STORM PREDICTION CENTER...NWS/NCEP...NORMAN OK DAY 1 CONVECTIVE OUTLOOK...REF AWIPS GRAPHIC PGWE46 KWNS. VALID 041630Z - 051200Z THERE IS A HIGH RISK OF SVR TSTMS OVER PORTIONS OF ERN KS/WRN MO/WRN AR/ERN OK...TO THE RIGHT OF A LINE FROM 35 NE DUA 35 WSW JLN 20 NNE TOP 15 N STJ P35 25 SSE IRK 15 ENE TBN 35 SSW UNO 15 SSE HOT 30 ENE PRX 35 NE DUA. THERE IS A MDT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 40 S DAL DAL DUA TUL 20 E EMP 25 NE MHK BIE OMA 45 WSW DSM OTM 30 ESE BRL 25 SSW DEC 25 WNW EVV 35 SE PAH 25 S MEM GGG 45 SW TYR 40 S DAL. THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 20 N MWL 15 WSW ADM 30 NE PNC 25 SSE CNK 50 NE HLC 50 SW MHN 35 N CDR PHP 30 W BKX RST 15 ENE MSN 30 E SBN 20 N DAY 20 ENE JKL 30 ESE CHA 20 SE CBM 35 ENE MLU 50 SW LFK HDO 55 NNE DRT 15 WNW BWD 20 N MWL. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 20 E CHS 15 SSE AUO 10 NW MCB 25 ESE BPT ...CONT... 10 WSW GLS 10 E COT 50 ESE P07 30 SSW ABI 45 E SPS 25 NNE OKC 40 SSW ICT 25 WSW HUT 15 SSE HLC 15 NNW IML 45 NW AKO 10 E DEN 50 WSW COS 15 S DRO 15 W PGA 45 E U31 20 ESE 4LW 10 NNW DLS 70 WNW 4OM ...CONT... 65 NE MOT 40 SW DVL 35 ESE JMS OSC ...CONT... 25 SW ERI 10 NW LBE SHD 15 ESE RDU 30 SW ILM. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 25 SSE SRQ VRB. ...AN OUTBREAK OF SEVERE THUNDERSTORMS AND TORNADOES IS STILL ANTICIPATED ACROSS PORTIONS OF THE EAST-CENTRAL PLAINS TO THE MID MS RIVER VALLEY... SURFACE CYCLONE WILL CONTINUE TO DEEPEN INTO SERN NEB..AS DRY LINE FRONT SURGES EWD ACROSS CENTRAL KS/OK THIS AFTERNOON. EARLIER MCS OVER MO HAS REINFORCED WARM FRONT FROM NEAR THE NERN KS/SERN NEB BORDER SSEWD INTO CENTRAL AR...WHICH THEN EXTENDS MORE ESEWD INTO CENTRAL MS/SRN AL. THOUGH STABILIZING EFFECTS FROM EARLIER CONVECTION WILL HINDER NWD MOTION FOR A WHILE...STRONG PRESSURE FALLS AND IMPRESSIVE LOW LEVEL WAA WILL AID IN QUICKLY LIFTING THIS BOUNDARY NEWD ACROSS MUCH OF AR AND INTO NRN MO/SWRN IA BY THE MID/LATE AFTERNOON. IN ITS WAKE...A RAPIDLY DESTABILIZING AIR MASS WILL OCCUR AHEAD OF APPROACHING DRY LINE WHERE MLCAPES WILL EXCEED 2500 J/KG. MOSTLY LIKELY AREA OF MOIST-CONVECTIVE INITIATION IS EXPECTED FROM NEAR THE SURFACE LOW SWD ACROSS ERN KS AND POSSIBLY NERN OK FROM 18Z-20Z...WHERE STRONGEST LIFT NORTH OF MID/UPPER LEVEL SPEED MAX WILL OVERSPREAD INCREASING CONVERGENCE AT THE SURFACE. STORMS WILL RAPIDLY BECOME SEVERE IN THE FORM OF DISCRETE SUPERCELLS. DEVELOPMENT IS EXPECTED TO OCCUR ACROSS ERN OK AND INTO NRN/ERN TX...AS WELL AS INTO NRN LA/AR AND POSSIBLY NRN MS/WRN TN THROUGH THE LATE AFTERNOON/EVENING AS UPPER JET BECOMES MORE WLY AND STRONG HEATING ERODES CAP ACROSS THE WARM SECTOR. THIS ACTIVITY WILL ALSO LIKELY REMAIN SUPERCELLULAR. THE THREATS OF TORNADOES... INCLUDING LONG-LIVED TORNADIC SUPERCELLS...AND VERY LARGE HAIL WILL OCCUR ACROSS THE ENTIRE REGION. VERY POTENT COMBINATION OF STRONG INSTABILITY...LOW AND DEEP LAYER SHEAR AND DEEP LIFTING INDICATE SIGNIFICANT TORNADOES ARE LIKELY FROM THE MID AFTERNOON UNTIL WELL AFTER DARK. ACTIVITY WILL LIKELY EVOLVE INTO A SQUALL LINE OR BROKEN LINE OF SUPERCELLS/LEWPS DURING THE EVENING FROM ERN IA ACROSS THE MID MS RIVER VALLEY AND INTO THE ARKLATEX. THIS ACTIVITY WILL LIKELY SPREAD EWD WELL AWAY FROM SURFACE FRONT...AND OVERSPREAD MUCH OF THE TN/OH RIVER VALLEYS AS WELL AS TOWARDS THE SRN GREAT LAKES THROUGH THE NIGHT. ..EVANS/BANACOS.. 05/04/03