN WILL REMAIN IN PLACE ACROSS THE NRN U.S. AS AN UPPER-LEVEL TROUGH DRIFTS EWD ACROSS SRN CANADA INTO THE UPPER MIDWEST SUNDAY. AT THE SFC...A COLD FRONT WILL MOVE SEWD ACROSS THE NRN MS VALLEY AND SHOULD BE POSITIONED FROM WI EXTENDING SWWD INTO NRN MO AND ERN KS BY SUNDAY AFTERNOON. SOUTH OF THE BOUNDARY...DEWPOINTS FROM 65 TO 75 F SHOULD BE PRESENT RESULTING IN AN AXIS OF MODERATE INSTABILITY. ALTHOUGH A CAPPING INVERSION WILL LIKELY EXIST THROUGH MUCH OF THE DAY...SFC HEATING AND LOW-LEVEL CONVERGENCE ALONG THE BOUNDARY SHOULD BE ENOUGH FOR THUNDERSTORM INITIATION BY MID-AFTERNOON. SCATTERED THUNDERSTORMS SHOULD INCREASE IN COVERAGE THROUGH LATE AFTERNOON WITH THE GREATEST COVERAGE OVER NRN MO AND NRN IL. ADDITIONAL THUNDERSTORM DEVELOPMENT WILL BE LIKELY ALONG A SECONDARY INSTABILITY AXIS EXTENDING NWD FROM THE CNTRL APPALACHIAN MTNS INTO OH AS SHOWN BY THE NAM AND GFS SOLUTIONS. FORECAST SOUNDINGS ALONG AND AHEAD OF THE BOUNDARY SUNDAY AFTERNOON SHOW 0-6 KM SHEAR VALUES FROM 25 TO 35 KT SUGGESTING INSTABILITY/SHEAR PROFILES WILL BE SUFFICIENT FOR SEVERE MULTICELL STORMS. LOW-LEVEL LAPSE RATES ARE FORECAST TO BE VERY STEEP ESPECIALLY ACROSS NE KS...NRN MO...NRN IL AND OH FAVORING ISOLATED WIND DAMAGE WITH THE STRONGER CELLS. WARM MID-LEVEL TEMPS SHOULD CONFINE HAIL POTENTIAL TO THE STRONGEST OF CONVECTION. ALTHOUGH THUNDERSTORMS SHOULD CONTINUE OVERNIGHT CO-LOCATED WITH BANDS OF LARGE-SCALE ASCENT ASSOCIATED WITH THE UPPER-TROUGH...DECREASING INSTABILITY SHOULD ALLOW THE SEVERE THREAT TO DIMINISH BY LATE EVENING. ...ERN CO... AN UPPER-LEVEL RIDGE IS FORECAST TO BUILD OVER THE WRN U.S. AS A COLD FRONT BECOMES NEARLY STATIONARY FROM ERN WY EXTENDING SEWD INTO SRN NEB SUNDAY. SOUTH OF THE BOUNDARY DEWPOINTS SHOULD BE IN THE 50S F ALLOWING FOR SOME DESTABILIZATION SUNDAY ALONG AN EAST TO WEST AXIS FROM NE CO THROUGH NRN KS. SFC HEATING SHOULD RESULT IN THUNDERSTORM INITIATION IN THE HIGHER TERRAIN OF CNTRL CO BY MIDDAY WITH STORMS INCREASING IN COVERAGE AND MOVING EWD INTO THE PLAINS. FORECAST SOUNDINGS ACROSS NE CO SUNDAY AFTERNOON SHOW VERY STEEP LAPSE RATES AND 0-6 KM SHEAR VALUES AROUND 20 KT WHICH MAY BE ENOUGH FOR AN ISOLATED SEVERE THREAT WITH THE STRONGER MULTICELL STORMS. HOWEVER...THE AMOUNT OF DESTABILIZATION STILL REMAINS UNCERTAIN AND LARGE-SCALE ASCENT SHOULD REMAIN WEAK. THESE FACTORS MAY KEEP THE SEVERE THREAT MARGINAL SUNDAY AFTERNOON. ...NRN CA/SRN ORE... AN UPPER-LEVEL RIDGE WILL BUILD ACROSS THE ROCKIES AS AN UPPER-LOW OVER THE ERN PACIFIC MOVES SLOWLY NEWD TOWARD NRN CA SUNDAY. IN THE LOWER ELEVATIONS OF NRN CA AND SRN ORE...DEWPOINTS WILL LIKELY REMAIN NEAR 50 F ALLOWING SOME DESTABILIZATION BY AFTERNOON. SCATTERED THUNDERSTORMS SHOULD DEVELOP AND MOVE NEWD ACROSS NRN CA AND SRN ORE AS LARGE-SCALE ASCENT INCREASES AHEAD OF APPROACHING SYSTEM. FORECAST SOUNDINGS IN NRN CA INCREASE VERTICAL SHEAR PROFILES BY LATE AFTERNOON AS THE EXIT REGION OF A MID-LEVEL JET MOVES NEWD ACROSS THE REGION. THIS COMBINED WITH VERY STEEP LAPSE RATES WILL BE FAVORABLE FOR AN ISOLATED SEVERE THREAT WITH THE STRONGER CELLS NEAR PEAK HEATING. HOWEVER...THE SEVERE THREAT MAY REMAIN MARGINAL DUE TO RELATIVELY WEAK DESTABILIZATION. ...EAST TX/LA... A WEAK FLOW REGIME IS FORECAST TO BE IN PLACE ACROSS THE SRN U.S. SUNDAY. AT THE SFC...DEWPOINTS IN THE 70S F SHOULD RESULT IN MODERATE INSTABILITY ALONG THE GULF COAST AREAS. THUNDERSTORMS WILL LIKELY DEVELOP DUE TO SFC HEATING AND LARGE-SCALE ASCENT ASSOCIATED WITH AN ELY MOVING WAVE IN THE NRN GULF OF MEXICO. THUNDERSTORMS SHOULD INITIATE BY EARLY AFTERNOON AND SPREAD WWD ACROSS LA AND EAST TX. FORECAST SOUNDINGS SHOW STEEP LOW-LEVEL LAPSE RATES WHICH MAY BE SUFFICIENT FOR A MARGINAL WIND DAMAGE THREAT WITH THE STRONGEST OF STORMS NEAR PEAK HEATING SUNDAY AFTERNOON. ..BROYLES.. 08/05/2006  From swody2 at goshenarc.org Sun Aug 6 06:10:39 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 06 Aug 2006 02:10:39 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 060609 SWODY2 SPC AC 060608 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0108 AM CDT SUN AUG 06 2006 VALID 071200Z - 081200Z ...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS MID-ATLANTIC AND NEW ENGLAND... ...SYNOPSIS... MID-UPPER LEVEL SYNOPTIC PATTERN IS FCST TO REMAIN PROGRESSIVE ACROSS NRN CONUS...AMIDST PREVAILING AMPLIFICATION OF MEAN RIDGE ACROSS ROCKIES AND TROUGH OVER QUE. MID/UPPER LEVEL LOW -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY OVER MB -- IS FCST TO DEAMPLIFY DAY-1 AND ACCELERATE EWD ACROSS NRN QUE DAY-2. SPEED MAX ALOFT -- ASSOCIATED WITH WEAKER PERTURBATION NOW OVER WRN ALBERTA -- IS FCST TO DIG SEWD THROUGH W SIDE OF MEAN TROUGH...AND ACROSS PORTIONS SRN QUE/NRN NY/NRN NEW ENGLAND DURING THIS PERIOD. AT SFC...COLD FRONT NOW ANALYZED FROM NRN MN TO CENTRAL HIGH PLAINS IS EXPECTED TO MOVE EWD ACROSS ERN GREAT LAKES...MID ATLANTIC AND NEW ENGLAND REGIONS THROUGH 8/12Z. FRONT WILL MOVE MORE SLOWLY SWD ACROSS OH VALLEY REGION...WHILE STALLING AND BECOMING MORE DIFFUSE ACROSS CENTRAL PLAINS. ...NERN CONUS TO MO... SCATTERED TSTMS ARE EXPECTED TO DEVELOP ALONG/AHEAD OF SFC COLD FRONT DURING DAYLIGHT HOURS...ORGANIZED LARGELY IN LINEAR/SEGMENTED FASHION. ACTIVITY SHOULD MOVE EWD ACROSS OUTLOOK AREA WITH LEWP/BOW FORMATIONS POSSIBLE...DAMAGING WIND BEING MAIN THREAT. PRIND STRONGEST ISALLOBARIC FORCING SHOULD REMAIN FARTHER N ACROSS QUE AND CANADIAN MARITIMES...HOWEVER ASSOCIATED SWLY FLOW IS EXPECTED TO ADVECT FAVORABLE BOUNDARY LAYER THETAE CLOSER TO ATLANTIC COAST AND KEEP MOST OF RELATIVELY STABLE MARINE AIR MASS SHUNTED FARTHER E ACROSS CAPE COD REGION AND DOWNEAST MAINE. IN COMBINATION WITH SFC DIABATIC HEATING...THIS SHOULD RESULT IN ENOUGH DIURNAL DESTABILIZATION TO SUPPORT CONVECTIVE DEVELOPMENT/MAINTENANCE. PASSAGE OF MID-UPPER LEVEL SPEED MAX OVER SFC COLD FRONT...AND ACROSS PREFRONTAL WARM/MOIST SECTOR...IS EXPECTED TO ENHANCE DEEP-LAYER SPEED SHEAR AND POTENTIAL ORGANIZATION OF TSTMS ACROSS THIS AREA. ALTHOUGH NEARLY UNIDIRECTIONAL VERTICAL WIND PROFILES ARE PROGGED...DEEP-LAYER BULK SHEAR MAY SUPPORT SUPERCELL STRUCTURE WITH ANY DISCRETE ACTIVITY THAT MAY DEVELOP. ORGANIZED SVR POTENTIAL SHOULD DIMINISH WITH SWWD EXTENT AHEAD OF FRONT...CORRESPONDING TO PROGRESSIVELY WEAKER DEEP-LAYER SHEAR AND WEAKER LARGE SCALE FORCING. HOWEVER...COMBINATION OF MESOSCALE FOCI...RICH LOW LEVEL MOISTURE...AND STRONG SFC HEATING MAY HELP TO CONCENTRATE LOCALIZED/CLUSTERED MULTICELL SVR POTENTIAL ALMOST ANYWHERE FROM MID/UPPER OH VALLEY WWD ACROSS MO/ERN KS. ...CENTRAL HIGH PLAINS... STEEP MIDLEVEL LAPSE RATES...STRONG SFC HEATING...AT LEAST MRGLLY FAVORABLE MOISTURE AND PRESENCE OF FRONTAL ZONE SHOULD CONTRIBUTE TO RELATIVE CONCENTRATION OF TSTMS WITH HAIL/GUSTS NEAR SVR LEVELS POSSIBLE...MAINLY AFTERNOON INTO EARLY EVENING. STRONG DIRECTIONAL SHEAR IS LIKELY ALONG AND N OF SFC FRONTAL ZONE...WHERE BOUNDARY LAYER MOIST AXIS WILL BE EXTENDED WWD AMIDST ELY FLOW COMPONENT. WITH LACK OF MORE ROBUST MIDLEVEL WINDS OR DEEP-LAYER SHEAR...MESOSCALE PROCESSES WILL DETERMINE RELATIVE CONCENTRATIONS OF SVR POTENTIAL. ...NWRN CONUS... DAMAGING GUSTS MAY OCCUR WITH MOST INTENSE CONVECTION ACROSS THIS REGION...MAINLY DURING MID-LATE AFTERNOON. MID-UPPER LEVEL CUT-OFF LOW NOW EVIDENT OFFSHORE CA IS FCST TO DEAMPLIFY AND EJECT NEWD ACROSS PORTIONS NRN CA AND ORE DURING THIS PERIOD. MODELS ARE COMING INTO CLOSER AGREEMENT ON TIMING OF THIS PROCESS...WITH ENHANCED DEEP-LAYER SHEAR SPREADING ACROSS PORTIONS INTERIOR ORE DURING PEAK AFTERNOON WARMING. MAIN CONCERN WILL BE MARGINALITY AND SPORADIC DISTRIBUTION OF LOW LEVEL MOISTURE. ...WRN GULF COASTAL PLAIN... RELATIVE CONCENTRATION OF DIURNAL CONVECTION IS EXPECTED ACROSS THIS REGION IN ASSOCIATION WITH MID-UPPER LEVEL TROUGH IN ELY FLOW ALOFT. STRONG SFC HEARING AND MESOSCALE BOUNDARIES -- MAINLY OUTFLOW RELATED -- MAY CONCENTRATE SVR POTENTIAL WITH A FEW MULTICELL CLUSTERS LIKELY TO HAVE BULK OF STG-SVR WIND POTENTIAL. ..EDWARDS.. 08/06/2006  From swody2 at goshenarc.org Sun Aug 6 17:18:26 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 06 Aug 2006 13:18:26 -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 SUN AUG 06 2006 VALID 071200Z - 081200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE NERN U.S.... ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE CNTRL PLAINS... ...NERN U.S... AN UPPER-LEVEL TROUGH OVER SERN CANADA IS FORECAST TO CONTINUE EWD TONIGHT AND DIG ESEWD TOWARD THE NERN U.S. MONDAY. IN RESPONSE...A COLD FRONT WILL MOVE SEWD INTO WRN NY MONDAY AFTERNOON. MOISTURE ADVECTION WILL CONTINUE AHEAD OF THE APPROACHING FRONT ALLOWING SFC DEWPOINTS TO RISE INTO THE 60S F ACROSS MUCH OF THE REGION. THIS SHOULD ALLOW MODERATE INSTABILITY TO DEVELOP BY MIDDAY FROM PARTS OF NEW ENGLAND EXTENDING SSWWD THROUGH NY...PA AND MD. INCREASING LARGE-SCALE ASCENT ACROSS THE REGION AHEAD OF THE APPROACHING UPPER-LEVEL TROUGH SHOULD SUPPORT THE DEVELOPMENT OF SCATTERED THUNDERSTORMS ALONG THE INSTABILITY AXIS DURING THE AFTERNOON. FORECAST SOUNDINGS ACROSS THE REGION MONDAY AFTERNOON SHOW 0-6 KM SHEAR VALUES IN THE 30 TO 45 KT RANGE SUGGESTING SUPERCELLS WILL BE POSSIBLE ESPECIALLY WHERE INSTABILITY IS LOCALLY MAXIMIZED. SEVERE MULTICELLS WILL ALSO BE POSSIBLE WITH HAIL AND WIND DAMAGE LIKELY WITH THE STRONGER STORMS AROUND PEAK HEATING. ALTHOUGH SEVERE STORMS WILL BE LIKELY ACROSS THE REGION MONDAY AFTERNOON...LAPSE RATES ESPECIALLY AT MID-LEVELS ARE NOT FORECAST TO BE PARTICULARLY STEEP SUGGESTING A MORE WIDESPREAD SEVERE WEATHER EVENT IS NOT LIKELY. ...CNTRL PLAINS... UPPER-LEVEL HIGH PRESSURE IS FORECAST TO REMAIN IN PLACE ACROSS THE SRN PLAINS AS A COLD FRONT MOVES SWD INTO SRN KS AND WRN MO. AHEAD OF THE BOUNDARY...SFC DEWPOINTS IN THE 60S F SHOULD RESULT IN AN AXIS OF MODERATE INSTABILITY. AS THE CAPPING INVERSION WEAKENS...SCATTERED THUNDERSTORMS SHOULD DEVELOP ALONG AND SOUTH OF THE BOUNDARY DURING THE AFTERNOON. FORECAST SOUNDINGS ACROSS THE REGION MONDAY AFTERNOON SHOW 0-6 KM SHEAR VALUES IN THE 30 TO 35 KT RANGE MOSTLY DUE TO DIRECTIONAL SHEAR. THIS SUGGESTS SEVERE MULTICELLS WILL BE POSSIBLE WITH THE GREATEST SEVERE THREAT LIKELY WITH THE LARGER THUNDERSTORM CLUSTERS. HAIL AND ISOLATED WIND DAMAGE SHOULD BE THE PRIMARY THREATS. ...NRN CA/ORE... AN UPPER-LEVEL TROUGH IS FORECAST TO MOVE INTO NRN CA MONDAY SPREADING STRONG LARGE-SCALE ASCENT NEWD ACROSS THE REGION. THIS SHOULD SUPPORT SCATTERED THUNDERSTORM DEVELOPMENT MONDAY AFTERNOON IN NRN CA AND ORE. FORECAST SOUNDINGS IN NRN CA AND ORE MONDAY AFTERNOON SHOW STEEP LAPSE RATES WITH ADEQUATE SHEAR PROFILES FOR SEVERE STORMS. HOWEVER...THE AMOUNT OF DESTABILIZATION THAT WILL OCCUR MONDAY REMAINS UNCERTAIN. IF ENOUGH INSTABILITY DEVELOPS BY AFTERNOON...HAIL AND ISOLATED WIND DAMAGE WOULD BE POSSIBLE WITH THE STRONGER CELLS. HOWEVER...WILL NOT UPGRADE TO SLIGHT RISK ATTM. A SLIGHT RISK MAY BECOME NECESSARY IN LATER OUTLOOKS ONCE CERTAINTY CONCERNING INSTABILITY INCREASES. ..BROYLES.. 08/06/2006  From swody2 at goshenarc.org Sat Aug 12 05:46:03 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 12 Aug 2006 01:46:03 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 120547 SWODY2 SPC AC 120545 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1245 AM CDT SAT AUG 12 2006 VALID 131200Z - 141200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE UPPER MS VALLEY/WRN GREAT LAKES SWWD ACROSS THE CNTRL PLAINS... ...SYNOPSIS... BROAD SUB-TROPICAL RIDGE AXIS WILL CONTINUE TO DOMINATE THE SRN HALF OF THE U.S. THIS PERIOD WITH GENERALLY PROGRESSIVE FLOW EXISTING ACROSS THE NRN STATES FROM COAST TO COAST. PRIMARY FEATURE AFFECTING ORGANIZED CONVECTIVE WEATHER WILL BE A PROGRESSIVE TROUGH...EMBEDDED WITHIN THE FASTER FLOW REGIME...MOVING FROM SCNTRL CANADA/NRN PLAINS AREA ESEWD TO THE UPPER MS VALLEY/WRN GREAT LAKES. COLD FRONT ACCOMPANYING THIS SHORT WAVE TROUGH WILL SPREAD SWD ACROSS THE NRN AND CNTRL HIGH PLAINS...SEWD ACROSS THE MO RIVER VALLEY...AND EWD ACROSS UPPER MS VALLEY TO THE NRN GREAT LAKES REGIONS FROM SUNDAY AND INTO EARLY MONDAY. THE EAST COAST WILL REMAIN UNDER THE INFLUENCE OF STABLE CONTINENTAL POLAR AIR MASS. THE LEADING EDGE OF THIS AIR MASS WILL CONTINUE TO BE DEFINED BY A QUASI-STATIONARY FRONTAL BAND...AND SCATTERED DEEP CONVECTION INCREASING DURING THE AFTERNOON...FROM THE NERN GULF AND FL WWD TO THE LOWER MS VALLEY. A SUBTROPICAL DISTURBANCE DRIFTING NWWD AROUND THE SRN PERIPHERY OF BROAD CNTRL/SRN U.S. UPPER RIDGE...COUPLED WITH MOIST LOW LEVEL UPSLOPE FLOW AND HIGH PW AIR...WILL RESULT IN NUMEROUS STORMS ACROSS THE SOUTHWEST AND UPPER RIO GRANDE VALLEY. ...NRN PLAINS ACROSS UPPER MS VALLEY... MODEL GUIDANCE HAS COME INTO BETTER AGREEMENT WITH THE MOTION OF THE FRONT ACROSS THESE AREAS. PRIMARY SHORT WAVE TROUGH TO AFFECT THE NRN PLAINS AREA ON SUNDAY WAS CURRENTLY ROUNDING THE BASE OF THE LARGER SCALE TROUGH OVER THE PACIFIC NORTHWEST. THIS FEATURE IS FORECAST TO MAINTAIN MODEST AMPLITUDE WHILE CROSSING THE ROCKIES THROUGH SATURDAY. A LEADING IMPULSE...CURRENTLY LIFTING INTO SCNTRL CANADA...WILL DRIVE A FRONT ACROSS MUCH OF ND AND NWRN SD THROUGH SATURDAY. THIS BOUNDARY SHOULD STRETCH FROM MN TO WY BY SUNDAY MORNING. ONGOING MORNING CONVECTION WITHIN WARM CONVEYOR AXIS AHEAD OF THE COLD FRONT MAY EXIST OVER ERN SD INTO MN. ANOTHER CLUSTER OF POST-FRONTAL STORMS MAY BE ONGOING AT THE START OF THE PERIOD ACROSS THE NRN HIGH PLAINS IN AREA OF ENHANCED ASCENT AHEAD OF THE APPROACHING SHORT WAVE TROUGH OVER MT. AIR MASS IN THE WAKE OF MN MCS AND AHEAD OF THE FRONT SHOULD BECOME INCREASINGLY UNSTABLE THROUGH THE AFTERNOON GIVEN RICH LOW LEVEL MOISTURE AND MODERATE HEATING. SREF GUIDANCE INDICATES MLCAPE VALUES OF 800-1500 J/KG WILL BE POSSIBLE AHEAD OF THE FRONT...FROM MN INTO NRN NEB. EXPECT CONVECTIVE INHIBITION IN THIS CORRIDOR TO BE EFFECTIVELY ERODED AS FRONTAL CIRCULATION DEVELOPS SEWD INTO THE AREA FROM AFTERNOON THROUGH EVENING. BOTH SHEAR AND FORCING APPEAR STRONGEST IMMEDIATELY BEHIND THE COLD FRONT AND EXPECT LINE SEGMENTS AND PERHAPS A FEW SUPERCELLS TO PRODUCE SEVERE HAIL AND WIND OVER NRN PORTIONS OF THE SLGT RISK AREA AS THE FRONT AND POSSIBLE SQUALL LINE ADVANCE EWD/SEWD. ...CNTRL PLAINS... WHILE GREATER WARM SECTOR SHEAR AND FORCING ARE FORECAST TO EXIST ACROSS THE NRN PLAINS AND UPPER MS VALLEY AREAS THROUGH THE AFTERNOON AND EVENING...STRONGER DESTABILIZATION IS FORECAST ACROSS PORTIONS OF THE MO RIVER VALLEY AND ADJACENT PLAINS WHERE AIR MASS IS LIKELY TO BE CAPPED. HEATING AND WEAK LARGE SCALE FORCING AHEAD OF THE FRONT SHOULD ACT TO LOCALLY OVERCOME THE CAP IN THESE AREAS BY AFTERNOON WITH ROBUST CONVECTIVE DEVELOPMENT EXPECTED THROUGH EVENING. EVEN THOUGH VERTICAL SHEAR DIMINISHES WITH SWD EXTENT ACROSS THE REGION...THIS MAY BE OFFSET BY MAGNITUDE OF INSTABILITY. EXPECT WEAKLY ORGANIZED MULTICELLULAR STORMS TO DEVELOP INTO LINEAR MCS AS THE FRONT SPREADS SEWD. HAIL AND HIGH WINDS MAY ACCOMPANY THIS ACTIVITY WITH THE CONVECTION DEVELOPING ACROSS SRN NEB/IA...AND INTO KS/MO AREAS THROUGH SUNDAY NIGHT. ..CARBIN.. 08/12/2006  From swody2 at goshenarc.org Sat Aug 12 16:48:48 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 12 Aug 2006 12:48:48 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 121649 SWODY2 SPC AC 121648 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1148 AM CDT SAT AUG 12 2006 VALID 131200Z - 141200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE CNTRL/NRN PLAINS AND UPPER MS VLY REGION... ...SYNOPSIS... ACTIVE NRN STREAM WILL CONTINUE INTO SUNDAY AS A POTENT UPPER TROUGH PROGRESSES EWD FROM THE NWRN STATES TODAY TO THE UPPER MS VLY BY SUNDAY NIGHT. ASSOCD COLD FRONT WILL REACH A MN...SD... NERN CO LINE BY 00Z MON AND TO AN UPPER GRTLKS TO SRN HI PLAINS LINE BY 12Z MON. ...NRN PLAINS TO UPPER MS VALLEY... SEVERAL AREAS OF CONVECTION SHOULD BE ONGOING ACROSS A LARGE PORTION OF NWRN MN...THE DAKS AND NEB EARLY SUNDAY MORNING. STRONGEST STORMS SHOULD EXIST ACROSS MN ALONG THE NOSE OF THE WARM SUB-TROPICAL CONVEYOR AHEAD OF THE APPROACHING MID-LEVEL TROUGH. THIS ACTIVITY SHOULD EITHER WEAKEN OR MOVE INTO NWRN ONT BY AFTN. AIR MASS IN WAKE OF THE MORNING ACTIVITY AND AHEAD OF THE PRIMARY COLD FRONT SHOULD BECOME INCREASINGLY UNSTABLE THROUGH SUNDAY AFTN GIVEN RICH LOW-LEVEL MOISTURE AND MODEST HEATING. BUT...SUB- TROPICAL CONVEYOR AND POTENTIAL FOR CLOUD SUGGEST THAT LAPSE RATES MAY SUFFER AND BE LOWER THAN RECENT DAYS. NONETHELESS...TSTMS SHOULD INTENSIFY/DEVELOP ALONG SERN EDGE OF MORNING CLOUD/TSTM CLUSTERS ACROSS PORTIONS OF MN AND IA BY MID-AFTN AS CINH IS WEAKENED VIA FRONTAL CIRCULATION AND LARGE SCALE HEIGHT FALLS. SHEAR AND FORCING WILL BE STRONGEST WEST OF THE FRONT AND GIVEN ORIENTATION OF THE DEEP LAYER SHEAR VECTORS...TSTMS WILL TEND TO EVOLVE QUICKLY INTO LINE SEGMENTS WITH PERHAPS EMBEDDED SUPERCELLS. DAMAGING WINDS WILL BE THE PRIMARY SEVERE THREAT...BUT HAIL AND AN ISOLD TORNADO CANNOT BE RULED OUT. BY EVE...A FAIRLY EXTENSIVE SQUALL LINE WILL LIKELY EXIST ACROSS THE UPPER MS VLY THAT WILL MOVE EWD AND WEAKEN OVERNIGHT. ...CNTRL PLAINS... THOUGH STRONGEST DEEP LAYER SHEAR AND ASCENT ARE EXPECTED ACROSS THE NRN PLAINS...AIR MASS IS FORECAST TO BE MUCH MORE UNSTABLE ACROSS PARTS OF THE MO VLY AND ADJACENT PLAINS. HERE...MID-LEVEL LAPSE RATES WILL BE STEEPER AND BOUNDARY LAYER CAPPED FOR MOST OF THE AFTN. RESULTANT STRONGER LOW-LEVEL HEATING SHOULD WEAKEN THE CAP AND GIVEN WEAK LARGE SCALE FORCING AHEAD OF THE SEWD MOVING COLD FRONT...TSTMS SHOULD DEVELOP LATE IN THE AFTN FROM SERN NEB SWWD INTO WRN KS. MAGNITUDE OF BUOYANCY MAY COMPENSATE FOR THE WEAKER VERTICAL SHEAR AND ORGANIZED MULTICELL STORMS WILL BE POSSIBLE. MORE VIGOROUS STORMS WILL PRODUCE DAMAGING WINDS AND HAIL. AN MCS OR TWO IS LIKELY TO EVOLVE OVERNIGHT ACROSS PARTS OF IA SWWD INTO KS...THOUGH THE SEVERE THREATS WILL LIKELY DIMINISH DURING SUNDAY EVE. ..RACY.. 08/12/2006  From swody2 at goshenarc.org Sun Aug 13 05:55:57 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 13 Aug 2006 01:55:57 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 130556 SWODY2 SPC AC 130556 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1256 AM CDT SUN AUG 13 2006 VALID 141200Z - 151200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF THE MIDWEST/OH VALLEY... ...SYNOPSIS... PROGRESSIVE UPPER TROUGH WILL CONTINUE TO DEVELOP EWD ACROSS ONTARIO AND THE GREAT LAKES REGION THROUGH MONDAY WITH ASSOCIATED COLD FRONT SPREADING ACROSS THE MIDWEST...AND TRAILING SWWD INTO THE SRN PLAINS/HIGH PLAINS THROUGH THE DAY AND EVENING. LOW LEVEL FRONTAL CIRCULATION WILL DEVELOP INTO VERY MOIST AIR MASS FROM THE OH VALLEY/MIDWEST AREAS SWWD TO THE PLAINS. MEANWHILE...STRONGER FLOW AND DYNAMICS WITH THE ASSOCIATED UPPER TROUGH WILL SPREAD QUICKLY EAST ATOP RELATIVELY COOLER AND DRIER AIR MASS FROM THE ERN GREAT LAKES THROUGH THE NORTHEAST. ...MIDWEST/OH VALLEY... SCATTERED AREAS OF CONVECTION MAY BE ONGOING NEAR THE COLD FRONT EARLY MONDAY FROM LOWER MI TO IL/MO. PROGRESSIVE NATURE OF THE UPPER TROUGH AND WEAK HEIGHT FALLS SHOULD PROMOTE THE EWD/SEWD MOTION OF THE FRONTAL ZONE INTO AN INCREASINGLY WARM AND MOIST AIR MASS DURING THE DAY. PREFRONTAL ENVIRONMENT WILL TRANSITION FROM LOW CAPE/HIGH SHEAR ACROSS THE UPPER MIDWEST/LOWER MI AREAS...TO HIGH CAPE AND WEAKER SHEAR ACROSS THE OH VALLEY. THUS...EXPECT A POSSIBLE TRANSITION IN CHARACTER OF CONVECTION...FROM FAST MOVING LOW-TOPPED LINE SEGMENTS NORTH...TO MORE MULTICELLULAR SLOWER MOVING STORMS SOUTH. ACTIVITY ACROSS THE OH VALLEY MAY BECOME MORE LINEAR AS THE FRONT MOVES DEVELOPS INTO THIS AREA THROUGH THE EVENING. AT THIS TIME...PRIMARY SEVERE WEATHER HAZARD APPEARS TO BE SCATTERED DAMAGING WINDS. ...SRN PLAINS/HIGH PLAINS... VERY WARM AND MOIST AIR MASS WILL EXIST AHEAD OF THE BOUNDARY FROM AR WWD TO NM. EXPECT THE FRONTAL BOUNDARY WILL PROVIDE A FOCUS FOR TSTM DEVELOPMENT AND PERSISTENCE. WITH GREATER FORCING ASSOCIATED WITH THIS FRONT WELL REMOVED FROM THE REGION...LARGE SCALE SUPPORT WILL BE LIMITED. BUT SOME LARGE SCALE SUPPORT FOR DEEPER LIFT MAY BE PROVIDED BY RESIDUAL MCVS...AS WELL AS WEAK SUBTROPICAL DISTURBANCE TRAVERSING PARTS OF THE SRN HIGH PLAINS. WEAKLY ORGANIZED AND DIURNALLY DRIVEN MULTICELLULAR CONVECTION SHOULD POSE SOME THREAT FOR ISOLATED DAMAGING WINDS AND PERHAPS MARGINALLY SEVERE HAIL. ...LOWER MS VALLEY TO FL... PRESENCE OF REMNANT BAROCLINIC ZONE...STRONG HEATING...AND TROPICAL MOISTURE WILL ALL CONTRIBUTE TO AFTERNOON TSTM DEVELOPMENT ACROSS THESE AREAS. WHILE DEEP LAYER FLOW AND LAPSE RATES WILL REMAIN MEAGER...BOUNDARY/CELL INTERACTIONS...AND PERHAPS SOME POTENTIAL FOR GREATER FORCING/SHEAR NEAR UPPER LOW OVER FL...COULD RESULT IN ISOLATED WET MICROBURSTS OR PERHAPS A BRIEF TORNADO/WATERSPOUT. ..CARBIN.. 08/13/2006  From swody2 at goshenarc.org Sun Aug 13 16:44:55 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 13 Aug 2006 12:44:55 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 131645 SWODY2 SPC AC 131644 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1144 AM CDT SUN AUG 13 2006 VALID 141200Z - 151200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE OH VLY... ...SYNOPSIS... A PROGRESSIVE UPPER TROUGH WILL MOVE FROM THE NRN PLAINS TODAY THEN EWD ACROSS ONTARIO AND THE GRTLKS THROUGH MON. ASSOCD COLD FRONT WILL SPREAD ACROSS THE MIDWEST AND TRAIL SWWD INTO THE SRN HIGH PLAINS BY MON EVE. THIS FRONT WILL BE THE FOCUS FOR PSBL SVR TSTMS MON AFTN-EVE. ...MIDWEST/OH VALLEY... SCT CONVECTION SHOULD BE ONGOING ACROSS THE GRTLKS REGION SWWD INTO THE UPPER MIDWEST EARLY ON MON VCNTY THE APPROACHING COLD FRONT. THIS FRONT WILL DEVELOP SEWD INTO AN INCREASINGLY WARM/MOIST AIR MASS DURING THE AFTN. STEEPER MID-LEVEL LAPSE RATES AND BOUNDARY LAYER HEATING WILL EXIST ALONG TRAILING PORTIONS OF THE FRONT WITH THE STRONGER FLOW LOCATED FARTHER N. THIS WILL LEAD TO A TRANSITION FROM LOW CAPE/MODEST SHEAR ACROSS THE GRTLKS AND UPPER OH VLY TO HIGH CAPE/WEAKER SHEAR OVER THE LWR OH VLY. AS A RESULT...THERE WILL BE A TRANSITION IN CHARACTER OF CONVECTION... FROM FAST MOVING LOW-TOPPED LINE SEGMENTS N...TO MORE MULTICELLULAR SLOWER MOVING STORMS S. THE PRIMARY SEVERE RISK WILL BE DAMAGING WINDS. ...OZARKS WWD TO SRN PLAINS/HIGH PLAINS... SUB-TROPICAL PLUME OF MSTR WILL STREAM NEWD ACROSS THE SRN PLAINS ON MON. HEATING AND FAVORABLY MOIST AIR MASS AHEAD OF THE SWD MOVING COLD FRONT WILL BE THE FOCUS FOR TSTM DEVELOPMENT FROM THE OZARKS WWD INTO THE SRN HIGH PLAINS. HIGHER CONCENTRATION OF STORMS SHOULD EXIST ACROSS SERN CO...NERN NM...AND THE TX/OK PNHDLS WHERE UPSLOPE FLOW CONTRIBUTES TO LARGE SCALE LIFT. WEAKLY ORGANIZED AND MOSTLY DIURNALLY DRIVEN MULTICELLULAR CONVECTION SHOULD POSE SOME THREAT FOR ISOLATED DAMAGING WINDS AND PERHAPS HAIL. BUT GIVEN THE HIGH PWAT AIR MASS...HEAVY RAINFALL APPEARS TO BE THE PRIMARY THREAT. ...LWR MS VALLEY TO FL... PERSISTENT REMNANT BAROCLINIC ZONE...HEATING AND AMPLY MOIST BOUNDARY LAYER WILL CONTRIBUTE TO DIURNAL TSTMS FROM THE LWR MS VLY TO FL. DEEP LAYER SHEAR AND MID-LEVEL LAPSE RATES WILL BE MEAGER. THUS...MAINLY MULTICELL PULSE-TYPE OF SEVERE CAN BE EXPECTED GIVING LOCAL DAMAGING WIND GUSTS OR A BRIEF TORNADO/WATERSPOUT. ..RACY.. 08/13/2006  From swody2 at goshenarc.org Mon Aug 14 05:49:22 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 14 Aug 2006 01:49:22 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 140550 SWODY2 SPC AC 140549 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1249 AM CDT MON AUG 14 2006 VALID 151200Z - 161200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... FASTER/PROGRESSIVE FLOW WILL REMAIN CONFINED TO THE NRN AREAS WHILE BROAD UPPER RIDGE PERSISTS ACROSS THE SOUTH...GENERALLY EAST OF THE ROCKIES. A COUPLE OF DIFFICULT TO FORECAST SUBTROPICAL DISTURBANCES CONTINUE TO BE SUGGESTED BY THE LATEST GUIDANCE ALONG THE SRN PERIPHERY OF THE UPPER RIDGE. ONE OF THESE DISTURBANCES MOVES CLOSE TO...OR OVER...FL AND THE ERN GULF. THE OTHER SYSTEM DEVELOPS SLOWLY NWD ACROSS PARTS OF THE UPPER RIO GRANDE VALLEY. THE COLD FRONT SPREADING ACROSS THE OH VALLEY AND NORTHEAST DURING THE DAY 1 PERIOD WILL SETTLE INTO THE MID ATLANTIC..CNTRL/SRN APPALACHIANS...AND TN VALLEY AREAS BY EARLY TUESDAY. THIS BOUNDARY WILL CONTINUE TO WEAKEN AS STRONGER LARGE SCALE SUPPORT FOR UPWARD MOTION MOVES OVER THE NEW ENGLAND COASTAL WATERS. WEAK CONVERGENCE ALONG THE TRAILING BOUNDARY WILL DEVELOP INTO VERY MOIST AND POTENTIALLY UNSTABLE AIR MASS SWWD/WWD FROM VA TO THE LOWER MS VALLEY. ...LOWER MS VALLEY TO SRN APPALACHIANS TO SRN VA... FRONTAL CIRCULATION WILL DEVELOP INTO MOIST AND UNSTABLE AIR MASS AND PROMOTE THE DEVELOPMENT OF TSTMS...POSSIBLY INCREASING IN COVERAGE AND INTENSITY DURING THE DAY. GENERALLY WEAK FLOW AND LAPSE RATES PRECLUDE A HIGHER SEVERE RISK AT THIS TIME. A FEW STORM CLUSTERS...CELL MERGERS...AND LOCALLY STRONGER LOW LEVEL SHEAR COULD RESULT IN BRIEFLY INTENSE ACTIVITY NEAR THE DECAYING FRONT AND ALONG RESIDUAL/GULF AND SEA BREEZE BOUNDARIES. ISOLATED WET MICROBURSTS APPEAR POSSIBLE. ...SOUTHWEST... LOW LEVEL UPSLOPE FLOW IN WAKE OF RECENT FRONTAL INTRUSION/WIND SHIFT MAY AID TSTM DEVELOPMENT ACROSS PARTS OF NM/AZ THROUGH THE AFTERNOON. SUBTROPICAL MOISTURE PLUME ACROSS THE AREA...AND POSSIBILITY OF WEAK DISTURBANCES CHANNELED BETWEEN ANTICYCLONE TO THE EAST AND TROUGHING ACROSS THE WEST...WILL FURTHER SUPPORT THE DEVELOPMENT OF DEEP CONVECTION OVER THE SRN MOGOLLON PLATEAU AND HIGHER ELEVATIONS OF NM. GENERALLY WEAK LOW LEVEL ELY FLOW TOPPED BY SLY MID LEVEL FLOW WILL RESULT IN ADEQUATE DIRECTIONAL SHEAR FOR A FEW LONGER-LIVED UPDRAFTS CAPABLE OF ISOLATED DOWNBURST WINDS AND MARGINALLY SEVERE HAIL. ...NRN PLAINS... FAST FLOW WITHIN BUILDING RIDGE ACROSS THE PLAINS WILL EXIST ATOP STRONGLY HEATED AND MARGINALLY MOIST AIR MASS. ALTHOUGH MOST OF THE AREA IS EXPECTED TO REMAIN CAPPED...ISOLATED CONVECTION COULD BREACH THE CAP BY LATE IN THE DAY FROM ERN MT INTO ND. PERSISTENT WARM AIR ADVECTION AND DESTABILIZATION ON THE NOSE OF LOW LEVEL JET...COUPLED WITH LOW AMPLITUDE IMPULSES EMANATING FROM DEVELOPING WRN U.S. TROUGH...COULD SUSTAIN A COUPLE OF SEVERE STORMS WITH HAIL AND WIND POTENTIAL OVER THE NRN PLAINS THROUGH EARLY WEDNESDAY MORNING. ..CARBIN.. 08/14/2006  From swody2 at goshenarc.org Mon Aug 14 17:07:46 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 14 Aug 2006 13:07:46 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 141707 SWODY2 SPC AC 141706 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1206 PM CDT MON AUG 14 2006 VALID 151200Z - 161200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... SYNOPTIC PATTERN WILL BE CHARACTERIZED BY PROGRESSIVE NRN STREAM FLOW BELT...AND MESSY RIDGING WITH SOME WEAK/EMBEDDED SHORTWAVE PERTURBATIONS OVER S-CENTRAL/SERN STATES. STRONG SHORTWAVE TROUGH -- CURRENTLY ANALYZED OVER ONT AND UPPER GREAT LAKES -- IS FCST TO MOVE EWD ACROSS SRN QUE...NY AND NEW ENGLAND DURING DAY-2. ASSOCIATED SFC COLD FRONT IS FCST TO MOVE OFFSHORE MOST OF NEW ENGLAND AND MID-ATLANTIC REGION DURING MORNING/EARLY AFTERNOON HOURS...TRAILING SWWD ACROSS TN/NRN GA AND BECOMING QUASISTATIONARY OVER OK. MEANWHILE...HEIGHTS ARE FCST TO FALL ACROSS MUCH OF W COAST AND GREAT BASIN REGIONS...AHEAD OF SHORTWAVE TROUGH NOW EVIDENT IN MOISTURE CHANNEL IMAGERY INVOF 49N147W. THIS FEATURE IS PROGGED TO STRENGTHEN AND DIG SEWD...MOVING ONSHORE NRN CA LATE DAY-2 OR EARLY DAY-3. SWLY FLOW ALOFT -- POSSIBLY WITH ONE OR TWO WEAK/EMBEDDED PERTURBATIONS -- SHOULD DEVELOP OVER NRN ROCKIES AND NRN HIGH PLAINS BY 16/00Z...WHILE MIDLEVEL RIDGING SHIFTS EWD OVER DAKOTAS. ASSOCIATED LEE-SIDE PRESSURE FALLS ARE FCST AT SFC ACROSS PORTIONS NRN WY AND ERN MT...WITH SFC FRONTOGENESIS OVER PORTIONS NRN MT AND SRN SASK. ...NRN PLAINS... ISOLATED TO WIDELY SCATTERED TSTMS ARE POSSIBLE DURING AFTERNOON INTO EVENING ACROSS ERN MT AND/OR WRN DAKOTAS...SHIFTING EWD DURING EVENING. SOME OF THIS ACTIVITY MAY LAST THROUGH EVENING HOURS AND OVERNIGHT ALONG NOSE OF 30-40 KT LLJ...MOVING EWD TO NEWD ACROSS PORTIONS DAKOTAS. OCCASIONAL HAIL/GUSTS NEAR SVR LEVELS ARE POSSIBLE. AS RIDGING ALOFT MOVES OVER AND THEN E OF THIS AREA...TIGHTENING HEIGHT GRADIENT ALOFT AND LEE-SIDE PRESSURE FALLS IN LOW LEVELS WILL RESULT IN STRENGTHENING OF DEEP-LAYER VERTICAL SHEAR. FCST HODOGRAPHS SUGGEST MRGL POTENTIAL FOR SUPERCELLS...AND ASSOCIATED RISK OF HAIL. LACK OF MORE ROBUST LOW LEVEL MOISTURE WILL LIMIT BUOYANCY AND OVERALL TSTM COVERAGE...DESPITE STEEP MIDLEVEL LAPSE RATES APCHG DRY ADIABATIC. HOWEVER...WELL-MIXED SUBCLOUD LAYERS DURING AFTERNOON INTO EARLY EVENING...BEFORE NEAR-SFC LAYER COOLS SUBSTANTIALLY...WILL SUPPORT HAIL/GUSTS NEAR SVR LIMITS WITH ANY ACTIVITY THAT DOES DEVELOP. ...SERN CONUS... SUFFICIENT BUOYANCY...MOISTURE...HEATING AND WEAK AFTERNOON CINH ARE EXPECTED FOR SCATTERED TO LOCALLY NUMEROUS TSTMS. RICH BOUNDARY LAYER MOISTURE -- CHARACTERIZED BY SFC DEW POINTS UPPER 60S TO MID 70S F -- WILL BE COMMON ALONG AND S OF FRONT. A FEW MULTICELL CLUSTERS ARE POSSIBLE WITH FRONT AND OUTFLOW BOUNDARIES BEING PRIMARY FOCI. ISOLATED DAMAGING GUSTS ARE POSSIBLE...PRIMARILY DURING AFTERNOON INTO EARLY EVENING. WEAKNESS OF DEEP-LAYER FLOW AND VERTICAL SHEAR APPEAR TO PRECLUDE WELL ORGANIZED SVR THREAT. CONVERGENCE ALONG CAROLINAS/GA PORTION OF FRONT MAY BE REDUCED BY ISALLOBARIC INFLUENCES ON SFC WIND FIELDS RELATED TO LOW LEVEL DISTURBANCE NOW OVER BAHAMAS. REF NHC OUTLOOKS UNDER ABNT20 KNHC FOR LATEST INFO ON TROPICAL DEVELOPMENT POTENTIAL. CONVECTIVE POTENTIAL ALONG WRN SEGMENT OF FRONT -- ARKLATEX REGION TO LOWER MS VALLEY -- MAY BE ENHANCED BY LARGE SCALE ASCENT ASSOCIATED WITH PORTION OF WEAK/SUBTROPICAL UPPER LOW DRIFTING NEWD FROM W-CENTRAL TX. ...SWRN CONUS... TSTMS SHOULD DEVELOP OVER MUCH OF SRN NM AND SERN AZ...AS WELL AS FAR W TX...DURING AFTERNOON AND EVENING. ISOLATED GUSTS NEAR SVR LEVELS ARE POSSIBLE FROM MOST INTENSE TSTMS...HOWEVER POTENTIAL APPEARS TOO CONDITIONAL/MRGL TO WARRANT CATEGORICAL OUTLOOK ATTM. RICH LOW LEVEL MOISTURE FOR THIS REGION WILL PERSIST THROUGH DAY-2...WITH SFC DEW POINTS COMMONLY 60S F LOWER ELEVATIONS...AND 50S IN MOUNTAINS. THIS WILL SUPPORT TSTMS WITH WEAK CINH AND HEATING OF HIGHER TERRAIN...IN RELATIVELY CLOUD-FREE AREAS. ONE SIGNIFICANT LIMITING FACTOR MAY BE BROAD AREA OF CLOUDS WITH SOME EMBEDDED PRECIP...LEFT BEHIND BY AFTERNOON/OVERNIGHT ACTIVITY DAY-1. THIS WOULD DELAY/RESTRICT SFC HEATING BUT ALSO FOCUS SOME POTENTIAL FOR DEVELOPMENT ALONG DIFFERENTIAL HEATING ZONES. ..EDWARDS.. 08/14/2006  From swody2 at goshenarc.org Tue Aug 15 06:08:25 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 15 Aug 2006 02:08:25 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 150604 SWODY2 SPC AC 150603 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0103 AM CDT TUE AUG 15 2006 VALID 161200Z - 171200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF ERN MT AND ND... ...SYNOPSIS... NWRN U.S. UPPER TROUGH SHOULD EDGE EAST OVER THE NRN GREAT BASIN AND NRN ROCKIES DURING WEDNESDAY. A BELT OF MODEST /30-40KT/ WSWLY MID LEVEL FLOW WILL EXTEND FROM THE BASE OF THE TROUGH...ACROSS THE NRN PLAINS...AND THEN THROUGH A SHORT WAVE RIDGE AXIS FROM THE UPPER MS VALLEY TO GREAT LAKES. LOWER-AMPLITUDE DISTURBANCES ARE FORECAST TO EMANATE FROM THE LARGER SCALE TROUGH WITH VERY WEAK HEIGHT FALLS SPREADING ACROSS THE NRN PLAINS THROUGH WEDNESDAY NIGHT. IT IS ALSO POSSIBLE THAT A MORE SUBTLE SHORT WAVE IMPULSE...PERHAPS CONVECTIVELY ENHANCED...MAY EMERGE FROM SUBTROPICAL STREAM ACROSS THE SRN PLAINS AND AID LARGE SCALE BACKGROUND ASCENT OVER THE SRN AND CNTRL HIGH PLAINS...EWD TO THE MO VALLEY. MODELS CONTINUE TO INDICATE SUBTROPICAL GYRE WILL DRIFT INTO THE GULF WHILE A SMALLER SCALE LOW FORMS NEAR THE SOUTHEAST U.S. COAST. BOTH THESE FEATURES WILL BE TO THE SOUTH AND EAST OF A DECAYING SYNOPTIC FRONTAL BOUNDARY SITUATED FROM THE CAROLINAS TO THE DEEP SOUTH. ...NRN PLAINS... LOW LEVEL SLY FLOW AND MOISTURE TRANSPORT WILL STRENGTHEN ACROSS THE CNTRL AND NRN PLAINS THIS PERIOD IN RESPONSE TO ISALLOBARIC AND DIABATIC FORCING RESULTING FROM APPROACH OF ROCKIES TROUGH AND DIURNAL HEATING. IT IS LIKELY THAT A STRONG EML/CAP WILL ACT TO INHIBIT CONVECTIVE DEVELOPMENT ACROSS MUCH OF THE WARM SECTOR BUT AIR MASS ACROSS THE REGION SHOULD BECOME MODERATELY UNSTABLE GIVEN DEWPOINTS IN THE 60S AND TEMPERATURES IN THE UPPER 80S AND LOWER 90S. GIVEN STRONG CAP AND ONLY MARGINAL LARGE SCALE SUPPORT FOR ASCENT FROM LOW AMPLITUDE MID LEVEL IMPULSE...LATE DAY STORM INITIATION APPEARS MOST LIKELY NEAR AND NORTH OF WSW-ENE ORIENTED DEEP-LAYER BAROCLINIC ZONE...FROM MT INTO NCNTRL ND. ADDITIONAL TSTM ACTIVITY...IN LOWER CAPE ENVIRONMENT...APPEARS LIKELY FROM ERN ORE ACROSS PARTS OF ID AND WRN MT...CLOSER TO THE STRONGER FORCING AND AIDED BY OROGRAPHIC FORCING. ISOLATED HIGH-BASED CONVECTION MAY ALSO FORM WHERE CAP CAN BE LOCALLY OVERCOME NEAR LEE/THERMAL TROUGH OR DRYLINE FROM WRN/CNTRL SD...SSWWD INTO NEB. OVER ERN MT AND ND...INSTABILITY FLOWING FROM CAPPED ENVIRONMENT INTO FRONTAL AND POST-FRONTAL CONVECTION WILL LIKELY FUEL A FEW INTENSE STORM UPDRAFTS WHERE DEEP LAYER SHEAR WILL BE MORE THAN SUFFICIENT FOR CELL ROTATION AND HAIL PRODUCTION. IT IS POSSIBLE THAT OUTFLOW FROM THIS ACTIVITY WILL ENHANCE MESOSCALE FORCING ALONG THE LOW LEVEL BOUNDARY TO PROMOTE ADDITIONAL SURFACE-BASED STORMS OVER SRN/ERN SECTIONS OF ND. HAIL AND WIND THREAT MAY EVOLVE FROM THIS CONVECTION AND SPREAD EAST TOWARD PARTS OF WRN MN DURING THE NIGHT. ...CNTRL PLAINS TO MO VALLEY... WEAK QG-FORCING ATOP LEE TROUGH AND/OR RESIDUAL FRONTAL BOUNDARY BISECTING KS SHOULD PROMOTE AFTERNOON AND EVENING TSTM DEVELOPMENT OVER THE PLAINS. GENERALLY WEAK DEEP-LAYER SHEAR AND LAPSE RATES IN WARM MOIST/MOIST ENVIRONMENT SUGGEST ONLY ISOLATED AND MARGINAL HAIL/WIND POTENTIAL. HOWEVER...LOCALLY ENHANCED LOW LEVEL SHEAR AND INSTABILITY NEAR THE RESIDUAL FRONT MIGHT SUPPORT A SUPERCELL OR TWO FROM CNTRL KS NWD TO SRN NEB. IT IS POSSIBLE THAT A FEW STRONG TSTMS MAY PERSIST IN WAA REGIME ACROSS KS/NEB INTO THE NIGHT. THIS ACTIVITY MAY CONGEAL INTO A SMALL MCS AND BE SUSTAINED ACROSS THE MO VALLEY AS NOCTURNAL LLJ INTENSIFIES OVERNIGHT. ..CARBIN.. 08/15/2006  From swody2 at goshenarc.org Tue Aug 15 17:30:08 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 15 Aug 2006 13:30:08 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 151730 SWODY2 SPC AC 151729 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1229 PM CDT TUE AUG 15 2006 VALID 161200Z - 171200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... PROGRESSIVE NRN STREAM SHORTWAVE PATTERN WILL CONTINUE THROUGH PERIOD IN MID/UPPER LEVELS...DOWNSTREAM FROM AMPLIFYING TROUGH OVER PACIFIC NW. BROAD FETCH OF SWLY FLOW ALOFT...FROM NRN GREAT BASIN ACROSS NRN ROCKIES AND NRN HIGH PLAINS...WILL CONTRIBUTE TO LEE-SIDE PRESSURE FALLS AND LOW LEVEL WAA ACROSS CENTRAL/NRN HIGH PLAINS. BY 17/00Z...QUASISTATIONARY FRONTAL ZONE IS EXPECTED FROM SRN MB SWWD INTO CENTRAL WY. SFC FRONTAL ZONE -- STRONGLY MODULATED BY CONVECTIVE OUTFLOWS -- SHOULD LINGER FROM VA/NC TIDEWATER REGION SWWD ACROSS MS...BECOMING DIFFUSE NWWD ACROSS CENTRAL PLAINS. FARTHER S...SHORTWAVE TROUGH -- EVIDENT IN MOISTURE CHANNEL IMAGERY OVER NWRN MEX -- MAY LIFT NEWD ACROSS PORTIONS SRN ROCKIES AND/OR SRN HIGH PLAINS DURING PERIOD. MEANWHILE...TROUGH NOW OVER NM SHOULD LIFT NEWD ACROSS PORTIONS NEB/IA. PROGS ARE VERY INCONSISTENT WITH SRN FEATURE...WHICH IS NOT SURPRISING GIVEN ITS ORIGIN IN RELATIVE VOID OF MEX UPPER AIR DATA. THEREFORE CONSIDERABLE UNCERTAINTY REMAINS WITH ITS POTENTIAL TRACK...AND BY EXTENSION...GEN THUNDER POTENTIAL WITHIN ASSOCIATED PLUME OF LARGE SCALE ASCENT. ...CENTRAL/NRN PLAINS... LOW LEVEL MOISTURE IS EXPECTED TO INCREASE WITH SWD EXTENT...REMAINING MRGL OVER NRN PLAINS WITH DEW POINTS UPPER 40S TO UPPER 50S F...BUT WITH 60S TO LOW 70S OVER PORTIONS KS. BY CONTRAST...MID/UPPER LEVEL LAPSE RATES AND DEEP-LAYER SHEAR GENERALLY SHOULD INCREASE WITH NWRN EXTENT. CAP MAY WEAKEN DURING MID-LATE AFTERNOON SUFFICIENTLY FOR TSTMS OVER PORTIONS CENTRAL/ERN MT...DAKOTAS...NEB AND WRN/NRN KS. BOUNDARY LAYER FORCING FOR SFC-BASED CONVECTION APPEARS RATHER ILL-DEFINED S OF FRONT AND AWAY FROM POSTFRONTAL OROGRAPHIC LIFT ZONE IN MT. CONVERGENCE IS NOT EXPECTED TO BE PARTICULARLY STRONG ALONG FRONT...WHILE MOISTURE WILL BE IN QUESTION OVER OROGRAPHIC LIFT REGION. GIVEN THESE OFFSETS IN MOST FAVORABLE INGREDIENTS FOR SVR POTENTIAL...AND CONVECTIVE SPATIAL/COVERAGE UNCERTAINTIES...WILL KEEP UNCONDITIONAL SVR PROBABILITIES BELOW CATEGORICAL OUTLOOK CRITERIA ATTM. ...SERN STATES... WIDELY SCATTERED TSTMS -- IN PULSE FORM AND IN MULTICELLULAR CLUSTERS -- ARE EXPECTED ACROSS MUCH OF REGION ALONG AND S OF FRONT. CONVECTIVE POTENTIAL ACROSS COASTAL PLAIN OF CAROLINAS MAY BE INFLUENCED BY POTENTIAL TROPICAL DEVELOPMENT ASSOCIATED WITH AREA OF LOW LEVEL LOW PRESSURE NOW EVIDENT OVER ATLANTIC SE OF SC COAST. SEE NHC OUTLOOKS UNDER WMO HEADER ABNT20 KNHC FOR MORE INFO. MORE ROBUST DIURNAL DESTABILIZATION IS FCST FROM GA SWWD ACROSS SRN PORTIONS MS/AL/LA...WHERE STRONG SFC HEATING AND DEW POINTS 70S F WILL YIELD MODERATE-STRONG BUOYANCY. LOCALIZED POTENTIAL FOR STG-SVR GUSTS MAY DEVELOP...ESPECIALLY WITH TSTMS DEVELOPING INVOF BOUNDARIES RELATED TO OUTFLOW...SEA BREEZE AND RESIDUAL SYNOPTIC FRONT. ...INTERIOR NWRN CONUS... STRONG LARGE SCALE ASCENT/COOLING WILL OCCUR AHEAD OF DIGGING MID/UPPER LEVEL TROUGH...RESULTING IN STEEPENED LOW/MIDDLE LEVEL LAPSE RATES...IN TANDEM WITH DAYTIME SFC HEATING. THIS SHOULD RESULT IN WEAK AFTERNOON CINH AND POTENTIAL FOR WIDELY SCATTERED TSTMS TO DEVELOP...IN ENVIRONMENT OF AT LEAST MRGL BOUNDARY LAYER MOISTURE. STRONGEST ACTIVITY MAY PRODUCE HAIL AND/OR GUSTS NEAR SEVERE LEVELS. ..EDWARDS.. 08/15/2006  From swody2 at goshenarc.org Wed Aug 16 06:07:25 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 16 Aug 2006 02:07:25 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 160605 SWODY2 SPC AC 160604 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0104 AM CDT WED AUG 16 2006 VALID 171200Z - 181200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE NRN PLAINS... ...SYNOPSIS... POSITIVE TILT UPPER TROUGH WILL MOVE OVER THE INTERIOR NORTHWEST AND NRN ROCKIES THIS PERIOD WITH ONE OR MORE SMALLER SCALE DISTURBANCES EMANATING FROM THIS FEATURE AND TRANSLATING DOWNSTREAM WITHIN BAND OF FAST WSWLY MID LEVEL FLOW FROM MT/WY TO THE DAKOTAS/MN. EXPANSIVE ANTICYCLONE WILL COVER MUCH OF THE SRN U.S FROM THE DESERT SOUTHWEST TO THE MID ATLANTIC COAST WITH SEVERAL SMALLER SCALE MID LEVEL VORTICES ROTATING AROUND THE EDGES OF THE MID/UPPER LEVEL HIGH. ONE OR TWO OF THESE WEAKER DISTURBANCES WILL DEVELOP NEWD ACROSS THE SRN/CNTRL PLAINS TO THE MO AND MID MS VALLEY AREAS THROUGH EARLY FRIDAY. ...NRN PLAINS... A WSW-ENE ORIENTED DEEP-LAYER BAROCLINIC ZONE IS FORECAST TO EXIST ACROSS THE DAKOTAS ON THE SRN EDGE OF FASTER WSWLY FLOW ALOFT. THIS BOUNDARY WILL PROVIDE A FOCUS FOR TSTM DEVELOPMENT THROUGH THE PERIOD AS SHORT WAVE TROUGHS TRAVERSE THE REGION AND ENHANCE SYNOPTIC/MESOSCALE FORCING FOR ASCENT. STRONG EML/CAP ACROSS THE WARM SECTOR SUGGESTS PRIMARY DEVELOPMENT MAY OCCUR ON AND NORTH OF THE BOUNDARY. INFLOW OF WARM AND UNSTABLE AIR FROM CAPPED AIR MASS INTO THE FRONTAL ZONE SHOULD FUEL ROBUST STORMS IN STRONGLY SHEARED FLOW. THIS ACTIVITY WILL BE CAPABLE OF PRODUCING HAIL AND HIGH WINDS AS IT DEVELOPS EWD/SEWD FROM ERN MT/WRN DAKOTAS TO THE ERN DAKOTAS THROUGH THURSDAY NIGHT. ...CNTRL PLAINS... RESIDUAL BOUNDARY ACROSS THE CNTRL PLAINS /NRN KS TO IA/ WILL ACT AS A WEAK WARM FRONT ACROSS THE REGION THROUGH THURSDAY. PARTS OF THE BOUNDARY MAY BE LOCALLY REINFORCED THROUGH CONVECTIVE OUTFLOW AND/OR DIFFERENTIAL HEATING. WARM AND UNSTABLE AIR MASS ACROSS THE REGION WILL FUEL STRONG TO ISOLATED SEVERE TSTM DEVELOPMENT WHERE CAP CAN BE OVERCOME BY HEATING AND SYNOPTIC/MESOSCALE FORCING NEAR THE BOUNDARY. SOME SUPPORT FOR LARGE SCALE LIFT MAY BE PROVIDED BY THE PASSAGE OF SUBTLE SHORT WAVE IMPULSES ROTATING AROUND AND OUT OF THE SUBTROPICAL RIDGE. A CONVECTIVE COMPLEX MAY EVOLVE FROM AREAS OF AFTERNOON AND EVENING CONVECTION. AS ACTIVITY COALESCES AND GROWS UPSCALE...INTENSIFYING LOW LEVEL JET WITHIN PLAINS WARM CONVEYOR BELT MAY SUSTAIN A STORM COMPLEX THROUGH THE NIGHT FROM THE MO VALLEY EWD TO THE MID/UPPER MS VALLEY. ..CARBIN.. 08/16/2006  From swody2 at goshenarc.org Wed Aug 16 17:32:03 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 16 Aug 2006 13:32:03 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 161731 SWODY2 SPC AC 161731 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1231 PM CDT WED AUG 16 2006 VALID 171200Z - 181200Z ...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS NRN PLAINS... ...SYNOPSIS... PRONOUNCED MID-UPPER LEVEL TROUGH -- NOW MOVING INLAND PACIFIC NW -- IS EXPECTED TO SHIFT FARTHER EWD ACROSS INTERIOR NW TO NRN ROCKIES DURING DAY2...AS ASSOCIATED SWLY FLOW ALOFT AND MIDLEVEL SPEED MAX SPREAD OVER NRN HIGH PLANS AND ND. MEANWHILE...WEAK SRN STREAM PERTURBATION -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY OVER NWRN MEX S OF SWRN NM -- IS FCST TO LIFT NEWD ACROSS SRN/CENTRAL HIGH PLAINS DURING THIS PERIOD. AT SFC...COLD FRONT IS EXPECTED TO MOVE SEWD FROM CANADIAN HIGH PLAINS AND MT...ACROSS DAKOTAS AND FAR NRN MN. FRONTAL-WAVE CYCLONE SHOULD FORM INVOF BLACK HILLS...IN ADVANCE OF APCHG MID-UPPER TROUGH. AS THIS OCCURS...COLD FRONT SHOULD DECELERATE ACROSS NRN SD/SRN ND AREA AND REMAIN QUASISTATIONARY UNTIL PASSAGE OF SFC LOW LATE DAY-2 AND EARLY DAY-3. MEANWHILE...WARM FRONTAL ZONE NOW OVER SRN PLAINS IS FCST TO SHIFT/REDEVELOP NNEWD TO LOWER MO VALLEY. ...NRN PLAINS... SCATTERED TSTMS ARE EXPECTED TO DEVELOP FROM MID-LATE AFTERNOON ONWARD...WITH EVOLUTION TO ORGANIZED MCS POSSIBLE AFTER DARK ACROSS PORTIONS DAKOTAS INTO WRN MN. DAMAGING GUSTS AND LARGE HAIL WILL BE POSSIBLE. TORNADO POTENTIAL IS MORE CONDITIONAL/MRGL...AND DEPENDENT ON MESOSCALE TO STORM-SCALE BOUNDARY RELATED PROCESSES. FORECAST SOUNDINGS ACROSS THIS REGION SUGGEST FAVORABLE VERTICAL SHEAR PROFILES ALONG AND N OF FRONT FOR SUPERCELLS...WITH STRONG DIRECTIONAL VEERING CONTRIBUTING TO EFFECTIVE SHEARS AOA 50 KT. THERMODYNAMICS SHOULD BECOME INCREASINGLY FAVORABLE THROUGH AFTERNOON ALSO...AS SFC DIABATIC HEATING AND FRONTAL LIFT REDUCE CINH IN FAVORABLY MOIST BOUNDARY LAYER ENVIRONMENT. MOIST ADVECTION AND EVAPOTRANSPIRATIVE EFFECTS SHOULD RESULT IN AXIS OF SFC DEW POINTS MID 60S ALONG OR JUST N OF FRONT...COMBINING WITH STEP MIDLEVEL LAPSE RATES TO SUPPORT MLCAPES OVER 2000 J/KG OVER CENTRAL/WRN DAKOTAS. ISOLATED STG-SVR STMS ALSO WILL BE POSSIBLE WWD ACROSS MUCH OF MT IN POST-FRONTAL ZONE OF BOUNDARY LAYER UPSLOPE FLOW...JUXTAPOSED WITH COOLING ALOFT AND AT LEAST MRGL MOISTURE. SVR POTENTIAL IS EXPECTED TO BE CONCENTRATED IN FAIRLY DENSE FASHION INVOF BOUNDARY LAYER MOIST AXIS FROM AFTERNOON THROUGH EVENING HOURS. MAIN UNCERTAINTY ATTM IS POSITIONING OF FRONT AND MOIST AXIS ON MESO BETA SCALE. PROBABILITIES THEREFORE MAY NEED TO BE BOOSTED WITHIN BROADER 15 PERCENT AREA...ONCE THOSE ELEMENTS BECOME MORE CERTAIN IN SUCCEEDING OUTLOOKS. ...CENTRAL PLAINS... VERTICAL SHEAR IS FCST TO DIMINISH WITH SWD EXTENT FROM DAKOTAS FRONTAL ZONE. HOWEVER...PLUME OF FAVORABLE LOW LEVEL MOISTURE WILL BE IN PLACE FROM SRN HIGH PLAINS NNEWD ACROSS MUCH OF CENTRAL PLAINS REGION...ALONG WITH WEAK AFTERNOON CINH IN RELATIVELY CLOUD-FREE AREAS. MULTICELL AND PULSE STORMS WILL PREDOMINATE...MOST INTENSE OF WHICH MAY PRODUCE GUSTS NEAR SEVERE LEVELS DURING LATE AFTERNOON/EARLY EVENING. ...IA/IL... SEVERAL DETERMINISTIC PROGS ARE CONSISTENT IN DEVELOPMENT OF TSTM CLUSTER ALONG OR N OF SFC WARM FRONT DURING EVENING...WHICH WOULD MOVE SLOWLY ESEWD ACROSS MS RIVER WITH SOME POTENTIAL FOR DAMAGING GUSTS AND MRGL HAIL. AIR MASS IN THIS REGION WILL BE CHARACTERIZED BY REGIONAL MOISTURE MAXIMUM...ASSOCIATED BOTH WITH PRIOR MOIST ADVECTION AND WITH EVAPOTRANSPIRATION AT SFC. THIS AREA ALSO WILL BE WITHIN WAA/MOISTURE TRANSPORT REGIME...NEAR NOSE OF 30 KT NOCTURNAL LLJ. THIS WILL SUPPORT PERSISTENCE OF ANY LATE AFTERNOON/EARLY EVENING DEVELOPMENT OVERNIGHT. RELATIVELY WEAK MIDLEVEL FLOW WILL LIMIT BULK SHEAR...AND THERE IS SOME CONCERN THAT CAP MAY NOT BREAK DIURNALLY INVOF WARM FRONT. THEREFORE SVR PROBABILITIES ARE KEPT MRGL ATTM. ..EDWARDS.. 08/16/2006  From swody2 at goshenarc.org Thu Aug 17 06:08:03 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Thu, 17 Aug 2006 02:08:03 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 170605 SWODY2 SPC AC 170604 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0104 AM CDT THU AUG 17 2006 VALID 181200Z - 191200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE DAKOTAS AND NERN NEB... ...SYNOPSIS... UPPER TROUGH CURRENTLY MOVING INTO THE INTERIOR NORTHWEST WILL BRING MODEST MID LEVEL HEIGHT FALLS FROM THE NRN PLAINS TO UPPER MS VALLEY THROUGH EARLY SATURDAY. THIS DISTURBANCE WILL CONTINUE TO DAMPEN THE NRN PERIPHERY OF THE LARGE UPPER HIGH BLANKETING MUCH OF THE CNTRL AND SRN U.S...AND WILL INDUCE FRONTAL WAVE DEVELOPMENT ACROSS SD FRIDAY AFTERNOON. COLD FRONT ACCOMPANYING UPPER TROUGH AND ASSOCIATED SURFACE WAVE WILL SPREAD SOUTH ACROSS THE CNTRL PLAINS THROUGH FRIDAY NIGHT AS UPPER TROUGH AND SURFACE LOW TRACK GENERALLY EAST TOWARD THE UPPER MS VALLEY. NAM-WRF AND GFS MODELS DIFFER SLIGHTLY ON THE TIMING OF THE NRN STREAM FEATURES WITH THE GFS INDICATING A FASTER EWD/SEWD MOVEMENT TO THE UPPER TROUGH AND COLD FRONT THROUGH EARLY SATURDAY. THIS OUTLOOK IS FURTHER COMPLICATED BY A SERIES OF MORE SUBTLE SUBTROPICAL SRN STREAM DISTURBANCES IN WEAKER FLOW AROUND THE NRN EDGE OF THE DEEP-LAYER ANTICYCLONE. A LEADING FEATURE IN THIS WAVE TRAIN WAS ALREADY AIDING MESOSCALE CONVECTIVE COMPLEX OVER THE MO VALLEY ATTM. ADDITIONAL IMPULSES ARE FORECAST TO EVOLVE AND EMANATE FROM HIGH PLAINS CONVECTION OVER THE NEXT DAY OR SO. THESE WEAK DISTURBANCES WILL SPREAD EAST AND ENHANCE ASCENT ATOP A QUASI-STATIONARY WARM FRONT FROM MO/IA...ACROSS THE MIDWEST...TO THE OH VALLEY THROUGH EARLY SATURDAY. ...DAKOTAS/NEB... STRONGER FORCING ASSOCIATED WITH UPPER TROUGH AND COLD FRONT WILL SPREAD ESEWD OVER THE NRN PLAINS DURING THE DAY AND ENHANCE LIFT ACROSS INCREASINGLY UNSTABLE AIR MASS. MODELS APPEAR TO BE OVERFORECASTING LOW LEVEL MOISTURE ACROSS THE AREA BUT MLCAPE VALUES TO 2000 J/KG APPEAR POSSIBLE OVER NEB/SD GIVEN MID TO UPPER 60S DEWPOINTS AND TEMPERATURES IN THE 80S TO 90S. SUFFICIENT SHEAR AND INSTABILITY ARE FORECAST ACROSS SERN ND AND SD FOR SUPERCELLS WITH HAIL. TORNADO POTENTIAL MAY INCREASE SHOULD THIS CONVECTION REMAIN DISCRETE AND PERSIST NEAR SURFACE WAVE. ACROSS NEB...SHEAR WILL INITIALLY BE WEAKER BUT POTENTIAL INSTABILITY IS FORECAST TO BE GREATER. HEATING AND LARGE SCALE LIFT WILL ACT TO OVERCOME THE CAP ACROSS THIS AREA AND SHOULD RESULT IN SCATTERED TSTM DEVELOPMENT THROUGH EVENING. ROBUST MULTICELL CONVECTION SHOULD POSE SOME THREAT OF LARGE HAIL AND LOCAL DOWNBURST WINDS BEFORE COLD FRONT MOVES ACROSS THE REGION OVERNIGHT. ...MO/IA EAST TO OH VALLEY... AN MCS OR TWO MAY BE ONGOING AT THE START OF THE PERIOD WITHIN PLAINS WARM CONVEYOR BELT FROM MO VALLEY EAST ACROSS THE MS VALLEY. CONVECTION MAY REGENERATE OR CONTINUE TO SPREAD EAST ACROSS THE MIDWEST THROUGH THE DAY SUSTAINED BY MCVS/SHORT WAVE TROUGHS AND PERSISTENT WARM AIR ADVECTION ON THE EDGE OF THE STRONGER CAP. POCKETS OF GREATER MID LEVEL FLOW ASSOCIATED WITH MCVS/SUBTLE SHORT WAVES...COUPLED WITH AREAS OF STRONGER DESTABILIZATION...COULD SUPPORT CLUSTERS OF SEVERE STORMS WITH WIND AND HAIL. UNCERTAINTIES WITH RESPECT TO TIMING AND AMPLITUDE OF MID LEVEL IMPULSES...CAP STRENGTH...LOCATION OF MCS OUTFLOW...AND STRENGTH OF SHEAR...ALL PLAY INTO KEEPING SEVERE PROBABILITIES LOW AT THIS TIME. ..CARBIN.. 08/17/2006  From swody2 at goshenarc.org Thu Aug 17 17:33:04 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Thu, 17 Aug 2006 13:33:04 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 171732 SWODY2 SPC AC 171731 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1231 PM CDT THU AUG 17 2006 VALID 181200Z - 191200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE MID MO VALLEY REGION EWD INTO THE MIDWEST/OH VALLEY... ...SYNOPSIS... LARGE UPPER RIDGE WILL PREVAIL ACROSS MUCH OF THE ERN 2/3 OF THE CONUS...WHILE MAIN SHORT-WAVE TROUGH MOVES EWD FROM THE NRN ROCKIES INTO THE NRN PLAINS ALONG NRN PERIPHERY OF RIDGE. ADDITIONALLY...SEVERAL SMALLER-SCALE VORTICITY MAXIMA ARE EXPECTED TO SHIFT EWD ACROSS THE PLAINS/MIDWEST...AHEAD OF MAIN SHORT-WAVE TROUGH. AT THE SURFACE...COLD FRONT INITIALLY FORECAST FROM THE UPPER GREAT LAKES INTO THE CENTRAL ROCKIES IS EXPECTED TO WEAKEN WITH TIME AS IT SHIFTS EWD/SEWD. RESULTING SURFACE PATTERN SHOULD BECOME INCREASINGLY ILL-DEFINED...EXTENDING FROM THE PLAINS EWD INTO THE MIDWEST/OH VALLEY REGION. ...MID MO/MID MS VALLEY REGIONS INTO THE OH VALLEY... LARGE AREA OF WEAK WARM ADVECTION IS FORECAST ACROSS THIS REGION...AS UPPER HEIGHTS FALL AHEAD OF ADVANCING SHORT-WAVE TROUGH. SEVERAL CLUSTERS OF CONVECTION SHOULD BE ONGOING AT THE START OF THE PERIOD...WHICH COMBINED WITH THE INCREASINGLY ILL-DEFINED SURFACE PATTERN SUGGEST A RATHER COMPLEX SEVERE WEATHER FORECAST. IN GENERAL...SUFFICIENT INSTABILITY AND MARGINAL SHEAR ARE ANTICIPATED INVOF BAROCLINIC ZONE...WHILE STRONGER SHEAR REMAINS N OF THE WARM SECTOR WITHIN THE COOLER AIR AND CAPPING INVERSION PREVAILS WITHIN WARM SECTOR AWAY FROM SURFACE BOUNDARIES. GREATEST THREAT APPEARS TO EXIST ACROSS THE MID MO VALLEY REGION...AS LOW-LEVEL CONVERGENCE INCREASES AHEAD OF APPROACHING SHORT-WAVE FEATURE DURING THE AFTERNOON. EXPECT STORMS TO DEVELOP INVOF WEAKENING SURFACE BOUNDARY -- AND PERHAPS ALONG REMNANT OUTFLOWS...WHERE SUFFICIENT INSTABILITY BUT MARGINAL SHEAR SUGGEST MULTICELL/WEAK SUPERCELL STORMS CAPABLE OF HAIL AND/OR LOCALLY-DAMAGING WINDS. LESSER SEVERE THREAT SHOULD EXTEND EWD INTO THE MIDWEST/OH VALLEY...WHERE WEAKER SHEAR IS FORECAST ALONG REMNANT WARM FRONT/BAROCLINIC ZONE. OVERNIGHT...MODEST SWLY LOW-LEVEL JET IS FORECAST TO DEVELOP ACROSS MO AND VICINITY...WHICH SHOULD SUPPORT A CONTINUATION OF CONVECTION -- LIKELY IN THE FORM OF ONE OR MORE MCS. OVERALL HOWEVER...DIURNALLY-STABILIZING AIRMASS SUGGESTS A SLOWLY DECREASING SEVERE THREAT THROUGH THE END OF THE PERIOD. ..GOSS.. 08/17/2006  From swody2 at goshenarc.org Fri Aug 18 05:54:13 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Fri, 18 Aug 2006 01:54:13 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 180554 SWODY2 SPC AC 180553 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1253 AM CDT FRI AUG 18 2006 VALID 191200Z - 201200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... DOMINANT UPPER RIDGE WILL BE SUPPRESSED INTO THE SRN U.S. SATURDAY AS SHORTWAVE TROUGH DIGS SEWD INTO THE GREAT LAKES REGION. IN THE WAKE OF THIS FEATURE...SFC PRESSURES WILL RISE MARKEDLY ACROSS THE CNTRL PLAINS/MS VALLEY FORCING A COLD FRONT SOUTH OF ANY MEANINGFUL FLOW ALOFT INTO THAT REGION MOSTLY DOMINATED BY LARGE SCALE UPPER RIDGING. ...OH VALLEY/TN VALLEY... WEAK HEIGHT FALLS WILL SPREAD ACROSS THE GREAT LAKES INTO PORTIONS OF THE OH VALLEY DURING THE DAY2 PERIOD...COINCIDENT WITH FRONTAL PASSAGE FROM UPSTATE NY...SWWD INTO SRN IL BY EARLY EVENING. TROPOSPHERIC MOISTURE IS EXPECTED TO REMAIN QUITE HIGH ALONG/AHEAD OF FRONTAL ZONE WHERE PRECIPITABLE WATER VALUES MAY EXCEED 2 INCHES. AS EXPECTED...FORECAST SOUNDINGS ACROSS THIS REGION SUGGEST WEAK LAPSE RATES AND MOIST PROFILES ALONG ADVANCING COLD FRONT. DUE TO MOIST PROFILES IT APPEARS ANY ASCENT AHEAD OF SHORTWAVE WILL PROVE EFFICIENT IN GENERATING CLOUDS AND THUNDERSTORMS. AIRMASS SHOULD BE MOST BUOYANT ALONG AN E-W AXIS SOUTH OF STRONGER HEIGHT FALLS ACROSS THE TN VALLEY REGION. AS A RESULT...IT APPEARS THUNDERSTORMS THAT DEVELOP ACROSS PORTIONS OF KY INTO NRN TN WILL EVOLVE WITHIN A MORE FAVORABLE THERMODYNAMIC ENVIRONMENT FOR LOCALLY STRONG WIND GUSTS. EVEN SO ORGANIZED SEVERE THREAT APPEARS LIMITED AT THIS TIME...DESPITE THE LIKELIHOOD THAT ORGANIZED CONVECTION AND WIDESPREAD THUNDERSTORMS SHOULD EVOLVE ALONG COLD FRONT. ...SRN HIGH PLAINS/SRN ROCKIES... NELY BOUNDARY LAYER FLOW WILL INCREASE ACROSS THE SRN HIGH PLAINS INTO ERN NM DURING THE PERIOD AS SFC RIDGE BUILDS SWWD ACROSS KS INTO THE TX PANHANDLE. CONVECTION WILL LIKELY DEVELOP WITHIN WEAK UPSLOPE ENVIRONMENT WHERE DEEP LAYER SHEAR WILL BE NEGLIGIBLE BENEATH UPPER RIDGE. GUSTY WINDS OR PERHAPS SMALL HAIL MAY ACCOMPANY STRONGER STORMS ACROSS THIS REGION. ADDITIONALLY...ISOLATED STORMS THAT DEVELOP WITHIN WEAKLY CONVERGENT FRONTAL ZONE INTO OK COULD GENERATE GUSTY WINDS AS WELL. THIS REGION WILL BE SOMEWHAT MORE SUPPORTIVE OF MICROBURSTS DUE TO STEEP LOW LEVEL LAPSE RATES AND DRY SUB CLOUD AIRMASS. ..DARROW.. 08/18/2006  From swody2 at goshenarc.org Tue Aug 22 17:31:40 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 22 Aug 2006 13:31:40 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 221730 SWODY2 SPC AC 221729 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1229 PM CDT TUE AUG 22 2006 VALID 231200Z - 241200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE UPPER MS VALLEY TO LAKE MI... ...SYNOPSIS... A SERIES OF SHORT WAVE TROUGHS WILL TRANSLATE THROUGH MEAN UPPER RIDGE ACROSS THE NRN HIGH PLAINS AND NRN PLAINS THIS PERIOD AND DRIVE EPISODES OF STRONG TO SEVERE TSTM DEVELOPMENT. THE LEADING FEATURE TO RESULT IN MCS DEVELOPMENT ACROSS ERN DAKOTAS/MN THROUGH THE DAY 1 PERIOD WAS CURRENTLY SPREADING ACROSS MT. THIS IMPULSE WILL CREST THE UPPER RIDGE ACROSS THE NRN PLAINS LATE THIS EVENING BEFORE SLIDING SEWD ACROSS THE UPPER MS VALLEY THROUGH EARLY WEDNESDAY. A STRONGER TROUGH IS FORECAST TO MOVE INLAND ACROSS THE PACIFIC NORTHWEST DURING DAY 2. THIS TROUGH WAS CURRENTLY MOVING TOWARD THE COAST OF NRN CA AND IS EXPECTED TO PRODUCE RELATIVELY STRONG HEIGHT FALLS ACROSS MT/WY AREA BY LATE IN THE DAY 2 PERIOD...EARLY THURSDAY. RIDGING...SURFACE AND ALOFT...IS EXPECTED TO KEEP MOSTLY TRANQUIL CONDITIONS ACROSS MUCH OF THE CENTER OF THE CONUS WHILE DEEP TROPICAL MOISTURE REMAINS SITUATED ACROSS THE SOUTHERN STATES FROM AZ TO FL. ...UPPER MS VALLEY TO LAKE MI... STRONG MCS EXPECTED TO BE ONGOING ACROSS MN/WRN WI WEDNESDAY MORNING BASED ON LATEST SHORT-RANGE DETERMINISTIC AND ENSEMBLE GUIDANCE. THIS SYSTEM WILL BE SUPPORTED BY STRONG LOW LEVEL WARM AIR AND MOISTURE ADVECTION ON THE NOSE OF SWLY LOW LEVEL JET. LEADING EDGE OF THIS DEEP CONVECTION WILL TRANSLATE INTO INCREASINGLY STABLE AIR MASS ACROSS NRN WI AND THE U.P. OF MI. HOWEVER...FLANKING PORTION OF THE MCS AND RESULTANT OUTFLOW WILL SETTLE INTO INCREASINGLY UNSTABLE AIR MASS ACROSS SRN MN AND SRN WI DURING THE AFTERNOON AND ACT TO REINFORCE THE QUASISTATIONARY WARM FRONT ACROSS THESE AREAS. MODELS INDICATE THAT LIFT AND DESTABILIZATION ALONG THE OUTFLOW BOUNDARY/WARM FRONT WILL BE SUFFICIENT FOR ADDITIONAL CONVECTIVE DEVELOPMENT DURING THE DAY. EXPECT SEVERE STORM POTENTIAL TO INCREASE AS THIS ACTIVITY TAPS STRENGTHENING INSTABILITY. PRESENCE OF STRONG VERTICAL SPEED AND DIRECTIONAL SHEAR ACROSS THE REGION WILL FURTHER SUPPORT ORGANIZED/PERSISTENT UPDRAFTS CAPABLE OF PRODUCING VERY LARGE HAIL AND HIGH WINDS. INITIAL ACTIVITY MAY BE ROOTED SLIGHTLY ABOVE CAPPED BOUNDARY LAYER WITH STRONG WARM SECTOR HEATING POSSIBLY PROMOTING MORE SURFACE-BASED DEVELOPMENT NEAR THE WARM FRONT BY AFTERNOON. IF THIS CAN OCCUR...MODEST LOW LEVEL DIRECTIONAL SHEAR/HELICITY COUPLED WITH MAGNITUDE OF FORECAST INSTABILITY MAY ENHANCE TORNADO POTENTIAL FOR ANY DISCRETE CELLS TRACKING SEWD NEAR THE FRONT. CURRENT INDICATIONS SUGGEST THAT THIS POTENTIAL MAY REMAIN ISOLATED/BRIEF GIVEN STRENGTH OF CAP AND LACK OF STRONGER FORCING. ...NRN HIGH PLAINS LATE... STRONG FORCING FOR ASCENT IS EXPECTED TO EMERGE ACROSS MT/WRN ND LATER IN THE PERIOD AS UPPER TROUGH AND HEIGHT FALLS DEVELOP ACROSS THE REGION. LINEAR CONVECTIVE DEVELOPMENT IN LOW-CAPE HIGH-SHEAR ENVIRONMENT ALONG ADVANCING COLD FRONT OVER WRN/CNTRL MT COULD SUPPORT SOME LATE NIGHT TSTMS WITH ISOLATED DAMAGING WINDS. FARTHER EAST...FROM ERN MT INTO ND...LOW LEVEL ELY FLOW NORTH OF DEVELOPING LEE-SIDE LOW MIGHT SUSTAIN MOIST UPSLOPE FLOW WITH POTENTIAL FOR MODEST INSTABILITY AND STRONG FORCING PROVIDING FOR A FEW SEVERE STORMS WITH HAIL/WIND INTO EARLY THURSDAY MORNING. ..CARBIN.. 08/22/2006  From swody2 at goshenarc.org Wed Aug 23 05:59:35 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 23 Aug 2006 01:59:35 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 230558 SWODY2 SPC AC 230557 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1257 AM CDT WED AUG 23 2006 VALID 241200Z - 251200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE NRN/CNTRL PLAINS TO THE UPPER GREAT LAKES... DEEP CONVECTION SHOULD READILY DEVELOP ACROSS MUCH OF THE NRN PLAINS INTO THE UPPER MS VALLEY REGION THURSDAY AHEAD OF SHORTWAVE TROUGH AND UPPER HEIGHT FALLS. WHILE MODELS REMAIN CONSISTENT IN EJECTING SHORTWAVE ACROSS THE DAKOTAS BY EARLY EVENING...LOW LEVEL WARM ADVECTION MAY PROVE AS MUCH RESPONSIBLE FOR EXPECTED THUNDERSTORM DEVELOPMENT FROM ND INTO CNTRL MN...TO THE NORTH OF THE WELL DEFINED WARM FRONTAL ZONE. LATEST THINKING IS THUNDERSTORM CLUSTERS MAY EVOLVE EARLY IN THE PERIOD ACROSS WRN ND...POSSIBLY AN EXTENSION OF OVERNIGHT ACTIVITY THAT SPREADS ACROSS MT AHEAD OF UPPER SHORTWAVE. AN MCS MAY EVOLVE WITHIN STRONG ZONE OF FORCING AND PROPAGATE EWD...WELL TO THE NORTH OF E-W WIND SHIFT. HAIL IS THE MOST LIKELY SEVERE THREAT WITH THIS ELEVATED CONVECTION. WITH TIME BOUNDARY LAYER INSTABILITY SHOULD INCREASE NEAR THE WARM FRONT ACROSS SERN SD INTO SRN MN/NRN IA...IMMEDIATELY AHEAD OF SFC LOW. THIS ZONE IS THE MOST LIKELY REGION FOR BOUNDARY LAYER SUPERCELL DEVELOPMENT DURING THE LATE AFTERNOON HOURS. FORECAST SOUNDINGS SUGGEST CAP WILL HOLD MUCH OF THE DAY ACROSS THE WARM SECTOR...WITH SUSTAINED ASCENT NEAR THE FRONT EXPECTED TO WEAKEN THE INHIBITION SUFFICIENTLY FOR NEAR SFC-BASED UPDRAFTS AFTER 21Z. IF STORMS CAN INDEED DEVELOP ALONG THE WARM FRONT IT APPEARS EWD STORM MOTIONS WOULD PROVE FAVORABLE FOR SUSTAINED HIGHER HELICITY INFLOW...WITH THE POSSIBILITY FOR A FEW TORNADOES. OTHERWISE...AN EXPANDING ZONE OF WARM ADVECTION...ELEVATED THUNDERSTORMS SHOULD EVOLVE ACROSS CNTRL MN INTO WI DURING THE OVERNIGHT HOURS. TRAILING COLD FRONT WILL LIKELY AID IN THE INITIATION OF HIGH BASED MULTI-CELL...POSSIBLY SUPERCELLULAR...THUNDERSTORMS FROM CNTRL NEB INTO NWRN KS BY 00Z. THIS ACTIVITY SHOULD PROPAGATE SWD THROUGH THE CENTRAL PLAINS ENHANCED BY INCREASING LLJ ACROSS KS DURING THE OVERNIGHT HOURS. WIND AND SOME HAIL SHOULD BE THE PRIMARY THREATS WITH THIS ACTIVITY. ..DARROW.. 08/23/2006  From swody2 at goshenarc.org Wed Aug 23 17:53:17 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 23 Aug 2006 13:53:17 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 231746 SWODY2 SPC AC 231745 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1245 PM CDT WED AUG 23 2006 VALID 241200Z - 251200Z ...THERE IS A SLGT RISK OF SVR TSTMS NRN PLAINS TO UPPER MS VALLEY... ...SYNOPSIS... STRONG SHORT WAVE TROUGH WAS CURRENTLY MOVING ACROSS THE PACIFIC NORTHWEST AND WILL TRACK EAST ACROSS THE NRN ROCKIES THROUGH TONIGHT. HEIGHT FALLS AND WIDESPREAD UPWARD VERTICAL MOTION ASSOCIATED WITH THIS SYSTEM ARE FORECAST TO EMERGE OVER THE NRN HIGH PLAINS THURSDAY MORNING BEFORE DEVELOPING EAST ACROSS THE NRN/CNTRL PLAINS AND UPPER MS VALLEY THROUGH THURSDAY NIGHT. AS PRIMARY RESULTING LEE-SIDE CYCLONE UNDERGOES OCCLUSION AND LIFTS NWD ACROSS ND...TRIPLE-POINT LOW WILL TRACK EWD ALONG STRONG WARM FRONT FROM SD INTO SRN MN AS COLD FRONT SPREADS SEWD INTO THE CNTRL PLAINS THROUGH THE EVENING. GIVEN MAGNITUDE OF FORCING AND ANTICIPATED SHEAR AND INSTABILITY ACROSS THE NRN PLAINS AREA...IT IS POSSIBLE THAT PARTS OF THE REGION MAY BE UPGRADED TO HIGHER SEVERE PROBABILITIES/MDT RISK IN LATER OUTLOOKS AS MESOSCALE DETAILS BECOME MORE CERTAIN. LOWER-AMPLITUDE IMPULSES WILL SPREAD ESEWD ATOP LOW-LEVEL BAROCLINIC ZONE FROM LOWER MI TO THE MID ATLANTIC SEABOARD AND SHOULD PROMOTE ACTIVE AREAS OF SHOWERS AND TSTMS ACROSS THESE AREAS THROUGH THURSDAY. ...NRN PLAINS TO UPPER MS VALLEY... MODELS ARE IN GENERALLY GOOD AGREEMENT THAT STRONG TO LOCALLY EXTREME INSTABILITY WILL DEVELOP ACROSS CAPPED WARM SECTOR THROUGH THE AFTERNOON. STRONG FORCING WITH UPPER TROUGH AND ASSOCIATED MID LEVEL SPEED MAX WILL ACT TO OVERCOME CONVECTIVE INHIBITION WITH POTENTIALLY EXPLOSIVE TSTM DEVELOPMENT OCCURRING NEAR AND NORTH OF SURFACE LOW AND WARM FRONT FROM LATE MORNING INTO THE AFTERNOON. INITIAL ACTIVITY...FROM ND TO SRN MN...MAY BE ROOTED ABOVE CAPPED BOUNDARY LAYER BUT WILL STILL POSE A THREAT VERY LARGE HAIL AND HIGH WINDS WITH TIME. STRENGTH OF SHEAR FORECAST ACROSS THE REGION...AND POTENTIAL FOR ENHANCED ASCENT WITHIN LEFT EXIT REGION OF INTENSIFYING MID LEVEL JET...SUGGEST WIDESPREAD SEVERE HAIL AND DAMAGING WIND COULD UNFOLD ACROSS PORTIONS OF SERN ND...ERN SD...AND SWRN MN THROUGH THE EVENING. TORNADO THREAT MAY BE MODULATED BY WEAKNESS IN LOWER LEVEL FLOW THAT RESULTS IN GENERALLY LIMITED SRH...IN ADDITION TO WARM SECTOR CAPPING AND POTENTIALLY HIGHER LFC. HOWEVER...IF SUPERCELLS CAN BECOME ROOTED IN THE BOUNDARY LAYER AND PERSIST NEAR THE WARM FRONT...A FEW TORNADOES APPEAR POSSIBLE. PARTS OF THE REGION MAY REQUIRE UPGRADE TO A MDT RISK IN LATER OUTLOOKS. ...MIDWEST TO NORTHEAST/MID ATLANTIC... HARD TO TIME LOW-AMPLITUDE SHORT WAVES WILL TRAVERSE LOW LEVEL FRONTAL ZONE AND ACT TO ENHANCE TSTM DEVELOPMENT AND ORGANIZATION FROM LOWER MI/OH EWD ACROSS PA/NJ AREAS DURING THE AFTERNOON. WHILE LAPSE RATES ACROSS THESE AREAS APPEAR SOMEWHAT MARGINAL FOR VIGOROUS STORM UPDRAFTS...IT IS POSSIBLE THAT MESOSCALE FORCING AND POCKETS OF STRONGER DESTABILIZATION COULD SUSTAIN STORMS IN AREAS WHERE SHEAR MAY ALSO SUPPORT SUPERCELLS. POTENTIAL FOR WEAK SURFACE DEVELOPMENT ACROSS ERN PA TO DELMARVA AREA BY LATER AFTERNOON COULD FURTHER AID STORM ORGANIZATION WITH A DAMAGING WIND/ISOLATED TORNADO EVENT POSSIBLE. PARTS OF THIS CORRIDOR MAY BE UPGRADED TO SLGT RISK IN LATER OUTLOOKS AS FORECAST DETAILS BECOME CLEARER. ..CARBIN.. 08/23/2006  From swody2 at goshenarc.org Thu Aug 24 05:37:45 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Thu, 24 Aug 2006 01:37:45 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 240538 SWODY2 SPC AC 240537 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1237 AM CDT THU AUG 24 2006 VALID 251200Z - 261200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS SERN WI TO SRN PORTIONS OF LAKE MI... NRN PLAINS SPEED MAX/SHORTWAVE TROUGH WILL MOVE QUICKLY ACROSS THE UPPER MS VALLEY INTO THE GREAT LAKES REGION EARLY IN THE DAY2 PERIOD. THIS FEATURE WILL UNDOUBTEDLY AID A BAND OF WARM ADVECTION/ELEVATED THUNDERSTORMS NORTH OF RETREATING FRONTAL ZONE FROM PORTIONS OF MN...SEWD INTO NRN LOWER MI EARLY IN THE PERIOD. LOW LEVEL TRAJECTORIES ACROSS THE LOWER GREAT LAKES INTO THIS REGION ARE NOT PARTICULARLY MOIST/BUOYANT THIS MORNING...AND SHOULD NOT MOISTEN SIGNIFICANTLY WITHIN THE COOL SECTOR PRIOR TO LARGE SCALE ASCENT/CONVECTIVE OVERTURNING. ALTHOUGH HAIL MAY ACCOMPANY STRONGER STORMS WITHIN THIS ZONE...IT APPEARS ELEVATED CAPE MAY BE TOO WEAK FOR MORE THAN MARGINALLY SEVERE HAIL. OF MORE CONCERN IS THE POSSIBILITY FOR WARM SECTOR THUNDERSTORM DEVELOPMENT BENEATH THE UPPER SHORTWAVE TROUGH...POSSIBLY AS EARLY AS 18Z. STRONGEST BOUNDARY LAYER HEATING SHOULD OCCUR ACROSS NRN IL INTO SERN WI...IMMEDIATELY AHEAD OF WEAK SFC LOW...ALLOWING A NARROW AXIS OF MODEST INSTABILITY TO DEVELOP...1500-2000 J/KG. FORECAST SOUNDINGS SUGGEST ORGANIZED MULTI-CELL UPDRAFTS...OR PERHAPS ISOLATED SUPERCELLS...SHOULD EVOLVE OVER SERN WI BY EARLY AFTERNOON...THEN SPREAD ESEWD TOWARD SRN LAKE MI. HAIL AND GUSTY WINDS ARE THE MAIN SEVERE THREATS. ...CNTRL PLAINS... TRAILING FRONTAL BOUNDARY WILL SAG INTO KS AND SERN CO FRIDAY AS MAIN BELT OF WLY FLOW ALOFT REMAINS WELL NORTH OF THIS REGION. MARGINAL VERTICAL SHEAR WILL NOT PROVE CONDUCIVE FOR MORE THAN WEAKLY ORGANIZED MULTI-CELL UPDRAFTS ALONG THIS WIND SHIFT. MODELS DIFFER ON SWD EXTENT OF THIS BOUNDARY ACROSS KS/OK...POSSIBLY DUE TO EXTENSIVE CONVECTION AND OUTFLOW PROCESSES. STRONGEST UPDRAFTS SHOULD OCCUR IN ZONE OF GREATEST BOUNDARY LAYER HEATING/INSTABILITY...RESULTING IN ISOLATED DAMAGING WIND GUSTS OR MARGINALLY SEVERE HAIL. ..DARROW.. 08/24/2006  From swody2 at goshenarc.org Thu Aug 24 17:27:16 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Thu, 24 Aug 2006 13:27:16 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 241727 SWODY2 SPC AC 241726 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1226 PM CDT THU AUG 24 2006 VALID 251200Z - 261200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF THE UPPER MIDWEST/GREAT LAKES REGION... ...THERE IS A SLGT RISK OF SVR TSTMS OVER KS INTO NRN OK... ...SYNOPSIS... STRONG SHORT WAVE TROUGH NOW MOVING INTO THE WRN DAKOTAS IS FORECAST TO WEAKEN DURING THE DAY TWO PERIOD AS IT TRANSLATES EWD THROUGH THE GREAT LAKES REGION...UNDERCUTTING AMPLIFIED RIDGE OVER ONTARIO. WEAKER DOWNSTREAM IMPULSES WILL SHIFT EWD ALONG SRN PERIPHERY OF ERN CANADA LONG WAVE TROUGH ACROSS THE LOWER GREAT LAKES AND CNTRL/SRN NEW ENGLAND. MEANWHILE TO THE W...UPSTREAM TROUGH WILL EVOLVE INTO A CUTOFF LOW OVER THE ERN GREAT BASIN. IN THE LOW-LEVELS...SURFACE LOW ASSOCIATED WITH THE GREAT LAKES SHORT WAVE TROUGH WILL DEVELOP EWD FROM SRN WI ACROSS LOWER MI INTO SWRN ONTARIO WITH TRAILING COLD FRONT PUSHING SWD THROUGH THE LOWER MO VALLEY AND CNTRL HIGH PLAINS. ATTENDANT WARM FRONT IS FORECAST TO LIFT NWD THROUGH LOWER MI WITH ERN EXTENSION OF THIS BOUNDARY REMAINING MORE QUASI-STATIONARY FROM THE LOWER GREAT LAKES SEWD TO THE MIDDLE ATLANTIC COAST. ...UPPER MIDWEST/GREAT LAKES REGION... WARM SECTOR AIR MASS IS FORECAST TO REMAIN QUITE MOIST FRIDAY AHEAD OF SURFACE LOW AND COLD FRONT WITH DEWPOINTS IN THE MID 60S TO LOWER 70S. WHILE MID-LEVEL LAPSE RATES ARE NOT FORECAST TO BE PARTICULARLY STEEP...DAYTIME HEATING COUPLED WITH THIS BOUNDARY-LAYER MOISTURE ARE EXPECTED TO CONTRIBUTE TO MODERATE AFTERNOON INSTABILITY WITH MLCAPES OF 1500-3000 J/KG DEVELOPING FROM SRN WI/NRN IL WWD INTO NRN MO. ELEVATED TSTMS CAPABLE OF MARGINALLY SEVERE HAIL WILL LIKELY PERSIST THROUGH THE DAY FRIDAY N OF WARM FRONT OVER NRN WI/THE UP/NRN LOWER MI...DRIVEN BY LOW-LEVEL WAA AHEAD OF WEAKENING SHORT WAVE TROUGH. POTENTIALLY MORE INTENSE...SURFACE-BASED STORM DEVELOPMENT WILL BECOME INCREASINGLY LIKELY BY AFTERNOON FROM VICINITY OF SURFACE LOW SWD ALONG COLD FRONT FROM CNTRL/SRN WI INTO NRN IL AS DIABATIC HEATING AND LARGE-SCALE FORCING FOR ASCENT EFFECTIVELY ERODE THE CAP. PRESENCE OF 70-80 KT UPPER JET STREAK ACCOMPANYING SHORT WAVE TROUGH WILL RESULT IN SUFFICIENT DEEP LAYER SHEAR FOR SUPERCELLS AND BOWING STRUCTURES CAPABLE OF MAINLY LARGE HAIL AND DAMAGING WINDS. APPEARS BEST POTENTIAL FOR A TORNADO OR TWO WILL BE WITH ANY STORMS DEVELOPING NEARER TO SURFACE LOW AND ATTENDANT WARM FRONT WHERE LOW-LEVEL SHEAR WILL BE ENHANCED FROM E-CNTRL WI EWD INTO CNTRL OR NRN LOWER MI. ...KS... THERE REMAINS SOME UNCERTAINTY AS TO THE POSITION OF TRUE SYNOPTIC FRONT AND ANY OUTFLOW BOUNDARIES REMNANT FROM CONVECTION DEVELOPING DURING THE LATTER HALF OF THE DAY ONE PERIOD. LATEST SHORT TERM MODEL GUIDANCE DOES SUGGEST THAT STEEP LOW/MID-LEVEL LAPSE AND MOIST BOUNDARY-LAYER CONDITIONS WILL BECOME CO-LOCATED ACROSS REGION NEAR OR JUST N OF SURFACE FRONT FRIDAY AFTERNOON...CONTRIBUTING TO MLCAPES OF 1500-2500 J/KG. IT APPEARS THAT DAYTIME HEATING...LOW-LEVEL CONVERGENCE ALONG PRE-EXISTING BOUNDARIES AND LARGER-SCALE FORCING IN RIGHT ENTRANCE REGION OF UPPER JET STREAK OVER THE NRN PLAINS WILL ALL CONTRIBUTE TO AN INCREASE IN SURFACE-BASED STORM ACTIVITY DURING THE AFTERNOON AND EVENING HOURS. WHILE ONLY 15-25 KT MID-LEVEL FLOW IS FORECAST...UPPER TROPOSPHERIC WIND FIELDS WILL REMAIN 50-60 KTS. WHEN COUPLED WITH ELY LOW-LEVEL WINDS N OF SURFACE FRONT...EFFECTIVE BULK SHEAR OF 30-40 KTS IS FORECAST...SUPPORTIVE OF ORGANIZED...ROTATING UPDRAFTS CAPABLE OF SEVERE HAIL AND LOCALLY DAMAGING WINDS. ...CNTRL HIGH PLAINS... VERTICAL SHEAR WILL REMAIN SUPPORTIVE OF UPDRAFT ROTATION NWWD INTO CNTRL WY WITHIN POST-FRONTAL UPSLOPE REGIME. HOWEVER...PRIMARY FACTOR LIMITING A MORE ORGANIZED SEVERE THREAT WILL BE LIMITED INSTABILITY. A FEW POCKETS OF AT LEAST WEAK INSTABILITY /MLCAPES OF 250-500 J/KG/ WILL LIKELY DEVELOP BY AFTERNOON AND IF STORMS CAN DEVELOP AND BECOME SUSTAINED...THEN POTENTIAL WOULD EXIST FOR SOME HAIL AND GUSTY WINDS. ...LOWER GREAT LAKES TO THE MID ATLANTIC COAST... CONSIDERABLE UNCERTAINTY EXISTS WITH REGARD TO CONVECTIVE EVOLUTION DOWNSTREAM FROM CNTRL GREAT LAKES LOW ALONG ATTENDANT WARM FRONT OR QUASI-STATIONARY BOUNDARY. AS MENTIONED ABOVE...IT APPEARS THAT SEVERAL WEAK IMPULSES WILL ROTATE THROUGH THE BASE OF ERN CANADA LONG WAVE TROUGH...THE TIMING OF WHICH REMAINS DIFFICULT. IN ADDITION...THE DEGREE OF AIR MASS DESTABILIZATION REMAINS IN QUESTION. VERTICAL SHEAR INVOF THE SURFACE FRONT WILL REMAIN QUITE FAVORABLE FOR SUPERCELLS THROUGH THE PERIOD GIVEN THE DEVELOPMENT AND MAINTENENCE OF MOIST DEEP CONVECTION. ONCE FINER SCALE DETAILS BECOME MORE CLEAR...PORTIONS OF REGION MAY NEED TO BE UPGRADED TO A SLIGHT RISK IN SUBSEQUENT DAY ONE OUTLOOKS. ..MEAD.. 08/24/2006  From swody2 at goshenarc.org Fri Aug 25 05:59:56 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Fri, 25 Aug 2006 01:59:56 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 250600 SWODY2 SPC AC 250559 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1259 AM CDT FRI AUG 25 2006 VALID 261200Z - 271200Z ...THERE IS A SLGT RISK OF SVR TSTMS SAT AFTN/SAT EVE ACROSS PARTS OF THE GREAT LAKES/UPR OH VLY.... ...THERE IS A SLGT RISK OF SVR TSTMS LATE SAT AFTN/SAT EVE ACROSS PARTS OF THE SRN PLAINS/OZARKS.... ...THERE IS A SLGT RISK OF SVR TSTMS LATE SAT AFTN/SAT EVE...EAST OF THE FRONT RANGE OF THE ROCKIES.... MODELS INDICATE THAT A SUBTLE WEAKENING OF THE CENTRAL/SOUTHERN U.S. SUBTROPICAL RIDGE...WHICH HAS BEEN UNDERWAY THE PAST WEEK OR SO...WILL CONTINUE THROUGH THIS FORECAST PERIOD...IN RESPONSE TO PROGRESSION OF SHORT WAVE TROUGHS WITHIN THE POLAR WESTERLIES. THE PRIMARY BELT WILL GENERALLY REMAIN JUST NORTH OF THE CANADIAN/U.S. BORDER...WITH A SIGNIFICANT EMBEDDED SHORT WAVE PROGGED EAST OF MANITOBA EARLY SATURDAY THROUGH MUCH OF ONTARIO BY 12Z SUNDAY. PHASING OF THIS FEATURE WITH AN IMPULSE IN A WEAKER SOUTHERN BELT IS FORECAST TO OCCUR LATE SATURDAY THROUGH SATURDAY EVENING ACROSS THE GREAT LAKES/OHIO VALLEY REGION. MEANWHILE...A MORE SIGNIFICANT SOUTHERN BRANCH TROUGH SEEMS LIKELY TO LAG TO THE WEST...BUT STILL CONTINUE TO SLOWLY DIG SOUTHEAST OF THE NORTHERN GREAT BASIN INTO THE CENTRAL ROCKIES. FORCING WITH THE LARGE-SCALE FEATURES...SEASONABLY MOIST LOW-LEVEL ENVIRONMENT AND AN INFLUX OF MOISTURE FROM THE LOWER LATITUDE EASTERN PACIFIC WILL PROBABLY ALL CONTRIBUTE TO A CONSIDERABLE AMOUNT OF CONVECTIVE ACTIVITY SATURDAY/SATURDAY NIGHT. WEAK FRONTAL SURGE INTO THE OHIO VALLEY AND SOUTHERN PLAINS WILL PROVIDE ONE FOCUS FOR ACTIVITY...AS WILL A BAROCLINIC ZONE ACROSS THE LOWER GREAT LAKES/NORTHERN MID ATLANTIC REGION...ASSOCIATED WITH A RETREATING SURFACE RIDGE. A WEAK IMPULSE MIGRATING AROUND THE SOUTHWESTERN PERIPHERY OF MID-LEVEL HIGH CENTER OVER THE MID ATLANTIC STATES WILL CONTRIBUTE TO SCATTERED AFTERNOON/EVENING STORMS ACROSS MUCH OF THE GULF STATES. AND...DIURNAL THUNDERSTORM ACTIVITY WILL BECOME FOCUSED PRIMARILY ACROSS THE HIGHER TERRAIN OF THE INTERMOUNTAIN WEST/ROCKIES. ...LOWER GREAT LAKES/OHIO VALLEY... LACK OF COLDER AIR ALOFT/STEEPER MID-LEVEL LAPSE RATES WILL BE THE PRIMARY LIMITING FACTOR TO SEVERE POTENTIAL SATURDAY. POTENTIAL CLOUD COVER IS ALSO A CONCERN...BUT CONSIDERABLE HEATING IS EXPECTED ACROSS MUCH OF INDIANA/OHIO INTO PARTS OF WESTERN PENNSYLVANIA...WHERE VEERING WINDS WITH HEIGHT BENEATH WEAK TO MODERATE WESTERLY MID-LEVEL FLOW WILL BE MARGINALLY SUFFICIENT FOR SUPERCELLS. SHEAR WILL BE STRONGER...BUT WITH WEAKER INSTABILITY...ACROSS LOWER MICHIGAN...WHERE STORMS COULD INITIATE BY EARLY SATURDAY AFTERNOON. THEN...AS LARGE-SCALE FORCING FOR UPWARD VERTICAL MOTION INCREASES LATE SATURDAY AFTERNOON INTO SATURDAY EVENING...STRONG/SEVERE STORMS ARE EXPECTED TO INCREASE ACROSS THE UPPER OHIO VALLEY. ISOLATED TORNADOES ARE POSSIBLE...BUT...AT THIS TIME...IT APPEARS LARGE HAIL/DAMAGING WIND GUSTS WILL BE PRIMARY THREATS BEFORE SEVERE POTENTIAL DIMINISHES ACROSS THE LOWER GREAT LAKES REGION LATE SATURDAY EVENING. ...SOUTHERN PLAINS/OZARK PLATEAU... STABILIZING INFLUENCE OF WEAKENING CONVECTIVE CLUSTER EXPECTED ALONG FRONT ACROSS THE EAST CENTRAL PLAINS/OZARK PLATEAU EARLY SATURDAY IS A CONCERN FOR SEVERE POTENTIAL. AT THE PRESENT TIME...IT APPEARS STRONGEST DESTABILIZATION WILL OCCUR SOUTH OF SURFACE BOUNDARY...IN THE WAKE OF THIS FEATURE...AS IT SHIFTS EASTWARD THROUGH THE MIDDLE MISSISSIPPI/LOWER OHIO VALLEY. LOW-LEVEL CONVERGENCE ALONG FRONT AND/OR WARM ADVECTION ALONG/NORTH OF PRE-FRONTAL THERMAL RIDGE WILL AID CONVECTIVE DEVELOPMENT LATE SATURDAY AFTERNOON/EVENING...FROM PARTS OF NORTH CENTRAL OKLAHOMA INTO THE OZARKS. VERTICAL SHEAR WILL BE WEAK...BUT VERY WARM DEEP MIXED BOUNDARY WITH CAPE AROUND 2000 J/KG WILL BE SUPPORTIVE OF VIGOROUS STORMS WITH POTENTIAL FOR STRONG DOWNBURSTS...AND POTENTIALLY DAMAGING SURFACE WINDS. ...GREAT BASIN/CENTRAL HIGH PLAINS... DRYING/WEAK INSTABILITY IS EXPECTED TO BE A LIMITING FACTOR FOR SEVERE POTENTIAL NEAR COLD CORE OF UPPER TROUGH...FROM PARTS OF NORTHERN UTAH INTO SOUTHWEST WYOMING/NORTHWEST COLORADO...EARLY SATURDAY. HOWEVER...DESTABILIZATION IN MOIST UPSLOPE FLOW REGIME ALONG AND TO THE LEE OF THE FRONT RANGE OF THE ROCKIES IS EXPECTED TO BE SUFFICIENT FOR VIGOROUS CONVECTIVE DEVELOPMENT LATE SATURDAY AFTERNOON AND EVENING. LOW/MID-LEVEL FLOW WILL BE WEAK...BUT VEERING WITH HEIGHT BENEATH STRONG SOUTHWESTERLY HIGH LEVEL FLOW WILL PROVIDE FAVORABLE HODOGRAPHS FOR SUPERCELLS...ENHANCING RISK FOR LARGE HAIL/DAMAGING WINDS...POSSIBLY A TORNADO OR TWO. ..KERR.. 08/25/2006  From swody2 at goshenarc.org Fri Aug 25 17:24:35 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Fri, 25 Aug 2006 13:24:35 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 251725 SWODY2 SPC AC 251724 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1224 PM CDT FRI AUG 25 2006 VALID 261200Z - 271200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM PORTIONS OF THE GREAT LAKES AND NRN OH VALLEY SEWD TO THE DELMARVA... ...THERE IS A SLGT RISK OF SVR TSTMS FROM PARTS OF THE CNTRL/SRN HIGH PLAINS EWD TO THE OZARK PLATEAU... ...SYNOPSIS... ACTIVE WAVE TRAIN WITHIN PRIMARY BELT OF POLAR WESTERLIES WILL EXIST ACROSS CANADA DURING THE DAY TWO PERIOD WITH A LOWER LATITUDE UPPER LOW EVOLVING INTO AN OPEN WAVE OVER THE GREAT BASIN INTO CNTRL ROCKIES. IN THE LOW-LEVELS...SURFACE LOW ASSOCIATED WITH A WEAK IMPULSE MOVING THROUGH THE GREAT LAKES WILL DEVELOP EWD FROM LAKE MI INTO SWRN ONTARIO WHILE TRAILING COLD FRONT SLOWLY SAGS SWD THROUGH THE MID MS VALLEY AND SRN HIGH PLAINS. TO THE E...QUASI-STATIONARY BOUNDARY...DELINEATING WRN EDGE OF ANTICYCLONE OVER ME INTO NEW BRUNSWICK...WILL EXTEND FROM THE GREAT LAKES LOW SEWD TO THE MID ATLANTIC COAST. ...GREAT LAKES/NRN OH VALLEY TO THE DELMARVA... SHORT WAVE TROUGH CURRENTLY OVER CNTRL WY IS FORECAST TO TRANSLATE NEWD THROUGH THE NRN PLAINS AND UPPER MS VALLEY DURING THE DAY ONE PERIOD...AND EVENTUALLY MORE EWD THROUGH LOWER MI INTO NY SATURDAY/SATURDAY NIGHT. FORCING FOR ASCENT ASSOCIATED WITH THIS FEATURE AND CONVERGENCE ALONG ABOVE MENTIONED LOW-LEVEL BOUNDARIES WILL PROVIDE THE FOCUS FOR STRONG TO SEVERE STORMS DURING THE AFTERNOON AND EVENING HOURS. IT APPEARS THAT CLOUDS/ONGOING PRECIPITATION MAY SLOW DESTABILIZATION PROCESS NEAR SURFACE FRONTAL SYSTEM SATURDAY. HOWEVER...COMPARABLY STRONGER DIABATIC HEATING AND MOIST BOUNDARY LAYER CONDITIONS WITHIN INFLOW AIR MASS FROM CNTRL MO/IL INTO NRN IND/SRN LOWER MI...AND FARTHER E OVER WV/MD/NRN VA WILL CONTRIBUTE TO MODERATE AFTERNOON INSTABILITY WITH MLCAPES OF 1000-2000 J/KG. AS THIS OCCURS...EXPECT A GRADUAL INCREASE IN STORM COVERAGE AND INTENSITY THROUGH THE AFTERNOON FROM VICINITY OF SURFACE LOW OVER CNTRL LOWER MI SWWD ALONG FRONT INTO NRN PARTS OF IND/IL...AND SEWD ALONG QUASI-STATIONARY BOUNDARY FROM WRN NY INTO PA/MD/NJ. STRONGEST VERTICAL SHEAR OWING TO ENHANCED LOW-LEVEL WAA/VEERING WIND PROFILES WILL EXIST FROM LOWER MI SURFACE LOW SEWD ALONG QUASI-STATIONARY BOUNDARY WHERE POTENTIAL WILL EXIST FOR ORGANIZED...ROTATING UPDRAFTS CAPABLE OF DAMAGING WINDS...SOME SEVERE HAIL AND PERHAPS A TORNADO OR TWO. ALONG COLD FRONT...VERTICAL SHEAR PROFILES ARE MUCH MORE UNIDIRECTIONAL...THOUGH 30-35 KTS OF VERTICAL SPEED SHEAR WILL BE SUPPORTIVE OF ORGANIZED STORMS CAPABLE OF SEVERE WINDS AND HAIL. ...CNTRL/SRN HIGH PLAINS INTO OZARK PLATEAU... RICHEST BOUNDARY LAYER MOISTURE AND RESULTANT DESTABILIZATION /MLCAPES OF 1500-3000 J/KG/ IS EXPECTED TO OCCUR ALONG W-E PORTION OF SYNOPTIC FRONT FROM OK/TX PNHDLS ENEWD INTO CNTRL/SRN MO. DESPITE THE ABSENCE OF ANY APPRECIABLE LARGE-SCALE FORCING FOR ASCENT...STRONG DIABATIC HEATING WITHIN PRE-FRONTAL AIR MASS WILL CONTRIBUTE TO AN INCREASE IN TSTM ACTIVITY THROUGH THE AFTERNOON AND EVENING HOURS ALONG LENGTH OF FRONTAL ZONE. DEEP LAYER BULK SHEAR WILL REMAIN MARGINAL /25-30 KTS/ FOR ORGANIZED SEVERE STORMS...THOUGH THE MODERATE INSTABILITY AND PRESENCE OF STEEP LOW LEVEL LAPSE RATES INDICATE THE POTENTIAL FOR DAMAGING WIND GUSTS AND PERHAPS SOME SEVERE HAIL. OVER THE HIGH PLAINS REGION FROM SERN WY INTO NERN NM...INSTABILITY WILL BE WEAKER /MLCAPES 500-1500 J/KG/ THAN POINTS TO THE SE OWING TO DRIER BOUNDARY LAYER CONDITIONS. HOWEVER...THE PRESENCE OF STEEP LOW TO MID LEVEL LAPSE RATES AND STRONGER VERTICAL SHEAR /30-40 KTS/ WILL SUPPORT SEVERE STORMS...INCLUDING THE POTENTIAL FOR A COUPLE SUPERCELLS CAPABLE OF LARGE HAIL AND LOCALLY STRONG WIND GUSTS. ..MEAD.. 08/25/2006  From swody2 at goshenarc.org Sat Aug 26 05:53:42 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 26 Aug 2006 01:53:42 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 260554 SWODY2 SPC AC 260553 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1253 AM CDT SAT AUG 26 2006 VALID 271200Z - 281200Z ...THERE IS A SLGT RISK OF SVR TSTMS SUN AFTN/EVE ACROSS THE UPPER OHIO VALLEY.... SHORT WAVE TROUGHS WITHIN SPLIT BELTS OF POLAR WESTERLIES WILL REMAIN PROGRESSIVE THROUGH THIS FORECAST PERIOD. MODELS SUGGEST PHASING OF A SIGNIFICANT NORTHERN STREAM TROUGH AND A WEAKER SOUTHERN STREAM IMPULSE WILL OCCUR LATE TODAY INTO EARLY SUNDAY ACROSS THE GREAT LAKES REGION. HOWEVER...THIS APPEARS LIKELY TO BE SHORT-LIVED...AS THE NORTHERN SYSTEM IS FORECAST TO LIFT THROUGH QUEBEC LATER SUNDAY INTO EARLY MONDAY. SOUTHERN IMPULSE IS PROGGED TO TURN SOUTHEAST OF THE LOWER GREAT LAKES AND CONTINUE ACROSS THE MID ATLANTIC COAST...AS UPSTREAM SHORT WAVE RIDGING BUILDS INTO THE GREAT LAKES. THIS WILL OCCUR AHEAD OF A MORE SIGNIFICANT SOUTHERN STREAM TROUGH SLOWLY ADVANCING EAST OF THE CENTRAL ROCKIES. MEANWHILE...A SUBTROPICAL RIDGE WILL GENERALLY HOLD FIRM FROM THE SOUTHEASTERN STATES INTO THE LOWER LATITUDE WESTERN ATLANTIC. AND...AN UPPER RIDGE WILL BUILD ACROSS THE INTERMOUNTAIN WEST... AHEAD OF ANOTHER VIGOROUS NORTHERN BRANCH TROUGH DIGGING ACROSS THE NORTHEAST PACIFIC. ...UPPER OHIO VALLEY/LOWER GREAT LAKES INTO THE NORTHEAST... IN THE WAKE OF A SIGNIFICANT UPPER TROUGH ALREADY EAST OF THE NORTH ATLANTIC COAST BY EARLY SUNDAY...SURFACE RIDGING WILL BE SLOW TO RETREAT EAST OF NORTHERN/MID ATLANTIC COASTAL AREAS. THIS WILL MAINTAIN COOLER SOUTHEASTERLY FLOW ALONG COASTAL AREAS...AND WARM ADVECTION CLOUDINESS LIKELY WILL MINIMIZE DESTABILIZATION AHEAD OF APPROACHING SOUTHERN BRANCH IMPULSE. HOWEVER...AHEAD OF A COLD FRONT ADVANCING INTO THE UPPER OHIO VALLEY...AT LEAST WEAK SURFACE HEATING OF VERY MOIST BOUNDARY LAYER...CHARACTERIZED BY SURFACE DEW POINTS NEAR 70F...IS EXPECTED TO CONTRIBUTE TO CAPE OF 1000 TO 1500. THOUGH ANTICIPATED INSTABILITY IS NOT PARTICULARLY STRONG...DEEP LAYER SHEAR BENEATH MODERATE WEST NORTHWESTERLY MID-LEVEL FLOW IS FORECAST TO BE MARGINALLY SUFFICIENT FOR UPDRAFT ROTATION. A FEW SEVERE STORMS ARE POSSIBLE...INCLUDING ISOLATED SUPERCELLS WITH ENHANCED RISK OF HAIL/DAMAGING WIND GUSTS...PERHAPS A TORNADO OR TWO. INITIATION OF STORMS APPEARS LIKELY BY EARLY SUNDAY AFTERNOON ACROSS PARTS OF NORTHERN OHIO/NORTHWESTERN PENNSYLVANIA...POSSIBLY PARTS OF WESTERN NEW YORK STATE...BEFORE DEVELOPING SOUTHEASTWARD INTO/ACROSS THE NORTH CENTRAL APPALACHIANS BY SUNDAY EVENING. ...CENTRAL ROCKIES INTO SOUTHERN PLAINS/OZARKS... CONSIDERABLE UNCERTAINTY EXISTS CONCERNING SEVERE POTENTIAL SUNDAY. WIDESPREAD CONVECTIVE DEVELOPMENT APPEARS POSSIBLE AIDED BY LARGE-SCALE FORCING ACCOMPANYING SOUTHERN BRANCH TROUGH. HOWEVER...STABILIZING INFLUENCE OF EARLY SUNDAY MORNING CONVECTION ALONG CONVECTIVELY GENERATED/ENHANCED BOUNDARY ADVANCING SOUTHWARD TOWARD THE RED RIVER VALLEY...AND THROUGH THE OZARKS...IS UNCERTAIN. AND...TENDENCY MAY BE FOR BOUNDARY TO ADVANCE SOUTH OF STRONGER MID/UPPER FLOW...MINIMIZING SHEAR IN AXIS OF STRONGER INSTABILITY. ..KERR.. 08/26/2006  From swody2 at goshenarc.org Sat Aug 26 17:14:12 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 26 Aug 2006 13:14:12 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 261714 SWODY2 SPC AC 261713 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1213 PM CDT SAT AUG 26 2006 VALID 271200Z - 281200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER THE UPPER OH VALLEY... ...THERE IS A SLGT RISK OF SVR TSTMS OVER SERN CO...SWRN KS...AND THE OK/NRN TX PNHDLS... ...SYNOPSIS... PROGRESSIVE WAVE TRAIN OF POLAR WESTERLIES WILL CONTINUE ACROSS CANADA THIS FORECAST PERIOD. A LOWER LATITUDE TROUGH OVER THE INTERMOUNTAIN W WILL GRADUALLY SHIFT EWD INTO THE CNTRL PLAINS IN RESPONSE TO THE APPROACH OF A STRONG UPSTREAM SYSTEM FROM THE GULF OF AK. IN THE LOW-LEVELS...SURFACE LOW PRESSURE OVER LOWER MI SUNDAY MORNING WILL DEVELOP EWD INTO N-CNTRL PA BY SUNDAY NIGHT WITH A TRAILING BAROCLINIC ZONE STRETCHING WWD THROUGH THE OH VALLEY TO SECONDARY LOW PRESSURE DEVELOPING NEWD FROM OK INTO SWRN MO. THE WRN EXTENSION OF THIS BOUNDARY WILL GRADUALLY SHIFT SWD THROUGH THE SRN HIGH PLAINS. ...UPPER OH VALLEY... AIR MASS DESTABILIZATION IS EXPECTED TO BE TEMPERED BY CONSIDERABLE CLOUDS AND PRECIPITATION SUNDAY IN ADVANCE OF SURFACE LOW AND ATTENDANT FRONT SHIFTING EWD THROUGH THE REGION. HOWEVER...THE PRESENCE OF A MOIST LOW-LEVEL AIR MASS CHARACTERIZED BY DEWPOINTS IN THE UPPER 60S TO LOW 70S COUPLED WITH SOME DIABATIC HEATING WILL LIKELY RESULT IN POCKETS OF MODERATE INSTABILITY WITH MLCAPES APPROACHING 1000-1500 J/KG. TSTMS ARE FORECAST TO INCREASE IN COVERAGE AND INTENSITY BY EARLY AFTERNOON FROM WRN PARTS OF NY/PA SWWD INTO CNTRL OH AS SURFACE FRONT ENCOUNTERS DESTABILIZING AIR MASS...AND DEEPER LAYER FORCING FOR ASCENT IS ENHANCED BY WEAK IMPULSES MOVING THROUGH THE OH VALLEY. MODEST LOW-LEVEL VEERING WIND PROFILES WITH 30-40 KTS OF WNWLY MID-LEVEL FLOW WILL RESULT IN SUFFICIENT VERTICAL SHEAR FOR A FEW ORGANIZED SEVERE STORMS INCLUDING SUPERCELLS CAPABLE OF SEVERE HAIL...DAMAGING WINDS AND PERHAPS A COUPLE OF TORNADOES. ERN EXTENT OF SEVERE THREAT WILL BE LIMITED BY STABLE LOW-LEVEL TRAJECTORIES ORIGINATING FROM SURFACE HIGH OVER THE CANADIAN MARITIMES. ...SERN CO/SWRN KS/OK AND TX PNHDLS... LOW-LEVEL AIR MASS IS NOT EXPECTED TO BECOME PARTICULARLY WARM OWING TO SOURCE REGION BEING CONVECTIVELY PROCESSED AIR ORIGINATING OVER OK AND THE ERN OK/TX PNHDLS. HOWEVER...DAYTIME HEATING COUPLED WITH HEIGHT FALLS/DYNAMIC COOLING AHEAD OF UPPER SYSTEM MOVING THROUGH THE CNTRL ROCKIES WILL CONTRIBUTE TO MODIFICATION VIA STEEPENING LOW TO MID LEVEL LAPSE RATES WITH RESULTANT MLCAPES APPROACHING 500-1500 J/KG. WEAK LEE CYCLOGENESIS OCCURRING OVER SERN CO WILL LIKELY RESULT IN SUFFICIENT LOW-LEVEL CONVERGENCE TO INITIATE TSTMS BY MID TO LATE AFTERNOON WITH ACTIVITY MOVING/DEVELOPING EWD OR SEWD INTO SWRN KS/OK AND TX PNHDLS SUNDAY NIGHT. DESPITE THE MODEST INSTABILITY...THE INCREASED LARGE-SCALE FORCING FOR ASCENT AND 40-50 KTS OF EFFECTIVE BULK SHEAR SHOULD SUPPORT ORGANIZED...ROTATING UPDRAFTS WITH THE PRIMARY THREAT BEING SEVERE HAIL. A TORNADO OR TWO ALSO WILL BE POSSIBLE IN ADDITION TO LOCALLY DAMAGING WINDS. ...OK/NRN TX INTO THE MID MS VALLEY... CONSIDERABLE UNCERTAINTY EXISTS WITH REGARD TO CONVECTIVE INITIATION AND EVOLUTION THROUGH THE FORECAST OWING TO COMPLICATING EFFECTS ANTECEDENT CONVECTION AND RESULTANT LOCATION OF SURFACE BOUNDARIES. AS SUCH...A HOT AND MOIST LOW-LEVEL AIR MASS WILL ONCE AGAIN DEVELOP ACROSS WARM SECTOR...SUPPORTING MLCAPES OF 2000-3000 J/KG. IT APPEARS THAT THE STRONGER VERTICAL SHEAR WILL LIKELY EXIST N OF PRIMARY LOW-LEVEL BAROCLINIC ZONE WITH GENERALLY 20-30 KTS OF DEEP LAYER SHEAR ANTICIPATED ACROSS AREA OF STRONGEST AIR MASS DESTABILIZATION. THIS ENVIRONMENT SHOULD SUPPORT ORGANIZED MULTICELL CLUSTERS CAPABLE OF SOME HAIL AND DAMAGING WINDS THROUGH THE AFTERNOON AND EVENING HOURS. ONCE FINER SCALE DETAILS BECOME MORE CLEAR...PARTS OF AREA MAY NEED TO BE UPGRADED TO A SLIGHT RISK. ..MEAD.. 08/26/2006  From swody2 at goshenarc.org Sun Aug 27 05:50:32 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 27 Aug 2006 01:50:32 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 270550 SWODY2 SPC AC 270549 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1249 AM CDT SUN AUG 27 2006 VALID 281200Z - 291200Z ...NO SVR TSTM AREAS FORECAST... SUBTROPICAL RIDGING WILL REMAIN PROMINENT ACROSS THE GULF AND SOUTH ATLANTIC COAST STATES THROUGH THIS FORECAST PERIOD. HOWEVER...MODELS SUGGEST AMPLIFICATION WILL OCCUR WITHIN THE POLAR WESTERLIES...WITH A SIGNIFICANT TROUGH DIGGING ALONG THE BRITISH COLUMBIA/NORTHERN PACIFIC COAST BY 12Z TUESDAY. DOWNSTREAM EVOLUTION IN THE SOUTHERN BRANCH OF SPLIT WESTERLIES REMAINS A BIT MORE UNCERTAIN...BUT IT APPEARS LIKELY THAT THE CENTRAL STATES TROUGH WILL MAINTAIN A POSITIVE TILT AND BECOME INCREASINGLY SHEARED...IN CONFLUENT REGIME BETWEEN SOUTHEASTERN RIDGE AND A NORTHERN BRANCH TROUGH ACROSS THE EASTERN CANADIAN PROVINCES. A SURFACE FRONTAL ZONE WILL BE SLOW TO PROGRESS THROUGH THE OHIO VALLEY MONDAY...BUT SOUTHWARD ADVANCEMENT INTO THE SOUTHERN PLAINS SHOULD OCCUR. MONSOONAL MOISTURE ADVECTING AROUND MID-LEVEL RIDGE WILL CONTRIBUTE TO WIDESPREAD CONVECTIVE DEVELOPMENT ALONG AND SOUTH OF THIS FRONT...AS THE SOUTHERN BRANCH TROUGH SHIFTS EASTWARD INTO THE CENTRAL PLAINS. IN THE WAKE OF UPPER SYSTEM...MOISTURE WILL REMAIN SUFFICIENT AND INHIBITION WEAK ENOUGH TO ALLOW FAIRLY WIDESPREAD THUNDERSTORM ACTIVITY ACROSS THE SOUTHERN AND CENTRAL ROCKIES AS WELL. ...CENTRAL/EASTERN STATES... SURFACE FRONTAL ZONE IS EXPECTED TO STALL FROM THE NORTHERN MID ATLANTIC COAST THROUGH THE VICINITY OF THE OHIO RIVER. WHILE THIS FEATURE...AND WEAK WAVES ALONG IT...WILL PROVIDE THE FOCUS FOR CONVECTIVE DEVELOPMENT MONDAY...DESTABILIZATION MAY BE LIMITED BY CONSIDERABLE CLOUD COVER AND MOIST MID-LEVEL ENVIRONMENT WITH WEAK LAPSE RATES. WITH FLOW FIELDS/DEEP LAYER SHEAR ASSOCIATED WITH THE SOUTHERN STREAM LIKELY ONLY MODERATE AT BEST...SEVERE POTENTIAL SEEMS SMALL. HOWEVER...HIGH PRECIPITABLE WATER CONTENT AROUND 2 INCHES OR BETTER MAY STILL CONTRIBUTE TO LOCALLY HEAVY DOWNPOURS...AND PERHAPS A FEW WET DOWNBURSTS. FARTHER WEST...IT APPEARS THAT A PRE-FRONTAL CONGLOMERATE OUTFLOW BOUNDARY WILL BECOME THE PRIMARY FOCUS FOR CONVECTIVE DEVELOPMENT BY MONDAY AFTERNOON...ACROSS CENTRAL ARKANSAS INTO NORTHEAST/NORTH CENTRAL TEXAS. THIS WILL BE WELL SOUTH OF BETTER MID-LEVEL FLOW/DEEP LAYER SHEAR...BUT STRONG SURFACE HEATING PROBABLY WILL CONTRIBUTE TO A HOT DEEP MIXED BOUNDARY LAYER...WHICH SHOULD BE FAVORABLE FOR LOCALIZED DOWNBURSTS NEAR HEAVIER PRECIPITATION CORES. THREAT IS EXPECTED TO DIMINISH EARLY MONDAY EVENING WITH ONSET OF RADIATIONAL COOLING. ..KERR.. 08/27/2006  From swody2 at goshenarc.org Sun Aug 27 17:02:29 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 27 Aug 2006 13:02:29 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 271702 SWODY2 SPC AC 271701 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1201 PM CDT SUN AUG 27 2006 VALID 281200Z - 291200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... STRONG TROUGH...ANCHORED BY UPPER LOW ALONG THE NWRN BRITISH COLUMBIA COAST...WILL DIG SEWD TOWARD THE PACIFIC NW COAST WITH RESULTANT AMPLIFICATION OF DOWNSTREAM RIDGING OVER THE N-CNTRL CONUS INTO CANADIAN PRAIRIES. AS THIS OCCURS UPPER LOW OVER THE CNTRL PLAINS WILL BECOME BLOCKED BETWEEN RIDGE OVER THE ROCKIES AND SUBTROPICAL RIDGE OFF THE SERN U.S. COAST...WITH SYSTEM GRADUALLY SHEARING INTO INCREASINGLY CONFLUENT FLOW OVER THE OH VALLEY AND LOWER GREAT LAKES. IN THE LOW-LEVELS...SURFACE LOW OVER THE MID MS VALLEY WILL DEVELOP ENEWD ALONG BAROCLINIC ZONE ACROSS THE OH VALLEY. THE ERN EXTENSION OF THIS BOUNDARY WILL STRETCH EWD TO THE MIDDLE ATLANTIC COAST...WHILE TRAILING PORTION EXTENDS SWWD TO THE SRN HIGH PLAINS. ...MID MS VALLEY EWD ACROSS THE OH VALLEY TO THE MID ATLANTIC COAST... A MOIST AND UNSTABLE LOW-LEVEL AIR MASS COUPLED WITH THE PRESENCE OF THE SURFACE BOUNDARY AND WEAK IMPULSES EMANATING FROM CNTRL PLAINS TROUGH WILL SUPPORT SCATTERED TSTM DEVELOPMENT ACROSS THE REGION MONDAY INTO MONDAY NIGHT. WHILE LAPSE RATES ARE FORECAST TO REMAIN POOR AND NEAR MOIST ADIABATIC...POCKETS OF STRONGER DIABATIC HEATING SHOULD SUPPORT LOCALLY STRONGER INSTABILITY WITH MLCAPES INCREASING TO 1000-1500 J/KG. ASIDE FROM THE POOR LAPSE RATES...IT APPEARS THAT ANY ORGANIZED SEVERE THREAT WILL BE LIMITED BY THE MARGINAL VERTICAL SHEAR AS THE STRONGER MID AND HIGH-LEVEL FLOW WILL REMAIN N OF THE PRIMARY BAROCLINIC ZONE. POTENTIAL WILL EXIST FOR ISOLATED...STRONG TO MARGINALLY SEVERE TSTM CLUSTERS WITH THE PRIMARY SEVERE THREAT BEING LOCALLY DAMAGING WINDS. ...ARKLATEX INTO CNTRL NM... COMPARATIVELY STRONGER BOUNDARY LAYER HEATING IS FORECAST ACROSS PORTIONS OF CNTRL/SRN TX MONDAY WITH TEMPERATURES WARMING INTO THE 90S AHEAD OF SURFACE FRONT AND ANY RESIDUAL OUTFLOW BOUNDARIES. WHEN COUPLED WITH DEWPOINTS IN THE 60S TO LOWER 70S...AIR MASS SHOULD BECOME MODERATELY UNSTABLE WITH MLCAPES OF 1500-2500 J/KG. RELATIVELY WEAK CAPPING SHOULD ALLOW TSTMS TO INCREASE IN COVERAGE AND INTENSITY THROUGH THE AFTERNOON FROM CNTRL/SRN AR SWWD INTO CNTRL TX. HERE TOO...VERTICAL SHEAR WILL REMAIN RELATIVELY WEAK...EFFECTIVELY LIMITING STORM ORGANIZATION. STILL...POTENTIAL WILL EXIST FOR MULTICELL CLUSTERS CAPABLE OF DAMAGING WINDS. FARTHER TO THE W...POST-FRONTAL UPSLOPE REGIME IS FORECAST TO BECOME ESTABLISHED IN THE LEE OF THE SRN ROCKIES WITH TSTMS EXPECTED BY AFTERNOON ALONG THE HIGHER TERRAIN OF CNTRL NM. DESPITE A DRIER LOW-LEVEL AIR MASS THAN POINTS TO THE E...THE DEVELOPMENT OF STEEP LOW TO MID-LEVEL LAPSE RATES WILL SUPPORT POCKETS OF MODERATE INSTABILITY WITH MLCAPES OF 500-1000 J/KG. WHILE RELATIVELY STRONG VEERING IS FORECAST IN THE LOWEST 3 KM AGL...WIND FIELDS AND RESULTANT SHEAR MAGNITUDE WILL REMAIN MARGINAL. A FEW ORGANIZED STORMS /PERHAPS EXHIBITING SOME MID-LEVEL ROTATION/ WILL BE POSSIBLE WITH THE PRIMARY SEVERE THREAT BEING SEVERE HAIL. ..MEAD.. 08/27/2006  From swody2 at goshenarc.org Mon Aug 28 05:50:40 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 28 Aug 2006 01:50:40 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 280550 SWODY2 SPC AC 280549 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1249 AM CDT MON AUG 28 2006 VALID 291200Z - 301200Z ...NO SVR TSTM AREAS FORECAST... MODELS CONTINUE TO INDICATE THAT A MORE AMPLIFIED AND LESS PROGRESSIVE UPPER FLOW PATTERN WILL DEVELOP ACROSS NORTH AMERICA LATER TODAY INTO TUESDAY. DISCREPANCIES EXIST...PERHAPS MOST NOTABLY CONCERNING THE EVOLUTION OF CENTRAL U.S. TROUGH WITHIN THE SOUTHERN BRANCH OF A SPLIT FLOW REGIME...DOWNSTREAM OF A SIGNIFICANT NORTHERN BRANCH TROUGH EVOLVING ACROSS WESTERN CANADA AND THE NORTHERN U.S. INTERMOUNTAIN REGION. THE IMPACT OF THESE FEATURES ON LINGERING SUBTROPICAL RIDGE ACROSS THE SOUTHERN TIER STATES IS ALSO UNCERTAIN...BUT MOST SUBSTANTIAL WEAKENING SEEMS LIKELY TO OCCUR ACROSS THE SOUTHERN PLATEAU. NCEP SREF AND BULK OF MODEL DATA SUGGEST RIDGING WILL BE SLOWEST TO WEAKEN OVER THE LOWER LATITUDE WESTERN ATLANTIC. AND ERNESTO...TRACKING AROUND SOUTHWESTERN PERIPHERY OF HIGH CENTER BEFORE LIFTING AHEAD OF WEAK SOUTHERN BRANCH TROUGH...SEEMS MOST LIKELY TO MIGRATE ACROSS THE LOWER KEYS INTO THE VICINITY OF THE SOUTHERN FLORIDA GULF COAST BY 12Z WEDNESDAY. ...MID ATLANTIC STATES... MODELS CONTINUE TO SUGGEST THAT A WEAK SURFACE LOW WILL DEVELOP TO THE LEE OF THE CENTRAL APPALACHIANS...ALONG OR SOUTH OF SURFACE FRONT ADVANCING SOUTHWARD INTO THE MID ATLANTIC REGION. THIS COULD PROVIDE THE FOCUS FOR AT LEAST SCATTERED CONVECTIVE DEVELOPMENT ACROSS PARTS OF EASTERN VIRGINIA...AND PERHAPS NORTHEASTERN NORTH CAROLINA...INTO THE DELMARVA PENINSULA...WHERE BOUNDARY LAYER IS EXPECTED TO BE QUITE MOIST WITH DEW POINTS AROUND 70F. WEAK MID-LEVEL LAPSE RATES WILL PROBABLY LIMIT CAPE TO WEAK TO MODERATE LEVELS AT OR ABOVE 1000 J/KG. HOWEVER...SHEAR PROFILES WILL BE MARGINALLY FAVORABLE FOR UPDRAFT ROTATION... BENEATH 30+ KT WESTERLY MID-LEVEL FLOW...IN CONFLUENT REGIME DOWNSTREAM OF SOUTHERN BRANCH TROUGH. AND...INSTABILITY MAY BE SUFFICIENT FOR AN ISOLATED SUPERCELL OR TWO...MAINLY DURING/ SHORTLY AFTER PEAK DAYTIME HEATING. IF THIS OCCURS...POTENTIAL EXISTS FOR A TORNADO...IN ADDITION TO DAMAGING WIND GUSTS...AND POSSIBLY SOME HAIL. ...FLORIDA... UNCERTAINTIES CONCERNING TRACK/STRENGTH OF ERNESTO...AND ASSOCIATED WIND FIELDS AND LOW-LEVEL SHEAR ARE STILL LARGE. HOWEVER...POTENTIAL FOR AT LEAST ISOLATED TORNADOES WILL PROBABLY INCREASE ACROSS THE FLORIDA KEYS INTO THE SOUTHERN PENINSULA LATE TUESDAY/TUESDAY NIGHT...NORTH/NORTHEAST OF APPROACHING CIRCULATION CENTER. ...NORTHWEST... LACK OF MOISTURE IN WARM PRE-FRONTAL ENVIRONMENT IS EXPECTED TO MINIMIZE CONVECTIVE POTENTIAL ASSOCIATED WITH VIGOROUS UPPER TROUGH DIGGING INTO THE NORTHERN INTERMOUNTAIN REGION. OROGRAPHY MAY AID DEVELOPMENT OF THUNDERSTORMS ACROSS THE MOUNTAINS OF NORTHERN IDAHO/WESTERN MONTANA...SOME OF WHICH COULD DEVELOP EAST OF THE HIGHER TERRAIN WITH POTENTIAL FOR ISOLATED MICROBURSTS IN DEEP MIXED BOUNDARY LAYER. ...SOUTHWEST... A NORTHWARD SURGE OF LOW-LEVEL MOISTURE THROUGH THE GULF OF CALIFORNIA INTO THE LOWER COLORADO VALLEY AND SOUTHERN PLATEAU APPEARS LIKELY TO OCCUR BY TUESDAY. FAIRLY STRONG DAYTIME HEATING AND WEAKENING INHIBITION ARE EXPECTED TO CONTRIBUTE TO INCREASING THUNDERSTORM ACTIVITY TUESDAY AFTERNOON. SHEAR WILL BE WEAK... BUT DEEP MIXED BOUNDARY LAYER WITH CAPE AS LARGE AS 1000 J/KG WILL PROBABLY BE SUFFICIENT FOR A FEW VIGOROUS STORMS...SOME OF WHICH MAY BE ACCOMPANIED BY LOCALIZED DOWNBURSTS...POSSIBLY SOME SMALL HAIL. ..KERR.. 08/28/2006  From swody2 at goshenarc.org Mon Aug 28 17:40:08 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 28 Aug 2006 13:40:08 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 281740 SWODY2 SPC AC 281739 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1239 PM CDT MON AUG 28 2006 VALID 291200Z - 301200Z ...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS DELMARVA/MID-ATLANTIC REGION... ...SYNOPSIS... SEASONALLY HIGH-AMPLITUDE AND PROGRESSIVE SYNOPTIC PATTERN WILL PERSIST OVER MUCH OF CONUS THROUGH PERIOD. HEIGHTS WILL FALL ACROSS PACIFIC NW IN ADVANCE OF TROUGH NOW EVIDENT IN MOISTURE CHANNEL IMAGERY OVER SERN GULF OF AK AND ADJACENT NERN PACIFIC. MID-UPPER LEVEL LOW NOW LOCATED INVOF YKN IS PROGGED TO MOVE ESEWD ACROSS IL/INDIANA THROUGH PERIOD. CONFIDENCE IN THIS TRACK IS GAINED FROM REASONABLY STRONG CONSENSUS AND LITTLE VARIATION AMONGST 28/12Z DETERMINISTIC SHORT-RANGE MODELS...REGARDING LOCATION AND POSITIVE TILT OF ASSOCIATED TROUGH. SOME DIFFERENCES ARE EVIDENT IN STRENGTH...NAMELY WHETHER TROUGH WILL CONTINUE HOLDING CLOSED LOW OR EVOLVE TO OPEN-WAVE STRUCTURE. ASSOCIATED SFC LOW -- NOW ANALYZED OVER MO/IA BORDER -- IS FCST TO MOVE GENERALLY EWD ALONG FRONTAL ZONE TO COASTAL DELMARVA/MID-ATLANTIC BY 30/00Z. TRAILING COLD FRONT WILL MOVE SEWD OVER OH VALLEY...SRN/CENTRAL APPALACHIANS...AND ALL BUT COASTAL PLAIN OF TX BY SAME TIME. AS OF THIS WRITING...TS ERNESTO IS MOVING NWWD ACROSS SERN CUBA. LATEST NHC TRACK FCST FOR ITS CENTER...AS WELL AS TRENDS IN THESE FCSTS...SUGGEST MOST FAVORABLE AREA FOR TORNADOES WILL REMAIN OFFSHORE OVER ATLANTIC. AS SUCH...NO PROBABILITIES ARE INCORPORATED ATTM...THOUGH ANY LEFTWARD DEVIATION FROM THIS TRACK MIGHT RESULT IN PERIPHERAL SUPERCELL POTENTIAL ALONG FL E COAST. ...MID-ATLANTIC/DELMARVA REGION... WIDELY SCATTERED TSTMS ARE EXPECTED TO DEVELOP IN ZONE OF MAXIMIZED LOW LEVEL ASCENT AND HEATING...SE THROUGH E OF SFC LOW...LATE MORNING THROUGH AFTERNOON. THERE IS SOME CONCERN THAT CLOUD COVER MAY LIMIT DIURNAL HEATING...HOWEVER WEAK CINH AND CONVERGENCE INVOF LOW SHOULD SUPPORT ENOUGH SUPERCELL POTENTIAL TO WARRANT CATEGORICAL SLGT RISK. MOST FAVORABLE ZONE FOR SVR SHOULD BE FROM LOW EWD INVOF FRONT...WHERE SUPERCELLS ARE MOST PROBABLE. PRIND THIS AREA WILL COMPRISE A NARROW CORRIDOR -- JUXTAPOSING NRN PERIPHERY OF MOST FAVORABLE BOUNDARY LAYER HEATING/MOISTURE...SRN PERIPHERY OF STRONGER MIDLEVEL FLOW...AND RELATIVELY BACKED LOW LEVEL WINDS IN ORDER TO MAXIMIZE DEEP-LAYER VERTICAL SHEAR. ACCORDINGLY...MODEL FCST SOUNDINGS INDICATE 35-35 KT EFFECTIVE SHEAR...AND 0-1 KM SRH 100-200 J/KG FOR EWD STORM MOTIONS. IN ENVIRONMENT OF RELATIVELY LOW LCL AND FAVORABLE KINEMATIC PROFILES NEAR WARM FRONT...A TORNADO OR TWO IS POSSIBLE. DAMAGING GUST THREAT MAINLY WOULD BE FROM AFTERNOON CONVECTION WHOSE SUBCLOUD LAYERS ARE OPTIMALLY MIXED BY HEATING. LOW-MIDLEVEL ABSOLUTE WARMTH AND LAPSE RATES NEAR MOIST-ADIABATIC ALOFT WILL LIMIT BOTH RATE OF CONVECTIVE DEVELOPMENT AND POTENTIAL FOR LARGE HAIL. ...MID-UPPER MS VALLEY REGION... ALTHOUGH BOUNDARY LAYER WILL BE POSTFRONTAL AND CHARACTERIZED BY AMBIENT CAA OVER THIS REGION...WIDELY SCATTERED TSTMS ARE POSSIBLE DURING AFTERNOON..BENEATH COLD CORE REGION OF MID/UPPER LOW. DIABATIC HEATING WILL OFFSET SFC CAA ENOUGH TO REMOVE CINH IN SOME AREAS...IN COMBINATION WITH RESIDUAL/EVAPOTRANSPIRATED MOISTURE. LAPSE RATES SHOULD BECOME STEEP ENOUGH TO SUPPORT MLCAPES LOCALLY EXCEEDING 1000 J/KG. STRONGEST CELLS MAY PRODUCE HAIL AND GUSTS NEAR SVR LEVELS. ...SRN AND PERHAPS CENTRAL AZ... STRONG SFC HEATING IS ANTICIPATED ACROSS MUCH OF THIS REGION CONCURRENT WITH INCREASE IN LOW LEVEL MOISTURE...SUPPORTING CONVECTIVE POTENTIAL DURING MID-LATE AFTERNOON OVER HIGHER ELEVATIONS AND LATE AFTERNOON INTO EVENING OVER LOWER DESERTS. DEEP/LOW-MIDLEVEL ELY FLOW COMPONENT -- PARTICULARLY OVER SRN AZ -- WOULD AID MOVEMENT OF CONVECTION OFF MOUNTAINS AND OVER HOT/DEEPLY MIXED DESERT BOUNDARY LAYERS...IN SUPPORT OF AT LEAST MRGL POTENTIAL FOR STG-SVR GUSTS. ..EDWARDS.. 08/28/2006  From swody2 at goshenarc.org Wed Aug 30 05:22:34 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 30 Aug 2006 01:22:34 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 300523 SWODY2 SPC AC 300522 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1222 AM CDT WED AUG 30 2006 VALID 311200Z - 011200Z ...THERE IS A SLGT RISK OF SVR TSTMS LATE THU AFTN AND EVE ACROSS PARTS OF THE CNTRL HIGH PLAINS.... VARIABILITY STILL EXISTS AMONG THE MODELS WITH REGARD TO THE SPECIFICS OF THE EVOLUTION OF THE LARGE-SCALE UPPER FLOW PATTERN DURING THIS FORECAST PERIOD. IN GENERAL...THOUGH...A MORE AMPLIFIED...AND LESS PROGRESSIVE/BLOCKED REGIME IS FORECAST TO CONTINUE TO DEVELOP. A WEAK CLOSED LOW IN THE SOUTHERN BRANCH OF THE POLAR WESTERLIES IS PROGGED TO BECOME CUT-OFF OVER THE LOWER OHIO VALLEY BY THURSDAY...WITH A PERTURBATION...EMANATING FROM THE TROPICS...LIFTING OUT OF THE NORTHWESTERN GULF OF MEXICO AROUND ITS SOUTHERN PERIPHERY. TO THE SOUTHEAST OF THE LOW...AN INCREASINGLY SHEARED ERNESTO IS PROGGED TO ACCELERATE FROM SOUTH ATLANTIC COASTAL AREAS THROUGH MUCH OF THE EASTERN CAROLINAS BY 12Z FRIDAY. UPSTREAM...MODELS SUGGEST A SUBTROPICAL HIGH CENTER WILL EXPAND ONCE AGAIN ACROSS THE NORTHERN MEXICAN PLATEAU. BUT...THIS WILL BE TEMPERED TO THE NORTH BY THE CONTINUING SLOW EASTWARD MIGRATION OF AN AMPLIFIED POLAR TROUGH...AND EMBEDDED SHORT WAVES...EASTWARD INTO/THROUGH THE CENTRAL CANADIAN PRAIRIES AND NORTHERN U.S. PLAINS. ...SOUTHEAST... CONSIDERABLE UNCERTAINTIES REMAIN CONCERNING TORNADO POTENTIAL WITH ERNESTO. LOW-LEVEL CIRCULATION CENTER MAY NOT MAKE LANDFALL ACROSS COASTAL EASTERN SOUTH CAROLINA UNTIL NEAR OR SHORTLY AFTER DARK THURSDAY EVENING. A BRIEF PERIOD OF SOMEWHAT ENHANCED RISK OF AN ISOLATED TORNADO OR TWO COULD EXIST IN FAVORABLE LOW-LEVEL CONVERGENCE AND SHEAR...MAINLY ALONG COASTAL AREAS TO ITS NORTHEAST. HOWEVER...SLIGHT BOUNDARY LAYER COOLING AFTER DARK... AS ERNESTO CONTINUES INLAND...MAY ULTIMATELY MITIGATE THREAT. ...CENTRAL HIGH PLAINS... ALTHOUGH A RETURN FLOW OF GULF MOISTURE IS NOT LIKELY...MODELS INDICATE MOISTENING WILL OCCUR IN LEE SURFACE TROUGH NEAR THE KANSAS/COLORADO BORDER. SURFACE DEW POINTS NEAR 60F APPEAR LIKELY...AND THIS SHOULD BE SUFFICIENT FOR MODERATE DESTABILIZATION AS LAPSE RATES STEEPEN WITH DAYTIME HEATING...ALONG WITH AT LEAST WEAK MID-LEVEL COOLING. BOUNDARY LAYER CAPE ON THE ORDER OF 2000 J/KG IS ANTICIPATED BY LATE THURSDAY AFTERNOON...WHEN FORCING NEAR INTERSECTION OF COLD FRONT AND SURFACE TROUGH/WEAK DRY LINE IS EXPECTED TO ELIMINATED CAPPING ASSOCIATED WITH ELEVATED MIXED LAYER. THIS SEEMS MOST PROBABLE ACROSS NORTHEAST COLORADO OR NORTHWEST KANSAS...WHERE WEAK BUT VEERING WINDS WITH HEIGHT FROM LOWER TO MID-LEVELS...BENEATH MODERATE WESTERLY HIGH LEVEL FLOW...SHOULD BY SUFFICIENT FOR ISOLATED SUPERCELLS. FORCING ASSOCIATED WITH DIFLUENT/DIVERGENT UPPER FLOW FIELD BETWEEN BASE OF POLAR TROUGH AND CREST OF SUBTROPICAL RIDGE SHOULD ENHANCE DEVELOPMENT. AND...ONE OR MORE SMALL CONVECTIVE CLUSTERS COULD EVOLVE THROUGH EARLY THURSDAY EVENING...PROPAGATING SOUTHWARD ACROSS THE CENTRAL HIGH PLAINS...ALONG INSTABILITY AXIS NEAR LEE SURFACE TROUGH. ..KERR.. 08/30/2006  From swody2 at goshenarc.org Wed Aug 30 17:26:50 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 30 Aug 2006 13:26:50 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 301727 SWODY2 SPC AC 301726 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1226 PM CDT WED AUG 30 2006 VALID 311200Z - 011200Z ...THERE IS A SLGT RISK OF SVR TSTMS ERN CAROLINAS... ...THERE IS A SLGT RISK OF SVR TSTMS CNTRL HIGH PLAINS... ...SYNOPSIS... COMPLEX INTERACTION AMONG A NUMBER OF MULTI-STREAM AND MULTI-SCALE PERTURBATIONS WILL COMMENCE BY LATE IN THE DAY 2 PERIOD AND CONTINUE INTO FRIDAY. ERNESTO/S DEEP-LAYER TROPICAL CIRCULATION IS FORECAST TO LIFT NNEWD ALONG THE SOUTHEAST U.S. COASTLINE AND MOVE ACROSS THE ERN CAROLINAS THROUGH FRIDAY MORNING. THIS DISTURBANCE MAY EVENTUALLY BECOME INCORPORATED INTO THE LARGER SCALE CYCLONIC CIRCULATION ASSOCIATED WITH THE CUT-OFF LOW MEANDERING OVER THE MIDWEST/OH VALLEY. MEANWHILE...LARGE AND PROGRESSIVE UPPER TROUGH WILL CONTINUE TO TRACK EAST FROM THE NRN ROCKIES TO THE NRN PLAINS THIS PERIOD. STRONGEST HEIGHT FALLS ASSOCIATED THIS SYSTEM WILL LIKELY OCCUR FROM THE NRN PLAINS TO MANITOBA. HOWEVER...PRONOUNCED HEIGHT RISES AND CORRESPONDING SURFACE PRESSURE RISES BEHIND THE TROUGH...SPREADING FROM THE INTERIOR NORTHWEST ACROSS THE NRN ROCKIES...WILL AID IN DRIVING A COLD FRONT SWD/SEWD ACROSS THE CNTRL HIGH PLAINS THROUGH LATE THURSDAY NIGHT. SUBTROPICAL RIDGE WILL PERSIST FROM THE RIO GRANDE VALLEY WNWWD ACROSS THE SOUTHWEST WITH MONSOON MOISTURE PERSISTING ACROSS PARTS OF AZ/NM. ...ERN CAROLINAS... THERE IS RELATIVELY GOOD AGREEMENT AMONG A VARIETY OF GUIDANCE THAT STRONG TO INTENSE LOW LEVEL SHEAR WILL STEADILY INCREASE ACROSS THE ERN CAROLINAS THROUGH THURSDAY NIGHT. VERY MOIST AIR MASS...LIFT ALONG RESIDUAL FRONT AND OUTFLOW BOUNDARIES...AND INCREASING FORCING ASSOCIATED WITH THE ADVANCING ERNESTO CIRCULATION...WILL ALL CONTRIBUTE TO THE POTENTIAL FOR WIDESPREAD DEEP CONVECTION. CONVECTIVE BANDS ROTATING AROUND THE TROPICAL LOW SHOULD TRANSLATE NWD/NWWD AND INLAND ACROSS THE COASTLINE FROM NERN SC TO THE OUTER BANKS OF NC THROUGH FRIDAY NIGHT. GIVEN A STEADY INCREASE IN LOW LEVEL ELY FLOW...AND CORRESPONDING STRENGTHENING OF SRH IN THE NERN QUADRANT OF TROPICAL LOW...A FEW ISOLATED/BRIEF TORNADOES APPEAR POSSIBLE. ...CNTRL HIGH PLAINS... WHILE STRONG MOISTURE RETURN DOES NOT APPEAR LIKELY ACROSS THE REGION...MODEST BOUNDARY LAYER MOISTENING WILL OCCUR NEAR LEE-TROUGH AND ADVANCING COLD FRONT FROM SWRN NEB SWD ALONG CO/KS BORDER. SURFACE DEWPOINTS AROUND 60F AND TEMPERATURES CLIMBING THROUGH THE 80S WILL CONTRIBUTE TO MODERATE DESTABILIZATION WITH LAPSE RATES STEEPENING WITH DAYTIME HEATING. MEAN LAYER CAPE ON THE ORDER OF 1500 J/KG IS ANTICIPATED BY AFTERNOON...WHEN FORCING NEAR INTERSECTION OF COLD FRONT AND SURFACE TROUGH/WEAK DRY LINE SHOULD LOCALLY ELIMINATE CAPPING ASSOCIATED WITH ELEVATED MIXED LAYER. WEAK BUT VEERING WINDS WITH HEIGHT FROM LOWER TO MID-LEVELS...BENEATH MODERATE WESTERLY HIGH LEVEL FLOW...SHOULD PROVE ADEQUATE FOR ISOLATED SUPERCELLS WITH HAIL AND HIGH WINDS. ADDITIONAL ACTIVITY WITH SEVERE HAIL POTENTIAL MAY ALSO OCCUR IN RELATIVELY MOIST POST-FRONTAL UPSLOPE FLOW REGIME FROM NEB PNHDL TO THE CO FRONT RANGE. DESPITE WEAK SYNOPTIC SCALE HEIGHT FALLS...DIFFLUENT MID AND UPPER LEVEL FLOW...AND FOCUSED LIFT ALONG THE FRONT/LEE TROUGH...ARE EXPECTED TO RESULT IN ONE OR MORE SMALL CONVECTIVE CLUSTERS EVOLVING ACROSS THE HIGH PLAINS AREA THROUGH THURSDAY EVENING. THIS ACTIVITY MAY MERGE AND GROW UPSCALE INTO AN MCS WITH ISOLATED SEVERE WEATHER POSSIBLY SPREADING SSEWD FROM WRN KS THROUGH LATE THURSDAY NIGHT. ..CARBIN.. 08/30/2006  From swody2 at goshenarc.org Thu Aug 31 05:24:05 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Thu, 31 Aug 2006 01:24:05 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 310524 SWODY2 SPC AC 310523 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1223 AM CDT THU AUG 31 2006 VALID 011200Z - 021200Z ...THERE IS A SLGT RISK OF SVR TSTMS FRI ACROSS PARTS OF THE MID ATLANTIC COAST STATES.... MODELS MAINTAIN THEIR DIFFERENCES CONCERNING THE DETAILS OF THE LARGE SCALE PATTERN EVOLUTION INTO THE EARLY PART OF THE WEEKEND. BUT...IN GENERAL TERMS...AN AMPLIFIED POLAR TROUGH STILL APPEARS LIKELY TO BEGIN SPLIT AS IT VERY SLOWLY PROGRESSES ACROSS THE CENTRAL CANADIAN PROVINCES AND THE NORTH CENTRAL U.S. FRIDAY INTO EARLY SATURDAY. AN EMBEDDED SHORT WAVE IN THE NORTHERN PORTION OF THE TROUGH IS PROGGED TO REMAIN A BIT MORE PROGRESSIVE WITHIN STRONGER BELT OF WESTERLIES...WELL NORTH OF THE CANADIAN/U.S. BORDER. A SHORT WAVE EMBEDDED WITHIN THE SOUTHERN PORTION OF THE TROUGH IS PROGGED TO DIG INTO THE WEAKER SOUTHERN STREAM...AND BEGIN TO EVOLVE INTO ANOTHER CLOSED LOW ACROSS THE NORTHERN PLAINS/UPPER MISSISSIPPI VALLEY. WHILE THIS OCCURS...DOWNSTREAM CLOSED LOW/TROUGH MAY BEGIN TO SHIFT OR REDEVELOP EASTWARD/NORTHEASTWARD THROUGH THE OHIO VALLEY...AS MID-LEVEL REMNANTS OF ERNESTO ROTATE AROUND ITS EASTERN AND NORTHEASTERN PERIPHERY. ...MID ATLANTIC COAST STATES... A WEAK SURFACE BOUNDARY IS EXPECTED TO LINGER TO THE LEE OF THE CENTRAL/SOUTHERN APPALACHIANS INTO THE DELMARVA PENINSULA THROUGH EARLY FRIDAY. AS REMNANT LOW-LEVEL CIRCULATION ASSOCIATED WITH ERNESTO INTERACTS WITH THIS FEATURE...TORNADIC POTENTIAL COULD BECOME ENHANCED ACROSS PARTS OF EASTERN VIRGINIA INTO THE DELMARVA REGION. LATER IN THE DAY...A BRIEF PERIOD OF SURFACE HEATING STILL APPEARS POSSIBLE IN VERY MOIST WARM SECTOR ACROSS THIS SAME REGION...IN THE WAKE OF THE MID-LEVEL IMPULSE. IF THIS OCCURS... LOW-LEVEL CONVERGENCE IN AN UNSTABLE BOUNDARY LAYER MAY SUPPORT ADDITIONAL SCATTERED CONVECTIVE DEVELOPMENT...AND LOW-LEVEL SHEAR/ AMBIENT VERTICAL VORTICITY IS EXPECTED TO REMAIN FAVORABLE FOR ISOLATED TORNADOES. ...CENTRAL STATES... MODELS STILL VARY SUBSTANTIALLY WITH THE TIMING OF INITIAL COOL SURGE INTO THE LEE OF THE CENTRAL ROCKIES. INFLUENCE OF WEAKENING MORNING CONVECTION AND LINGERING CLOUD COVER IS ALSO A CONCERN TO POTENTIAL FOR DESTABILIZATION IN MORE MOIST POST-FRONTAL/OUTFLOW REGIME ACROSS THE CENTRAL HIGH PAINS. IT APPEARS THE STRONGEST INSTABILITY WILL DEVELOP NEAR THE IMMEDIATE VICINITY OF BOUNDARY ...TO THE SOUTHEAST OF THE FRONT RANGE INTO THE TEXAS/OKLAHOMA PANHANDLE REGION. BUT...PEAK LATE AFTERNOON CAPE VALUES ON THE ORDER OF 1000 TO 1500 J/KG...IN ONLY WEAK TO MODERATE SHEAR BENEATH NORTHWESTERLY MID-LEVEL FLOW...SEEMS LIKELY TO MARGINALIZE SEVERE WEATHER POTENTIAL. ..KERR.. 08/31/2006  From swody2 at goshenarc.org Thu Aug 31 17:29:50 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Thu, 31 Aug 2006 13:29:50 -0400 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 311730 SWODY2 SPC AC 311729 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1229 PM CDT THU AUG 31 2006 VALID 011200Z - 021200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF ERN NC...ERN VA...SRN MD AND DE... ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF ERN CO AND FAR WRN KS... ...ERN SEABOARD... BASED ON THE HURRICANE CENTER FORECAST TRACK OF ERNESTO/SEE TPC FORECAST ADVISORY 28...TROPICAL STORM ERNESTO IS FORECAST TO CONTINUE A NWD MOVEMENT AND SHOULD BE LOCATED IN ECNTRL NC BY 12Z FRI. ALTHOUGH ERNESTO IS FORECAST TO REMAIN A TROPICAL STORM...SOME ORGANIZATION AND STRENGTHENING MAY OCCUR TONIGHT BEFORE ERNESTO MOVES INLAND NEAR WILMINGTON NC. STRONG ELY WINDS AHEAD OF THE STORM WILL INCREASE DEWPOINTS ACROSS NC FROM EAST TO WEST TONIGHT RESULTING IN A GRADUAL INCREASE OF INSTABILITY. IN ADDITION...FORECAST SOUNDINGS ACROSS THE REGION AT 12Z FRIDAY SHOW STRONG LOW-LEVEL SHEAR PROFILES ACROSS THE ENTIRE STATE OF NC WITH THE MOST FAVORABLE DEEP LAYER SHEAR ACROSS THE ERN HALF OF THE STATE. THIS SUGGESTS THE POTENTIAL FOR ROTATING STORMS WILL BE MOST LIKELY EAST OF THE CENTER WITH THE GREATEST THREAT IN THE COASTAL PLAINS EAST OF I-40 AND I-95. THE HIGH SFC DEWPOINTS AND STRONG LOW-LEVEL SHEAR PROFILES APPEAR FAVORABLE FOR TORNADOES. THE GREATEST THREAT FOR TORNADOES SHOULD OCCUR BETWEEN 12Z AND 18Z AS THE TROPICAL STORM MOVES FURTHER INLAND. FOR THIS REASON...HAVE ADJUSTED THE SLIGHT RISK AREA SWD ACROSS ERN NC TO ACCOUNT FOR A SLIGHTLY SLOWER FORWARD SPEED OF ERNESTO. THE TORNADO THREAT MAY ALSO CONTINUE NWD INTO ERN VA...MD AND DE AS INSTABILITY INCREASES FRIDAY AFTERNOON EAST OF THE CENTER OF ERNESTO. ...SRN PLAINS/CNTRL HIGH PLAINS... AN UPPER-LEVEL TROUGH OVER THE NRN ROCKIES/NRN HIGH PLAINS WILL CONTINUE MOVING SLOWLY EWD TONIGHT INTO THE NRN PLAINS. THE UPPER-TROUGH IS FORECAST TO BECOME MORE AMPLIFIED WITH TIME AND THE FAR SRN EXTENT OF THE TROUGH SHOULD AFFECT THE CNTRL HIGH PLAINS BY FRIDAY AFTERNOON. AT THE SFC...A MOIST AXIS SHOULD REMAIN IN PLACE EXTENDING NWD FROM THE TX PANHANDLE INTO ERN CO WHERE SFC DEWPOINTS SHOULD BE IN THE 55-65 F RANGE. AN AREA OF MODERATE INSTABILITY APPEARS MOST LIKELY TO DEVELOP NEAR THE PALMER DIVIDE AND ACROSS SE CO DURING THE DAY FRIDAY. MODEL FORECASTS ARE ALSO CONSISTENT WITH DEVELOPING A CLUSTER OF STRONG CONVECTION NEAR A BAND OF ENHANCED LOW-LEVEL CONVERGENCE ALONG A COLD FRONT IN ERN CO BY AFTERNOON. FORECAST SOUNDINGS ACROSS ERN CO FRIDAY AFTERNOON SHOW MODERATE TO STRONG SHEAR PROFILES WITH STEEP LOW-LEVEL LAPSE RATES SUGGESTING SUPERCELLS WITH LARGE HAIL WILL BE POSSIBLE. ISOLATED WIND DAMAGE MAY ALSO OCCUR AS AN MCS MOVES SWD ACROSS SERN CO BY EARLY EVENING. FOR THIS REASON...WILL UPGRADE THE AREA TO SLIGHT RISK. FURTHER SOUTH SOUTHEAST ACROSS THE TX PANHANDLE...MODERATE INSTABILITY MAY ALSO DEVELOP BY FRIDAY AFTERNOON. HOWEVER...THE UPPER-TROUGH IS NOT FORECAST TO AFFECT THE AREA AND DEEP LAYER SHEAR IS FORECAST TO BE WEAKER THAN AREAS FURTHER NORTH. FOR THIS REASON...ANY THREAT FOR HAIL AND DAMAGING WINDS IS EXPECTED TO MARGINAL AND ISOLATED. ..BROYLES.. 08/31/2006