The SPC is forecasting ...severe storms expected over parts of the northeastern states and new england today through early tonight.... Please read the latest public statement about this event.
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SPC AC 010548 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1148 PM CST THU NOV 30 2006 VALID 011200Z - 021200Z ...THERE IS A MDT RISK OF SVR TSTMS FOR PORTIONS OF MD...PA AND NY... ...THERE IS A SLGT RISK OF SVR TSTMS FROM NC THROUGH THE MID ATLANTIC...NERN U.S. AND ERN PORTIONS OF THE OH VALLEY... ...SYNOPSIS... SHORTWAVE TROUGH OVER THE LOWER MS VALLEY THIS EVENING WILL EJECT NEWD INTO THE LOWER GREAT LAKES AND NERN U.S. BY FRIDAY AFTERNOON. ATTENDANT SURFACE CYCLONE CURRENTLY OVER WRN KY WILL OCCLUDE AS IT LIFTS NWD INTO THE GREAT LAKES BY LATE MORNING. HOWEVER...SECONDARY CYCLOGENESIS IS EXPECTED FARTHER EAST ACROSS NY AS STRONG FORCING FOR ASCENT WITHIN DIVERGENT EXIT REGION OF CYCLONIC UPPER JET LIFTS NEWD INTO THIS REGION. ARCTIC FRONT CURRENTLY EXTENDS FROM THE UPPER GREAT LAKES AREA SWWD TO A SURFACE LOW NEAR WRN KY THEN SWD INTO THE CNTRL GULF AREA. NRN PORTION OF THIS BOUNDARY WILL MOVE LITTLE DUE TO ACCELERATING SLY FLOW IN WARM SECTOR ACCOMPANYING CYCLOGENESIS. HOWEVER...SRN PORTION OF THIS BOUNDARY WILL CONTINUE EAST THROUGH THE SERN STATES...MID ATLANTIC AND NERN U.S. BEFORE MOVING OFFSHORE FRIDAY NIGHT. ...MID ATLANTIC THROUGH NERN STATES AND ERN PORTION OF OH VALLEY... LOW LEVEL JET WILL STRENGTHEN TO IN EXCESS OF 70 KT FROM NC INTO THE NERN U.S. AS SECONDARY CYCLONE DEEPENS OVER NY. LOW TO MID 60S BOUNDARY LAYER DEWPOINTS CURRENTLY RESIDE ACROSS VA AND THE CAROLINAS. THE STRENGTHENING SLY LOW LEVEL JET WILL CONTRIBUTE TO NWD ADVECTION OF THIS MOISTURE THROUGH FRIDAY. AS UPPER TROUGH EJECTS NEGATIVELY TILTED INTO THE NERN STATES...A MID LEVEL THERMAL TROUGH WILL SPREAD OVER A PORTION OF THE WARM SECTOR AND CONTRIBUTE TO SLIGHTLY BETTER MID LEVEL LAPSE RATES THAN IN THURSDAYS WARM SECTOR. PRE-FRONTAL MUCAPE AROUND 500 J/KG WILL BE POSSIBLE...ESPECIALLY IF POCKETS OF HEATING CAN DEVELOP. INSTABILITY COULD BE SLIGHTLY HIGHER WITHIN ZONE OF FORCED DEEP LAYER ASCENT ALONG SURFACE FRONT. CONVECTION WILL LIKELY BE ONGOING ALONG THE FRONT OVER PORTIONS OF THE OH VALLEY EARLY FRIDAY. STRENGTHENING LOW-MID LEVEL WIND FIELDS AND INCREASING ISALLOBARIC AND FRONTOGENETIC FORCING SHOULD MAINTAIN A FORCED LINE OF STORMS EWD THROUGH THE NERN STATES. THIS ACTIVITY WILL LIKELY STRENGTHEN AS THE ATMOSPHERE UNDERGOES FURTHER DESTABILIZATION DURING THE AFTERNOON. LOW LEVEL AND CLOUD LAYER SHEAR PROFILES WITH LARGE HODOGRAPHS WILL SUPPORT ORGANIZED STORMS INCLUDING LEWP/BOWS WITHIN THE LINE. A FEW SUPERCELL STRUCTURES WILL ALSO BE POSSIBLE ALONG THE LINE OR IF STORMS MANAGE TO DEVELOP AHEAD OF THE LINE. WITH THE LOW LEVEL JET STRENGTHENING TO 60+ KT JUST OFF THE SURFACE...POTENTIAL WILL EXIST FOR THIS MOMENTUM TO BE TRANSPORTED DOWN TO THE SURFACE AS FRONTAL CONVECTION SPREADS EWD. PRIMARY THREAT WILL BE DAMAGING WIND...BUT AN ISOLATED TORNADO OR TWO MAY ALSO BE POSSIBLE. GREATEST THREAT FOR SWATHS OF WIDESPREAD DAMAGING WIND IS EXPECTED IN MODERATE RISK AREA WITH MORE ISOLATED WIND POTENTIAL IN SLIGHT RISK REGION. ...NC... STRONGEST FORCING WILL LIFT N OF THIS REGION. THIS ALONG WITH MODEST LAPSE RATES AND INSTABILITY MAY SERVE TO LIMIT OVERALL SEVERE THREAT. HOWEVER...GIVEN STRENGTH OF LOW LEVEL WIND FIELDS...WILL MAINTAIN A THREAT FOR ISOLATED WIND DAMAGING WITH ANY CONVECTION DEVELOPING ALONG OR JUST AHEAD OF THE FRONT. ..DIAL.. 12/01/2006 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z