ACUS1 KMKC 021055 SWODY1 MKC AC 021055 CONVECTIVE OUTLOOK...REF AFOS NMCGPH94O. VALID 021200Z - 031200Z REF WW NUMBER 0489...VALID TIL 1300Z REF WW NUMBER 0490...VALID TIL 1500Z THERE IS A MDT RISK OF SVR TSTMS OVER SERN OH...MUCH OF PA...EXTREME SRN NY...WV...VA...MD...DE...MUCH OF NJ AND NERN NC. THE MDT RISK IS TO THE RIGHT OF A LINE FROM 15 S EWN GSO 5I3 30 ESE LUK CMH YNG 30 SE ROC 45 WSW ALB NEL. THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 15 ESE SAV 55 E RMG 30 SW MKL PAH MIE MTC ...CONT... 15 N EFK EEN ACK. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 20 NNE SSI GAD MEM P02 10 NW BMI 20 E AUW MQT. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 40 WNW OFK 30 S EAR CYS 30 NNE RKS ENV TPH 30 NE FAT 45 NW SAC 25 SE MFR 25 SE YKM 40 ENE GEG 40 SW CTB LWT 4BQ 35 SE RAP 40 WNW OFK. ...SEVERE THUNDERSTORM FORECAST DISCUSSION... HUDSON BAY VORTEX WILL REMAIN ANCHORED IN PLACE TODAY WITH STRONG RIDGE NOT EXPECTED TO MOVE ALONG THE GULF COAST REGION. THIS IS RESULTING IN VERY STRONG WLY FLOW ACROSS THE NRN HALF OF THE U.S. EARLY THIS MORNING WATER VAPOR IMAGERY SUGGESTS SEVERAL SHORTWAVE TROUGHS WILL ROTATE AROUND VORTEX AND AFFECT THE NERN U.S./MIDDLE ATLANTIC REGION. THE MAIN SPEED MAX OF CONCERN /H5 AROUND 80KT/ IS APPROACHING SRN LAKE MI ATTM. WITH RIDGE AXIS OVER THE SRN PLAINS THIS SPEED MAX SHOULD DIG SLIGHTLY SOUTH OF EAST AND APPROACH WV/PA BY EARLY AFTERNOON. IN ADDITION...UPPER LEVELS WILL BE HIGHLY DIFLUENT WITH RIDGE POSITIONED SW OF REGION. AS A RESULT...FORECAST SHEAR PROFILES STRONGLY SUPPORT SEVERE THUNDERSTORMS WITH SIGNIFICANT SPEED SHEAR AND DEEP LAYERED VEERING EXPECTED. SURFACE DEW POINTS ARE ALREADY IN THE LOWER 60S AS FAR NE AS SRN OH...AND THIS AIRMASS WILL RETURN NEWD AHEAD OF THIS FEATURE THROUGH THE OH VALLEY INTO PA BY MID AFTERNOON. WITH AFTERNOON TEMPERATURES EXPECTED TO CLIMB INTO THE LOWER 80S TO MID 80S...SURFACE-BASED CAPE VALUES SHOULD EXCEED 2000 J/KG OVER MUCH OF THE MODERATE RISK AREA. IT APPEARS AIRMASS WILL QUICKLY DESTABILIZE OVER THE OH VALLEY BY MID DAY WITH CONVECTION EXPECTED TO DEVELOP ALONG ADVANCING COLD FRONT AHEAD OF SPEED MAX. COMBINATION OF SHEAR AND INSTABILITY SUGGESTS A FEW SUPERCELLS ARE POSSIBLE WITH ISOLATED TORNADOES. HOWEVER DAMAGING WIND AND LARGE HAIL SHOULD BE MAIN THREAT. ACTIVITY WILL QUICKLY ORGANIZE OVER ERN OH/WRN PA AND SPREAD EWD DURING THE LATE AFTERNOON/EVENING HOURS. FARTHER SOUTH...ISOLATED SEVERE STORMS SHOULD DEVELOP OVER THE HIGHER TERRAIN OF CENTRAL/SRN APPALACHIANS BY MID AFTERNOON. ALTHOUGH STRONGER LOW LEVEL FORCING IS EXPECTED TO REMAIN ALONG FRONT TO THE NORTH...HIGHLY DIFLUENT UPPER LEVEL FLOW WILL AID UPDRAFT ORGANIZATION. ANY STORMS THAT DEVELOP ACROSS THIS REGION WILL SPREAD SEWD ACROSS THE COASTAL CAROLINAS DURING THE EVENING HOURS. ..DARROW.. 06/02/98
