CATEGORICAL OUTLOOK
TORNADO OUTLOOK
WIND OUTLOOK
HAIL OUTLOOK
SPC AC 291252 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0752 AM CDT TUE MAY 29 2012 VALID 291300Z - 301200Z ...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON INTO TONIGHT FROM THE UPPER OH VALLEY EWD INTO NEW ENGLAND AND THE MID-ATLANTIC COAST... ...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON AND TONIGHT FOR PARTS OF THE CNTRL/SRN PLAINS... ...SYNOPSIS... AN UPPER-LEVEL LOW ALONG THE MN/ONTARIO BORDER WILL GRADUALLY EVOLVE INTO AN OPEN WAVE DURING THE D1 PERIOD AS IT PROGRESSES ENEWD INTO WRN QUEBEC. THIS SYSTEM WILL BE ATTENDED BY A BELT OF 50-60 KT MIDLEVEL FLOW AND 500-MB HEIGHT FALLS OF 60-120 M/12-HR WHICH WILL OVERSPREAD THE ST. LAWRENCE VALLEY...LOWER GREAT LAKES...AND NEW ENGLAND. ELSEWHERE...MIDLEVEL HEIGHTS WILL REBOUND SLIGHTLY ACROSS THE GREAT PLAINS IN THE WAKE OF THE GREAT LAKES SYSTEM...AND AHEAD OF AN UPSTREAM UPPER SHORT-WAVE TROUGH TRANSLATING SEWD FROM SRN BRITISH COLUMBIA THROUGH THE NRN ROCKIES. AT THE SURFACE...A COLD FRONT INITIALLY FROM LOW PRESSURE OVER WRN QUEBEC SWWD THROUGH SWRN ONTARIO INTO THE MID-MS VALLEY WILL ADVANCE EWD INTO NEW ENGLAND AND THE MID-ATLANTIC STATES BY 30/12Z. THE WRN EXTENSION OF THIS BOUNDARY WILL REMAIN QUASI-STATIONARY...STRETCHING FROM THE OZARKS WWD TO AN AREA OF LOW PRESSURE OVER WRN OK AT 30/00Z. A DRYLINE IS FORECAST TO EXTEND SWD FROM THE LOW PRESSURE INTO W-CNTRL TX AND WRN PARTS OF THE EDWARDS PLATEAU REGION AT THIS TIME. MEANWHILE...TROPICAL DEPRESSION BERYL WILL BEGIN TO ACCELERATE NEWD FROM S-CNTRL GA THROUGH THE LOWER SAVANNAH RIVER VALLEY. ...NEW ENGLAND INTO THE LOWER GREAT LAKES AND MID-ATLANTIC STATES... AN EXPANSIVE PRE-FRONTAL BAND OF TSTMS IS ONGOING AS OF 12Z FROM SWRN ONTARIO/LAKE ERIE SWWD INTO NRN KY...LIKELY FORCED BY THE LEADING EDGE OF STRONGER HEIGHT FALLS ASSOCIATED WITH UPPER SYSTEM MOVING THROUGH THE GREAT LAKES. BASED ON SATELLITE IMAGERY...DOWNSTREAM AIR MASS ACROSS NY/PA SHOULD EXPERIENCE STRONG DAYTIME HEATING. WHEN COUPLED WITH DEWPOINTS IN THE 60S AND MIDLEVEL LAPSE RATES OF AROUND 7 C/KM...ENVIRONMENT WILL BECOME MODERATE-STRONGLY UNSTABLE WITH MLCAPE VALUES INCREASING TO 2000-3000 J/KG. THIS DESTABILIZATION ALONG WITH THE EWD PROGRESSION OF UPPER TROUGH WILL SUPPORT A MARKED INCREASE IN STORM VIGOR AND COVERAGE BY EARLY AFTERNOON ALONG COLD FRONT AND/OR LEADING EDGE OF COLD POOL ASSOCIATED WITH THE ONGOING STORMS. THE STRONGEST MID- AND HIGH-LEVEL WIND FIELD ASSOCIATED WITH THE TROUGH IS FORECAST TO LAG THE WARM SECTOR TO THE W...LIMITING DEEP-LAYER SHEAR MAGNITUDES TO GENERALLY 30-40 KT. EXPECT THE STRONG INSTABILITY TO COMPENSATE WITH ENVIRONMENT BECOMING SUPPORTIVE OF MULTIPLE ORGANIZED STORM MODES...INCLUDING BOWING LINE SEGMENTS AND SUPERCELLS WITH THE POTENTIAL FOR CORRIDORS OF WIND DAMAGE AND SWATHS OF LARGE HAIL. THE GREATEST RISK FOR A TORNADO OR TWO WILL EXIST ALONG WARM FRONT OVER NEW ENGLAND WHERE LOW-LEVEL SHEAR WILL BE ENHANCED. THE SEVERE WEATHER THREAT WILL SPREAD EWD TOWARD THE MID-ATLANTIC COAST AND WRN NEW ENGLAND BY LATE AFTERNOON INTO THIS EVENING BEFORE GRADUALLY DIMINISHING LATER TONIGHT WITH THE STABILIZATION OF THE BOUNDARY LAYER. ...CNTRL/SRN PLAINS... AS MENTIONED ABOVE...MIDLEVEL HEIGHTS WILL REBOUND SLIGHTLY TODAY WITH PASSAGE OF SYNOPTIC SYSTEM TO THE NE. AS SUCH...DAYTIME HEATING AND LOW-LEVEL CONVERGENCE ALONG STATIONARY FRONT AND DRYLINE WILL BE THE PRIMARY MECHANISMS FORCING TSTM DEVELOPMENT THIS AFTERNOON. LATEST CONVECTION-ALLOWING AND MESOSCALE MODEL GUIDANCE INDICATE THAT THE HIGHEST PROBABILITY OF STORM INITIATION WILL BE ALONG FRONT OVER SRN KS/NRN OK BETWEEN 29/21Z-30/00Z. OTHER ISOLATED STORMS WILL BE POSSIBLE AT THIS TIME SWWD ALONG THE DRYLINE INTO W-CNTRL TX. THE COMBINATION OF STRONG DAYTIME HEATING...BOUNDARY LAYER DEWPOINTS IN THE 60S...AND STEEP MIDLEVEL LAPSE RATES ARE EXPECTED TO YIELD A MODERATE-STRONGLY UNSTABLE AIR MASS BY MID-LATE AFTERNOON WITH MLCAPE VALUES OF 2000-3500 J/KG. WHEN COUPLED WITH A VERTICALLY VEERING WIND PROFILE AND 40-50 KT OF EFFECTIVE BULK SHEAR...SETUP WILL BE QUITE FAVORABLE FOR SUPERCELLS CAPABLE OF VERY LARGE HAIL AND PERHAPS A COUPLE TORNADOES WITHIN THE FIRST FEW HOURS AFTER STORM INITIATION. WITH TIME...CONVECTION-ALLOWING MODEL GUIDANCE IS SUGGESTIVE OF UPSCALE GROWTH INTO A SEWD-MOVING BOW ECHO SYSTEM WHICH WOULD SIGNAL A TRANSITION TO A MORE WIDESPREAD DAMAGING WIND THREAT ACROSS PORTIONS OF OK...PERHAPS INTO NRN TX TONIGHT. ...FL/ERN GA/SRN SC... THE COMBINATION OF A MOIST BOUNDARY LAYER AND BREAKS IN CLOUD COVER WILL YIELD POCKETS OF MODEST DESTABILIZATION TODAY INVOF BERYL. GIVEN A STILL MODESTLY STRONG WIND FIELD...A LOW PROBABILITY RISK FOR DAMAGING WINDS AND A TORNADO WILL CONTINUE THROUGH THIS AFTERNOON. ..MEAD/ROGERS.. 05/29/2012 NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z CURRENT UTC TIME: 1505Z (10:05AM), RELOAD THIS PAGE TO UPDATE THE TIME 
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