ACUS1 KMKC 311959 SWODY1 MKC AC 311958 CONVECTIVE OUTLOOK...REF AFOS NMCGPH94O. VALID 311930Z - 011200Z REF WW NUMBER 0477...VALID TIL 2300Z REF WW NUMBER 0478...VALID TIL 0000Z REF WW NUMBER 0479...VALID TIL 0200Z REF WW NUMBER 0480...VALID TIL 0200Z THERE IS A MDT RISK OF SVR TSTMS OVER SOUTHWEST NEW HAMPSHIRE... SOUTHERN VERMONT...ALL BUT UPSTATE NEW YORK AND EASTERN LONG ISLAND...WESTERN PARTS OF MASSACHUSETTS AND CONNECTICUT...NORTHERN AND CENTRAL NEW JERSEY...PENNSYLVANIA...NORTHERN MARYLAND... NORTHERN AND FAR WESTERN VIRGINIA...WEST VIRGINIA...MUCH OF OHIO...CENTRAL AND SOUTHERN INDIANA...EXTREME SOUTHEAST ILLINOIS... MOST OF KENTUCKY...AND EXTREME NORTHERN TENNESSEE. THE MODERATE RISK IS TO THE RIGHT OF A LINE FROM 25 SSW ART 15 E LEB ISP 20 S TTN 15 WSW BWI 25 SW SHD 30 W TRI 40 NE DYR 15 N PAH 35 E SLO 25 S FWA 15 N FDY 35 W CLE. THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 30 NNE HAT 30 ESE RWI 25 NW SOP AVL CHA 20 N MSL 20 NE MEM ARG 45 SW BLV 20 SW LAF 10 N FWA 50 N CLE 40 N BUF 25 NNW MSS 45 N BML 15 SW PSM 15 S PVD. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM MYR ATL 15 ENE CBM 35 WSW MEM 35 W ARG UNO 35 ENE VIH DNV 20 NNW FWA 10 ESE DTW. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM SRQ 15 N VRB. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 45 WNW HVR 3HT 40 W COD IDA SUN S80 63S 30 NNW 63S. ...SEVERE THUNDERSTORM FORECAST DISCUSSION... ...MIDDLE MISSISSIPPI RIVER VALLEY TO NORTHEAST STATES... VERY UNSTABLE AIRMASS IS LOCATED OVER THE AREA...WITH SBCAPE OF 2000-4000 J/KG FROM NEW YORK STATE TO ARKANSAS. THUNDERSTORMS SHOULD CONTINUE TO INCREASE IN INTENSITY AND COVERAGE THROUGH THE EARLY EVENING HOURS ALONG ADVANCING COLD FRONT. 500 MB WEST-NORTHWEST FLOW OF 50-70 KNOTS WILL PERSIST OVER CENTRAL AND SOUTHERN PORTIONS OF THE MODERATE RISK AREA THROUGH THE NIGHT...CREATING FAVORABLE VERTICAL WIND SHEAR PROFILES FOR SEVERE THUNDERSTORMS. 12Z ETA SUGGESTS THAT STRONGEST DIFFERENTIAL VORTICITY ADVECTION WILL MOVE FROM THE OHIO AREA TO THE MIDDLE ATLANTIC COASTLINE BY 01/12Z. THIS APPEARS REASONABLE LOOKING AT LATEST WATER VAPOR IMAGERY...WITH SHORT WAVE TROUGH EVIDENT FROM LOWER MICHIGAN TO IOWA AT THIS TIME. DEEP LAYER SHEAR AND ELEVATED MIXED LAYER ARE IN PLACE AHEAD OF ADVANCING COLD FRONT...SO POTENTIAL FOR ISOLATED TORNADIC SUPERCELLS AND BOW ECHOES WILL CONTINUE THROUGH MUCH OF THE NIGHT. ..CRAVEN.. 05/31/98