STORM PREDICTION CENTER...NWS/NCEP...NORMAN OK DAY 1 CONVECTIVE OUTLOOK...REF AWIPS GRAPHIC PGWE46 KWNS. VALID 121200Z - 131200Z THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 15 SE LTS 45 WNW END 25 SW HUT 10 W TOP 45 NNW COU 20 W STL 45 N POF 20 ESE UNO 30 ESE HRO 10 SSE FSM 20 W DUA SPS 15 SE LTS. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 25 SSW PSX 40 NW HOU 40 ESE LFK 35 WNW JAN 20 NE LGC 20 SW AGS 25 SW CHS. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 15 ENE HOT 35 E PRX 45 E DAL 35 N ACT 15 S ABI 25 SW LTS 30 E GAG 30 NNW P28 25 NNW SLN 25 ENE FNB 35 S CGX 40 WNW CLE 20 NNW YNG 35 S HLG 25 ENE HTS 25 SSE PAH 15 ENE HOT. ...SYNOPSIS... WATER VAPOR IMAGERY AND 00Z UPPER AIR ANALYSES REVEAL A WEAK MID- UPPER LEVEL SHORTWAVE TROUGH APPROACHING NRN ID. THIS TROUGH SHOULD MOVE ESEWD TO NEB/WRN IA/NRN KS BY LATE AFTERNOON...AND CONTINUE TO THE MID MS/LOWER OH VALLEYS BY THE END OF THE PERIOD. AT THE SURFACE...A COLD FRONT IS MOVING SLOWLY SWD ACROSS ERN NEB/NW IA...AND THIS BOUNDARY SHOULD REACH NE KS/EXTREME NRN MO BY LATE AFTERNOON. A WEAK LEE CYCLONE NOW IN EXTREME NE NM WILL DEVELOP ESEWD TOWARD WRN OK DURING THE DAY AND GRADUALLY WEAKEN...WHILE ANOTHER WEAK LOW DEVELOPS FARTHER NE ALONG THE BAROCLINIC ZONE AND MOVES ACROSS IL/INDIANA OVERNIGHT. THE SURFACE FRONT AND/OR THE DRYLINE TO THE NE OF THE SURFACE LOW SHOULD BE THE PRIMARY FOCUS FOR THUNDERSTORM DEVELOPMENT FROM LATE AFTERNOON INTO THE OVERNIGHT HOURS. ...ERN KS/MO/NW AR/OK AREA... DEW POINTS NEAR 60 F HAVE SPREAD NWD TO THE RED RIVER AS OF 03Z...AND THE 00Z ETA/ETA-KF FORECASTS OF 60 DEW POINTS INTO SE KS/SW MO BY LATE AFTERNOON APPEAR REASONABLE. WITH AFTERNOON TEMPERATURES IN THE RANGE OF 75-80 F WITHIN WARM SECTOR...EXPECT MLCAPE VALUES NEAR 2500 J/KG FROM N TX ACROSS CENTRAL/ERN OK TO SE KS DURING THE LATE AFTERNOON. CONVECTIVE INITIATION APPEARS MOST LIKELY INVOF E/SE KS/W CENTRAL MO FROM 21-00Z TO THE NE OF THE SURFACE LOW AND ALONG THE SURFACE COLD FRONT...WHICH WILL ALSO BE IN PROXIMITY TO A WEAK MID LEVEL TROUGH MOVING ESEWD ACROSS NRN KS. EXPECT THUNDERSTORMS TO THEN SPREAD EWD ACROSS MO...AND POSSIBLY DEVELOP SWWD ALONG THE WEAK COLD FRONT IN KS AND THE DRYLINE IN OK. FARTHER S IN TX...CONVECTIVE INITIATION IS MUCH LESS CERTAIN DUE TO AT BEST WEAK FORCING FOR ASCENT ON THE DRYLINE...AND THE LIKELIHOOD OF WEAK CAP PERSISTING THROUGH THE AFTERNOON/EVENING. 30-40 KT MID LEVEL WLY FLOW AND 15-25 KT LOW-LEVEL S/SSWLY FLOW WILL RESULT IN SUFFICIENT DEEP LAYER SHEAR FOR ORGANIZED SEVERE STORMS...INCLUDING SUPERCELLS. 0-6 KM SHEAR VECTOR ORIENTATION AND WEAK ASCENT/SOME CONVECTIVE INHIBITION MAY SUPPORT DISCRETE SUPERCELLS ALONG THE DRYLINE...THOUGH STORM COVERAGE ALONG THE DRYLINE SHOULD REMAIN ISOLATED. OTHERWISE...EXPECT STORMS TO GRADUALLY MERGE INTO MORE OF A BAND ALONG THE FRONT ACROSS SE KS/NE OK/MO/NW AR BY TONIGHT. GIVEN THE FORECAST COMBINATIONS OF INSTABILITY...VERTICAL SHEAR...AND SEASONABLY COOL MID LEVEL TEMPERATURES...EXPECT LARGE HAIL AND DAMAGING WINDS TO BE THE MAIN SEVERE THREATS. LOW-LEVEL MOISTURE/SHEAR ARE NOT EXPECTED TO BE PARTICULARLY FAVORABLE FOR SUPERCELLULAR TORNADOES...THOUGH AN ISOLATED TORNADO OR TWO MAY OCCUR. ...GULF COAST AREA... RICH LOW-LEVEL MOISTURE RESIDES FROM CENTRAL FL ACROSS THE NRN GULF TO S TX. AS THIS MOISTURE SPREADS INLAND ACROSS THE GULF COAST LATER TODAY AND TONIGHT...A FEW CLUSTERS OF THUNDERSTORMS WILL BE POSSIBLE IN THE WEAK WAA REGIME. RELATIVELY WEAK VERTICAL SHEAR AND MODEST MID LEVEL LAPSE RATES SUGGEST THE SEVERE THREAT SHOULD BE MINIMAL ACROSS THIS AREA. ..THOMPSON.. 03/12/03