From swody2 at goshenarc.org Fri Dec 1 05:52:17 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Fri, 01 Dec 2006 00:52:17 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 010554 SWODY2 SPC AC 010553 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1153 PM CST THU NOV 30 2006 VALID 021200Z - 031200Z ...NO TSTM AREAS FORECAST... ALTHOUGH THE MOST SIGNIFICANT EMBEDDED SHORT WAVE IMPULSE IS PROGGED TO CONTINUE ACCELERATING OFF THE NORTH ATLANTIC COAST... MODELS SUGGEST THAT AN AMPLIFIED TROUGH IN THE POLAR WESTERLIES WILL PERSIST ACROSS MUCH OF THE NATION EAST OF THE ROCKIES THROUGH THIS FORECAST PERIOD. UPSTREAM RIDGING WILL LINGER ALONG THE PACIFIC COAST...WITH ANOTHER BROAD TROUGH IN THE SUBTROPICAL STREAM...WEST OF BAJA...BEFORE THIS BELT OF FLOW MERGES INTO THE BASE OF THE POLAR TROUGH...ACROSS THE GULF AND SOUTH ATLANTIC COASTS. THE EVOLVING UPPER PATTERN WILL SUPPORT THE DEVELOPMENT OF A LARGE COLD SURFACE RIDGE...WHICH WILL ENCOMPASS MUCH OF THE NATION BY 12Z SATURDAY. THE EXCEPTION WILL BE THE SOUTHERN FLORIDA PENINSULA... WHERE WARM AND HUMID CONDITIONS WILL PERSIST SATURDAY...TO THE SOUTH OF THE STALLING LEADING EDGE OF THE COLD INTRUSION ACROSS THE CENTRAL PENINSULA. THE PRE-FRONTAL ENVIRONMENT LIKELY WILL REMAIN CAPPED BY A MID-LEVEL SUBTROPICAL RIDGE. AND...RELATIVELY WARM MID-LEVELS ARE EXPECTED TO MINIMIZE CONVECTIVE POTENTIAL IN A BELT OF LOW-LEVEL ISENTROPIC ASCENT TO THE NORTH OF THE SURFACE BOUNDARY...ACROSS NORTHERN FLORIDA INTO SOUTHERN GEORGIA/COASTAL SOUTH CAROLINA. RISK OF THUNDERSTORMS SATURDAY/SATURDAY NIGHT ACROSS THE SOUTHEAST...AND THE REMAINDER OF THE U.S...APPEARS NEGLIGIBLE. ..KERR.. 12/01/2006  From swody2 at goshenarc.org Fri Dec 1 16:59:27 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Fri, 01 Dec 2006 11:59:27 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 011700 SWODY2 SPC AC 011658 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1058 AM CST FRI DEC 01 2006 VALID 021200Z - 031200Z ...NO TSTM AREAS FORECAST... ...SYNOPSIS/FORECAST... IN WAKE OF THE STRONG WINTER STORM EXITING SERN CANADA LATE TONIGHT...TWO-STREAM UPPER FLOW REGIME WILL CONVERGE OVER THE CNTRL/ERN PARTS OF THE CONUS. AS A RESULT...BUILDING SFC PRESSURES WILL FORCE A CP AIR MASS SWD OVER MOST OF THE COUNTRY PRECLUDING TSTMS. SUBTROPICAL RIDGE OVER FL WILL MAINTAIN A MORE MODIFIED CP/MT AIR MASS ACROSS FL AHEAD OF THE FRONT...BUT THERMODYNAMIC PROFILES WILL NOT BE PARTICULARLY CONDUCIVE FOR TSTMS. ..RACY.. 12/01/2006  From swody2 at goshenarc.org Sat Dec 2 05:34:25 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 02 Dec 2006 00:34:25 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 020536 SWODY2 SPC AC 020535 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1135 PM CST FRI DEC 01 2006 VALID 031200Z - 041200Z ...NO SVR TSTM AREAS FORECAST... MODELS INDICATE THAT A LARGE-SCALE TROUGH IN THE POLAR WESTERLIES WILL REMAIN AMPLIFIED ACROSS THE CENTRAL/EASTERN U.S. THROUGH THIS FORECAST PERIOD. DIGGING IMPULSES WITHIN THIS REGIME...UPSTREAM OF TROUGH AXIS...ARE PROGGED TO MERGE INTO ONE SIGNIFICANT SHORT WAVE IN THE BASE OF THE LARGER SCALE TROUGH...NEAR/EAST OF THE MISSISSIPPI VALLEY LATE SUNDAY/SUNDAY EVENING...BEFORE SYSTEM ACCELERATES TOWARD THE ATLANTIC SEABOARD THROUGH 12Z MONDAY. SOME DIFFERENCE EXIST AMONG THE MODELS CONCERNING THE SPEED AT WHICH THIS OCCURS...BUT THE GFS AND ECMWF REMAIN VERY SIMILAR WITH REGARD TO THE FORECAST INITIATION OF SURFACE CYCLOGENESIS ALONG STALLED SURFACE FRONT OFF THE SOUTHERN/MID ATLANTIC COAST. COMMENCEMENT OF MORE RAPID SURFACE WAVE DEVELOPMENT CURRENTLY APPEARS MOST PROBABLE JUST EAST OF THE NORTH CAROLINA COAST LATE SUNDAY AFTERNOON. SCATTERED WEAK THUNDERSTORMS SEEM POSSIBLE ABOVE WARM FRONTAL INVERSION LAYER ACROSS THE CAROLINA COASTAL PLAIN...BUT THE MOST VIGOROUS WARM SECTOR CONVECTION SHOULD BE CONFINED TO AREAS WELL OFFSHORE. RISK OF THUNDERSTORMS ELSEWHERE ACROSS THE U.S. APPEARS NEGLIGIBLE. ..KERR.. 12/02/2006  From swody2 at goshenarc.org Sat Dec 2 16:59:21 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 02 Dec 2006 11:59:21 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 021700 SWODY2 SPC AC 021658 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1058 AM CST SAT DEC 02 2006 VALID 031200Z - 041200Z ...NO SVR TSTM AREAS FORECAST... ...NC OUTER BANKS... POSITIVE-TILT TROUGH EMBEDDED WITHIN THE POLAR WLYS WILL MOVE FROM THE PLAINS TO THE ERN SEABOARD ON SUNDAY. AHEAD OF THIS SYSTEM... WEAK CYCLOGENESIS SHOULD TAKE PLACE OFFSHORE THE CAROLINAS ALONG THE WRN GULF STREAM WATERS BY SUNDAY AFTN. THIS LOW WILL THEN TRACK NEWD DURING SUNDAY EVENING. MARGINAL INSTABILITY SHOULD DEVELOP ATOP THE MORE STABLE BOUNDARY LAYER ACROSS FAR ERN NC SUNDAY NIGHT. THUS...SPORADIC LIGHTNING MAY BE POSSIBLE WITHIN THE DEFORMATION ZONE EXPECTED TO EVOLVE ACROSS THE NC OUTER BANKS. ..RACY.. 12/02/2006  From swody2 at goshenarc.org Sun Dec 3 05:24:16 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 03 Dec 2006 00:24:16 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 030526 SWODY2 SPC AC 030525 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1125 PM CST SAT DEC 02 2006 VALID 041200Z - 051200Z ...NO TSTM AREAS FORECAST... MODELS INDICATE THAT THE LARGE-SCALE TROUGH IN THE POLAR WESTERLIES ...EAST OF THE ROCKIES...WILL PERSIST INTO THIS FORECAST PERIOD. SOME LOSS OF AMPLITUDE AND EASTWARD EXPANSION ACROSS THE WESTERN ATLANTIC IS FORECAST TO OCCUR...AS A SIGNIFICANT SHORT WAVE TROUGH RAPIDLY LIFTS NORTHEAST OF THE NORTH ATLANTIC COAST AND CANADIAN MARITIMES BY 12Z TUESDAY. THE LOW-LEVEL CYCLONE ACCOMPANYING THIS SYSTEM WILL CONTINUE TO DEEPEN...AND A TRAILING COLD FRONT IS PROGGED TO ADVANCE SOUTH OF THE REMAINDER OF THE FLORIDA PENINSULA AND KEYS. SHOWERS ARE POSSIBLE WITH THE FRONTAL PASSAGE MONDAY...BUT ALL INDICATIONS ARE THAT A LINGERING WARM MID-LEVEL ENVIRONMENT WILL INHIBIT DEEP CONVECTIVE DEVELOPMENT...MINIMIZING RISK FOR THUNDERSTORMS. IN THE WAKE OF THE FRONT...A LARGE COLD SURFACE RIDGE WILL ENCOMPASS MUCH OF THE GULF OF MEXICO...THE SOUTH CENTRAL/SOUTHEASTERN STATES...AND ADJACENT ATLANTIC WATERS. MID-LEVEL MOISTENING...ASSOCIATED WITH AN IMPULSE EMANATING FROM THE SUBTROPICAL PACIFIC...MAY OCCUR ACROSS THE NORTHERN MEXICAN PLATEAU INTO PARTS OF TEXAS. AND...A COLD MID-LEVEL SHORT WAVE TROUGH IN THE SOUTHERN BRANCH OF THE POLAR WESTERLIES IS PROGGED TO PROGRESS INLAND ACROSS VANCOUVER ISLAND AND SOUTHERN BRITISH COLUMBIA. HOWEVER...THERMODYNAMIC PROFILES APPEAR LIKELY TO REMAIN STABLY STRATIFIED ACROSS THESE AREAS...AND MUCH OF THE REMAINDER OF THE NATION...PRECLUDING ANY APPRECIABLE RISK OF THUNDERSTORM ACTIVITY. ..KERR.. 12/03/2006  From swody2 at goshenarc.org Sun Dec 3 16:49:19 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 03 Dec 2006 11:49:19 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 031651 SWODY2 SPC AC 031650 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1050 AM CST SUN DEC 03 2006 VALID 041200Z - 051200Z ...NO TSTM AREAS FORECAST... A LARGE SCALE TROUGH MOVING INTO THE ERN STATES WILL DEAMPLIFY THROUGH MONDAY. SFC CYCLONE EVOLVING ALONG THE GULF STREAM WILL DEPART TO THE NORTHEAST WITH A COLD FRONT MOVING INTO SRN FL. RESIDUAL WARM LAYER ALOFT WILL LIKELY BE HOSTILE TO DEEP MOIST CONVECTION ALONG THIS FRONT. TO THE WEST...FAST MOVING SHORTWAVE TROUGH WILL MOVE ACROSS THE PAC NW AND CANADIAN ROCKIES BY MONDAY NIGHT. PRIMARY COLD POCKET WILL REMAIN NORTH OF THE INTERNATIONAL BORDER WITH A MORE STABLE ENVIRONMENT FARTHER S. THIS WILL PRECLUDE THE RISK OF TSTMS. ELSEWHERE...A CP AIR MASS WILL RESIDE ACROSS THE REMAINDER OF THE CONUS WITH TSTM PROBABILITIES LESS THAN 10 PERCENT. ..RACY.. 12/03/2006  From swody2 at goshenarc.org Mon Dec 4 05:17:40 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 04 Dec 2006 00:17:40 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 040519 SWODY2 SPC AC 040518 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1118 PM CST SUN DEC 03 2006 VALID 051200Z - 061200Z ...NO TSTM AREAS FORECAST... THE SECOND IN A SERIES OF COLD INTRUSIONS TO THE LEE OF THE ROCKIES IS WELL UNDERWAY...ALREADY PENETRATING DEEP INTO THE WESTERN GULF OF MEXICO...AND LIKELY THE REMAINDER OF THE GULF OF MEXICO/FLORIDA PENINSULA AND ADJACENT ATLANTIC WATERS BY 12Z TUESDAY. DURING THE DAY TUESDAY...AS A FAIRLY SIGNIFICANT SHORT WAVE TROUGH SHIFTS OFF THE NORTH ATLANTIC COAST...MODELS SUGGEST THAT THE CENTER OF THE LARGE SURFACE RIDGE WILL RETREAT FROM THE LOWER MISSISSIPPI VALLEY INTO AREAS NEAR/JUST EAST OF THE MID ATLANTIC COAST BY 12Z WEDNESDAY. SOME MODIFICATION OF THE BOUNDARY LAYER OVER THE GULF OF MEXICO MAY BEGIN TO OCCUR DURING THIS FORECAST PERIOD...BUT SURFACE RIDGING IS PROGGED TO LINGER ALONG GULF COASTAL AREAS. AND...AS ANOTHER SIGNIFICANT SHORT WAVE TROUGH BEGINS TO AMPLIFY ACROSS THE NORTH CENTRAL STATES...WITHIN THE PERSISTENT BROADER SCALE POLAR TROUGH...ANOTHER SURFACE RIDGE WILL BEGIN TO BUILD BENEATH THE CONFLUENT REGIME TO THE LEE OF THE CANADIAN/U.S. ROCKIES. AN INFLUX OF MID-LEVEL MOISTURE FROM THE LOWER LATITUDE EASTERN PACIFIC INTO PARTS OF CENTRAL/SOUTHERN TEXAS COULD OCCUR WITH THE EASTWARD PROGRESSION OF A WEAKENING SUBTROPICAL IMPULSE. BUT...AT THE PRESENT TIME...IT APPEARS DESTABILIZATION WILL BE TOO MINIMAL TO SUPPORT AN APPRECIABLE RISK OF THUNDERSTORM ACTIVITY. ..KERR.. 12/04/2006  From swody2 at goshenarc.org Mon Dec 4 17:25:00 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 04 Dec 2006 12:25:00 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 041726 SWODY2 SPC AC 041724 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1124 AM CST MON DEC 04 2006 VALID 051200Z - 061200Z ...NO TSTM AREAS FORECAST... DRY/STABLE CONDITIONS ARE EXPECTED TO PRECLUDE ORGANIZED THUNDERSTORM ACTIVITY NATIONWIDE ON TUESDAY. ..HART.. 12/04/2006  From swody2 at goshenarc.org Tue Dec 5 05:06:25 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 05 Dec 2006 00:06:25 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 050508 SWODY2 SPC AC 050507 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1107 PM CST MON DEC 04 2006 VALID 061200Z - 071200Z ...NO TSTM AREAS FORECAST... BROAD TROUGHING IS EXPECTED TO PERSIST IN THE POLAR WESTERLIES... ACROSS MUCH OF THE CENTRAL AND EASTERN U.S...INTO WEDNESDAY. BUT ...MODEL GUIDANCE CONTINUES TO INDICATE THAT THE LAST IN A SERIES OF AMPLIFICATIONS WITHIN THIS REGIME WILL TAKE PLACE...AS A STRONG SHORT WAVE TROUGH DIGS OUT OF THE CANADIAN NORTHWEST TERRITORIES THROUGH MUCH OF THE UPPER MIDWEST. THIS FEATURE WILL BE PRECEDED IN THE NORTH CENTRAL STATES BY ANOTHER IMPULSE...EMANATING FROM THE NORTHEAST PACIFIC. AND...MODELS SUGGEST THAT A NEW SURFACE COLD INTRUSION MAY ALREADY BE OCCURRING THROUGH THE PLAINS EARLY WEDNESDAY...BEFORE STRONG COLD HIGH PRESSURE BUILDS THROUGH MOST AREAS FROM THE ROCKIES TO THE APPALACHIANS...INCLUDING MUCH OF THE GULF OF MEXICO...BY 12Z THURSDAY. WHILE SOME WARMING/MOISTENING OF THE BOUNDARY LAYER OVER THE GULF OF MEXICO AND WATERS OFF THE SOUTH ATLANTIC COAST MAY OCCUR BY WEDNESDAY...IN THE WAKE OF A PRIOR COLD INTRUSION...CURRENT INDICATIONS ARE THAT THIS WILL NOT BECOME SUFFICIENT TO SUPPORT A SIGNIFICANT INLAND RETURN FLOW. THUNDERSTORM ACTIVITY...IF ANY...ALONG/AHEAD OF ADVANCING SURFACE COLD FRONT...LIKELY WILL REMAIN CONFINED TO THE WATERS OFF THE FLORIDA GULF AND ATLANTIC COASTS...AND NEAR THE GULF STREAM...OFF THE NORTH CAROLINA COAST. ..KERR.. 12/05/2006  From swody2 at goshenarc.org Tue Dec 5 17:19:31 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 05 Dec 2006 12:19:31 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 051721 SWODY2 SPC AC 051719 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1119 AM CST TUE DEC 05 2006 VALID 061200Z - 071200Z ...NO TSTM AREAS FORECAST... ...SYNOPSIS... WEAK WARM ADVECTION WILL DEVELOP OVER THE ERN GULF OF MEXICO AHEAD OF SWD-PLUNGING COLD FRONT WEDNESDAY. STRONGEST SUSTAINED ASCENT WILL DEVELOP LATE IN THE PERIOD...LIKELY ENHANCING CONVECTIVE THREAT WEST OF THE FL PENINSULA. AT THIS TIME IT APPEARS THE PROSPECT FOR DEEP MOIST CONVECTION WILL REMAIN TOO NEGLIGIBLE ALONG COLD FRONT TO WARRANT ANY ORGANIZED THUNDER POTENTIAL. ..DARROW.. 12/05/2006  From swody2 at goshenarc.org Wed Dec 6 06:00:42 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 06 Dec 2006 01:00:42 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 060602 SWODY2 SPC AC 060600 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1200 AM CST WED DEC 06 2006 VALID 071200Z - 081200Z ...NO SVR TSTM AREAS FORECAST... THE LAST IN A SERIES OF AMPLIFICATIONS WITHIN PERSISTENT LARGE- SCALE POLAR TROUGH OVER THE CENTRAL AND EASTERN U.S. APPEARS TO BE UNDERWAY...MUCH AS FORECAST BY THE MODELS. THIS IS OCCURRING MOSTLY IN RESPONSE TO A STRONG DIGGING SHORT WAVE TROUGH ...EMANATING FROM THE CANADIAN NORTHWEST TERRITORIES...NEAR THE ARCTIC CIRCLE. THE GFS AND ECMWF INDICATE THAT THIS IMPULSE WILL CONTINUE ACROSS MUCH OF THE UPPER MIDWEST/UPPER GREAT LAKES REGION BY 12Z THURSDAY...BEFORE TURNING EAST ACROSS THE UPPER OHIO VALLEY AND LOWER GREAT LAKES REGION...INTO NORTHERN AND MID ATLANTIC COASTAL AREAS BY 12Z FRIDAY. BENEATH THE CONFLUENT REGIME UPSTREAM OF THE LARGE-SCALE TROUGH AXIS...THE CENTER OF A MASSIVE COLD SURFACE RIDGE IS PROGGED TO SHIFT SOUTHEASTWARD THROUGH THE EAST CENTRAL PLAINS AND OZARK PLATEAU. AND...THE LEADING EDGE OF THE COLD AIR WILL ADVANCE OFF ATLANTIC COASTAL AREAS...THE REMAINDER OF THE FLORIDA PENINSULA AND GULF OF MEXICO. THIS FEATURE WILL CONTRIBUTE TO STABLE THERMODYNAMIC PROFILES ACROSS MUCH OF THE NATION...WITH GENERALLY NEGLIGIBLE CONVECTIVE POTENTIAL. ...FLORIDA... MODIFICATION OF LOWER LEVELS IN THE WAKE OF A PRIOR COLD INTRUSION IS NOT EXPECTED TO BECOME SUFFICIENT TO OVERCOME MID-LEVEL INHIBITION. A FEW SHOWERS ARE POSSIBLE THURSDAY/THURSDAY EVENING ...AHEAD OF THE MAIN COLD SURGE ACROSS THE CENTRAL/SOUTHERN PENINSULA. BUT...ANYTHING MUCH BEYOND A BRIEF ISOLATED THUNDERSTORM APPEARS MINIMAL. ...GREAT LAKES... LOW-LEVEL LAPSE RATES AND CAPE SEEM LIKELY TO BECOME ENHANCED THURSDAY...AS LOWER/MID TROPOSPHERIC COLD CORE ASSOCIATED WITH THE VIGOROUS SHORT WAVE TROUGH SHIFTS ACROSS THE WARMER LOWER GREAT LAKES REGION. IT SEEMS PROBABLE THAT A FEW LIGHTNING STRIKES WILL ACCOMPANY STRONGER LAKE EFFECT CONVECTION...PARTICULARLY OVER THE OPEN WATERS INTO SOUTHEAST SHORES OF LAKE HURON. ..KERR.. 12/06/2006  From swody2 at goshenarc.org Wed Dec 6 17:20:01 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 06 Dec 2006 12:20:01 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 061721 SWODY2 SPC AC 061719 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1119 AM CST WED DEC 06 2006 VALID 071200Z - 081200Z ...NO SVR TSTM AREAS FORECAST... ...GREAT LAKES... LOW LEVEL LAPSE RATES WILL STEEPEN SIGNIFICANTLY FROM THE UPPER GREAT LAKES ACROSS LAKE ERIE DURING THE DAY2 PERIOD. LATEST MODEL GUIDANCE SUGGESTS EL LEVELS WILL BE AT LEAST 3KM DEEP WITH MOIST CONVECTION THAT DEVELOPS OVER WARMER LAKE WATERS. FOR THIS REASON IT APPEARS LIGHTNING WILL BE NOTED WITH STRONGER UPDRAFTS AND HEAVIER SNOW SQUALLS...ESPECIALLY DOWNWIND OF LAKE MI THROUGH 18Z...AND ACROSS LAKE ERIE THROUGH LATE EVENING. ...ELSEWHERE... LOW LEVEL CONVERGENCE WILL PROVE QUITE WEAK AHEAD OF COLD FRONT PLUNGING SWD ACROSS THE SRN PENINSULA OF FL. IT APPEARS CONVECTION WILL PROVE WEAK AND ANY LIGHTING THAT DEVELOPS SHOULD BE EXTREMELY ISOLATED...AND MAINLY OFFSHORE. ..DARROW.. 12/06/2006  From swody2 at goshenarc.org Fri Dec 8 06:10:59 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Fri, 08 Dec 2006 01:10:59 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 080610 SWODY2 SPC AC 080609 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1209 AM CST FRI DEC 08 2006 VALID 091200Z - 101200Z ...NO SVR TSTM AREAS FORECAST... AN UPPER-LEVEL RIDGE WILL BE IN PLACE SATURDAY MORNING ACROSS THE CNTRL STATES. THIS FEATURE IS FORECAST TO MOVE EWD INTO THE MS VALLEY BY SATURDAY EVENING. AT THE SFC...A LARGE HIGH PRESSURE AREA WILL DOMINATE ACROSS THE ERN U.S. AS A LEE TROUGH FORMS EAST OF THE ROCKIES. DUE TO THE LARGE SFC HIGH...VERY LITTLE LOW-LEVEL MOISTURE WILL BE IN PLACE ACROSS THE PLAINS...MS VALLEY AND ERN STATES FOR CONVECTIVE ACTIVITY SATURDAY AND SATURDAY NIGHT. FURTHER WEST...AN UPPER-LEVEL TROUGH WILL APPROACH THE CA COAST SATURDAY NIGHT. MODEL FORECASTS SHOW SUFFICIENT MOISTURE AND INSTABILITY FOR THUNDERSTORM ACTIVITY ALONG THE COAST NEAR SAN FRANCISCO LATE IN THE PERIOD AS THE UPPER-TROUGH MOVES INLAND. ..BROYLES.. 12/08/2006  From swody2 at goshenarc.org Fri Dec 8 16:40:11 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Fri, 08 Dec 2006 11:40:11 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 081641 SWODY2 SPC AC 081639 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1039 AM CST FRI DEC 08 2006 VALID 091200Z - 101200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... ANOTHER IN A SERIES OF UPPER SHORT-WAVE TROUGHS IS FORECAST TO MOVE ONSHORE OVER THE WRN CONUS DURING THE SECOND HALF OF THE PERIOD. THOUGH INSTABILITY SHOULD REMAIN QUITE LIMITED ONSHORE...A FEW LIGHTNING STRIKES MAY OCCUR OVER COASTAL AREAS OF NRN AND CENTRAL CA SWD TO NEAR POINT CONCEPTION. ELSEWHERE...LARGE SURFACE HIGH PRESSURE -- AND ASSOCIATED COOL/STABLE AIRMASS -- WILL PREVAIL OVER THE ERN HALF OF THE CONUS BENEATH SLOWLY-PROGRESSIVE UPPER RIDGE. THEREFORE...DEEP MOIST CONVECTION IS NOT ANTICIPATED. ..GOSS.. 12/08/2006  From swody2 at goshenarc.org Sat Dec 9 06:19:01 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 09 Dec 2006 01:19:01 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 090620 SWODY2 SPC AC 090618 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1218 AM CST SAT DEC 09 2006 VALID 101200Z - 111200Z ...NO SVR TSTM AREAS FORECAST... AN UPPER-LEVEL TROUGH IS FORECAST TO BE IN CALIFORNIA AT THE BEGINNING OF THE PERIOD. THIS FEATURE WILL MOVE EWD INTO THE INTERMOUNTAIN WEST DURING THE DAY ON SUNDAY. STEEP LAPSE RATES ASSOCIATED WITH THE UPPER-TROUGH AND SFC HEATING MAY HELP ISOLATED THUNDERSTORMS TO INITIATE IN THE FOUR CORNERS REGION SUNDAY AFTERNOON. BACK FURTHER WEST...LARGE-SCALE ASCENT MAY PERSIST ALONG THE WEST COAST IN THE WAKE OF THE EXITING UPPER-TROUGH AS A SECONDARY THROUGH TAKES ITS PLACE. IN ADDITION...LIFT MAY BE ENHANCED AS THE ENTRANCE REGION OF THE MID-LEVEL JET MOVES ACROSS SUNDAY AFTERNOON. THIS ALONG WITH ONSHORE FLOW AND COLD TEMPS ALOFT MAY ALLOW ISOLATED THUNDERSTORMS TO DEVELOP ALONG THE COASTS OF NRN CA AND ORE MAINLY SUNDAY MORNING AND AFTERNOON. HOWEVER...NO SEVERE WEATHER THREAT IS EXPECTED TO DEVELOP ACROSS THE CONUS SUNDAY OR SUNDAY NIGHT. ..BROYLES.. 12/09/2006  From swody2 at goshenarc.org Sat Dec 9 17:27:44 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 09 Dec 2006 12:27:44 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 091728 SWODY2 SPC AC 091727 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1127 AM CST SAT DEC 09 2006 VALID 101200Z - 111200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... A GENERALLY COOL/STABLE BOUNDARY-LAYER WILL PREVAIL E OF THE ROCKIES THIS PERIOD...AS WEAK UPPER TROUGH MOVES THROUGH THE LARGER-SCALE RIDGE AND SURFACE HIGH PRESSURE PERSISTS ACROSS MOST OF THE ERN HALF OF THE CONUS. MEANWHILE...A SECOND UPPER TROUGH WILL PROGRESS EWD ACROSS THE W COAST AND INTO THE ROCKIES THROUGH THE PERIOD. COLD AIR ALOFT/STEEP MID-LEVEL LAPSE RATES MAY CONTRIBUTE TO SUFFICIENT CAPE FOR A FEW LIGHTNING STRIKES -- PARTICULARLY INVOF THE FOUR CORNERS. ..GOSS.. 12/09/2006  From swody2 at goshenarc.org Sun Dec 10 05:51:52 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 10 Dec 2006 00:51:52 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 100552 SWODY2 SPC AC 100551 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1151 PM CST SAT DEC 09 2006 VALID 111200Z - 121200Z ...NO SVR TSTM AREAS FORECAST... A MERIDIONAL UPPER-TROUGH OVER THE ROCKIES WILL MOVE EWD INTO THE PLAINS STATES DURING THE DAY ON MONDAY. THE LOW-LEVEL MOIST AXIS SHOULD REMAIN WELL EAST OF THE STRONGER FORCING ASSOCIATED WITH THE TROUGH UNTIL AFTER DARK. ALTHOUGH A FEW THUNDERSTORMS MAY DEVELOP MONDAY AFTERNOON ACROSS THE TX COASTAL PLAINS...MOST OF THE THUNDERSTORM ACTIVITY SHOULD HOLD OFF UNTIL LATE EVENING OR AFTER MIDNIGHT. THE GREATEST CHANCE OF CONVECTIVE DEVELOPMENT SHOULD BE ACROSS ERN AR...LA AND SE TX WHEN THE LARGE-SCALE ASCENT ASSOCIATED WITH THE TROUGH AND THE LOW-LEVEL MOISTURE PHASE TOGETHER. ALTHOUGH WIND SHEAR WILL BE ADEQUATE FOR ORGANIZED STORMS...IT APPEARS INSTABILITY WILL BE WEAK ACROSS THE REGION. FOR THIS REASON...ANY SEVERE THREAT SHOULD REMAIN MARGINAL AND ISOLATED DURING THE OVERNIGHT PERIOD. ELSEWHERE...AN UPPER-LEVEL DISTURBANCE WILL MOVE ONSHORE IN THE PACIFIC NORTHWEST MONDAY AFTERNOON. THUNDERSTORMS WILL BE POSSIBLE DUE TO THE COLD AIR ALOFT AND STRONG LIFT ASSOCIATED WITH THE EXIT REGION OF A MID-LEVEL JET. HOWEVER...NONE OF THE ACTIVITY IS EXPECTED TO REACH SEVERE LIMITS. ..BROYLES.. 12/10/2006  From swody2 at goshenarc.org Sun Dec 10 17:29:18 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 10 Dec 2006 12:29:18 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 101730 SWODY2 SPC AC 101728 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1128 AM CST SUN DEC 10 2006 VALID 111200Z - 121200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... FAIRLY INTENSE/MERIDIONALLY-EXTENSIVE MID-LEVEL SHORT-WAVE TROUGH WILL MOVE INTO THE CENTRAL CONUS THIS PERIOD...WHILE A DOWNSTREAM INTENSIFYING RIDGE MOVES EWD ACROSS THE ERN CONUS. MEANWHILE...A SECOND TROUGH WILL AFFECT THE PAC NW COAST DURING THE PERIOD. THOUGH A FEW LIGHTNING STRIKES MAY OCCUR OVER THE WA COAST/OLYMPICS REGION LATE IN THE PERIOD...POTENTIALLY MORE WIDESPREAD THUNDERSTORM ACTIVITY MAY OCCUR LATE IN THE PERIOD OVER THE S CENTRAL CONUS. AS LOW-LEVEL MOISTURE INFLUX INCREASES AHEAD OF THIS FEATURE...SUFFICIENT ELEVATED CAPE MAY EVOLVE TO ALLOW SCATTERED/WEAK THUNDERSTORM DEVELOPMENT -- PARTICULARLY ACROSS THE ARKLATEX REGION AND VICINITY LATE IN THE PERIOD. ANY HAIL THREAT WITH THESE STORMS APPEARS ATTM TO BE VERY LOW DUE TO MEAGER INSTABILITY...AND THUS WILL NOT CARRY SEVERE PROBABILITIES THIS FORECAST. ..GOSS.. 12/10/2006  From swody2 at goshenarc.org Mon Dec 11 06:29:34 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 11 Dec 2006 01:29:34 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 110630 SWODY2 SPC AC 110628 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1228 AM CST MON DEC 11 2006 VALID 121200Z - 131200Z ...NO SVR TSTM AREAS FORECAST... ...LOWER MS VALLEY/TN VALLEY... A WELL-DEVELOPED UPPER-LEVEL LOW/TROUGH WILL BE LOCATED FROM THE UPPER MIDWEST EXTENDING SSWWD INTO THE SRN PLAINS AT THE BEGINNING OF THE DAY 2 PERIOD. A THREAT FOR ISOLATED THUNDERSTORMS MAY BE ONGOING IN THE MORNING ALONG THE LEADING EDGE OF LARGE-SCALE ASCENT LOCATED FROM THE LOWER OH VALLEY SSWWD TO THE LOWER MS VALLEY. AS SFC HEATING TAKES PLACE...CONVECTIVE COVERAGE SHOULD INCREASE WITH ISOLATED TO SCATTERED THUNDERSTORMS POSSIBLE ACROSS WRN KY...WRN TN...MS AND LA BY EARLY AFTERNOON. ALTHOUGH LOW-LEVEL MOISTURE SHOULD BE LIMITED...DESTABILIZATION SHOULD OCCUR IN POCKETS ALONG THE MS RIVER VALLEY DURING THE LATE MORNING AND EARLY AFTERNOON. IN ADDITION...STRONG SHEAR PROFILES SHOULD BE ADEQUATE FOR A MARGINAL SEVERE THREAT ESPECIALLY WHERE SUBSTANTIAL DESTABILIZATION OCCURS. THE SEVERE THREAT SHOULD BE VERY ISOLATED AND CONCENTRATED AROUND PEAK HEATING. ELSEWHERE...ISOLATED NON-SEVERE THUNDERSTORMS MAY OCCUR ALONG THE COAST OF THE PACIFIC NORTHWEST AS AN UPPER-TROUGH MOVES INLAND AROUND MIDDAY ON TUESDAY. ..BROYLES.. 12/11/2006  From swody2 at goshenarc.org Mon Dec 11 17:19:51 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 11 Dec 2006 12:19:51 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 111720 SWODY2 SPC AC 111718 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1118 AM CST MON DEC 11 2006 VALID 121200Z - 131200Z ...NO SVR TSTM AREAS FORECAST... A COMPLEX SPLIT UPPER FLOW PATTERN PERSISTS ACROSS MUCH OF NORTH AMERICA. WITHIN THIS REGIME...AN AMPLIFIED TROUGH...WHICH DEVELOPED OVER THE WEEKEND IN ONE STRONGER BELT ACROSS CALIFORNIA INTO THE SOUTH CENTRAL STATES...CONTINUES TO SHIFT EAST OF THE ROCKIES INTO THE CENTRAL/SOUTHERN PLAINS. MODELS INDICATE THAT THIS LARGER SCALE FEATURE WILL LIFT NORTHEASTWARD TOWARD THE MISSISSIPPI VALLEY BY 12Z TUESDAY...BEFORE PROGRESSING INTO/THROUGH THE GREAT LAKES/OHIO VALLEY REGION BY 12Z WEDNESDAY. THIS IS PROGGED TO OCCUR AS A STRONG HIGH-LEVEL JET STREAK NOSES INTO THE CANADIAN ROCKIES/NORTHERN U.S. INTERMOUNTAIN REGION...IN A STREAM EMANATING FROM THE WESTERN/CENTRAL PACIFIC. ASSOCIATED WITH THE SOUTHERN BRANCH TROUGH...MODELS CONTINUE TO INDICATE THAT LEE SURFACE CYCLOGENESIS WILL REMAIN WEAK. THIS WILL TEND TO MINIMIZE CONVECTIVE POTENTIAL ALONG/AHEAD OF ASSOCIATED SURFACE FRONT AS IT ADVANCES THROUGH THE CENTRAL U.S. EARLY THIS WEEK. ALSO...IN THE WAKE OF A SERIES OF SIGNIFICANT COLD INTRUSIONS... THE BOUNDARY LAYER OVER THE GULF OF MEXICO IS STILL IN THE PROCESS OF MODIFYING. BUT...A WEAK RETURN FLOW OF MOISTURE...CHARACTERIZED BY MID/UPPER 50S DEW POINTS...IS ONGOING FROM THE WESTERN GULF OF MEXICO INTO THE SOUTHEASTERN PLAINS. ...MIDDLE MISSISSIPPI VALLEY... VARIABILITY EXISTS AMONG THE MODELS CONCERNING THE DETAILS...BUT AN IMPULSE IS GENERALLY FORECAST TO PROGRESS THROUGH THE BASE OF THE LARGER SCALE TROUGH AS IT LIFTS INTO/THROUGH THE MISSISSIPPI VALLEY LATER TODAY INTO TUESDAY. THIS IS PROGGED TO CONTRIBUTE TO A STRENGTHENING SOUTHWESTERLY MID-LEVEL JET STREAK ACROSS THE MIDDLE MISSISSIPPI VALLEY BY TUESDAY AFTERNOON...WITH STRONGER MID-LEVEL COOLING ADVANCING NORTHEAST OF THE OZARK PLATEAU INTO THE LOWER OHIO VALLEY. THIS MAY BE PRECEDED BY AT LEAST WEAK SURFACE HEATING IN A DRY SLOT NOSING THROUGH THE MIDDLE MISSISSIPPI VALLEY...IN THE WAKE OF EARLY DAY PRE-FRONTAL WARM ADVECTION CONVECTION...WHICH WILL BE POSSIBLE IN A BAND THROUGH MUCH OF THE MISSISSIPPI VALLEY. MODEL FORECAST SOUNDINGS ACROSS PARTS OF EASTERN ARKANSAS AND SOUTHEAST MISSOURI...INTO CENTRAL/SOUTHERN ILLINOIS AND WESTERN KENTUCKY/TENNESSEE...INDICATE MIXED LAYER CAPE OF AROUND 500 J/KG DEVELOPING BY 20-21Z TUESDAY. THIS IS RATHER WEAK...BUT PROFILES ARE SUGGESTIVE OF SUFFICIENT CONVECTIVE INSTABILITY TO SUPPORT AT LEAST A LOW RISK OF MARGINALLY SEVERE HAIL/WIND GUSTS IN ANY STORMS DEVELOPING IN FAVORABLY SHEARED DEEP LAYER FLOW. AND... INHIBITION APPEARS LIKELY TO BECOME SUFFICIENTLY WEAK FOR A BROKEN LINE OF STORMS TO DEVELOP IN RESPONSE TO FRONTAL FORCING ADVANCING EAST OF THE MIDDLE MISSISSIPPI VALLEY BY EARLY TUESDAY EVENING. LIMITED SEVERE THREAT WILL PROBABLY DIMINISH AS THIS FORCING SHIFTS EASTWARD INTO COOLER AND MORE STABLE/STABILIZING BOUNDARY LAYER. ..KERR.. 12/11/2006  From swody2 at goshenarc.org Tue Dec 12 06:29:58 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 12 Dec 2006 01:29:58 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 120630 SWODY2 SPC AC 120629 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1229 AM CST TUE DEC 12 2006 VALID 131200Z - 141200Z ...NO SVR TSTM AREAS FORECAST... AT THE BEGINNING OF THE PERIOD...AN UPPER-LEVEL TROUGH OVER THE OH AND TN VALLEYS WILL DAMPEN AND MOVE QUICKLY ACROSS THE APPALACHIAN MTNS TO THE ERN SEABOARD BY WEDNESDAY AFTERNOON. THUNDERSTORM ACTIVITY WILL BE POSSIBLE IN THE COASTAL SECTIONS OF NC AND NEAR THE SC COAST AROUND MIDDAY AS SFC TEMPS WARM AND LARGE-SCALE ASCENT INCREASES AHEAD OF THE APPROACHING UPPER-LEVEL TROUGH. HOWEVER...THE BRUNT OF THE CONVECTIVE ACTIVITY SHOULD REMAIN WELL OFFSHORE. ELSEWHERE...A VIGOROUS SHORTWAVE TROUGH WILL MOVE ONSHORE IN THE PACIFIC NORTHWEST AS A 120 MID-LEVEL JET NOSES INTO THE REGION. VERY STRONG ASCENT COMBINED WITH COLD TEMPS ALOFT MAY BE ENOUGH FOR ISOLATED THUNDERSTORM ACTIVITY MAINLY ALONG THE IMMEDIATE COAST OF WA AND ORE. ..BROYLES.. 12/12/2006  From swody2 at goshenarc.org Tue Dec 12 17:19:31 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 12 Dec 2006 12:19:31 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 121720 SWODY2 SPC AC 121718 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1118 AM CST TUE DEC 12 2006 VALID 131200Z - 141200Z ...NO SVR TSTM AREAS FORECAST... MODELS INDICATE THAT A STRONG BELT OF WESTERLIES WILL PERSIST SOUTH OF BAJA INTO THE SOUTHEASTERN STATES DURING THIS FORECAST PERIOD. BUT...A STRONGER HIGH-LEVEL JET STREAK IS FORECAST TO CONTINUE TO DEVELOP EASTWARD OUT OF THE CENTRAL PACIFIC THROUGH MUCH OF THE NORTHERN TIER STATES. AS THIS OCCURS...THE CURRENT AMPLIFIED SOUTHERN BRANCH TROUGH IS PROGGED TO LOSE AMPLITUDE AND LIFT THROUGH THE GREAT LAKES/OHIO VALLEY BY WEDNESDAY MORNING...BEFORE CONTINUING ACROSS THE EASTERN CANADIAN PROVINCES BY 12Z THURSDAY. DRYING IN THE WAKE OF THIS FEATURE IS EXPECTED TO CONTRIBUTE TO LOW CONVECTIVE POTENTIAL ACROSS MUCH OF THE NATION. ...ATLANTIC COAST STATES... MOISTENING AHEAD OF WEAK FRONT/WIND SHIFT ASSOCIATED WITH THE SOUTHERN BRANCH TROUGH IS EXPECTED TO BE LIMITED...AND THE CORE OF COLD AIR ALOFT IS PROGGED TO LIFT TO THE NORTH/WEST OF ATLANTIC COASTAL AREAS. THIS SHOULD MINIMIZE THE RISK FOR THUNDERSTORMS OVER INLAND AREAS. THE PRIMARY CONVECTIVE DEVELOPMENT IS EXPECTED TO OCCUR OFFSHORE...NEAR THE GULF STREAM...LATE WEDNESDAY/WEDNESDAY NIGHT. ...PACIFIC NORTHWEST COAST... MODERATE TO STRONG MOIST LOW-LEVEL ONSHORE FLOW IS PROGGED TO THE WEST OF THE CASCADES THROUGH MUCH OF THE DAY...CONTRIBUTING TO SUFFICIENT DESTABILIZATION FOR SCATTERED CONVECTIVE DEVELOPMENT. HOWEVER...COLDER MID-LEVEL AIR MASS /AND MORE FAVORABLE EQUILIBRIUM TEMPERATURES FOR THUNDERSTORM ACTIVITY/ APPEARS LIKELY TO REMAIN CONFINED TO AREAS NORTH OF THE COLUMBIA RIVER...WHERE PRIMARY RISK SEEMS TO EXIST FOR OCCASIONAL/ISOLATED WEAK THUNDERSTORMS. ..KERR.. 12/12/2006  From swody2 at goshenarc.org Wed Dec 13 06:18:04 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 13 Dec 2006 01:18:04 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 130618 SWODY2 SPC AC 130617 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1217 AM CST WED DEC 13 2006 VALID 141200Z - 151200Z ...NO SVR TSTM AREAS FORECAST... A BROAD UPPER-LEVEL TROUGH OVER THE CNTRL AND ERN U.S. WILL AMPLIFY SOMEWHAT THURSDAY AS A MID-LEVEL JET DRIFTS ESEWD INTO THE NCNTRL STATES. AT THE SFC...A NEARLY STATIONARY FRONT WILL LIKELY BE LOCATED JUST OFF SHORE ALONG THE SRN ATLANTIC SEABOARD. MODEL FORECASTS DEVELOP CONVECTION ALONG AND NORTHWEST OF THE BOUNDARY ACROSS ERN GA AND ERN SC DURING THE DAY ON THURSDAY WITH CONVECTION EXPANDING NNEWD JUST OFF THE COAST OF THE CAROLINAS BY LATE AFTERNOON. THIS SCENARIO SEEMS REASONABLE DUE TO ADEQUATE LOW-LEVEL MOISTURE THAT SHOULD BE IN PLACE. HOWEVER...SHEAR SHOULD BE RELATIVELY WEAK AND NO SEVERE ACTIVITY IS EXPECTED. ELSEWHERE...A VIGOROUS UPPER-LEVEL TROUGH WILL AFFECT THE PACIFIC NORTHWEST AS AN IMPRESSIVE 120 KT MID-LEVEL JET PUNCHES INLAND THURSDAY. PRECIPITATION WILL INCREASE DURING THE DAY AND A FEW THUNDERSTORMS ARE POSSIBLE MAINLY NEAR THE COASTAL SECTIONS OF WA AND ORE DUE TO THE STRONG LARGE-SCALE ASCENT AND COLD MID-LEVEL TEMPS. ..BROYLES.. 12/13/2006  From swody2 at goshenarc.org Wed Dec 13 17:14:00 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 13 Dec 2006 12:14:00 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 131714 SWODY2 SPC AC 131713 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1113 AM CST WED DEC 13 2006 VALID 141200Z - 151200Z ...NO SVR TSTM AREAS FORECAST... A STRONG BELT OF WESTERLIES PERSISTS SOUTH OF BAJA THROUGH THE SOUTHEASTERN STATES. AND...A SHORT WAVE IMPULSE EMANATING FROM THIS STREAM CONTINUES TO DEAMPLIFY AS IT LIFTS INTO THE EASTERN CANADIAN PROVINCES. IN THE WAKE OF THIS FEATURE...LOW-LEVEL DRYING HAS OCCURRED ACROSS ALL BUT THE GULF OF MEXICO/FLORIDA PENINSULA AND SOUTH ATLANTIC COASTAL WATERS...WITH ANOTHER STRONG MID/UPPER JET STREAK NOSING OUT OF THE MID LATITUDE PACIFIC THROUGH THE NORTHERN TIER OF THE UNITED STATES. MODELS INDICATE SOME AMPLIFICATION OF SHORT WAVES EMBEDDED WITHIN THIS MORE NORTHERN STREAM WILL OCCUR LATER TODAY THROUGH THURSDAY...BUT THE IMPULSES ARE PROGGED TO REMAIN PROGRESSIVE...INCLUDING ONE ACROSS THE PACIFIC NORTHWEST COAST BY LATE THURSDAY NIGHT. MEANWHILE...A BROAD...BUT GENERALLY WEAK UPPER TROUGH IN THE SOUTHERN STREAM IS FORECAST TO GRADUALLY DEVELOP SOUTHEASTWARD ACROSS THE LOWER RIO GRANDE VALLEY/MEXICAN PLATEAU. ...FLORIDA... MODELS SUGGEST CURRENT LOWER-MID TROPOSPHERIC RIDGE OVER THE FLORIDA PENINSULA WILL WEAKEN LATER TODAY/TONIGHT. AND...IN THE SOUTHWESTERLY FLOW REGIME AHEAD OF LARGE-SCALE UPSTREAM TROUGH...A WEAK IMPULSE IS PROGGED TO MIGRATE ACROSS THE PENINSULA THURSDAY/ THURSDAY NIGHT. TIMING IS A BIT UNCERTAIN...BUT MOISTENING AND WEAKENING INHIBITION WITH THIS FEATURE SHOULD CONTRIBUTE TO AN INCREASINGLY FAVORABLE ENVIRONMENT FOR CONVECTION. DESTABILIZATION WILL PROBABLY NOT BECOME SUFFICIENT FOR PARTICULARLY VIGOROUS CONVECTION...BUT AT LEAST WIDELY SCATTERED THUNDERSTORMS APPEAR POSSIBLE DURING THE AFTERNOON AND EVENING HOURS. ...PACIFIC COAST... MODERATE TO STRONG MOIST LOW-LEVEL ONSHORE FLOW AND MID-LEVEL COOLING...IN WAKE OF SHORT WAVE TROUGH/ASSOCIATED COLD FRONT... WILL PROBABLY PROVE FAVORABLE FOR SCATTERED THUNDERSTORMS TO THE WEST OF THE CASCADES THURSDAY NIGHT. ..KERR.. 12/13/2006  From swody2 at goshenarc.org Thu Dec 14 06:28:22 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Thu, 14 Dec 2006 01:28:22 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 140629 SWODY2 SPC AC 140627 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1227 AM CST THU DEC 14 2006 VALID 151200Z - 161200Z ...NO SVR TSTM AREAS FORECAST... A LARGE BROAD UPPER-LEVEL TROUGH WILL MOVE EWD ACROSS THE OH AND TN VALLEYS INTO THE APPALACHIAN MTNS TONIGHT INTO FRIDAY. AT THE SFC...A NEARLY STATIONARY FRONT WILL LIKELY BE LOCATED IN NRN FL. SOUTH OF THE BOUNDARY ACROSS CNTRL AND SRN FL...LOW-LEVEL MOISTURE SHOULD BE SUFFICIENT FOR SFC-BASED THUNDERSTORM ACTIVITY FRIDAY MORNING AND AFTERNOON. CONSIDERING INSTABILITY SHOULD REMAIN WEAK ACROSS SRN FL...SHEAR PROFILES WILL LIKELY NOT BE STRONG ENOUGH FOR A SEVERE THREAT FRIDAY OR FRIDAY NIGHT ACROSS FL. ELSEWHERE...A VIGOROUS SHORT-WAVE TROUGH ASSOCIATED WITH A 100 KT MID-LEVEL JET WILL MOVE AWAY FROM THE PACIFIC NORTHWEST DURING THE DAY. A FEW THUNDERSTORMS WILL BE POSSIBLE IN THE COASTAL SECTIONS OF FAR NRN CA...ORE AND WA BEFORE LARGE-SCALE ASCENT DECREASES ALONG THE COAST FRIDAY AFTERNOON. ..BROYLES.. 12/14/2006  From swody2 at goshenarc.org Thu Dec 14 16:36:16 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Thu, 14 Dec 2006 11:36:16 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 141636 SWODY2 SPC AC 141636 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1036 AM CST THU DEC 14 2006 VALID 151200Z - 161200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... ACTIVE LARGE-SCALE PATTERN WILL CONTINUE THROUGH THE DAY TWO PERIOD AS STRONG HEIGHT FALLS DEVELOP ACROSS THE NRN PLAINS SWWD THROUGH THE GREAT BASIN IN ADVANCE OF INTENSIFYING LONG WAVE TROUGH. IN THE E...MOBILE UPPER TROUGH WILL TRANSLATE EWD FROM THE GREAT LAKES TO OFF THE NEW ENGLAND COAST BY SATURDAY MORNING. IN THE LOW-LEVELS...DEEP SURFACE LOW WILL DEVELOP EWD FROM SRN BRITISH COLUMBIA INTO ERN SASKATCHEWAN WITH TRAILING COLD FRONT PUSHING SWD THROUGH THE NRN INTERMOUNTAIN REGION AND GREAT BASIN. IN THE E...COLD FRONT WILL PUSH EWD THROUGH THE UPPER GREAT LAKES AND NEW ENGLAND. ...PACIFIC NW COAST... MOIST ONSHORE FLOW IN THE LOW-LEVELS COUPLED WITH COLD MID-LEVEL TEMPERATURES /-32 TO -36 C AT 500 MB/ WILL RESULT IN THE DEVELOPMENT OF STEEP LAPSE RATES AND WEAK CONVECTIVE INSTABILITY. POTENTIAL WILL EXIST FOR TSTMS EMBEDDED IN LARGER PRECIPITATION SHIELD...PARTICULARLY FRIDAY INTO FRIDAY EVENING. ...NRN INTERMOUNTAIN REGION... HERE TOO...ENVIRONMENT WILL BE CHARACTERIZED BY STEEP LAPSE RATES OWING LARGELY TO EWD EXTENSION OF AFOREMENTIONED MID-LEVEL COLD POOL. A FEW TSTMS WILL BE POSSIBLE ALONG SURFACE COLD FRONT AS DEEPER LAYER FORCING FOR ASCENT IS AUGMENTED BY TRAILING PORTION OF SHORT WAVE MOVING THROUGH MT. ...CNTRL/SRN FL PENINSULA... A MOIST AND UNSTABLE AIR MASS WILL PERSIST AHEAD OF WEAK LOW-LEVEL BOUNDARY PUSHING SWD THROUGH THE REGION. CONVERGENCE ALONG THIS FRONT COUPLED WITH LITTLE OR NO CONVECTIVE INHIBITION SHOULD RESULT IN AN INCREASE IN TSTM DEVELOPMENT FRIDAY MORNING AND AFTERNOON. ...NY... FORCING FOR ASCENT ASSOCIATED WITH MIGRATORY SHORT WAVE TROUGH AND RELATIVELY STEEP LAPSE RATES MAY CONTRIBUTE TO THE DEVELOPMENT OF SOME DEEPER CONVECTION AND A FEW LIGHTNING STRIKES ALONG SURFACE FRONT FRIDAY AFTERNOON. THIS ACTIVITY IS EXPECTED TO REMAIN TOO ISOLATED FOR INCLUSION OF AN ADDITIONAL THUNDER AREA. ..MEAD.. 12/14/2006  From swody2 at goshenarc.org Fri Dec 15 16:31:52 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Fri, 15 Dec 2006 11:31:52 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 151632 SWODY2 SPC AC 151631 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1031 AM CST FRI DEC 15 2006 VALID 161200Z - 171200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... INTENSIFICATION OF WRN CONUS TROUGH IS FORECAST DURING THE DAY TWO PERIOD WITH STRONG HEIGHT FALLS DEVELOPING THROUGH THE LOWER CO VALLEY...FOUR CORNERS REGION INTO CNTRL ROCKIES. IN THE LOW-LEVELS...SURFACE COLD FRONT WILL PUSH SEWD THROUGH THE UPPER MS VALLEY AND UPPER GREAT LAKES WITH THIS BOUNDARY EXTENDING SWWD TO DEEPENING LOW PRESSURE OVER CO. COLD FRONT WILL THEN TRAIL SWWD FROM THIS LOW INTO THE LOWER CO VALLEY AND EVENTUALLY INTO SRN ROCKIES. ...S FL AND THE KEYS... A MOIST AND WEAKLY UNSTABLE AIR MASS IS EXPECTED TO PERSIST INVOF STALLED FRONTAL BOUNDARY. WEAK CAPPING COUPLED WITH PERSISTENT LOW-LEVEL CONVERGENCE AND APPROACH OF SRN STREAM IMPULSE /NOW OVER THE NWRN GULF OF MEXICO/ SHOULD ALL CONTRIBUTE TO ISOLATED/SCATTERED TSTM DEVELOPMENT. WEAK LAPSE RATES AND SHEAR WILL PRECLUDE ANY SEVERE THREAT. OTHER MORE ISOLATED TSTM ACTIVITY WILL BE POSSIBLE FROM ERN PORTIONS OF THE GREAT BASIN THROUGH THE FOUR CORNERS REGION INTO CNTRL CO INVOF SURFACE FRONT AS STRONGER HEIGHT FALLS SPREAD EWD. MODEST LAPSE RATES WILL EXIST THOUGH RELATIVELY DRY AIR MASS WILL LIMIT DESTABILIZATION. THIS THREAT SHOULD REMAIN QUITE ISOLATED AND NO GENERAL THUNDER AREA WILL BE INCLUDED ATTM. ..MEAD.. 12/15/2006  From swody2 at goshenarc.org Sat Dec 16 05:42:44 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 16 Dec 2006 00:42:44 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 160543 SWODY2 SPC AC 160541 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1141 PM CST FRI DEC 15 2006 VALID 171200Z - 181200Z ...NO TSTM AREAS FORECAST... ...SYNOPSIS... STRONG MID-UPPER LEVEL SHORTWAVE TROUGH IS EVIDENT IN MOISTURE CHANNEL IMAGERY INVOF 130W...OFFSHORE PACIFIC NW. AS THIS FEATURE MOVES INLAND WRN CONUS...HIGH-AMPLITUDE AND POSITIVELY TILTED TROUGH IS FCST TO EVOLVE. THIS WILL YIELD LONG FETCH OF SW FLOW ALOFT FROM BAJA CA TO GREAT LAKES DAY-2. MEANWHILE...AT SFC...CYCLOGENESIS ALREADY UNDERWAY IN CENTRAL ROCKIES WILL CONTINUE WITH APCH OF UPPER TROUGH. FRONTAL ZONE -- ASSOCIATED WITH NRN STREAM SHORTWAVE NOW OVER SASK -- IS FCST TO MOVE SLOWLY SWD ACROSS PLAINS STATES AND MS VALLEY THROUGH EARLY DAY-2. FRONT THEN SHOULD ACCELERATE SWD OVER CENTRAL/SRN HIGH PLAINS IN RESPONSE TO WEAK FRONTAL-WAVE CYCLONE MOVING NEWD FROM SERN NEB/NERN KS REGION TOWARD GREAT LAKES. MEANWHILE RESIDUAL/QUASISTATIONARY FRONTAL ZONE WILL LINGER ACROSS ERN GULF...FL STRAITS AND BAHAMAS. ...FL KEYS... LOW LEVEL BAROCLINIC ZONE MAY CONTRIBUTE TO CONVECTION OVER FL STRAITS AND PERHAPS KEYS...WITH SOME BUOYANCY REACHING ICING LEVELS BASED ON MODEL FCST SOUNDINGS. HOWEVER...WEAK LAPSE RATES AND LACK OF MORE ROBUST CONVERGENCE INVOF FRONT SHOULD LIMIT CONVECTIVE COVERAGE...AND SHOULD KEEP MOST ACTIVITY S OF KEYS. ALTHOUGH VERY BRIEF/ISOLATED TSTMS CANNOT BE RULED OUT...POTENTIAL APPEARS TOO CONDITIONAL/MRGL FOR GEN THUNDER OUTLOOK ATTM. ...SRN PLAINS TO MO... PREFRONTAL LOW LEVEL WAA REGIME WILL BE WELL UNDERWAY THROUGH PERIOD...ALONG WITH RETURN FLOW OF PARTIALLY MODIFIED AIR MASS THAT WILL HAVE FOLLOWED LONG ANTICYCLONIC TRAJECTORIES OVER PORTIONS GULF OF MEXICO. RELATED MOISTENING MAY CONTRIBUTE TO DEVELOPMENT OF PRECIP AND SHOWERS INVOF LOW LEVEL FRONTAL ZONE LATE IN PERIOD...FROM FROM OK NEWD ACROSS IL. WITH FLOW ALOFT NEARLY PARALLEL TO FRONT AND APPARENT ABSENCE OF SIGNIFICANT MID-UPPER LEVEL ASCENT...LAPSE RATES ALOFT SHOULD REMAIN WEAK. MODEL FCST SOUNDINGS INDICATE SOME BUOYANCY IS POSSIBLE BUT MAINLY IN THERMAL LAYERS SUITABLE FOR WARM-CLOUD PRECIP PRODUCTION. TSTM PROBABILITY IS NONZERO BUT VERY WEAK...AND NOT JUSTIFYING GEN FCST ATTM. ..EDWARDS.. 12/16/2006  From swody2 at goshenarc.org Sat Dec 16 17:03:30 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 16 Dec 2006 12:03:30 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 161704 SWODY2 SPC AC 161702 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1102 AM CST SAT DEC 16 2006 VALID 171200Z - 181200Z ...NO TSTM AREAS FORECAST... ..SYNOPSIS... ACTIVE WAVE TRAIN OF POLAR WESTERLIES WILL EXIST FROM THE GULF OF AK EWD ACROSS CANADA TO THE MARITIMES WHILE LOWER LATITUDE TROUGH BECOMES PROGRESSIVELY MORE CUT OFF OVER THE GREAT BASIN INTO LOWER CO VALLEY. IN THE LOW-LEVELS...PRIMARY BAROCLINIC ZONE WILL EXIST FROM THE GREAT LAKES SWWD INTO THE SRN HIGH PLAINS WITH LOW PRESSURE DEVELOPING SEWD FROM CNTRL CO INTO NERN NM. ...S FL AND THE KEYS... RESIDUAL LOW-LEVEL BOUNDARY WILL PERSIST ALONG THE FL STRAITS INTO CUBA WITH CONVECTION FOCUSED NEAR AND N OF THIS FEATURE. IT APPEARS THAT THE GREATER TSTM COVERAGE WILL REMAIN CONFINED TO S OF THE FORECAST DOMAIN WITH ONLY ISOLATED LIGHTNING STRIKES POSSIBLE FURTHER N INTO THE KEYS AND FAR S FL. ...SRN PLAINS INTO OH VALLEY... LOW-LEVEL WAA REGIME WILL GRADUALLY DEVELOP NEWD ACROSS THE REGION THROUGH THE PERIOD IN ASSOCIATION WITH MIGRATORY LLJ MAXIMUM. THIS WILL SUPPORT THE NEWD ADVECTION OF AN INCREASINGLY MOIST LOW-LEVEL AIR MASS THOUGH POOR MID-LEVEL LAPSE RATES WILL LIMIT INSTABILITY. LATEST SHORT RANGE MODEL GUIDANCE INDICATES THE DEVELOPMENT OF SCATTERED CONVECTION SUNDAY NIGHT FROM OK INTO IL...HOWEVER FORECAST SOUNDINGS SUGGEST THAT THIS ACTIVITY SHOULD REMAIN RELATIVELY SHALLOW AND NOT SUPPORTIVE OF CHARGE SEPARATION. ...CO... A FEW LIGHTNING STRIKES WILL ALSO BE POSSIBLE SUNDAY OVER PORTIONS OF WRN/CNTRL CO AS HEIGHT FALLS/DYNAMIC COOLING RESULT IN THE DEVELOPMENT OF STEEP MID-LEVEL LAPSE RATES AND RESULTANT WEAK CONDITIONAL INSTABILITY. THIS THREAT IS EXPECTED TO REMAIN QUITE ISOLATED AND NO THUNDER AREA WILL BE INCLUDED. ..MEAD.. 12/16/2006  From swody2 at goshenarc.org Sun Dec 17 05:37:07 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 17 Dec 2006 00:37:07 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 170536 SWODY2 SPC AC 170535 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1135 PM CST SAT DEC 16 2006 VALID 181200Z - 191200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... SOME OF MID-UPPER LEVEL LOW -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY OVER CENTRAL/NRN CA -- IS FCST TO EJECT NEWD ACROSS NRN GREAT BASIN AND CENTRAL ROCKIES REGION THROUGH DAY 2. MEANWHILE...SPEED MAX WILL DIG SEWD AROUND SWRN SIDE OF ASSOCIATED HIGH-AMPLITUDE TROUGH...WITH REDEVELOPMENT OF MID-UPPER CYCLONE EXPECTED ACROSS SERN CA/NRN BAJA REGION. RESULTANT VORTEX SHOULD DEEPEN THERE BETWEEN 19/00Z-19/12Z...WHILE SHORTWAVE RIDGE BUILDS TO ITS NE...FROM NE TX TO ERN CO. OPERATIONAL WRF/SPECTRAL MODELS...AS WELL AS THEIR VARIOUS SREF MEMBERS...SHOW STRONG CONSENSUS ON PLACEMENT THIS FEATURE BY END OF PERIOD. MEANWHILE...NRN STREAM SHORTWAVE TROUGH -- NOW APPARENT OVER CENTRAL/NRN BC -- SHOULD AMPLIFY STEADILY AS IT MOVES ESEWD ACROSS NRN PLAINS AND UPPER GREAT LAKES DAY-2. EXPECT ASSOCIATED BAROCLINIC REINFORCEMENT OF FRONTAL ZONE -- NOW ANALYZED FROM LAKE MI SWWD ACROSS CENTRAL OK TO SRN TX PANHANDLE. FRONT THEN SHOULD MOVE SWD ACROSS PORTIONS WRN/CENTRAL TX...AND WWD INTO MOUNTAINS OF CENTRAL/SRN NM. ...S-CENTRAL/SWRN CONUS... MRGL GEN THUNDER POTENTIAL WILL DEVELOP OVER A BROAD AREA BY 19/12Z. PERSISTENT...ELEVATED...LOW LEVEL WAA AND MOIST ADVECTION ARE FCST ALONG AND N OF SFC FRONTAL ZONE...RESULTING IN LONG DURATION OF FAVORABLE ISENTROPIC ASCENT ACROSS MUCH OF SRN PLAINS INTO ERN NM. THIS REGIME ALSO WILL EXTEND ACROSS PORTIONS WRN NM AND CENTRAL/NRN AZ BENEATH NERN QUADRANT OF MID-UPPER LEVEL LOW...IN PROGRESSIVELY MORE NARROW BELT WITH WWD EXTENT. THIS SHOULD RESULT IN EXPANSIVE AREA OF PRECIP BY END OF PERIOD FROM LOWER CO RIVER VALLEY REGION EWD TO PORTIONS N-CENTRAL/NW TX. EPISODIC/EMBEDDED TSTMS ARE POSSIBLE. THETAE ADVECTION AND WEAK CINH WILL HELP TO OVERCOME SMALL MIDLEVEL LAPSE RATES...AMIDST MUCAPES GENERALLY UNDER 500 J/KG. POTENTIAL FOR THUNDER MAY EXTEND BENEATH COLD-CORE REGION OF QUASISTATIONARY VORTEX...WITH SHALLOW TSTMS PRODUCING SMALL HAIL. ORGANIZED SVR POTENTIAL APPEARS TOO CONDITIONAL/MRGL ATTM TO ASSIGN UNCONDITIONAL PROBABILITIES. ..EDWARDS.. 12/17/2006  From swody2 at goshenarc.org Sun Dec 17 16:41:38 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 17 Dec 2006 11:41:38 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 171642 SWODY2 SPC AC 171641 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1041 AM CST SUN DEC 17 2006 VALID 181200Z - 191200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... WAVE TRAIN OF POLAR WESTERLIES WILL EXIST FROM THE GULF OF AK EWD ACROSS CANADA WHILE LOWER LATITUDE TROUGH BECOMES PROGRESSIVELY CUT OFF OVER THE LOWER CO VALLEY. IN THE LOW-LEVELS...PASSAGE OF NRN BRANCH SHORT WAVE TROUGH THROUGH CNTRL CANADA WILL SERVE TO STRENGTHEN SURFACE HIGH OVER THE NRN/CNTRL PLAINS INTO UPPER GREAT LAKES. AS THIS OCCURS...COLD FRONT WILL CONTINUE TO PUSH SWD THROUGH THE MIDDLE INTO LOWER MS VALLEY WWD THROUGH THE SRN PLAINS TO DEVELOPING LOW PRESSURE ALONG THE AZ/NM BORDER. ...SWRN DESERTS INTO THE SRN PLAINS... RATHER COLD MID-LEVEL TEMPERATURES OF -26 TO -28 C AT 500 MB ASSOCIATED WITH EVOLVING UPPER LOW ARE EXPECTED TO LARGELY CONTRIBUTE TO STEEPENING LAPSE RATES INVOF DEVELOPING SURFACE LOW AND TROUGH. INCREASED DEEP-LAYER FORCING FOR ASCENT COUPLED WITH THE RESULTING MARGINAL INSTABILITY SHOULD SUPPORT AN INCREASE IN SHOWER AND ISOLATED/SCATTERED TSTM DEVELOPMENT MONDAY ACROSS PORTIONS OF AZ/NM. FARTHER TO THE E OVER TX...12Z RAOBS AND SURFACE OBSERVATIONS INDICATE LOW-LEVEL MOISTURE INCREASING BELOW QUITE POOR MID-LEVEL LAPSE RATES. HEIGHT FALLS DOWNSTREAM FROM SWRN U.S. UPPER LOW SHOULD CONTRIBUTE TO SOME MID-LEVEL COOLING/STEEPENING LAPSE RATES OVER THE SRN HIGH PLAINS DURING THE PERIOD WITH POCKETS OF WEAK...ELEVATED INSTABILITY DEVELOPING. INCREASING ISENTROPIC ASCENT OWING TO STRENGTHENING SELY LLJ NEAR AND N OF SURFACE COLD FRONT SHOULD SUPPORT AN INCREASE IN SHOWER AND TSTM DEVELOPMENT MAINLY MONDAY NIGHT FROM PORTIONS OF SERN/E-CNTRL NM EWD INTO THE RED RIVER VALLEY. ..MEAD.. 12/17/2006  From swody2 at goshenarc.org Mon Dec 18 05:52:58 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 18 Dec 2006 00:52:58 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 180553 SWODY2 SPC AC 180552 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1152 PM CST SUN DEC 17 2006 VALID 191200Z - 201200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... IN MID-UPPER LEVELS...HIGHLY AMPLIFIED AND POSITIVELY TILTED TROUGH IS EVIDENT IN MOISTURE CHANNEL IMAGERY FROM WY SWWD ACROSS SRN CA AND OVER PACIFIC WATERS WELL OFFSHORE NRN BAJA. AS OFFSHORE SPEED MAX DIGS INTO BASE OF TROUGH...THROUGH DAY-1...CLOSED AND TEMPORARILY CUT-OFF LOW WILL DEVELOP INVOF CA/MEX BORDER. LAST SEVERAL RUNS OF MOST OPERATIONAL MODELS AND SREF MEMBERS HAVE BEEN CONSISTENT IN EJECTING THIS FEATURE NEWD ACROSS 4-CORNERS REGION DURING WHAT IS NOW DAY-2 PERIOD...AND CONFIDENCE IN THIS SCENARIO IS INCREASING WITH TIME. AT SFC...COLD FRONT NOW ANALYZED FROM ERN IL SWWD ACROSS SERN OK...NWRN TX AND SERN NM...IS FCST TO MOVE SWD INTO S-CENTRAL AND SW TX THROUGH DAY-2. AMIDST INCREASING LOW LEVEL PRESSURE/HEIGHT FALLS AND KINEMATIC RESPONSE...ASSOCIATED WITH EJECTING SWRN LOW -- WRN PORTION OF FRONT MAY STALL AND RETREAT SLIGHTLY NWD ACROSS BIG BEND AND TRANS-PECOS REGIONS OF W TX. DURING LATTER HALF OF PERIOD...STRONG LOW LEVEL FRONTOGENESIS IS FCST OVER NM...WITH RESULTING COLD FRONT SWEEPING EWD OVER MUCH OF SRN HIGH PLAINS BY 20/12Z. ...S-CENTRAL/SWRN CONUS TO CENTRAL HIGH PLAINS... WIDELY SCATTERED TSTMS MAY BE ONGOING AT BEGINNING OF PERIOD OVER PORTIONS W TX AND NM...AMIDST STRONG LOW LEVEL WAA REGIME AND MOISTENING AIR MASS ABOVE SFC. THIS REGIME WILL CONTINUE THROUGH MUCH OF DAYLIGHT AND EVENING HOURS...SHIFTING/SPREADING NWD AND EWD AS AIR MASS CONTINUES TO MOISTEN. LIMITED BUOYANCY ALOFT AND RELATIVELY STABLE AIR NEAR SFC SHOULD PRECLUDE ORGANIZED SVR POTENTIAL DESPITE STRENGTHENING DEEP-LAYER SHEAR. BRIEF VERTICAL JUXTAPOSITION OF SFC-BASED WARM SECTOR WITH FAVORABLE VERTICAL SHEAR MAY OCCUR OVER PORTIONS SRN HILL COUNTRY AND LOWER-MIDDLE RIO GRANDE VALLEY REGION OF S TX. HOWEVER...LIKELY NEGATIVE FACTORS FOR SVR INCLUDE WEAK LOW LEVEL FORCING...AND UNFAVORABLE MIDLEVEL LAPSE RATES THAT MAY DRASTICALLY LIMIT BUOYANCY. CONVECTIVE COVERAGE SHOULD INCREASE AFTER DARK ACROSS W TX -- MAINLY ATOP RELATIVELY STABLE BOUNDARY LAYER AND IN ZONE OF STRONGEST LOW LEVEL FRONTOGENETIC FORCING. THIS ACTIVITY MAY DEVELOP/BUILD EWD AND NWD OVER PORTIONS WRN OK AND CENTRAL HIGH PLAINS BY END OF PERIOD. SOME TSTMS OVER CENTRAL/SRN HIGH PLAINS MAY YIELD WINTER PRECIP WHERE LOW LEVEL THERMAL STRATIFICATIONS ARE SUITABLE BENEATH ELEVATED BUOYANT LAYER. ...4-CORNERS REGION... ISOLATED TO WIDELY SCATTERED THUNDER IS POSSIBLE IN ZONE OF MOST INTENSE LARGE SCALE ASCENT/COOLING...BENEATH AND IMMEDIATELY AHEAD OF MID/UPPER LEVEL CYCLONE. ALTHOUGH LOW LEVEL THETAE WILL BE VERY LIMITED...LOW-MIDLEVEL LAPSE RATES MAY BECOME STEEP ENOUGH TO COMBINE WITH MRGL MOISTURE IN SUPPORT OF SHALLOW TSTMS -- SOME OF WHICH MAY BE ACCOMPANIED BY GRAUPEL AND SNOW. ..EDWARDS.. 12/18/2006  From swody2 at goshenarc.org Mon Dec 18 16:48:42 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 18 Dec 2006 11:48:42 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 181649 SWODY2 SPC AC 181647 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1047 AM CST MON DEC 18 2006 VALID 191200Z - 201200Z ...NO SVR TSTM AREAS FORECAST... ALTHOUGH OBVIOUS KICKER NOT PRESENT...MODELS NOW IN GOOD AGREEMENT THAT UPPER LOW OVER SRN CA WILL TRACK ENEWD ACROSS AZ INTO NRN NM/SRN CO BY 12Z WED. AHEAD OF THIS SYSTEM LARGE SCALE ASCENT AND INFLUX OF MOISTURE FROM WRN GULF WILL PRODUCE AN EXPANDING AREA OF PRECIPITATION FROM NM EWD INTO SRN HIGH PLAINS ON TUESDAY. WHILE INSTABILITY AND LAPSE RATES WILL BE LACKING FOR SEVERE THUNDERSTORMS...ELEVATED CONVECTION EXPECTED TO BECOME MORE WIDESPREAD PARTICULARLY LATER HALF OF THE PERIOD AS MID LEVEL COOLING AND STRONGER SHEAR OVERSPREAD THE SHALLOW BOUNDARY LAYER COLD DOME. IN ADDITION STEEPER LAPSE RATES JUST AHEAD OF COLD UPPER LOW SHOULD RESULT IN SHALLOW CONVECTION DURING THE DAY FROM NERN AZ EWD INTO NRN NM BY EVENING. ..HALES.. 12/18/2006  From swody2 at goshenarc.org Tue Dec 19 06:04:56 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 19 Dec 2006 01:04:56 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 190605 SWODY2 SPC AC 190604 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1204 AM CST TUE DEC 19 2006 VALID 201200Z - 211200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... MOST IMPORTANT MID-UPPER LEVEL FEATURE FOR THIS FCST WILL BE PRONOUNCED CYCLONE -- NOW PRESENT OVER SRN CA AND NRN BAJA. PROGS CONTINUE TO BECOME MORE TIGHTLY CLUSTERED IN STRONG CONSENSUS REGARDING TRACK...EJECTION AND GEOMETRY OF THIS FEATURE DURING NEXT FEW DAYS. THIS LOW SHOULD MOVE ACROSS SRN ROCKIES EARLY IN PERIOD...REACHING CENTRAL HIGH PLAINS BY 21/00Z...THEN TEMPORARILY DECELERATING OVER WRN KS/WRN NEB REGION AS SFC CYCLONE BECOME BETTER COLLOCATED WITH MID/UPPER VORTEX CENTER. ASSOCIATED SFC COLD FRONT IS FCST TO MOVE SEWD ACROSS CENTRAL/SRN TX ...REACHING COASTAL PLAIN AROUND 21/00Z-21/06Z...THEN WEAKENING THEREAFTER. POSITIVELY TILTED SHORTWAVE TROUGH IN SUBTROPICAL STREAM -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY OVER ERN PACIFIC SW OF BAJA -- IS FCST TO LIFT ENEWD ACROSS N-CENTRAL/NERN MEX EARLY IN PERIOD...THEN ACROSS TX COAST AND SRN LA BY 21/00Z. ONLY MINOR TIMING/AMPLITUDE DIFFERENCES EXIST WITH ASSOCIATED VORTICITY PATTERN AMONGST SPECTRAL...NGM...AND OPERATIONAL WRF. ...S-CENTRAL/SE TX... AT LEAST MRGL/CONDITIONAL SVR POTENTIAL MAY DEVELOP...BOUNDED ON W BY COLD FRONT...ON N BY PROGRESSIVELY MORE STABLE BOUNDARY LAYER...AND BY WEAKENING SHEAR WITH SWD EXTENT OVER DEEP S TX AND GULF. CONTINUING ELY SFC TRAJECTORIES OVER MUCH OF SRN PLAINS...EMANATING FROM STRONG MIDWESTERN/OH VALLEY ANTICYCLONE...WILL MAINTAIN RELATIVELY LOW THETAE AIR MASS AND KEEP OPTIMALLY HIGH THETAE AIR FROM PENETRATING VERY FAR INLAND. EXCEPTION MAY BE OVER S-CENTRAL/SE TX WHERE ISALLOBARICALLY FORCED BOUNDARY LAYER VEERING...TO MORE SLY/SELY DIRECTION...ALLOWS NARROW WEDGE OF MARINE AIR TO MOVE INLAND PRIOR TO COLD FROPA...CHARACTERIZED BY MID 60S TO NEAR 70 F DEW POINTS. RICH MOISTURE AND SUBTLE LARGE SCALE ASCENT ASSOCIATED WITH SRN STREAM TROUGH EACH MAY OFFSET VERY SMALL MIDLEVEL LAPSE RATES AND ALLOW ENOUGH BUOYANCY TO SUPPORT SFC-BASED TSTMS WITH AT LEAST MRGL/CONDITIONAL SVR POTENTIAL. DEEP-LAYER VERTICAL SHEAR IS FCST TO STRENGTHEN WITH TIME THROUGH 21/00Z AS SERN EDGE OF TIGHTENING MIDLEVEL HEIGHT GRADIENT SUPERIMPOSES ITSELF ATOP NRN PORTION OF MARINE AIR. FCST SOUNDINGS INDICATE ENLARGED LOW LEVEL HODOGRAPH AND 40-50 KT OF 0-6 KM SHEAR. ..EDWARDS.. 12/19/2006  From swody2 at goshenarc.org Tue Dec 19 17:24:55 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 19 Dec 2006 12:24:55 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 191725 SWODY2 SPC AC 191724 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1124 AM CST TUE DEC 19 2006 VALID 201200Z - 211200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... MODELS REMAIN CONSISTENT WITH LARGE/DEEP UPPER LOW TRACKING NEWD FROM THE SRN ROCKIES INTO THE CENTRAL HIGH PLAINS REGION DURING DAY 2. ALTHOUGH MODELS DIFFER SLIGHTLY WITH THE TIMING OF A POSITIVELY-TILTED SRN STREAM IMPULSE...THIS FEATURE SHOULD TRACK NEWD ACROSS THE TX COASTAL PLAIN AND LA DURING THE FIRST HALF OF THE PERIOD. SURFACE COLD FRONT IS EXPECTED TO SPREAD ESEWD THROUGH SRN/ ERN TX...REACHING DEEP S TX...TX COASTAL PLAIN TO WRN LA DURING 21/00-06Z. SURFACE BOUNDARY...CURRENTLY EXTENDING EWD FROM DEEP S TX INTO THE GULF OF MEXICO...IS EXPECTED TO MOVE NWD ON DAY 2 REACHING THE UPPER TX COAST REGION BY 21/00Z...AND THEN MAY SPREAD JUST INLAND OVER SW LA WEDNESDAY NIGHT. ...S-CENTRAL/SE TX TO SW LA... FORCING FOR ASCENT ASSOCIATED WITH THE LEAD SRN STREAM IMPULSE SHOULD BE EXITING MUCH OF THE TX COASTAL PLAIN WEDNESDAY MORNING... WITH RESULTANT TEMPORARY DECELERATION OF SWLY MID LEVEL FLOW. HOWEVER...HEIGHT GRADIENT SHOULD TIGHTEN SOME ALONG SERN PERIPHERY OF UPPER LOW AS NEXT MID/UPPER LEVEL JET MAX TRANSLATES THROUGH THIS PORTION OF UPPER SYSTEM...WEDNESDAY AFTERNOON TO WEDNESDAY NIGHT. DESPITE SURFACE DEWPOINTS IN THE MID 60S IN ADVANCE OF THE COLD FRONT...WEAK LAPSE RATES AND LIMITED SURFACE HEATING ARE EXPECTED TO RESULT IN MARGINAL INSTABILITY WITHIN WARM SECTOR AIR MASS. ALTHOUGH ASCENT IS EXPECTED TO BE WEAK FROM DEEP S TX TO SW LA...AS STRONGER HEIGHT FALLS OCCUR FARTHER N AHEAD OF THE UPPER LOW... FRONTAL ASCENT SHOULD BE SUFFICIENT FOR SURFACE BASED TSTM DEVELOPMENT. WEAK INSTABILITY COMBINED WITH INCREASING DEEP LAYER SHEAR SUGGESTS AT LEAST A MARGINAL/CONDITIONAL SEVERE POTENTIAL. SOME CONCERN FOR AN ISOLATED TORNADO THREAT MAY EXIST AT THE INTERSECTION OF THE ADVANCING COLD FRONT AND NWD MOVING SURFACE BOUNDARY WHERE FORECAST SOUNDINGS INDICATE LARGE LOW LEVEL HODOGRAPHS. THIS THREAT WOULD BE FROM PARTS OF THE MIDDLE TO UPPER TX COAST WEDNESDAY AFTERNOON AND INTO SW LA WEDNESDAY NIGHT. HOWEVER...THIS OUTLOOK WILL MAINTAIN LOW PROBABILITIES FOR SEVERE GIVEN WEAK INSTABILITY AND WEAK UPPER FORCING. ..PETERS.. 12/19/2006  From swody2 at goshenarc.org Wed Dec 20 05:54:14 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 20 Dec 2006 00:54:14 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 200554 SWODY2 SPC AC 200554 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1154 PM CST TUE DEC 19 2006 VALID 211200Z - 221200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... STRONG MID/UPPER LEVEL CYCLONE -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY OVER SRN AZ/WRN NM -- IS FCST TO LIFT NEWD ACROSS SRN HIGH PLAINS AND PIVOT OVER KS THROUGH PERIOD. MOST SREF MEMBERS AND OPERATIONAL MODELS INDICATE CYCLONE TRACK SOMEWHAT S OF PREVIOUS PROGS ACROSS KS...BEFORE DEEP-LAYER CYCLONE BECOMES MORE VERTICALLY STACKED AROUND 22/12Z. MOST PROGS DO DIFFER IN SPEED OF SYSTEM ALONG ESSENTIALLY SAME TRACK AFTER 22/00Z...WITH OPERATIONAL SPECTRAL AND SREF/RSM MEMBERS PLACING LOW IN IA...MOST ETA/ETA-KF MEMBERS OVER NE/MO BORDER REGION...AND WRF BACK IN NERN KS. THIS MAY BE RELATED TO HOW THESE MODELS HANDLE CYCLOIDAL MOTION OF MIDLEVEL VORTEX S OF UPPER LOW...AS ASSOCIATED VORTICITY MAXIMA PIVOT AROUND SRN/ERN SEMICIRCLES OF BROADER CIRCULATION. CONSENSUS FAVORS ETA/ETA-KF TRACK. THESE SPEED/TIMING DIFFERENCES TRANSLATE TO SFC...WHERE SPECTRAL RUNS FCST COLD FRONT ACROSS NWRN MS AND LA...WELL AHEAD OF MOST OTHERS. GIVEN LACK OF SUBSTANTIAL MID-UPPER SUPPORT FOR ERN SURGE OF LOW LEVEL FRONT...WILL TREND FCST TOWARD SLOWER WRF/ETA BASED FCST AT SFC. ...W GULF COASTAL PLAIN...MS DELTA REGION... CONDITIONAL SVR PROBABILITY EXISTS -- MAINLY IN FORM OF AT LEAST MRGL TORNADO THREAT AND PERHAPS DAMAGING WIND. ONCE MESOSCALE UNCERTAINTIES ARE BETTER RESOLVED...UNCONDITIONAL PROBABILITIES MAY BE RAISED ENOUGH TO WARRANT CATEGORICAL OUTLOOK. AHEAD OF SFC COLD FRONT...EXPECT DEEPLY MOIST PROFILES AND ASSOCIATED WEAK LAPSE RATES...BUT FAVORABLE KINEMATIC PROFILES. IF SUSTAINED/SFC-BASED TSTMS CAN FORM...VERTICAL SHEAR WILL BE FAVORABLE FOR SUPERCELLS AND SMALL BOWS. FCST SOUNDINGS SUGGEST CONSIDERABLE VEERING WITH HEIGHT AND AROUND 40-50 KT SHEAR IN 0-6 KM LAYER. CURRENT SFC ANALYSIS...FCST TRAJECTORIES AND MODIFIED WRF SOUNDINGS INDICATE MID 60S TO NEAR 70 F SFC DEW POINTS WILL PENETRATE INLAND EXTREME SE TX AND SRN LA...PERHAPS AS FAR N AS I-20 BY END OF PERIOD. BOUNDARY LAYER FORCING INVOF FRONT IS FCST TO DIMINISH WITH TIME AS STRONGEST PRESSURE FALLS MOVE AWAY FROM AREA...HOWEVER SBCINH SHOULD BE WEAK IN MARINE AIR MASS. THIS WILL LEAVE DEVELOPMENT STRONGLY DEPENDENT ON MESOSCALE FOCI SUCH AS OUTFLOWS...FRONTAL/PREFRONTAL CONFLUENCE LINES AND/OR DIURNAL/DIFFERENTIAL HEATING BOUNDARIES. BREAKS IN PRECIP/CLOUD COVER AND ASSOCIATED INSOLATION MAY ENHANCE BUOYANCY DURING DAYLIGHT HOURS...OTHERWISE MLCAPES SHOULD REMAIN GENERALLY AOB 500 J/KG. ..EDWARDS.. 12/20/2006  From swody2 at goshenarc.org Wed Dec 20 17:22:04 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 20 Dec 2006 12:22:04 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 201722 SWODY2 SPC AC 201721 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1121 AM CST WED DEC 20 2006 VALID 211200Z - 221200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... 12Z GFS/NAM HAVE COME INTO BETTER AGREEMENT WITH THE TEMPORAL RESOLUTION OF THE UPPER LOW AS IT TRACKS FROM SW KS AND TX PANHANDLE REGION NEWD TO THE EAST CENTRAL PLAINS/MID-LOWER MO VALLEY BY 22/12Z. THIS TRANSLATES TO THE SURFACE WITH MORE CONSISTENCY IN THE SPEED OF THE COLD FRONT AS IT SHOULD SPREAD SLOWLY EWD ACROSS THE MID AND LOWER MS VALLEY. ...LOWER MS VALLEY... DESPITE MOISTURE SPREADING NWD AHEAD OF THE COLD FRONT WITH SURFACE DEWPOINTS IN THE MID 60S REACHING PARTS OF NERN LA AND CENTRAL MS... EXTENSIVE CLOUDINESS SHOULD CONTINUE TO LIMIT THE POTENTIAL FOR SURFACE HEATING...AND THE DEVELOPMENT OF STRONGER INSTABILITY. THIS COMBINED WITH GENERALLY WEAK LAPSE RATES IS EXPECTED TO RESULT IN MARGINAL INSTABILITY. UPPER FORCING SHOULD REMAIN WEAK ACROSS THE LOWER MS VALLEY ON DAY 2...GIVEN SMALL HEIGHT FALLS LOCATED TO THE S OF THE TRACK OF THE UPPER LOW. SOME ASCENT SHOULD OCCUR AS WEAK SRN STREAM IMPULSES TRAVERSE GULF COAST PORTION OF LOWER MS VALLEY. NONETHELESS...WEAK UPPER FORCING COMBINED WITH FRONTAL ASCENT AND AMPLE LOW/MID LEVEL MOISTURE WILL SUPPORT CONTINUATION OF SHOWERS WITH EMBEDDED TSTMS FROM THE NWRN GULF COAST REGION NWD TO THE MID MS/LOWER OH VALLEYS. STRENGTH OF WIND FIELDS WITH SUFFICIENT DEEP LAYER SHEAR SUGGEST POTENTIAL FOR ISOLATED THUNDERSTORM INTENSIFICATION AND A MARGINAL SEVERE THREAT THROUGH THE FORECAST PERIOD. FORECAST SOUNDINGS INDICATE LOW LEVEL HODOGRAPH CURVATURE MAY SUPPORT AN ISOLATED TORNADO THREAT...IN ADDITION TO DAMAGING WINDS WITH THE STRONGER ACTIVITY. WEAK INSTABILITY AND UNCERTAINTY IN POTENTIAL COVERAGE OF SEVERE THREAT WILL MAINTAIN LOW SEVERE PROBABILITIES WITH THIS OUTLOOK. ..PETERS.. 12/20/2006  From swody2 at goshenarc.org Sun Dec 31 17:24:19 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 31 Dec 2006 12:24:19 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 311728 SWODY2 SPC AC 311727 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1127 AM CST SUN DEC 31 2006 VALID 011200Z - 021200Z ...NO SVR TSTM AREAS FORECAST... ...ERN SEABOARD/FLORIDA... AN UPPER-LEVEL TROUGH OVER THE MS VALLEY AT THE BEGINNING OF THE PERIOD WILL MOVE EWD INTO THE ATLANTIC STATES BY MONDAY AFTERNOON. A COLD FRONT WILL EXTEND SSWWD FROM THE CAROLINAS TO THE FL PANHANDLE AND THIS FEATURE WILL MOVE QUICKLY EWD TOWARD THE ATLANTIC COAST BY MIDDAY. SCATTERED THUNDERSTORMS COULD BE ONGOING ALONG AND AHEAD OF THE FRONT ESPECIALLY ACROSS SC...GA AND NRN FL EARLY IN THE DAY. THUNDERSTORM COVERAGE MAY EXPAND BY AFTERNOON AS SFC TEMPS WARM. ALTHOUGH LARGE-SCALE ASCENT SHOULD BE RELATIVELY STRONG DUE TO THE APPROACHING UPPER-LEVEL TROUGH...FORECAST SOUNDINGS MONDAY AFTERNOON ACROSS THE REGION SHOW WEAK INSTABILITY IN PLACE AHEAD OF THE FRONT. HOWEVER...STRONG SHEAR PROFILES IN THE ERN CAROLINAS DUE TO A 90 KT MID-LEVEL JET AND STEEPENING LOW-LEVEL LAPSE RATES ACROSS CNTRL FL MAY BE ENOUGH FOR A FEW MARGINALLY SEVERE THUNDERSTORMS MONDAY AFTERNOON. THE MAIN THREAT WOULD LIKELY BE STRONG GUSTY WINDS. ..BROYLES.. 12/31/2006  From swody2 at goshenarc.org Fri Dec 1 05:52:17 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Fri, 01 Dec 2006 00:52:17 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 010554 SWODY2 SPC AC 010553 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1153 PM CST THU NOV 30 2006 VALID 021200Z - 031200Z ...NO TSTM AREAS FORECAST... ALTHOUGH THE MOST SIGNIFICANT EMBEDDED SHORT WAVE IMPULSE IS PROGGED TO CONTINUE ACCELERATING OFF THE NORTH ATLANTIC COAST... MODELS SUGGEST THAT AN AMPLIFIED TROUGH IN THE POLAR WESTERLIES WILL PERSIST ACROSS MUCH OF THE NATION EAST OF THE ROCKIES THROUGH THIS FORECAST PERIOD. UPSTREAM RIDGING WILL LINGER ALONG THE PACIFIC COAST...WITH ANOTHER BROAD TROUGH IN THE SUBTROPICAL STREAM...WEST OF BAJA...BEFORE THIS BELT OF FLOW MERGES INTO THE BASE OF THE POLAR TROUGH...ACROSS THE GULF AND SOUTH ATLANTIC COASTS. THE EVOLVING UPPER PATTERN WILL SUPPORT THE DEVELOPMENT OF A LARGE COLD SURFACE RIDGE...WHICH WILL ENCOMPASS MUCH OF THE NATION BY 12Z SATURDAY. THE EXCEPTION WILL BE THE SOUTHERN FLORIDA PENINSULA... WHERE WARM AND HUMID CONDITIONS WILL PERSIST SATURDAY...TO THE SOUTH OF THE STALLING LEADING EDGE OF THE COLD INTRUSION ACROSS THE CENTRAL PENINSULA. THE PRE-FRONTAL ENVIRONMENT LIKELY WILL REMAIN CAPPED BY A MID-LEVEL SUBTROPICAL RIDGE. AND...RELATIVELY WARM MID-LEVELS ARE EXPECTED TO MINIMIZE CONVECTIVE POTENTIAL IN A BELT OF LOW-LEVEL ISENTROPIC ASCENT TO THE NORTH OF THE SURFACE BOUNDARY...ACROSS NORTHERN FLORIDA INTO SOUTHERN GEORGIA/COASTAL SOUTH CAROLINA. RISK OF THUNDERSTORMS SATURDAY/SATURDAY NIGHT ACROSS THE SOUTHEAST...AND THE REMAINDER OF THE U.S...APPEARS NEGLIGIBLE. ..KERR.. 12/01/2006  From swody2 at goshenarc.org Fri Dec 1 16:59:27 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Fri, 01 Dec 2006 11:59:27 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 011700 SWODY2 SPC AC 011658 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1058 AM CST FRI DEC 01 2006 VALID 021200Z - 031200Z ...NO TSTM AREAS FORECAST... ...SYNOPSIS/FORECAST... IN WAKE OF THE STRONG WINTER STORM EXITING SERN CANADA LATE TONIGHT...TWO-STREAM UPPER FLOW REGIME WILL CONVERGE OVER THE CNTRL/ERN PARTS OF THE CONUS. AS A RESULT...BUILDING SFC PRESSURES WILL FORCE A CP AIR MASS SWD OVER MOST OF THE COUNTRY PRECLUDING TSTMS. SUBTROPICAL RIDGE OVER FL WILL MAINTAIN A MORE MODIFIED CP/MT AIR MASS ACROSS FL AHEAD OF THE FRONT...BUT THERMODYNAMIC PROFILES WILL NOT BE PARTICULARLY CONDUCIVE FOR TSTMS. ..RACY.. 12/01/2006  From swody2 at goshenarc.org Sat Dec 2 05:34:25 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 02 Dec 2006 00:34:25 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 020536 SWODY2 SPC AC 020535 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1135 PM CST FRI DEC 01 2006 VALID 031200Z - 041200Z ...NO SVR TSTM AREAS FORECAST... MODELS INDICATE THAT A LARGE-SCALE TROUGH IN THE POLAR WESTERLIES WILL REMAIN AMPLIFIED ACROSS THE CENTRAL/EASTERN U.S. THROUGH THIS FORECAST PERIOD. DIGGING IMPULSES WITHIN THIS REGIME...UPSTREAM OF TROUGH AXIS...ARE PROGGED TO MERGE INTO ONE SIGNIFICANT SHORT WAVE IN THE BASE OF THE LARGER SCALE TROUGH...NEAR/EAST OF THE MISSISSIPPI VALLEY LATE SUNDAY/SUNDAY EVENING...BEFORE SYSTEM ACCELERATES TOWARD THE ATLANTIC SEABOARD THROUGH 12Z MONDAY. SOME DIFFERENCE EXIST AMONG THE MODELS CONCERNING THE SPEED AT WHICH THIS OCCURS...BUT THE GFS AND ECMWF REMAIN VERY SIMILAR WITH REGARD TO THE FORECAST INITIATION OF SURFACE CYCLOGENESIS ALONG STALLED SURFACE FRONT OFF THE SOUTHERN/MID ATLANTIC COAST. COMMENCEMENT OF MORE RAPID SURFACE WAVE DEVELOPMENT CURRENTLY APPEARS MOST PROBABLE JUST EAST OF THE NORTH CAROLINA COAST LATE SUNDAY AFTERNOON. SCATTERED WEAK THUNDERSTORMS SEEM POSSIBLE ABOVE WARM FRONTAL INVERSION LAYER ACROSS THE CAROLINA COASTAL PLAIN...BUT THE MOST VIGOROUS WARM SECTOR CONVECTION SHOULD BE CONFINED TO AREAS WELL OFFSHORE. RISK OF THUNDERSTORMS ELSEWHERE ACROSS THE U.S. APPEARS NEGLIGIBLE. ..KERR.. 12/02/2006  From swody2 at goshenarc.org Sat Dec 2 16:59:21 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 02 Dec 2006 11:59:21 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 021700 SWODY2 SPC AC 021658 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1058 AM CST SAT DEC 02 2006 VALID 031200Z - 041200Z ...NO SVR TSTM AREAS FORECAST... ...NC OUTER BANKS... POSITIVE-TILT TROUGH EMBEDDED WITHIN THE POLAR WLYS WILL MOVE FROM THE PLAINS TO THE ERN SEABOARD ON SUNDAY. AHEAD OF THIS SYSTEM... WEAK CYCLOGENESIS SHOULD TAKE PLACE OFFSHORE THE CAROLINAS ALONG THE WRN GULF STREAM WATERS BY SUNDAY AFTN. THIS LOW WILL THEN TRACK NEWD DURING SUNDAY EVENING. MARGINAL INSTABILITY SHOULD DEVELOP ATOP THE MORE STABLE BOUNDARY LAYER ACROSS FAR ERN NC SUNDAY NIGHT. THUS...SPORADIC LIGHTNING MAY BE POSSIBLE WITHIN THE DEFORMATION ZONE EXPECTED TO EVOLVE ACROSS THE NC OUTER BANKS. ..RACY.. 12/02/2006  From swody2 at goshenarc.org Sun Dec 3 05:24:16 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 03 Dec 2006 00:24:16 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 030526 SWODY2 SPC AC 030525 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1125 PM CST SAT DEC 02 2006 VALID 041200Z - 051200Z ...NO TSTM AREAS FORECAST... MODELS INDICATE THAT THE LARGE-SCALE TROUGH IN THE POLAR WESTERLIES ...EAST OF THE ROCKIES...WILL PERSIST INTO THIS FORECAST PERIOD. SOME LOSS OF AMPLITUDE AND EASTWARD EXPANSION ACROSS THE WESTERN ATLANTIC IS FORECAST TO OCCUR...AS A SIGNIFICANT SHORT WAVE TROUGH RAPIDLY LIFTS NORTHEAST OF THE NORTH ATLANTIC COAST AND CANADIAN MARITIMES BY 12Z TUESDAY. THE LOW-LEVEL CYCLONE ACCOMPANYING THIS SYSTEM WILL CONTINUE TO DEEPEN...AND A TRAILING COLD FRONT IS PROGGED TO ADVANCE SOUTH OF THE REMAINDER OF THE FLORIDA PENINSULA AND KEYS. SHOWERS ARE POSSIBLE WITH THE FRONTAL PASSAGE MONDAY...BUT ALL INDICATIONS ARE THAT A LINGERING WARM MID-LEVEL ENVIRONMENT WILL INHIBIT DEEP CONVECTIVE DEVELOPMENT...MINIMIZING RISK FOR THUNDERSTORMS. IN THE WAKE OF THE FRONT...A LARGE COLD SURFACE RIDGE WILL ENCOMPASS MUCH OF THE GULF OF MEXICO...THE SOUTH CENTRAL/SOUTHEASTERN STATES...AND ADJACENT ATLANTIC WATERS. MID-LEVEL MOISTENING...ASSOCIATED WITH AN IMPULSE EMANATING FROM THE SUBTROPICAL PACIFIC...MAY OCCUR ACROSS THE NORTHERN MEXICAN PLATEAU INTO PARTS OF TEXAS. AND...A COLD MID-LEVEL SHORT WAVE TROUGH IN THE SOUTHERN BRANCH OF THE POLAR WESTERLIES IS PROGGED TO PROGRESS INLAND ACROSS VANCOUVER ISLAND AND SOUTHERN BRITISH COLUMBIA. HOWEVER...THERMODYNAMIC PROFILES APPEAR LIKELY TO REMAIN STABLY STRATIFIED ACROSS THESE AREAS...AND MUCH OF THE REMAINDER OF THE NATION...PRECLUDING ANY APPRECIABLE RISK OF THUNDERSTORM ACTIVITY. ..KERR.. 12/03/2006  From swody2 at goshenarc.org Sun Dec 3 16:49:19 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 03 Dec 2006 11:49:19 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 031651 SWODY2 SPC AC 031650 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1050 AM CST SUN DEC 03 2006 VALID 041200Z - 051200Z ...NO TSTM AREAS FORECAST... A LARGE SCALE TROUGH MOVING INTO THE ERN STATES WILL DEAMPLIFY THROUGH MONDAY. SFC CYCLONE EVOLVING ALONG THE GULF STREAM WILL DEPART TO THE NORTHEAST WITH A COLD FRONT MOVING INTO SRN FL. RESIDUAL WARM LAYER ALOFT WILL LIKELY BE HOSTILE TO DEEP MOIST CONVECTION ALONG THIS FRONT. TO THE WEST...FAST MOVING SHORTWAVE TROUGH WILL MOVE ACROSS THE PAC NW AND CANADIAN ROCKIES BY MONDAY NIGHT. PRIMARY COLD POCKET WILL REMAIN NORTH OF THE INTERNATIONAL BORDER WITH A MORE STABLE ENVIRONMENT FARTHER S. THIS WILL PRECLUDE THE RISK OF TSTMS. ELSEWHERE...A CP AIR MASS WILL RESIDE ACROSS THE REMAINDER OF THE CONUS WITH TSTM PROBABILITIES LESS THAN 10 PERCENT. ..RACY.. 12/03/2006  From swody2 at goshenarc.org Mon Dec 4 05:17:40 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 04 Dec 2006 00:17:40 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 040519 SWODY2 SPC AC 040518 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1118 PM CST SUN DEC 03 2006 VALID 051200Z - 061200Z ...NO TSTM AREAS FORECAST... THE SECOND IN A SERIES OF COLD INTRUSIONS TO THE LEE OF THE ROCKIES IS WELL UNDERWAY...ALREADY PENETRATING DEEP INTO THE WESTERN GULF OF MEXICO...AND LIKELY THE REMAINDER OF THE GULF OF MEXICO/FLORIDA PENINSULA AND ADJACENT ATLANTIC WATERS BY 12Z TUESDAY. DURING THE DAY TUESDAY...AS A FAIRLY SIGNIFICANT SHORT WAVE TROUGH SHIFTS OFF THE NORTH ATLANTIC COAST...MODELS SUGGEST THAT THE CENTER OF THE LARGE SURFACE RIDGE WILL RETREAT FROM THE LOWER MISSISSIPPI VALLEY INTO AREAS NEAR/JUST EAST OF THE MID ATLANTIC COAST BY 12Z WEDNESDAY. SOME MODIFICATION OF THE BOUNDARY LAYER OVER THE GULF OF MEXICO MAY BEGIN TO OCCUR DURING THIS FORECAST PERIOD...BUT SURFACE RIDGING IS PROGGED TO LINGER ALONG GULF COASTAL AREAS. AND...AS ANOTHER SIGNIFICANT SHORT WAVE TROUGH BEGINS TO AMPLIFY ACROSS THE NORTH CENTRAL STATES...WITHIN THE PERSISTENT BROADER SCALE POLAR TROUGH...ANOTHER SURFACE RIDGE WILL BEGIN TO BUILD BENEATH THE CONFLUENT REGIME TO THE LEE OF THE CANADIAN/U.S. ROCKIES. AN INFLUX OF MID-LEVEL MOISTURE FROM THE LOWER LATITUDE EASTERN PACIFIC INTO PARTS OF CENTRAL/SOUTHERN TEXAS COULD OCCUR WITH THE EASTWARD PROGRESSION OF A WEAKENING SUBTROPICAL IMPULSE. BUT...AT THE PRESENT TIME...IT APPEARS DESTABILIZATION WILL BE TOO MINIMAL TO SUPPORT AN APPRECIABLE RISK OF THUNDERSTORM ACTIVITY. ..KERR.. 12/04/2006  From swody2 at goshenarc.org Mon Dec 4 17:25:00 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 04 Dec 2006 12:25:00 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 041726 SWODY2 SPC AC 041724 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1124 AM CST MON DEC 04 2006 VALID 051200Z - 061200Z ...NO TSTM AREAS FORECAST... DRY/STABLE CONDITIONS ARE EXPECTED TO PRECLUDE ORGANIZED THUNDERSTORM ACTIVITY NATIONWIDE ON TUESDAY. ..HART.. 12/04/2006  From swody2 at goshenarc.org Tue Dec 5 05:06:25 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 05 Dec 2006 00:06:25 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 050508 SWODY2 SPC AC 050507 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1107 PM CST MON DEC 04 2006 VALID 061200Z - 071200Z ...NO TSTM AREAS FORECAST... BROAD TROUGHING IS EXPECTED TO PERSIST IN THE POLAR WESTERLIES... ACROSS MUCH OF THE CENTRAL AND EASTERN U.S...INTO WEDNESDAY. BUT ...MODEL GUIDANCE CONTINUES TO INDICATE THAT THE LAST IN A SERIES OF AMPLIFICATIONS WITHIN THIS REGIME WILL TAKE PLACE...AS A STRONG SHORT WAVE TROUGH DIGS OUT OF THE CANADIAN NORTHWEST TERRITORIES THROUGH MUCH OF THE UPPER MIDWEST. THIS FEATURE WILL BE PRECEDED IN THE NORTH CENTRAL STATES BY ANOTHER IMPULSE...EMANATING FROM THE NORTHEAST PACIFIC. AND...MODELS SUGGEST THAT A NEW SURFACE COLD INTRUSION MAY ALREADY BE OCCURRING THROUGH THE PLAINS EARLY WEDNESDAY...BEFORE STRONG COLD HIGH PRESSURE BUILDS THROUGH MOST AREAS FROM THE ROCKIES TO THE APPALACHIANS...INCLUDING MUCH OF THE GULF OF MEXICO...BY 12Z THURSDAY. WHILE SOME WARMING/MOISTENING OF THE BOUNDARY LAYER OVER THE GULF OF MEXICO AND WATERS OFF THE SOUTH ATLANTIC COAST MAY OCCUR BY WEDNESDAY...IN THE WAKE OF A PRIOR COLD INTRUSION...CURRENT INDICATIONS ARE THAT THIS WILL NOT BECOME SUFFICIENT TO SUPPORT A SIGNIFICANT INLAND RETURN FLOW. THUNDERSTORM ACTIVITY...IF ANY...ALONG/AHEAD OF ADVANCING SURFACE COLD FRONT...LIKELY WILL REMAIN CONFINED TO THE WATERS OFF THE FLORIDA GULF AND ATLANTIC COASTS...AND NEAR THE GULF STREAM...OFF THE NORTH CAROLINA COAST. ..KERR.. 12/05/2006  From swody2 at goshenarc.org Tue Dec 5 17:19:31 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 05 Dec 2006 12:19:31 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 051721 SWODY2 SPC AC 051719 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1119 AM CST TUE DEC 05 2006 VALID 061200Z - 071200Z ...NO TSTM AREAS FORECAST... ...SYNOPSIS... WEAK WARM ADVECTION WILL DEVELOP OVER THE ERN GULF OF MEXICO AHEAD OF SWD-PLUNGING COLD FRONT WEDNESDAY. STRONGEST SUSTAINED ASCENT WILL DEVELOP LATE IN THE PERIOD...LIKELY ENHANCING CONVECTIVE THREAT WEST OF THE FL PENINSULA. AT THIS TIME IT APPEARS THE PROSPECT FOR DEEP MOIST CONVECTION WILL REMAIN TOO NEGLIGIBLE ALONG COLD FRONT TO WARRANT ANY ORGANIZED THUNDER POTENTIAL. ..DARROW.. 12/05/2006  From swody2 at goshenarc.org Wed Dec 6 06:00:42 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 06 Dec 2006 01:00:42 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 060602 SWODY2 SPC AC 060600 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1200 AM CST WED DEC 06 2006 VALID 071200Z - 081200Z ...NO SVR TSTM AREAS FORECAST... THE LAST IN A SERIES OF AMPLIFICATIONS WITHIN PERSISTENT LARGE- SCALE POLAR TROUGH OVER THE CENTRAL AND EASTERN U.S. APPEARS TO BE UNDERWAY...MUCH AS FORECAST BY THE MODELS. THIS IS OCCURRING MOSTLY IN RESPONSE TO A STRONG DIGGING SHORT WAVE TROUGH ...EMANATING FROM THE CANADIAN NORTHWEST TERRITORIES...NEAR THE ARCTIC CIRCLE. THE GFS AND ECMWF INDICATE THAT THIS IMPULSE WILL CONTINUE ACROSS MUCH OF THE UPPER MIDWEST/UPPER GREAT LAKES REGION BY 12Z THURSDAY...BEFORE TURNING EAST ACROSS THE UPPER OHIO VALLEY AND LOWER GREAT LAKES REGION...INTO NORTHERN AND MID ATLANTIC COASTAL AREAS BY 12Z FRIDAY. BENEATH THE CONFLUENT REGIME UPSTREAM OF THE LARGE-SCALE TROUGH AXIS...THE CENTER OF A MASSIVE COLD SURFACE RIDGE IS PROGGED TO SHIFT SOUTHEASTWARD THROUGH THE EAST CENTRAL PLAINS AND OZARK PLATEAU. AND...THE LEADING EDGE OF THE COLD AIR WILL ADVANCE OFF ATLANTIC COASTAL AREAS...THE REMAINDER OF THE FLORIDA PENINSULA AND GULF OF MEXICO. THIS FEATURE WILL CONTRIBUTE TO STABLE THERMODYNAMIC PROFILES ACROSS MUCH OF THE NATION...WITH GENERALLY NEGLIGIBLE CONVECTIVE POTENTIAL. ...FLORIDA... MODIFICATION OF LOWER LEVELS IN THE WAKE OF A PRIOR COLD INTRUSION IS NOT EXPECTED TO BECOME SUFFICIENT TO OVERCOME MID-LEVEL INHIBITION. A FEW SHOWERS ARE POSSIBLE THURSDAY/THURSDAY EVENING ...AHEAD OF THE MAIN COLD SURGE ACROSS THE CENTRAL/SOUTHERN PENINSULA. BUT...ANYTHING MUCH BEYOND A BRIEF ISOLATED THUNDERSTORM APPEARS MINIMAL. ...GREAT LAKES... LOW-LEVEL LAPSE RATES AND CAPE SEEM LIKELY TO BECOME ENHANCED THURSDAY...AS LOWER/MID TROPOSPHERIC COLD CORE ASSOCIATED WITH THE VIGOROUS SHORT WAVE TROUGH SHIFTS ACROSS THE WARMER LOWER GREAT LAKES REGION. IT SEEMS PROBABLE THAT A FEW LIGHTNING STRIKES WILL ACCOMPANY STRONGER LAKE EFFECT CONVECTION...PARTICULARLY OVER THE OPEN WATERS INTO SOUTHEAST SHORES OF LAKE HURON. ..KERR.. 12/06/2006  From swody2 at goshenarc.org Wed Dec 6 17:20:01 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 06 Dec 2006 12:20:01 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 061721 SWODY2 SPC AC 061719 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1119 AM CST WED DEC 06 2006 VALID 071200Z - 081200Z ...NO SVR TSTM AREAS FORECAST... ...GREAT LAKES... LOW LEVEL LAPSE RATES WILL STEEPEN SIGNIFICANTLY FROM THE UPPER GREAT LAKES ACROSS LAKE ERIE DURING THE DAY2 PERIOD. LATEST MODEL GUIDANCE SUGGESTS EL LEVELS WILL BE AT LEAST 3KM DEEP WITH MOIST CONVECTION THAT DEVELOPS OVER WARMER LAKE WATERS. FOR THIS REASON IT APPEARS LIGHTNING WILL BE NOTED WITH STRONGER UPDRAFTS AND HEAVIER SNOW SQUALLS...ESPECIALLY DOWNWIND OF LAKE MI THROUGH 18Z...AND ACROSS LAKE ERIE THROUGH LATE EVENING. ...ELSEWHERE... LOW LEVEL CONVERGENCE WILL PROVE QUITE WEAK AHEAD OF COLD FRONT PLUNGING SWD ACROSS THE SRN PENINSULA OF FL. IT APPEARS CONVECTION WILL PROVE WEAK AND ANY LIGHTING THAT DEVELOPS SHOULD BE EXTREMELY ISOLATED...AND MAINLY OFFSHORE. ..DARROW.. 12/06/2006  From swody2 at goshenarc.org Fri Dec 8 06:10:59 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Fri, 08 Dec 2006 01:10:59 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 080610 SWODY2 SPC AC 080609 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1209 AM CST FRI DEC 08 2006 VALID 091200Z - 101200Z ...NO SVR TSTM AREAS FORECAST... AN UPPER-LEVEL RIDGE WILL BE IN PLACE SATURDAY MORNING ACROSS THE CNTRL STATES. THIS FEATURE IS FORECAST TO MOVE EWD INTO THE MS VALLEY BY SATURDAY EVENING. AT THE SFC...A LARGE HIGH PRESSURE AREA WILL DOMINATE ACROSS THE ERN U.S. AS A LEE TROUGH FORMS EAST OF THE ROCKIES. DUE TO THE LARGE SFC HIGH...VERY LITTLE LOW-LEVEL MOISTURE WILL BE IN PLACE ACROSS THE PLAINS...MS VALLEY AND ERN STATES FOR CONVECTIVE ACTIVITY SATURDAY AND SATURDAY NIGHT. FURTHER WEST...AN UPPER-LEVEL TROUGH WILL APPROACH THE CA COAST SATURDAY NIGHT. MODEL FORECASTS SHOW SUFFICIENT MOISTURE AND INSTABILITY FOR THUNDERSTORM ACTIVITY ALONG THE COAST NEAR SAN FRANCISCO LATE IN THE PERIOD AS THE UPPER-TROUGH MOVES INLAND. ..BROYLES.. 12/08/2006  From swody2 at goshenarc.org Fri Dec 8 16:40:11 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Fri, 08 Dec 2006 11:40:11 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 081641 SWODY2 SPC AC 081639 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1039 AM CST FRI DEC 08 2006 VALID 091200Z - 101200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... ANOTHER IN A SERIES OF UPPER SHORT-WAVE TROUGHS IS FORECAST TO MOVE ONSHORE OVER THE WRN CONUS DURING THE SECOND HALF OF THE PERIOD. THOUGH INSTABILITY SHOULD REMAIN QUITE LIMITED ONSHORE...A FEW LIGHTNING STRIKES MAY OCCUR OVER COASTAL AREAS OF NRN AND CENTRAL CA SWD TO NEAR POINT CONCEPTION. ELSEWHERE...LARGE SURFACE HIGH PRESSURE -- AND ASSOCIATED COOL/STABLE AIRMASS -- WILL PREVAIL OVER THE ERN HALF OF THE CONUS BENEATH SLOWLY-PROGRESSIVE UPPER RIDGE. THEREFORE...DEEP MOIST CONVECTION IS NOT ANTICIPATED. ..GOSS.. 12/08/2006  From swody2 at goshenarc.org Sat Dec 9 06:19:01 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 09 Dec 2006 01:19:01 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 090620 SWODY2 SPC AC 090618 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1218 AM CST SAT DEC 09 2006 VALID 101200Z - 111200Z ...NO SVR TSTM AREAS FORECAST... AN UPPER-LEVEL TROUGH IS FORECAST TO BE IN CALIFORNIA AT THE BEGINNING OF THE PERIOD. THIS FEATURE WILL MOVE EWD INTO THE INTERMOUNTAIN WEST DURING THE DAY ON SUNDAY. STEEP LAPSE RATES ASSOCIATED WITH THE UPPER-TROUGH AND SFC HEATING MAY HELP ISOLATED THUNDERSTORMS TO INITIATE IN THE FOUR CORNERS REGION SUNDAY AFTERNOON. BACK FURTHER WEST...LARGE-SCALE ASCENT MAY PERSIST ALONG THE WEST COAST IN THE WAKE OF THE EXITING UPPER-TROUGH AS A SECONDARY THROUGH TAKES ITS PLACE. IN ADDITION...LIFT MAY BE ENHANCED AS THE ENTRANCE REGION OF THE MID-LEVEL JET MOVES ACROSS SUNDAY AFTERNOON. THIS ALONG WITH ONSHORE FLOW AND COLD TEMPS ALOFT MAY ALLOW ISOLATED THUNDERSTORMS TO DEVELOP ALONG THE COASTS OF NRN CA AND ORE MAINLY SUNDAY MORNING AND AFTERNOON. HOWEVER...NO SEVERE WEATHER THREAT IS EXPECTED TO DEVELOP ACROSS THE CONUS SUNDAY OR SUNDAY NIGHT. ..BROYLES.. 12/09/2006  From swody2 at goshenarc.org Sat Dec 9 17:27:44 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 09 Dec 2006 12:27:44 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 091728 SWODY2 SPC AC 091727 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1127 AM CST SAT DEC 09 2006 VALID 101200Z - 111200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... A GENERALLY COOL/STABLE BOUNDARY-LAYER WILL PREVAIL E OF THE ROCKIES THIS PERIOD...AS WEAK UPPER TROUGH MOVES THROUGH THE LARGER-SCALE RIDGE AND SURFACE HIGH PRESSURE PERSISTS ACROSS MOST OF THE ERN HALF OF THE CONUS. MEANWHILE...A SECOND UPPER TROUGH WILL PROGRESS EWD ACROSS THE W COAST AND INTO THE ROCKIES THROUGH THE PERIOD. COLD AIR ALOFT/STEEP MID-LEVEL LAPSE RATES MAY CONTRIBUTE TO SUFFICIENT CAPE FOR A FEW LIGHTNING STRIKES -- PARTICULARLY INVOF THE FOUR CORNERS. ..GOSS.. 12/09/2006  From swody2 at goshenarc.org Sun Dec 10 05:51:52 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 10 Dec 2006 00:51:52 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 100552 SWODY2 SPC AC 100551 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1151 PM CST SAT DEC 09 2006 VALID 111200Z - 121200Z ...NO SVR TSTM AREAS FORECAST... A MERIDIONAL UPPER-TROUGH OVER THE ROCKIES WILL MOVE EWD INTO THE PLAINS STATES DURING THE DAY ON MONDAY. THE LOW-LEVEL MOIST AXIS SHOULD REMAIN WELL EAST OF THE STRONGER FORCING ASSOCIATED WITH THE TROUGH UNTIL AFTER DARK. ALTHOUGH A FEW THUNDERSTORMS MAY DEVELOP MONDAY AFTERNOON ACROSS THE TX COASTAL PLAINS...MOST OF THE THUNDERSTORM ACTIVITY SHOULD HOLD OFF UNTIL LATE EVENING OR AFTER MIDNIGHT. THE GREATEST CHANCE OF CONVECTIVE DEVELOPMENT SHOULD BE ACROSS ERN AR...LA AND SE TX WHEN THE LARGE-SCALE ASCENT ASSOCIATED WITH THE TROUGH AND THE LOW-LEVEL MOISTURE PHASE TOGETHER. ALTHOUGH WIND SHEAR WILL BE ADEQUATE FOR ORGANIZED STORMS...IT APPEARS INSTABILITY WILL BE WEAK ACROSS THE REGION. FOR THIS REASON...ANY SEVERE THREAT SHOULD REMAIN MARGINAL AND ISOLATED DURING THE OVERNIGHT PERIOD. ELSEWHERE...AN UPPER-LEVEL DISTURBANCE WILL MOVE ONSHORE IN THE PACIFIC NORTHWEST MONDAY AFTERNOON. THUNDERSTORMS WILL BE POSSIBLE DUE TO THE COLD AIR ALOFT AND STRONG LIFT ASSOCIATED WITH THE EXIT REGION OF A MID-LEVEL JET. HOWEVER...NONE OF THE ACTIVITY IS EXPECTED TO REACH SEVERE LIMITS. ..BROYLES.. 12/10/2006  From swody2 at goshenarc.org Sun Dec 10 17:29:18 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 10 Dec 2006 12:29:18 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 101730 SWODY2 SPC AC 101728 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1128 AM CST SUN DEC 10 2006 VALID 111200Z - 121200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... FAIRLY INTENSE/MERIDIONALLY-EXTENSIVE MID-LEVEL SHORT-WAVE TROUGH WILL MOVE INTO THE CENTRAL CONUS THIS PERIOD...WHILE A DOWNSTREAM INTENSIFYING RIDGE MOVES EWD ACROSS THE ERN CONUS. MEANWHILE...A SECOND TROUGH WILL AFFECT THE PAC NW COAST DURING THE PERIOD. THOUGH A FEW LIGHTNING STRIKES MAY OCCUR OVER THE WA COAST/OLYMPICS REGION LATE IN THE PERIOD...POTENTIALLY MORE WIDESPREAD THUNDERSTORM ACTIVITY MAY OCCUR LATE IN THE PERIOD OVER THE S CENTRAL CONUS. AS LOW-LEVEL MOISTURE INFLUX INCREASES AHEAD OF THIS FEATURE...SUFFICIENT ELEVATED CAPE MAY EVOLVE TO ALLOW SCATTERED/WEAK THUNDERSTORM DEVELOPMENT -- PARTICULARLY ACROSS THE ARKLATEX REGION AND VICINITY LATE IN THE PERIOD. ANY HAIL THREAT WITH THESE STORMS APPEARS ATTM TO BE VERY LOW DUE TO MEAGER INSTABILITY...AND THUS WILL NOT CARRY SEVERE PROBABILITIES THIS FORECAST. ..GOSS.. 12/10/2006  From swody2 at goshenarc.org Mon Dec 11 06:29:34 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 11 Dec 2006 01:29:34 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 110630 SWODY2 SPC AC 110628 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1228 AM CST MON DEC 11 2006 VALID 121200Z - 131200Z ...NO SVR TSTM AREAS FORECAST... ...LOWER MS VALLEY/TN VALLEY... A WELL-DEVELOPED UPPER-LEVEL LOW/TROUGH WILL BE LOCATED FROM THE UPPER MIDWEST EXTENDING SSWWD INTO THE SRN PLAINS AT THE BEGINNING OF THE DAY 2 PERIOD. A THREAT FOR ISOLATED THUNDERSTORMS MAY BE ONGOING IN THE MORNING ALONG THE LEADING EDGE OF LARGE-SCALE ASCENT LOCATED FROM THE LOWER OH VALLEY SSWWD TO THE LOWER MS VALLEY. AS SFC HEATING TAKES PLACE...CONVECTIVE COVERAGE SHOULD INCREASE WITH ISOLATED TO SCATTERED THUNDERSTORMS POSSIBLE ACROSS WRN KY...WRN TN...MS AND LA BY EARLY AFTERNOON. ALTHOUGH LOW-LEVEL MOISTURE SHOULD BE LIMITED...DESTABILIZATION SHOULD OCCUR IN POCKETS ALONG THE MS RIVER VALLEY DURING THE LATE MORNING AND EARLY AFTERNOON. IN ADDITION...STRONG SHEAR PROFILES SHOULD BE ADEQUATE FOR A MARGINAL SEVERE THREAT ESPECIALLY WHERE SUBSTANTIAL DESTABILIZATION OCCURS. THE SEVERE THREAT SHOULD BE VERY ISOLATED AND CONCENTRATED AROUND PEAK HEATING. ELSEWHERE...ISOLATED NON-SEVERE THUNDERSTORMS MAY OCCUR ALONG THE COAST OF THE PACIFIC NORTHWEST AS AN UPPER-TROUGH MOVES INLAND AROUND MIDDAY ON TUESDAY. ..BROYLES.. 12/11/2006  From swody2 at goshenarc.org Mon Dec 11 17:19:51 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 11 Dec 2006 12:19:51 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 111720 SWODY2 SPC AC 111718 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1118 AM CST MON DEC 11 2006 VALID 121200Z - 131200Z ...NO SVR TSTM AREAS FORECAST... A COMPLEX SPLIT UPPER FLOW PATTERN PERSISTS ACROSS MUCH OF NORTH AMERICA. WITHIN THIS REGIME...AN AMPLIFIED TROUGH...WHICH DEVELOPED OVER THE WEEKEND IN ONE STRONGER BELT ACROSS CALIFORNIA INTO THE SOUTH CENTRAL STATES...CONTINUES TO SHIFT EAST OF THE ROCKIES INTO THE CENTRAL/SOUTHERN PLAINS. MODELS INDICATE THAT THIS LARGER SCALE FEATURE WILL LIFT NORTHEASTWARD TOWARD THE MISSISSIPPI VALLEY BY 12Z TUESDAY...BEFORE PROGRESSING INTO/THROUGH THE GREAT LAKES/OHIO VALLEY REGION BY 12Z WEDNESDAY. THIS IS PROGGED TO OCCUR AS A STRONG HIGH-LEVEL JET STREAK NOSES INTO THE CANADIAN ROCKIES/NORTHERN U.S. INTERMOUNTAIN REGION...IN A STREAM EMANATING FROM THE WESTERN/CENTRAL PACIFIC. ASSOCIATED WITH THE SOUTHERN BRANCH TROUGH...MODELS CONTINUE TO INDICATE THAT LEE SURFACE CYCLOGENESIS WILL REMAIN WEAK. THIS WILL TEND TO MINIMIZE CONVECTIVE POTENTIAL ALONG/AHEAD OF ASSOCIATED SURFACE FRONT AS IT ADVANCES THROUGH THE CENTRAL U.S. EARLY THIS WEEK. ALSO...IN THE WAKE OF A SERIES OF SIGNIFICANT COLD INTRUSIONS... THE BOUNDARY LAYER OVER THE GULF OF MEXICO IS STILL IN THE PROCESS OF MODIFYING. BUT...A WEAK RETURN FLOW OF MOISTURE...CHARACTERIZED BY MID/UPPER 50S DEW POINTS...IS ONGOING FROM THE WESTERN GULF OF MEXICO INTO THE SOUTHEASTERN PLAINS. ...MIDDLE MISSISSIPPI VALLEY... VARIABILITY EXISTS AMONG THE MODELS CONCERNING THE DETAILS...BUT AN IMPULSE IS GENERALLY FORECAST TO PROGRESS THROUGH THE BASE OF THE LARGER SCALE TROUGH AS IT LIFTS INTO/THROUGH THE MISSISSIPPI VALLEY LATER TODAY INTO TUESDAY. THIS IS PROGGED TO CONTRIBUTE TO A STRENGTHENING SOUTHWESTERLY MID-LEVEL JET STREAK ACROSS THE MIDDLE MISSISSIPPI VALLEY BY TUESDAY AFTERNOON...WITH STRONGER MID-LEVEL COOLING ADVANCING NORTHEAST OF THE OZARK PLATEAU INTO THE LOWER OHIO VALLEY. THIS MAY BE PRECEDED BY AT LEAST WEAK SURFACE HEATING IN A DRY SLOT NOSING THROUGH THE MIDDLE MISSISSIPPI VALLEY...IN THE WAKE OF EARLY DAY PRE-FRONTAL WARM ADVECTION CONVECTION...WHICH WILL BE POSSIBLE IN A BAND THROUGH MUCH OF THE MISSISSIPPI VALLEY. MODEL FORECAST SOUNDINGS ACROSS PARTS OF EASTERN ARKANSAS AND SOUTHEAST MISSOURI...INTO CENTRAL/SOUTHERN ILLINOIS AND WESTERN KENTUCKY/TENNESSEE...INDICATE MIXED LAYER CAPE OF AROUND 500 J/KG DEVELOPING BY 20-21Z TUESDAY. THIS IS RATHER WEAK...BUT PROFILES ARE SUGGESTIVE OF SUFFICIENT CONVECTIVE INSTABILITY TO SUPPORT AT LEAST A LOW RISK OF MARGINALLY SEVERE HAIL/WIND GUSTS IN ANY STORMS DEVELOPING IN FAVORABLY SHEARED DEEP LAYER FLOW. AND... INHIBITION APPEARS LIKELY TO BECOME SUFFICIENTLY WEAK FOR A BROKEN LINE OF STORMS TO DEVELOP IN RESPONSE TO FRONTAL FORCING ADVANCING EAST OF THE MIDDLE MISSISSIPPI VALLEY BY EARLY TUESDAY EVENING. LIMITED SEVERE THREAT WILL PROBABLY DIMINISH AS THIS FORCING SHIFTS EASTWARD INTO COOLER AND MORE STABLE/STABILIZING BOUNDARY LAYER. ..KERR.. 12/11/2006  From swody2 at goshenarc.org Tue Dec 12 06:29:58 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 12 Dec 2006 01:29:58 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 120630 SWODY2 SPC AC 120629 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1229 AM CST TUE DEC 12 2006 VALID 131200Z - 141200Z ...NO SVR TSTM AREAS FORECAST... AT THE BEGINNING OF THE PERIOD...AN UPPER-LEVEL TROUGH OVER THE OH AND TN VALLEYS WILL DAMPEN AND MOVE QUICKLY ACROSS THE APPALACHIAN MTNS TO THE ERN SEABOARD BY WEDNESDAY AFTERNOON. THUNDERSTORM ACTIVITY WILL BE POSSIBLE IN THE COASTAL SECTIONS OF NC AND NEAR THE SC COAST AROUND MIDDAY AS SFC TEMPS WARM AND LARGE-SCALE ASCENT INCREASES AHEAD OF THE APPROACHING UPPER-LEVEL TROUGH. HOWEVER...THE BRUNT OF THE CONVECTIVE ACTIVITY SHOULD REMAIN WELL OFFSHORE. ELSEWHERE...A VIGOROUS SHORTWAVE TROUGH WILL MOVE ONSHORE IN THE PACIFIC NORTHWEST AS A 120 MID-LEVEL JET NOSES INTO THE REGION. VERY STRONG ASCENT COMBINED WITH COLD TEMPS ALOFT MAY BE ENOUGH FOR ISOLATED THUNDERSTORM ACTIVITY MAINLY ALONG THE IMMEDIATE COAST OF WA AND ORE. ..BROYLES.. 12/12/2006  From swody2 at goshenarc.org Tue Dec 12 17:19:31 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 12 Dec 2006 12:19:31 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 121720 SWODY2 SPC AC 121718 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1118 AM CST TUE DEC 12 2006 VALID 131200Z - 141200Z ...NO SVR TSTM AREAS FORECAST... MODELS INDICATE THAT A STRONG BELT OF WESTERLIES WILL PERSIST SOUTH OF BAJA INTO THE SOUTHEASTERN STATES DURING THIS FORECAST PERIOD. BUT...A STRONGER HIGH-LEVEL JET STREAK IS FORECAST TO CONTINUE TO DEVELOP EASTWARD OUT OF THE CENTRAL PACIFIC THROUGH MUCH OF THE NORTHERN TIER STATES. AS THIS OCCURS...THE CURRENT AMPLIFIED SOUTHERN BRANCH TROUGH IS PROGGED TO LOSE AMPLITUDE AND LIFT THROUGH THE GREAT LAKES/OHIO VALLEY BY WEDNESDAY MORNING...BEFORE CONTINUING ACROSS THE EASTERN CANADIAN PROVINCES BY 12Z THURSDAY. DRYING IN THE WAKE OF THIS FEATURE IS EXPECTED TO CONTRIBUTE TO LOW CONVECTIVE POTENTIAL ACROSS MUCH OF THE NATION. ...ATLANTIC COAST STATES... MOISTENING AHEAD OF WEAK FRONT/WIND SHIFT ASSOCIATED WITH THE SOUTHERN BRANCH TROUGH IS EXPECTED TO BE LIMITED...AND THE CORE OF COLD AIR ALOFT IS PROGGED TO LIFT TO THE NORTH/WEST OF ATLANTIC COASTAL AREAS. THIS SHOULD MINIMIZE THE RISK FOR THUNDERSTORMS OVER INLAND AREAS. THE PRIMARY CONVECTIVE DEVELOPMENT IS EXPECTED TO OCCUR OFFSHORE...NEAR THE GULF STREAM...LATE WEDNESDAY/WEDNESDAY NIGHT. ...PACIFIC NORTHWEST COAST... MODERATE TO STRONG MOIST LOW-LEVEL ONSHORE FLOW IS PROGGED TO THE WEST OF THE CASCADES THROUGH MUCH OF THE DAY...CONTRIBUTING TO SUFFICIENT DESTABILIZATION FOR SCATTERED CONVECTIVE DEVELOPMENT. HOWEVER...COLDER MID-LEVEL AIR MASS /AND MORE FAVORABLE EQUILIBRIUM TEMPERATURES FOR THUNDERSTORM ACTIVITY/ APPEARS LIKELY TO REMAIN CONFINED TO AREAS NORTH OF THE COLUMBIA RIVER...WHERE PRIMARY RISK SEEMS TO EXIST FOR OCCASIONAL/ISOLATED WEAK THUNDERSTORMS. ..KERR.. 12/12/2006  From swody2 at goshenarc.org Wed Dec 13 06:18:04 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 13 Dec 2006 01:18:04 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 130618 SWODY2 SPC AC 130617 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1217 AM CST WED DEC 13 2006 VALID 141200Z - 151200Z ...NO SVR TSTM AREAS FORECAST... A BROAD UPPER-LEVEL TROUGH OVER THE CNTRL AND ERN U.S. WILL AMPLIFY SOMEWHAT THURSDAY AS A MID-LEVEL JET DRIFTS ESEWD INTO THE NCNTRL STATES. AT THE SFC...A NEARLY STATIONARY FRONT WILL LIKELY BE LOCATED JUST OFF SHORE ALONG THE SRN ATLANTIC SEABOARD. MODEL FORECASTS DEVELOP CONVECTION ALONG AND NORTHWEST OF THE BOUNDARY ACROSS ERN GA AND ERN SC DURING THE DAY ON THURSDAY WITH CONVECTION EXPANDING NNEWD JUST OFF THE COAST OF THE CAROLINAS BY LATE AFTERNOON. THIS SCENARIO SEEMS REASONABLE DUE TO ADEQUATE LOW-LEVEL MOISTURE THAT SHOULD BE IN PLACE. HOWEVER...SHEAR SHOULD BE RELATIVELY WEAK AND NO SEVERE ACTIVITY IS EXPECTED. ELSEWHERE...A VIGOROUS UPPER-LEVEL TROUGH WILL AFFECT THE PACIFIC NORTHWEST AS AN IMPRESSIVE 120 KT MID-LEVEL JET PUNCHES INLAND THURSDAY. PRECIPITATION WILL INCREASE DURING THE DAY AND A FEW THUNDERSTORMS ARE POSSIBLE MAINLY NEAR THE COASTAL SECTIONS OF WA AND ORE DUE TO THE STRONG LARGE-SCALE ASCENT AND COLD MID-LEVEL TEMPS. ..BROYLES.. 12/13/2006  From swody2 at goshenarc.org Wed Dec 13 17:14:00 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 13 Dec 2006 12:14:00 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 131714 SWODY2 SPC AC 131713 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1113 AM CST WED DEC 13 2006 VALID 141200Z - 151200Z ...NO SVR TSTM AREAS FORECAST... A STRONG BELT OF WESTERLIES PERSISTS SOUTH OF BAJA THROUGH THE SOUTHEASTERN STATES. AND...A SHORT WAVE IMPULSE EMANATING FROM THIS STREAM CONTINUES TO DEAMPLIFY AS IT LIFTS INTO THE EASTERN CANADIAN PROVINCES. IN THE WAKE OF THIS FEATURE...LOW-LEVEL DRYING HAS OCCURRED ACROSS ALL BUT THE GULF OF MEXICO/FLORIDA PENINSULA AND SOUTH ATLANTIC COASTAL WATERS...WITH ANOTHER STRONG MID/UPPER JET STREAK NOSING OUT OF THE MID LATITUDE PACIFIC THROUGH THE NORTHERN TIER OF THE UNITED STATES. MODELS INDICATE SOME AMPLIFICATION OF SHORT WAVES EMBEDDED WITHIN THIS MORE NORTHERN STREAM WILL OCCUR LATER TODAY THROUGH THURSDAY...BUT THE IMPULSES ARE PROGGED TO REMAIN PROGRESSIVE...INCLUDING ONE ACROSS THE PACIFIC NORTHWEST COAST BY LATE THURSDAY NIGHT. MEANWHILE...A BROAD...BUT GENERALLY WEAK UPPER TROUGH IN THE SOUTHERN STREAM IS FORECAST TO GRADUALLY DEVELOP SOUTHEASTWARD ACROSS THE LOWER RIO GRANDE VALLEY/MEXICAN PLATEAU. ...FLORIDA... MODELS SUGGEST CURRENT LOWER-MID TROPOSPHERIC RIDGE OVER THE FLORIDA PENINSULA WILL WEAKEN LATER TODAY/TONIGHT. AND...IN THE SOUTHWESTERLY FLOW REGIME AHEAD OF LARGE-SCALE UPSTREAM TROUGH...A WEAK IMPULSE IS PROGGED TO MIGRATE ACROSS THE PENINSULA THURSDAY/ THURSDAY NIGHT. TIMING IS A BIT UNCERTAIN...BUT MOISTENING AND WEAKENING INHIBITION WITH THIS FEATURE SHOULD CONTRIBUTE TO AN INCREASINGLY FAVORABLE ENVIRONMENT FOR CONVECTION. DESTABILIZATION WILL PROBABLY NOT BECOME SUFFICIENT FOR PARTICULARLY VIGOROUS CONVECTION...BUT AT LEAST WIDELY SCATTERED THUNDERSTORMS APPEAR POSSIBLE DURING THE AFTERNOON AND EVENING HOURS. ...PACIFIC COAST... MODERATE TO STRONG MOIST LOW-LEVEL ONSHORE FLOW AND MID-LEVEL COOLING...IN WAKE OF SHORT WAVE TROUGH/ASSOCIATED COLD FRONT... WILL PROBABLY PROVE FAVORABLE FOR SCATTERED THUNDERSTORMS TO THE WEST OF THE CASCADES THURSDAY NIGHT. ..KERR.. 12/13/2006  From swody2 at goshenarc.org Thu Dec 14 06:28:22 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Thu, 14 Dec 2006 01:28:22 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 140629 SWODY2 SPC AC 140627 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1227 AM CST THU DEC 14 2006 VALID 151200Z - 161200Z ...NO SVR TSTM AREAS FORECAST... A LARGE BROAD UPPER-LEVEL TROUGH WILL MOVE EWD ACROSS THE OH AND TN VALLEYS INTO THE APPALACHIAN MTNS TONIGHT INTO FRIDAY. AT THE SFC...A NEARLY STATIONARY FRONT WILL LIKELY BE LOCATED IN NRN FL. SOUTH OF THE BOUNDARY ACROSS CNTRL AND SRN FL...LOW-LEVEL MOISTURE SHOULD BE SUFFICIENT FOR SFC-BASED THUNDERSTORM ACTIVITY FRIDAY MORNING AND AFTERNOON. CONSIDERING INSTABILITY SHOULD REMAIN WEAK ACROSS SRN FL...SHEAR PROFILES WILL LIKELY NOT BE STRONG ENOUGH FOR A SEVERE THREAT FRIDAY OR FRIDAY NIGHT ACROSS FL. ELSEWHERE...A VIGOROUS SHORT-WAVE TROUGH ASSOCIATED WITH A 100 KT MID-LEVEL JET WILL MOVE AWAY FROM THE PACIFIC NORTHWEST DURING THE DAY. A FEW THUNDERSTORMS WILL BE POSSIBLE IN THE COASTAL SECTIONS OF FAR NRN CA...ORE AND WA BEFORE LARGE-SCALE ASCENT DECREASES ALONG THE COAST FRIDAY AFTERNOON. ..BROYLES.. 12/14/2006  From swody2 at goshenarc.org Thu Dec 14 16:36:16 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Thu, 14 Dec 2006 11:36:16 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 141636 SWODY2 SPC AC 141636 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1036 AM CST THU DEC 14 2006 VALID 151200Z - 161200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... ACTIVE LARGE-SCALE PATTERN WILL CONTINUE THROUGH THE DAY TWO PERIOD AS STRONG HEIGHT FALLS DEVELOP ACROSS THE NRN PLAINS SWWD THROUGH THE GREAT BASIN IN ADVANCE OF INTENSIFYING LONG WAVE TROUGH. IN THE E...MOBILE UPPER TROUGH WILL TRANSLATE EWD FROM THE GREAT LAKES TO OFF THE NEW ENGLAND COAST BY SATURDAY MORNING. IN THE LOW-LEVELS...DEEP SURFACE LOW WILL DEVELOP EWD FROM SRN BRITISH COLUMBIA INTO ERN SASKATCHEWAN WITH TRAILING COLD FRONT PUSHING SWD THROUGH THE NRN INTERMOUNTAIN REGION AND GREAT BASIN. IN THE E...COLD FRONT WILL PUSH EWD THROUGH THE UPPER GREAT LAKES AND NEW ENGLAND. ...PACIFIC NW COAST... MOIST ONSHORE FLOW IN THE LOW-LEVELS COUPLED WITH COLD MID-LEVEL TEMPERATURES /-32 TO -36 C AT 500 MB/ WILL RESULT IN THE DEVELOPMENT OF STEEP LAPSE RATES AND WEAK CONVECTIVE INSTABILITY. POTENTIAL WILL EXIST FOR TSTMS EMBEDDED IN LARGER PRECIPITATION SHIELD...PARTICULARLY FRIDAY INTO FRIDAY EVENING. ...NRN INTERMOUNTAIN REGION... HERE TOO...ENVIRONMENT WILL BE CHARACTERIZED BY STEEP LAPSE RATES OWING LARGELY TO EWD EXTENSION OF AFOREMENTIONED MID-LEVEL COLD POOL. A FEW TSTMS WILL BE POSSIBLE ALONG SURFACE COLD FRONT AS DEEPER LAYER FORCING FOR ASCENT IS AUGMENTED BY TRAILING PORTION OF SHORT WAVE MOVING THROUGH MT. ...CNTRL/SRN FL PENINSULA... A MOIST AND UNSTABLE AIR MASS WILL PERSIST AHEAD OF WEAK LOW-LEVEL BOUNDARY PUSHING SWD THROUGH THE REGION. CONVERGENCE ALONG THIS FRONT COUPLED WITH LITTLE OR NO CONVECTIVE INHIBITION SHOULD RESULT IN AN INCREASE IN TSTM DEVELOPMENT FRIDAY MORNING AND AFTERNOON. ...NY... FORCING FOR ASCENT ASSOCIATED WITH MIGRATORY SHORT WAVE TROUGH AND RELATIVELY STEEP LAPSE RATES MAY CONTRIBUTE TO THE DEVELOPMENT OF SOME DEEPER CONVECTION AND A FEW LIGHTNING STRIKES ALONG SURFACE FRONT FRIDAY AFTERNOON. THIS ACTIVITY IS EXPECTED TO REMAIN TOO ISOLATED FOR INCLUSION OF AN ADDITIONAL THUNDER AREA. ..MEAD.. 12/14/2006  From swody2 at goshenarc.org Fri Dec 15 16:31:52 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Fri, 15 Dec 2006 11:31:52 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 151632 SWODY2 SPC AC 151631 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1031 AM CST FRI DEC 15 2006 VALID 161200Z - 171200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... INTENSIFICATION OF WRN CONUS TROUGH IS FORECAST DURING THE DAY TWO PERIOD WITH STRONG HEIGHT FALLS DEVELOPING THROUGH THE LOWER CO VALLEY...FOUR CORNERS REGION INTO CNTRL ROCKIES. IN THE LOW-LEVELS...SURFACE COLD FRONT WILL PUSH SEWD THROUGH THE UPPER MS VALLEY AND UPPER GREAT LAKES WITH THIS BOUNDARY EXTENDING SWWD TO DEEPENING LOW PRESSURE OVER CO. COLD FRONT WILL THEN TRAIL SWWD FROM THIS LOW INTO THE LOWER CO VALLEY AND EVENTUALLY INTO SRN ROCKIES. ...S FL AND THE KEYS... A MOIST AND WEAKLY UNSTABLE AIR MASS IS EXPECTED TO PERSIST INVOF STALLED FRONTAL BOUNDARY. WEAK CAPPING COUPLED WITH PERSISTENT LOW-LEVEL CONVERGENCE AND APPROACH OF SRN STREAM IMPULSE /NOW OVER THE NWRN GULF OF MEXICO/ SHOULD ALL CONTRIBUTE TO ISOLATED/SCATTERED TSTM DEVELOPMENT. WEAK LAPSE RATES AND SHEAR WILL PRECLUDE ANY SEVERE THREAT. OTHER MORE ISOLATED TSTM ACTIVITY WILL BE POSSIBLE FROM ERN PORTIONS OF THE GREAT BASIN THROUGH THE FOUR CORNERS REGION INTO CNTRL CO INVOF SURFACE FRONT AS STRONGER HEIGHT FALLS SPREAD EWD. MODEST LAPSE RATES WILL EXIST THOUGH RELATIVELY DRY AIR MASS WILL LIMIT DESTABILIZATION. THIS THREAT SHOULD REMAIN QUITE ISOLATED AND NO GENERAL THUNDER AREA WILL BE INCLUDED ATTM. ..MEAD.. 12/15/2006  From swody2 at goshenarc.org Sat Dec 16 05:42:44 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 16 Dec 2006 00:42:44 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 160543 SWODY2 SPC AC 160541 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1141 PM CST FRI DEC 15 2006 VALID 171200Z - 181200Z ...NO TSTM AREAS FORECAST... ...SYNOPSIS... STRONG MID-UPPER LEVEL SHORTWAVE TROUGH IS EVIDENT IN MOISTURE CHANNEL IMAGERY INVOF 130W...OFFSHORE PACIFIC NW. AS THIS FEATURE MOVES INLAND WRN CONUS...HIGH-AMPLITUDE AND POSITIVELY TILTED TROUGH IS FCST TO EVOLVE. THIS WILL YIELD LONG FETCH OF SW FLOW ALOFT FROM BAJA CA TO GREAT LAKES DAY-2. MEANWHILE...AT SFC...CYCLOGENESIS ALREADY UNDERWAY IN CENTRAL ROCKIES WILL CONTINUE WITH APCH OF UPPER TROUGH. FRONTAL ZONE -- ASSOCIATED WITH NRN STREAM SHORTWAVE NOW OVER SASK -- IS FCST TO MOVE SLOWLY SWD ACROSS PLAINS STATES AND MS VALLEY THROUGH EARLY DAY-2. FRONT THEN SHOULD ACCELERATE SWD OVER CENTRAL/SRN HIGH PLAINS IN RESPONSE TO WEAK FRONTAL-WAVE CYCLONE MOVING NEWD FROM SERN NEB/NERN KS REGION TOWARD GREAT LAKES. MEANWHILE RESIDUAL/QUASISTATIONARY FRONTAL ZONE WILL LINGER ACROSS ERN GULF...FL STRAITS AND BAHAMAS. ...FL KEYS... LOW LEVEL BAROCLINIC ZONE MAY CONTRIBUTE TO CONVECTION OVER FL STRAITS AND PERHAPS KEYS...WITH SOME BUOYANCY REACHING ICING LEVELS BASED ON MODEL FCST SOUNDINGS. HOWEVER...WEAK LAPSE RATES AND LACK OF MORE ROBUST CONVERGENCE INVOF FRONT SHOULD LIMIT CONVECTIVE COVERAGE...AND SHOULD KEEP MOST ACTIVITY S OF KEYS. ALTHOUGH VERY BRIEF/ISOLATED TSTMS CANNOT BE RULED OUT...POTENTIAL APPEARS TOO CONDITIONAL/MRGL FOR GEN THUNDER OUTLOOK ATTM. ...SRN PLAINS TO MO... PREFRONTAL LOW LEVEL WAA REGIME WILL BE WELL UNDERWAY THROUGH PERIOD...ALONG WITH RETURN FLOW OF PARTIALLY MODIFIED AIR MASS THAT WILL HAVE FOLLOWED LONG ANTICYCLONIC TRAJECTORIES OVER PORTIONS GULF OF MEXICO. RELATED MOISTENING MAY CONTRIBUTE TO DEVELOPMENT OF PRECIP AND SHOWERS INVOF LOW LEVEL FRONTAL ZONE LATE IN PERIOD...FROM FROM OK NEWD ACROSS IL. WITH FLOW ALOFT NEARLY PARALLEL TO FRONT AND APPARENT ABSENCE OF SIGNIFICANT MID-UPPER LEVEL ASCENT...LAPSE RATES ALOFT SHOULD REMAIN WEAK. MODEL FCST SOUNDINGS INDICATE SOME BUOYANCY IS POSSIBLE BUT MAINLY IN THERMAL LAYERS SUITABLE FOR WARM-CLOUD PRECIP PRODUCTION. TSTM PROBABILITY IS NONZERO BUT VERY WEAK...AND NOT JUSTIFYING GEN FCST ATTM. ..EDWARDS.. 12/16/2006  From swody2 at goshenarc.org Sat Dec 16 17:03:30 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sat, 16 Dec 2006 12:03:30 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 161704 SWODY2 SPC AC 161702 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1102 AM CST SAT DEC 16 2006 VALID 171200Z - 181200Z ...NO TSTM AREAS FORECAST... ..SYNOPSIS... ACTIVE WAVE TRAIN OF POLAR WESTERLIES WILL EXIST FROM THE GULF OF AK EWD ACROSS CANADA TO THE MARITIMES WHILE LOWER LATITUDE TROUGH BECOMES PROGRESSIVELY MORE CUT OFF OVER THE GREAT BASIN INTO LOWER CO VALLEY. IN THE LOW-LEVELS...PRIMARY BAROCLINIC ZONE WILL EXIST FROM THE GREAT LAKES SWWD INTO THE SRN HIGH PLAINS WITH LOW PRESSURE DEVELOPING SEWD FROM CNTRL CO INTO NERN NM. ...S FL AND THE KEYS... RESIDUAL LOW-LEVEL BOUNDARY WILL PERSIST ALONG THE FL STRAITS INTO CUBA WITH CONVECTION FOCUSED NEAR AND N OF THIS FEATURE. IT APPEARS THAT THE GREATER TSTM COVERAGE WILL REMAIN CONFINED TO S OF THE FORECAST DOMAIN WITH ONLY ISOLATED LIGHTNING STRIKES POSSIBLE FURTHER N INTO THE KEYS AND FAR S FL. ...SRN PLAINS INTO OH VALLEY... LOW-LEVEL WAA REGIME WILL GRADUALLY DEVELOP NEWD ACROSS THE REGION THROUGH THE PERIOD IN ASSOCIATION WITH MIGRATORY LLJ MAXIMUM. THIS WILL SUPPORT THE NEWD ADVECTION OF AN INCREASINGLY MOIST LOW-LEVEL AIR MASS THOUGH POOR MID-LEVEL LAPSE RATES WILL LIMIT INSTABILITY. LATEST SHORT RANGE MODEL GUIDANCE INDICATES THE DEVELOPMENT OF SCATTERED CONVECTION SUNDAY NIGHT FROM OK INTO IL...HOWEVER FORECAST SOUNDINGS SUGGEST THAT THIS ACTIVITY SHOULD REMAIN RELATIVELY SHALLOW AND NOT SUPPORTIVE OF CHARGE SEPARATION. ...CO... A FEW LIGHTNING STRIKES WILL ALSO BE POSSIBLE SUNDAY OVER PORTIONS OF WRN/CNTRL CO AS HEIGHT FALLS/DYNAMIC COOLING RESULT IN THE DEVELOPMENT OF STEEP MID-LEVEL LAPSE RATES AND RESULTANT WEAK CONDITIONAL INSTABILITY. THIS THREAT IS EXPECTED TO REMAIN QUITE ISOLATED AND NO THUNDER AREA WILL BE INCLUDED. ..MEAD.. 12/16/2006  From swody2 at goshenarc.org Sun Dec 17 05:37:07 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 17 Dec 2006 00:37:07 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 170536 SWODY2 SPC AC 170535 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1135 PM CST SAT DEC 16 2006 VALID 181200Z - 191200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... SOME OF MID-UPPER LEVEL LOW -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY OVER CENTRAL/NRN CA -- IS FCST TO EJECT NEWD ACROSS NRN GREAT BASIN AND CENTRAL ROCKIES REGION THROUGH DAY 2. MEANWHILE...SPEED MAX WILL DIG SEWD AROUND SWRN SIDE OF ASSOCIATED HIGH-AMPLITUDE TROUGH...WITH REDEVELOPMENT OF MID-UPPER CYCLONE EXPECTED ACROSS SERN CA/NRN BAJA REGION. RESULTANT VORTEX SHOULD DEEPEN THERE BETWEEN 19/00Z-19/12Z...WHILE SHORTWAVE RIDGE BUILDS TO ITS NE...FROM NE TX TO ERN CO. OPERATIONAL WRF/SPECTRAL MODELS...AS WELL AS THEIR VARIOUS SREF MEMBERS...SHOW STRONG CONSENSUS ON PLACEMENT THIS FEATURE BY END OF PERIOD. MEANWHILE...NRN STREAM SHORTWAVE TROUGH -- NOW APPARENT OVER CENTRAL/NRN BC -- SHOULD AMPLIFY STEADILY AS IT MOVES ESEWD ACROSS NRN PLAINS AND UPPER GREAT LAKES DAY-2. EXPECT ASSOCIATED BAROCLINIC REINFORCEMENT OF FRONTAL ZONE -- NOW ANALYZED FROM LAKE MI SWWD ACROSS CENTRAL OK TO SRN TX PANHANDLE. FRONT THEN SHOULD MOVE SWD ACROSS PORTIONS WRN/CENTRAL TX...AND WWD INTO MOUNTAINS OF CENTRAL/SRN NM. ...S-CENTRAL/SWRN CONUS... MRGL GEN THUNDER POTENTIAL WILL DEVELOP OVER A BROAD AREA BY 19/12Z. PERSISTENT...ELEVATED...LOW LEVEL WAA AND MOIST ADVECTION ARE FCST ALONG AND N OF SFC FRONTAL ZONE...RESULTING IN LONG DURATION OF FAVORABLE ISENTROPIC ASCENT ACROSS MUCH OF SRN PLAINS INTO ERN NM. THIS REGIME ALSO WILL EXTEND ACROSS PORTIONS WRN NM AND CENTRAL/NRN AZ BENEATH NERN QUADRANT OF MID-UPPER LEVEL LOW...IN PROGRESSIVELY MORE NARROW BELT WITH WWD EXTENT. THIS SHOULD RESULT IN EXPANSIVE AREA OF PRECIP BY END OF PERIOD FROM LOWER CO RIVER VALLEY REGION EWD TO PORTIONS N-CENTRAL/NW TX. EPISODIC/EMBEDDED TSTMS ARE POSSIBLE. THETAE ADVECTION AND WEAK CINH WILL HELP TO OVERCOME SMALL MIDLEVEL LAPSE RATES...AMIDST MUCAPES GENERALLY UNDER 500 J/KG. POTENTIAL FOR THUNDER MAY EXTEND BENEATH COLD-CORE REGION OF QUASISTATIONARY VORTEX...WITH SHALLOW TSTMS PRODUCING SMALL HAIL. ORGANIZED SVR POTENTIAL APPEARS TOO CONDITIONAL/MRGL ATTM TO ASSIGN UNCONDITIONAL PROBABILITIES. ..EDWARDS.. 12/17/2006  From swody2 at goshenarc.org Sun Dec 17 16:41:38 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 17 Dec 2006 11:41:38 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 171642 SWODY2 SPC AC 171641 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1041 AM CST SUN DEC 17 2006 VALID 181200Z - 191200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... WAVE TRAIN OF POLAR WESTERLIES WILL EXIST FROM THE GULF OF AK EWD ACROSS CANADA WHILE LOWER LATITUDE TROUGH BECOMES PROGRESSIVELY CUT OFF OVER THE LOWER CO VALLEY. IN THE LOW-LEVELS...PASSAGE OF NRN BRANCH SHORT WAVE TROUGH THROUGH CNTRL CANADA WILL SERVE TO STRENGTHEN SURFACE HIGH OVER THE NRN/CNTRL PLAINS INTO UPPER GREAT LAKES. AS THIS OCCURS...COLD FRONT WILL CONTINUE TO PUSH SWD THROUGH THE MIDDLE INTO LOWER MS VALLEY WWD THROUGH THE SRN PLAINS TO DEVELOPING LOW PRESSURE ALONG THE AZ/NM BORDER. ...SWRN DESERTS INTO THE SRN PLAINS... RATHER COLD MID-LEVEL TEMPERATURES OF -26 TO -28 C AT 500 MB ASSOCIATED WITH EVOLVING UPPER LOW ARE EXPECTED TO LARGELY CONTRIBUTE TO STEEPENING LAPSE RATES INVOF DEVELOPING SURFACE LOW AND TROUGH. INCREASED DEEP-LAYER FORCING FOR ASCENT COUPLED WITH THE RESULTING MARGINAL INSTABILITY SHOULD SUPPORT AN INCREASE IN SHOWER AND ISOLATED/SCATTERED TSTM DEVELOPMENT MONDAY ACROSS PORTIONS OF AZ/NM. FARTHER TO THE E OVER TX...12Z RAOBS AND SURFACE OBSERVATIONS INDICATE LOW-LEVEL MOISTURE INCREASING BELOW QUITE POOR MID-LEVEL LAPSE RATES. HEIGHT FALLS DOWNSTREAM FROM SWRN U.S. UPPER LOW SHOULD CONTRIBUTE TO SOME MID-LEVEL COOLING/STEEPENING LAPSE RATES OVER THE SRN HIGH PLAINS DURING THE PERIOD WITH POCKETS OF WEAK...ELEVATED INSTABILITY DEVELOPING. INCREASING ISENTROPIC ASCENT OWING TO STRENGTHENING SELY LLJ NEAR AND N OF SURFACE COLD FRONT SHOULD SUPPORT AN INCREASE IN SHOWER AND TSTM DEVELOPMENT MAINLY MONDAY NIGHT FROM PORTIONS OF SERN/E-CNTRL NM EWD INTO THE RED RIVER VALLEY. ..MEAD.. 12/17/2006  From swody2 at goshenarc.org Mon Dec 18 05:52:58 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 18 Dec 2006 00:52:58 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 180553 SWODY2 SPC AC 180552 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1152 PM CST SUN DEC 17 2006 VALID 191200Z - 201200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... IN MID-UPPER LEVELS...HIGHLY AMPLIFIED AND POSITIVELY TILTED TROUGH IS EVIDENT IN MOISTURE CHANNEL IMAGERY FROM WY SWWD ACROSS SRN CA AND OVER PACIFIC WATERS WELL OFFSHORE NRN BAJA. AS OFFSHORE SPEED MAX DIGS INTO BASE OF TROUGH...THROUGH DAY-1...CLOSED AND TEMPORARILY CUT-OFF LOW WILL DEVELOP INVOF CA/MEX BORDER. LAST SEVERAL RUNS OF MOST OPERATIONAL MODELS AND SREF MEMBERS HAVE BEEN CONSISTENT IN EJECTING THIS FEATURE NEWD ACROSS 4-CORNERS REGION DURING WHAT IS NOW DAY-2 PERIOD...AND CONFIDENCE IN THIS SCENARIO IS INCREASING WITH TIME. AT SFC...COLD FRONT NOW ANALYZED FROM ERN IL SWWD ACROSS SERN OK...NWRN TX AND SERN NM...IS FCST TO MOVE SWD INTO S-CENTRAL AND SW TX THROUGH DAY-2. AMIDST INCREASING LOW LEVEL PRESSURE/HEIGHT FALLS AND KINEMATIC RESPONSE...ASSOCIATED WITH EJECTING SWRN LOW -- WRN PORTION OF FRONT MAY STALL AND RETREAT SLIGHTLY NWD ACROSS BIG BEND AND TRANS-PECOS REGIONS OF W TX. DURING LATTER HALF OF PERIOD...STRONG LOW LEVEL FRONTOGENESIS IS FCST OVER NM...WITH RESULTING COLD FRONT SWEEPING EWD OVER MUCH OF SRN HIGH PLAINS BY 20/12Z. ...S-CENTRAL/SWRN CONUS TO CENTRAL HIGH PLAINS... WIDELY SCATTERED TSTMS MAY BE ONGOING AT BEGINNING OF PERIOD OVER PORTIONS W TX AND NM...AMIDST STRONG LOW LEVEL WAA REGIME AND MOISTENING AIR MASS ABOVE SFC. THIS REGIME WILL CONTINUE THROUGH MUCH OF DAYLIGHT AND EVENING HOURS...SHIFTING/SPREADING NWD AND EWD AS AIR MASS CONTINUES TO MOISTEN. LIMITED BUOYANCY ALOFT AND RELATIVELY STABLE AIR NEAR SFC SHOULD PRECLUDE ORGANIZED SVR POTENTIAL DESPITE STRENGTHENING DEEP-LAYER SHEAR. BRIEF VERTICAL JUXTAPOSITION OF SFC-BASED WARM SECTOR WITH FAVORABLE VERTICAL SHEAR MAY OCCUR OVER PORTIONS SRN HILL COUNTRY AND LOWER-MIDDLE RIO GRANDE VALLEY REGION OF S TX. HOWEVER...LIKELY NEGATIVE FACTORS FOR SVR INCLUDE WEAK LOW LEVEL FORCING...AND UNFAVORABLE MIDLEVEL LAPSE RATES THAT MAY DRASTICALLY LIMIT BUOYANCY. CONVECTIVE COVERAGE SHOULD INCREASE AFTER DARK ACROSS W TX -- MAINLY ATOP RELATIVELY STABLE BOUNDARY LAYER AND IN ZONE OF STRONGEST LOW LEVEL FRONTOGENETIC FORCING. THIS ACTIVITY MAY DEVELOP/BUILD EWD AND NWD OVER PORTIONS WRN OK AND CENTRAL HIGH PLAINS BY END OF PERIOD. SOME TSTMS OVER CENTRAL/SRN HIGH PLAINS MAY YIELD WINTER PRECIP WHERE LOW LEVEL THERMAL STRATIFICATIONS ARE SUITABLE BENEATH ELEVATED BUOYANT LAYER. ...4-CORNERS REGION... ISOLATED TO WIDELY SCATTERED THUNDER IS POSSIBLE IN ZONE OF MOST INTENSE LARGE SCALE ASCENT/COOLING...BENEATH AND IMMEDIATELY AHEAD OF MID/UPPER LEVEL CYCLONE. ALTHOUGH LOW LEVEL THETAE WILL BE VERY LIMITED...LOW-MIDLEVEL LAPSE RATES MAY BECOME STEEP ENOUGH TO COMBINE WITH MRGL MOISTURE IN SUPPORT OF SHALLOW TSTMS -- SOME OF WHICH MAY BE ACCOMPANIED BY GRAUPEL AND SNOW. ..EDWARDS.. 12/18/2006  From swody2 at goshenarc.org Mon Dec 18 16:48:42 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Mon, 18 Dec 2006 11:48:42 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 181649 SWODY2 SPC AC 181647 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1047 AM CST MON DEC 18 2006 VALID 191200Z - 201200Z ...NO SVR TSTM AREAS FORECAST... ALTHOUGH OBVIOUS KICKER NOT PRESENT...MODELS NOW IN GOOD AGREEMENT THAT UPPER LOW OVER SRN CA WILL TRACK ENEWD ACROSS AZ INTO NRN NM/SRN CO BY 12Z WED. AHEAD OF THIS SYSTEM LARGE SCALE ASCENT AND INFLUX OF MOISTURE FROM WRN GULF WILL PRODUCE AN EXPANDING AREA OF PRECIPITATION FROM NM EWD INTO SRN HIGH PLAINS ON TUESDAY. WHILE INSTABILITY AND LAPSE RATES WILL BE LACKING FOR SEVERE THUNDERSTORMS...ELEVATED CONVECTION EXPECTED TO BECOME MORE WIDESPREAD PARTICULARLY LATER HALF OF THE PERIOD AS MID LEVEL COOLING AND STRONGER SHEAR OVERSPREAD THE SHALLOW BOUNDARY LAYER COLD DOME. IN ADDITION STEEPER LAPSE RATES JUST AHEAD OF COLD UPPER LOW SHOULD RESULT IN SHALLOW CONVECTION DURING THE DAY FROM NERN AZ EWD INTO NRN NM BY EVENING. ..HALES.. 12/18/2006  From swody2 at goshenarc.org Tue Dec 19 06:04:56 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 19 Dec 2006 01:04:56 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 190605 SWODY2 SPC AC 190604 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1204 AM CST TUE DEC 19 2006 VALID 201200Z - 211200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... MOST IMPORTANT MID-UPPER LEVEL FEATURE FOR THIS FCST WILL BE PRONOUNCED CYCLONE -- NOW PRESENT OVER SRN CA AND NRN BAJA. PROGS CONTINUE TO BECOME MORE TIGHTLY CLUSTERED IN STRONG CONSENSUS REGARDING TRACK...EJECTION AND GEOMETRY OF THIS FEATURE DURING NEXT FEW DAYS. THIS LOW SHOULD MOVE ACROSS SRN ROCKIES EARLY IN PERIOD...REACHING CENTRAL HIGH PLAINS BY 21/00Z...THEN TEMPORARILY DECELERATING OVER WRN KS/WRN NEB REGION AS SFC CYCLONE BECOME BETTER COLLOCATED WITH MID/UPPER VORTEX CENTER. ASSOCIATED SFC COLD FRONT IS FCST TO MOVE SEWD ACROSS CENTRAL/SRN TX ...REACHING COASTAL PLAIN AROUND 21/00Z-21/06Z...THEN WEAKENING THEREAFTER. POSITIVELY TILTED SHORTWAVE TROUGH IN SUBTROPICAL STREAM -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY OVER ERN PACIFIC SW OF BAJA -- IS FCST TO LIFT ENEWD ACROSS N-CENTRAL/NERN MEX EARLY IN PERIOD...THEN ACROSS TX COAST AND SRN LA BY 21/00Z. ONLY MINOR TIMING/AMPLITUDE DIFFERENCES EXIST WITH ASSOCIATED VORTICITY PATTERN AMONGST SPECTRAL...NGM...AND OPERATIONAL WRF. ...S-CENTRAL/SE TX... AT LEAST MRGL/CONDITIONAL SVR POTENTIAL MAY DEVELOP...BOUNDED ON W BY COLD FRONT...ON N BY PROGRESSIVELY MORE STABLE BOUNDARY LAYER...AND BY WEAKENING SHEAR WITH SWD EXTENT OVER DEEP S TX AND GULF. CONTINUING ELY SFC TRAJECTORIES OVER MUCH OF SRN PLAINS...EMANATING FROM STRONG MIDWESTERN/OH VALLEY ANTICYCLONE...WILL MAINTAIN RELATIVELY LOW THETAE AIR MASS AND KEEP OPTIMALLY HIGH THETAE AIR FROM PENETRATING VERY FAR INLAND. EXCEPTION MAY BE OVER S-CENTRAL/SE TX WHERE ISALLOBARICALLY FORCED BOUNDARY LAYER VEERING...TO MORE SLY/SELY DIRECTION...ALLOWS NARROW WEDGE OF MARINE AIR TO MOVE INLAND PRIOR TO COLD FROPA...CHARACTERIZED BY MID 60S TO NEAR 70 F DEW POINTS. RICH MOISTURE AND SUBTLE LARGE SCALE ASCENT ASSOCIATED WITH SRN STREAM TROUGH EACH MAY OFFSET VERY SMALL MIDLEVEL LAPSE RATES AND ALLOW ENOUGH BUOYANCY TO SUPPORT SFC-BASED TSTMS WITH AT LEAST MRGL/CONDITIONAL SVR POTENTIAL. DEEP-LAYER VERTICAL SHEAR IS FCST TO STRENGTHEN WITH TIME THROUGH 21/00Z AS SERN EDGE OF TIGHTENING MIDLEVEL HEIGHT GRADIENT SUPERIMPOSES ITSELF ATOP NRN PORTION OF MARINE AIR. FCST SOUNDINGS INDICATE ENLARGED LOW LEVEL HODOGRAPH AND 40-50 KT OF 0-6 KM SHEAR. ..EDWARDS.. 12/19/2006  From swody2 at goshenarc.org Tue Dec 19 17:24:55 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Tue, 19 Dec 2006 12:24:55 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 191725 SWODY2 SPC AC 191724 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1124 AM CST TUE DEC 19 2006 VALID 201200Z - 211200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... MODELS REMAIN CONSISTENT WITH LARGE/DEEP UPPER LOW TRACKING NEWD FROM THE SRN ROCKIES INTO THE CENTRAL HIGH PLAINS REGION DURING DAY 2. ALTHOUGH MODELS DIFFER SLIGHTLY WITH THE TIMING OF A POSITIVELY-TILTED SRN STREAM IMPULSE...THIS FEATURE SHOULD TRACK NEWD ACROSS THE TX COASTAL PLAIN AND LA DURING THE FIRST HALF OF THE PERIOD. SURFACE COLD FRONT IS EXPECTED TO SPREAD ESEWD THROUGH SRN/ ERN TX...REACHING DEEP S TX...TX COASTAL PLAIN TO WRN LA DURING 21/00-06Z. SURFACE BOUNDARY...CURRENTLY EXTENDING EWD FROM DEEP S TX INTO THE GULF OF MEXICO...IS EXPECTED TO MOVE NWD ON DAY 2 REACHING THE UPPER TX COAST REGION BY 21/00Z...AND THEN MAY SPREAD JUST INLAND OVER SW LA WEDNESDAY NIGHT. ...S-CENTRAL/SE TX TO SW LA... FORCING FOR ASCENT ASSOCIATED WITH THE LEAD SRN STREAM IMPULSE SHOULD BE EXITING MUCH OF THE TX COASTAL PLAIN WEDNESDAY MORNING... WITH RESULTANT TEMPORARY DECELERATION OF SWLY MID LEVEL FLOW. HOWEVER...HEIGHT GRADIENT SHOULD TIGHTEN SOME ALONG SERN PERIPHERY OF UPPER LOW AS NEXT MID/UPPER LEVEL JET MAX TRANSLATES THROUGH THIS PORTION OF UPPER SYSTEM...WEDNESDAY AFTERNOON TO WEDNESDAY NIGHT. DESPITE SURFACE DEWPOINTS IN THE MID 60S IN ADVANCE OF THE COLD FRONT...WEAK LAPSE RATES AND LIMITED SURFACE HEATING ARE EXPECTED TO RESULT IN MARGINAL INSTABILITY WITHIN WARM SECTOR AIR MASS. ALTHOUGH ASCENT IS EXPECTED TO BE WEAK FROM DEEP S TX TO SW LA...AS STRONGER HEIGHT FALLS OCCUR FARTHER N AHEAD OF THE UPPER LOW... FRONTAL ASCENT SHOULD BE SUFFICIENT FOR SURFACE BASED TSTM DEVELOPMENT. WEAK INSTABILITY COMBINED WITH INCREASING DEEP LAYER SHEAR SUGGESTS AT LEAST A MARGINAL/CONDITIONAL SEVERE POTENTIAL. SOME CONCERN FOR AN ISOLATED TORNADO THREAT MAY EXIST AT THE INTERSECTION OF THE ADVANCING COLD FRONT AND NWD MOVING SURFACE BOUNDARY WHERE FORECAST SOUNDINGS INDICATE LARGE LOW LEVEL HODOGRAPHS. THIS THREAT WOULD BE FROM PARTS OF THE MIDDLE TO UPPER TX COAST WEDNESDAY AFTERNOON AND INTO SW LA WEDNESDAY NIGHT. HOWEVER...THIS OUTLOOK WILL MAINTAIN LOW PROBABILITIES FOR SEVERE GIVEN WEAK INSTABILITY AND WEAK UPPER FORCING. ..PETERS.. 12/19/2006  From swody2 at goshenarc.org Wed Dec 20 05:54:14 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 20 Dec 2006 00:54:14 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 200554 SWODY2 SPC AC 200554 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1154 PM CST TUE DEC 19 2006 VALID 211200Z - 221200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... STRONG MID/UPPER LEVEL CYCLONE -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY OVER SRN AZ/WRN NM -- IS FCST TO LIFT NEWD ACROSS SRN HIGH PLAINS AND PIVOT OVER KS THROUGH PERIOD. MOST SREF MEMBERS AND OPERATIONAL MODELS INDICATE CYCLONE TRACK SOMEWHAT S OF PREVIOUS PROGS ACROSS KS...BEFORE DEEP-LAYER CYCLONE BECOMES MORE VERTICALLY STACKED AROUND 22/12Z. MOST PROGS DO DIFFER IN SPEED OF SYSTEM ALONG ESSENTIALLY SAME TRACK AFTER 22/00Z...WITH OPERATIONAL SPECTRAL AND SREF/RSM MEMBERS PLACING LOW IN IA...MOST ETA/ETA-KF MEMBERS OVER NE/MO BORDER REGION...AND WRF BACK IN NERN KS. THIS MAY BE RELATED TO HOW THESE MODELS HANDLE CYCLOIDAL MOTION OF MIDLEVEL VORTEX S OF UPPER LOW...AS ASSOCIATED VORTICITY MAXIMA PIVOT AROUND SRN/ERN SEMICIRCLES OF BROADER CIRCULATION. CONSENSUS FAVORS ETA/ETA-KF TRACK. THESE SPEED/TIMING DIFFERENCES TRANSLATE TO SFC...WHERE SPECTRAL RUNS FCST COLD FRONT ACROSS NWRN MS AND LA...WELL AHEAD OF MOST OTHERS. GIVEN LACK OF SUBSTANTIAL MID-UPPER SUPPORT FOR ERN SURGE OF LOW LEVEL FRONT...WILL TREND FCST TOWARD SLOWER WRF/ETA BASED FCST AT SFC. ...W GULF COASTAL PLAIN...MS DELTA REGION... CONDITIONAL SVR PROBABILITY EXISTS -- MAINLY IN FORM OF AT LEAST MRGL TORNADO THREAT AND PERHAPS DAMAGING WIND. ONCE MESOSCALE UNCERTAINTIES ARE BETTER RESOLVED...UNCONDITIONAL PROBABILITIES MAY BE RAISED ENOUGH TO WARRANT CATEGORICAL OUTLOOK. AHEAD OF SFC COLD FRONT...EXPECT DEEPLY MOIST PROFILES AND ASSOCIATED WEAK LAPSE RATES...BUT FAVORABLE KINEMATIC PROFILES. IF SUSTAINED/SFC-BASED TSTMS CAN FORM...VERTICAL SHEAR WILL BE FAVORABLE FOR SUPERCELLS AND SMALL BOWS. FCST SOUNDINGS SUGGEST CONSIDERABLE VEERING WITH HEIGHT AND AROUND 40-50 KT SHEAR IN 0-6 KM LAYER. CURRENT SFC ANALYSIS...FCST TRAJECTORIES AND MODIFIED WRF SOUNDINGS INDICATE MID 60S TO NEAR 70 F SFC DEW POINTS WILL PENETRATE INLAND EXTREME SE TX AND SRN LA...PERHAPS AS FAR N AS I-20 BY END OF PERIOD. BOUNDARY LAYER FORCING INVOF FRONT IS FCST TO DIMINISH WITH TIME AS STRONGEST PRESSURE FALLS MOVE AWAY FROM AREA...HOWEVER SBCINH SHOULD BE WEAK IN MARINE AIR MASS. THIS WILL LEAVE DEVELOPMENT STRONGLY DEPENDENT ON MESOSCALE FOCI SUCH AS OUTFLOWS...FRONTAL/PREFRONTAL CONFLUENCE LINES AND/OR DIURNAL/DIFFERENTIAL HEATING BOUNDARIES. BREAKS IN PRECIP/CLOUD COVER AND ASSOCIATED INSOLATION MAY ENHANCE BUOYANCY DURING DAYLIGHT HOURS...OTHERWISE MLCAPES SHOULD REMAIN GENERALLY AOB 500 J/KG. ..EDWARDS.. 12/20/2006  From swody2 at goshenarc.org Wed Dec 20 17:22:04 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Wed, 20 Dec 2006 12:22:04 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 201722 SWODY2 SPC AC 201721 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1121 AM CST WED DEC 20 2006 VALID 211200Z - 221200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... 12Z GFS/NAM HAVE COME INTO BETTER AGREEMENT WITH THE TEMPORAL RESOLUTION OF THE UPPER LOW AS IT TRACKS FROM SW KS AND TX PANHANDLE REGION NEWD TO THE EAST CENTRAL PLAINS/MID-LOWER MO VALLEY BY 22/12Z. THIS TRANSLATES TO THE SURFACE WITH MORE CONSISTENCY IN THE SPEED OF THE COLD FRONT AS IT SHOULD SPREAD SLOWLY EWD ACROSS THE MID AND LOWER MS VALLEY. ...LOWER MS VALLEY... DESPITE MOISTURE SPREADING NWD AHEAD OF THE COLD FRONT WITH SURFACE DEWPOINTS IN THE MID 60S REACHING PARTS OF NERN LA AND CENTRAL MS... EXTENSIVE CLOUDINESS SHOULD CONTINUE TO LIMIT THE POTENTIAL FOR SURFACE HEATING...AND THE DEVELOPMENT OF STRONGER INSTABILITY. THIS COMBINED WITH GENERALLY WEAK LAPSE RATES IS EXPECTED TO RESULT IN MARGINAL INSTABILITY. UPPER FORCING SHOULD REMAIN WEAK ACROSS THE LOWER MS VALLEY ON DAY 2...GIVEN SMALL HEIGHT FALLS LOCATED TO THE S OF THE TRACK OF THE UPPER LOW. SOME ASCENT SHOULD OCCUR AS WEAK SRN STREAM IMPULSES TRAVERSE GULF COAST PORTION OF LOWER MS VALLEY. NONETHELESS...WEAK UPPER FORCING COMBINED WITH FRONTAL ASCENT AND AMPLE LOW/MID LEVEL MOISTURE WILL SUPPORT CONTINUATION OF SHOWERS WITH EMBEDDED TSTMS FROM THE NWRN GULF COAST REGION NWD TO THE MID MS/LOWER OH VALLEYS. STRENGTH OF WIND FIELDS WITH SUFFICIENT DEEP LAYER SHEAR SUGGEST POTENTIAL FOR ISOLATED THUNDERSTORM INTENSIFICATION AND A MARGINAL SEVERE THREAT THROUGH THE FORECAST PERIOD. FORECAST SOUNDINGS INDICATE LOW LEVEL HODOGRAPH CURVATURE MAY SUPPORT AN ISOLATED TORNADO THREAT...IN ADDITION TO DAMAGING WINDS WITH THE STRONGER ACTIVITY. WEAK INSTABILITY AND UNCERTAINTY IN POTENTIAL COVERAGE OF SEVERE THREAT WILL MAINTAIN LOW SEVERE PROBABILITIES WITH THIS OUTLOOK. ..PETERS.. 12/20/2006  From swody2 at goshenarc.org Sun Dec 31 17:24:19 2006 From: swody2 at goshenarc.org (Severe Weather Outlook - Day 2) Date: Sun, 31 Dec 2006 12:24:19 -0500 Subject: [SWODY2] SWODY2 Message-ID: ACUS02 KWNS 311728 SWODY2 SPC AC 311727 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1127 AM CST SUN DEC 31 2006 VALID 011200Z - 021200Z ...NO SVR TSTM AREAS FORECAST... ...ERN SEABOARD/FLORIDA... AN UPPER-LEVEL TROUGH OVER THE MS VALLEY AT THE BEGINNING OF THE PERIOD WILL MOVE EWD INTO THE ATLANTIC STATES BY MONDAY AFTERNOON. A COLD FRONT WILL EXTEND SSWWD FROM THE CAROLINAS TO THE FL PANHANDLE AND THIS FEATURE WILL MOVE QUICKLY EWD TOWARD THE ATLANTIC COAST BY MIDDAY. SCATTERED THUNDERSTORMS COULD BE ONGOING ALONG AND AHEAD OF THE FRONT ESPECIALLY ACROSS SC...GA AND NRN FL EARLY IN THE DAY. THUNDERSTORM COVERAGE MAY EXPAND BY AFTERNOON AS SFC TEMPS WARM. ALTHOUGH LARGE-SCALE ASCENT SHOULD BE RELATIVELY STRONG DUE TO THE APPROACHING UPPER-LEVEL TROUGH...FORECAST SOUNDINGS MONDAY AFTERNOON ACROSS THE REGION SHOW WEAK INSTABILITY IN PLACE AHEAD OF THE FRONT. HOWEVER...STRONG SHEAR PROFILES IN THE ERN CAROLINAS DUE TO A 90 KT MID-LEVEL JET AND STEEPENING LOW-LEVEL LAPSE RATES ACROSS CNTRL FL MAY BE ENOUGH FOR A FEW MARGINALLY SEVERE THUNDERSTORMS MONDAY AFTERNOON. THE MAIN THREAT WOULD LIKELY BE STRONG GUSTY WINDS. ..BROYLES.. 12/31/2006