STORM PREDICTION CENTER...NWS/NCEP...NORMAN OK DAY 1 CONVECTIVE OUTLOOK...REF AWIPS GRAPHIC PGWE46 KWNS. VALID 101630Z - 111200Z THERE IS A HIGH RISK OF SVR TSTMS ACROSS NERN OK...NWRN AR... EXTREME SERN KS...MO...SERN IA...IL...IN..OH AND NRN KY TO THE RIGHT OF A LINE FROM 20 WSW MKO 35 NE TUL 30 ENE MKC 15 ESE LWD OTM 30 SE CID 30 SW RFD 20 NNE MMO LAF 15 N MIE 35 N DAY 20 NNW CMH 15 WSW ZZV 15 E UNI 30 SW HTS 25 N BWG 60 NNW LIT 15 NE PGO 20 WSW MKO. SURROUNDING THE HIGH RISK...THERE IS A MDT RISK OF SVR TSTMS ACROSS ERN OK...NERN TX...AR...NWRN MS...TN...NWRN NC...WRN VA...WV..SRN LWR MI...AND SERN WI TO THE RIGHT OF A LINE FROM 30 ENE ADM TUL 45 S OJC LWD 15 NNW CID MKE 20 NNE AZO 20 S CLE 15 NNE HLG 35 E EKN 45 ESE LYH 35 ESE GSO 30 NNW HSS 20 N CSV 55 SW BNA UOX 40 W GLH 25 NNE SHV TYR 40 E DAL 20 SSW DUA 30 ENE ADM. THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM ERI PSB 25 ENE SBY ...CONT... 30 S EWN HKY 30 SSW TYS 40 NNE BPT SAT JCT 35 E ABI BVO 45 E EMP TOP 35 SSE FOD 40 E MCW CWA 50 S ESC 20 ENE PLN. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM ILM 20 SSW FAY GSP ANB MCB 25 E LCH CRP 55 NNW MFE 55 WNW MFE ...CONT... 25 SSE P07 35 W SJT 35 NW ABI 25 NE PNC 30 WSW EMP RSL 10 S GLD 45 NNW CAO ALS BCE MLF ELY U31 65 N SAC 30 W MHS ONP 20 WNW CLM ...CONT... 35 NE 63S LWS BOI 40 SW SUN IDA JAC WRL 50 SSE 81V AIA LBF GRI 30 S FSD RWF 60 ENE STC 10 NE MQT ...CONT... 30 W ART 15 SE ISP. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM VRB 10 WNW PBI 30 NW MIA 55 WNW MIA 20 SE FMY 25 NNW FMY 15 NNE SRQ 45 NNE PIE 35 SSE GNV 30 WNW DAB 20 S DAB VRB. ...A SIGNIFICANT OUTBREAK OF SEVERE WEATHER...INCLUDING STRONG TO VIOLENT TORNADOES...ARE EXPECTED ACROSS PORTIONS OF THE MIDDLE MS AND OHIO VALLEYS THIS AFTERNOON AND EVENING... ...SYNOPSIS... UPPER LOW WAS LOCATED OVER THE CENTRAL ROCKIES THIS MORNING WITH NEGATIVELY TILTED SHORTWAVE TROUGH EXTENDING SEWD INTO WRN TX. A 90-100 KT MID LEVEL JET ON THE SERN SIDE OF THIS SYSTEM SHOULD EJECT UPPER LOW RAPIDLY NEWD INTO THE UPPER MIDWEST BY THIS EVENING...WITH THE ACCOMPANYING TROUGH MOVING INTO THE MID MS VALLEY. ANOTHER JET MAX WILL EXTEND FROM NERN TX NEWD INTO KY WITH THE DOUBLE JET STRUCTURE RESULTING IN STRONG DIFFLUENCE ALOFT/LIFT ACROSS THE HIGH RISK AREA. SURFACE LOW...CURRENTLY LOCATED OVER CENTRAL KS...IS PROGGED TO MOVE TO INTO NWRN MO BY EARLY AFTERNOON AND THEN NEWD INTO SWRN WI TONIGHT. ...MISSISSIPPI/OHIO VALLEYS/MID ATLANTIC STATES... LARGE CLUSTER OF SEVERE STORMS IS LOCATED ACROSS PORTIONS OF IL/INDIANA WITH AN APPARENT MCV LOCATED IN WEST CENTRAL INDIANA. A WARM FRONT EXTENDS EWD FROM THE MCV INTO SRN INDIANA AND IS LIFTING SLOWLY NWD. MODERATE INSTABILITY...STRONG LOW LEVEL SHEAR...ESPECIALLY NEAR MCV AND WARM FRONT...WILL REMAIN FAVORABLE FOR NUMEROUS TORNADOES AS THE SYSTEM MOVES EWD ACROSS INDIANA AND INTO SRN OH THIS AFTERNOON. MODERATE INSTABILITY AND STRONG DEEP LAYER SHEAR SHOULD MAINTAIN SEVERE WEATHER WITH THIS COMPLEX MOVES INTO WV AND EVENTUALLY THE MID ATLANTIC STATES. TORNADOES WILL REMAIN A THREAT....THOUGH UNIDIRECTIONAL FLOW SUGGESTS THAT WIND DAMAGE MAY BECOME THE GREATER THREAT. SURFACE BOUNDARY FROM EARLIER CONVECTION EXTENDS FROM NEAR STL WWD INTO EAST CENTRAL KS. THIS BOUNDARY IS MOVING SEWD ACROSS ERN MO...BUT HAS STALLED ON THE WRN END. AS STRONG FORCING SPREADS INTO THE AREA...THUNDERSTORMS SHOULD DEVELOP EXPLOSIVELY FROM NWRN MO SWWD INTO OK BY EARLY AFTERNOON. THE BOUNDARY LAYER HAD STABILIZED NORTH OF THE BOUNDARY...BUT RAPID DESTABILIZATION WILL OCCUR AS LOW MOVES NEWD AND A VERY UNSTABLE AIRMASS...CURRENTLY LOCATED OVER THE ERN HALF OF OK/SERN KS...SPREADS RAPIDLY NEWD. MLCAPES WILL EXCEED 3000 J/KG THIS AFTERNOON AND 60 KT DEEP LAYER SHEAR SHOULD BE SUFFICIENT FOR NUMEROUS SUPERCELLS. THE INCREASING UPPER LEVEL DIFFLUENCE AND 1 KM SRH OF 300-350 J/KG WILL BE FAVORABLE FOR VERY STRONG TORNADOES TO OCCUR THIS AFTERNOON...ESPECIALLY FROM NERN OK/NWRN AR NEWD ACROSS INTO MO AND SERN IA. HAIL AS LARGE AS BASEBALLS AND WIND GUSTS TO 100 MPH WILL ALSO BE POSSIBLE GIVEN THE STRENGTH OF THE FORCING...SHEAR AND INSTABILITY. FORECAST DEEPENING OF SURFACE LOW THIS EVENING WOULD ENHANCE LOW-LEVEL SHEAR/HODOGRAPHS...WITH A CONTINUED POTENTIAL FOR STRONG TORNADOES INTO THE EVENING ACROSS ERN MO/IL AND POSSIBLY WRN KY. THE STORMS ARE EXPECTED TO EVENTUALLY CONGEAL INTO AN INTENSE SQUALL LINE ACROSS THE LOWER/MIDDLE MS VALLEY THIS EVENING AS THE TROUGH LIFTS NEWD TOWARD THE UPPER MIDWEST AND WINDS VEER IN THE LOWER LEVELS. TORNADOES WOULD STILL BE POSSIBLE...BUT GREATEST SEVERE THREAT IS LIKELY TO TRANSITION TO A WIDESPREAD DAMAGING WIND EVENT. ..IMY.. 05/10/03