STORM PREDICTION CENTER...NWS/NCEP...NORMAN OK DAY 1 CONVECTIVE OUTLOOK...REF AWIPS GRAPHIC PGWE46 KWNS. VALID 051630Z - 061200Z THERE IS A MDT RISK OF SVR TSTMS THIS AFTERNOON AND TONIGHT OVER PARTS OF NORTHWEST TX AND SOUTHWEST OK...TO THE RIGHT OF A LINE FROM DUA DAL SEP ABI 55 S CDS CDS CSM OKC DUA. THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM FYV TXK TYR 45 WNW TPL DRT 45 ESE P07 MAF PVW 40 SSE LBL HUT CNU FYV. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 20 W CLM 40 ENE AST 25 N EUG 55 ESE OTH ACV. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 60 SSW MRF 20 SE CNM 45 NE ROW 40 SSE LVS 30 NNW SAF 40 E GCN 20 SE P38 40 ESE EKO 15 WNW TWF 35 SSW 27U 20 ENE HLN 45 WSW MLS 25 SSW REJ 20 ENE HSI 30 NW SGF 25 NNW BNA 35 NE TRI 15 WSW MRB 40 NNW ILG 15 E NEL. ...SOUTHERN PLAINS... STRONG UPPER TROUGH OVER NV IS FORECAST TO ROTATE EASTWARD ACROSS THE SOUTHERN ROCKIES TODAY/TONIGHT...SETTING THE STAGE FOR AN ACTIVE CONVECTIVE PERIOD ACROSS THE SOUTHERN PLAINS. STRONG SOUTHERLY LOW LEVEL WINDS ARE PRESENT OVER THIS REGION...WITH LATEST SJT VAD PROFILE SHOWING 20-30 KNOT SOUTHERLY WINDS AT 1KM. THIS WILL RAPIDLY RETURN RICH MOISTURE NORTHWARD...FASTER THAN MODELS SUGGEST. LOW LEVEL MOISTURE IS ALSO RETURNING MUCH FARTHER WEST THAN FORECAST...WITH MID 50S DEWPOINTS NOW EVIDENT AROUND MAF. PRESENT INDICATIONS ARE THAT SURFACE DRYLINE WILL BECOME ESTABLISHED THIS AFTERNOON FROM EAST OF MIDLAND TO WEST OF CHILDRESS. STRONG DAYTIME HEATING AND AFTERNOON DEWPOINTS IN THE 60S WILL RESULT IN MLCAPE VALUES OF OVER 2000 J/KG. COOL MID LEVEL TEMPERATURES SUGGEST THAT THE CAP WILL NOT BE VERY STRONG... ALLOWING SCATTERED THUNDERSTORMS TO DEVELOP NEAR THE DRYLINE BY 00Z. SOUTHEASTERLY SURFACE WINDS AND INCREASING WESTERLY FLOW ALOFT WILL PROVIDE STRONG VERTICAL SHEAR PROFILES...WITH DEEP LAYER SHEAR OVER 50 KNOTS AND 3KM HELICITY VALUES OF 150-300 M2/S2. INITIAL ACTIVITY IS EXPECTED TO BE SUPERCELLULAR...WITH VERY LARGE HAIL AND A FEW TORNADOES POSSIBLE. AS STORMS SPREAD NORTHEASTWARD INTO SOUTHWEST OK...THEY WILL CROSS THE SURFACE WARM FRONT AND BECOME ELEVATED. THIS SHOULD DIMINISH THE TORNADO THREAT. HOWEVER...POTENTIAL FOR VERY LARGE HAIL WILL PERSIST. LARGE MCS IS EXPECTED OVERNIGHT ACROSS OK AND NORTH CENTRAL TX WITH A CONTINUED THREAT OF LARGE HAIL AND DAMAGING WINDS. ...VA/NC... AXIS OF STRONG DAYTIME HEATING EXTENDS FROM CENTRAL NC INTO SOUTHEAST VA. THIS AREA IS EXPECTED TO BECOME MODERATELY UNSTABLE WITH MLCAPE VALUES OVER 1000 J/KG. SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP IN THIS REGION WITH THE THREAT OF GUSTY/DAMAGING WINDS AND HAIL IN STRONGER CELLS. HOWEVER...UPPER SYSTEM IS LIFTING AWAY AND LARGE SCALE FORCING IS DIMINISHING. THEREFORE...COVERAGE OF SEVERE DOES NOT APPEAR TO WARRANT A CATEGORICAL OUTLOOK. ..HART/CUPO.. 04/05/03