STORM PREDICTION CENTER...NWS/NCEP...NORMAN OK DAY 1 CONVECTIVE OUTLOOK...REF AWIPS GRAPHIC PGWE46 KWNS. VALID 231300Z - 241200Z THERE IS A MDT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 25 SW ABI 70 NNW ABI 40 WNW CSM 20 NE CSM 35 ENE FSI 45 SSW ADM 20 NNW ACT 35 WNW TPL 50 E JCT 25 W JCT 25 SW ABI. THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 20 ESE PSX 65 W COT ...CONT... 25 NW DRT 30 E BGS 40 ESE LBB 40 SSE AMA 10 NE LHX 35 WNW LIC 40 SE CYS 10 ESE BFF 20 SSE LBF 25 WSW SLN 15 SE MKO 30 WNW TXK 20 SE LFK 25 NE GLS. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 75 NE ISN 30 E PHP 35 NE OMA 35 NE IRK 25 S STL 30 NNW LUL 35 ESE GPT. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 25 SE P07 20 SE HOB 25 E TCC 45 E LVS 15 SSW SAF 60 S 4BL 20 NNW U24 30 W ENV 30 NNE S80 55 NW FCA. ...SYNOPSIS... CLOSED-OFF UPPER-LOW CENTER OVER THE FOUR CORNERS REGION WILL MOVE EWD INTO WRN KS BY LATE IN THE PERIOD. BROAD UPPER-LEVEL JET OVER THE SWRN DESERT WILL PUNCH EWD INTO FAR W TX THIS AFTERNOON AND INTO CNTRL/NRN TX BY LATE IN THE PERIOD. THIS WILL FORCE THE DRYLINE TO MIX QUICKLY E ACROSS W TX AND INTO WRN OK/CNTRL TX BY THIS EVENING. A WARM FRONT WILL LIFT NWD ACROSS N TX TODAY. ...CNTRL AND NRN TX/SWRN OK... SCENARIO IS BECOMING A LITTLE MORE CLEAR AT THIS POINT HOWEVER... UNCERTAINTY REMAINS. CURRENT THINKING IS THAT THE DRYLINE WILL BEGIN TO QUICKLY MIX E THIS MORNING AS SFC PRESSURES RISE OVER ERN NM. THE DRYLINE SHOULD BE POSITIONED FARTHER W THAN PROGGED AND SHOULD EXIST CLOSE TO A LINE FROM LBL TO CDS TO ABI BY 21Z. SURFACE DEWPOINTS OF 60-65 F WILL ADVECT NWD FROM ABI INTO NCNTRL TX AND ACROSS MUCH OF WRN OK BY LATE AFTERNOON. CONVECTION CURRENTLY ONGOING ALONG THE RED RIVER WILL MOVE NE ACROSS OK ALLOWING FOR THE AIR FROM CDS TO ABI TO REMAIN UNDISTURBED. AS A RESULT...SURFACE HEATING SHOULD BE MAXIMIZED FROM CNTRL TX TO SWRN OK RESULTING IN A MODERATELY UNSTABLE AIR MASS WITH MLCAPE FROM 1000-2000 J/KG. THE BROAD UPPER-LEVEL JET WILL INCREASE DIFFLUENCE OVER THE DRYLINE INCREASING LARGE-SCALE FORCING AND HELPING TO INITIATE THUNDERSTORMS IN THE VICINITY OF THE DRYLINE BY MID-AFTERNOON. WITH STRONG DIRECTIONAL SHEAR AND 0-6KM SHEAR PROGGED TO BE 50-60 KT OVER THE ENTIRE REGION...SUPERCELLS SHOULD DEVELOP NEAR THE DRYLINE AND MOVE EWD. VERY LARGE HAIL APPEARS MOST LIKELY ACROSS THE NRN HILL COUNTRY AND LOW-ROLLING PLAINS GIVEN SURFACE DEWPOINTS AND SURFACE HEATING SHOULD BE STRONGEST THERE. AS SUPERCELLS MOVE EWD AND INTERACT WITH THE W EDGE OF THE LOW-LEVEL JET...ISOLATED TORNADOES WILL BE POSSIBLE. SR HELICITIES OF 300-400 M2/S2 SUGGEST A FEW TORNADOES COULD BE SIGNIFICANT MAINLY ACROSS SWRN OK AND NWRN/NCNTRL TX. DAMAGING WIND THREAT WILL INCREASE DURING THE EVENING AS STORMS BECOME MORE LINEAR AND MOVE EWD ACROSS NCNTRL AND NERN TX. STRONG LOW AND MID-LEVEL SHEAR WILL MAINTAIN A SEVERE THREAT EWD TOWARDS THE I-35 CORRIDOR INTO THE EVENING...THOUGH ACTIVITY MAY BEGIN WEAKENING EAST OF THIS OVERNIGHT AS AIR MASS STABILIZES. ...NWRN OK/WRN KS/FAR ERN CO... INSTABILITY AND LOW-LEVEL MOISTURE IS MORE PROBLEMATIC ACROSS THIS REGION TODAY. CONVECTION CURRENTLY ACROSS THE CNTRL HIGH PLAINS SHOULD LIFT NWD INTO NE TODAY ALLOWING FOR TEMPERATURES TO HEAT UP INTO THE 60S AND LOWER 70S FROM NWRN OK TO FAR ERN CO. WITH DEWPOINTS OF 50-55 F...MLCAPE SHOULD REACH 500-1000 J/KG ACROSS THIS REGION. STRONG UPPER-LEVEL FORCING SHOULD ALLOW THUNDERSTORMS TO DEVELOP AND POSSIBLY BECOME A SQUALL-LINE FROM NWRN KS SEWD TO NWRN OK. 0-6 KM SHEAR OF 50-60 KT SHOULD PROMOTE THE DEVELOPMENT OF A FEW SUPERCELLS. 500 MB TEMPS AROUND -20 C AND STRONG DEEP LAYER SHEAR SHOULD RESULT IN A LARGE HAIL THREAT. ..BROYLES.. 04/23/03