SPC AC 231546      STORM PREDICTION CENTER...NWS/NCEP...NORMAN OK    DAY 1 CONVECTIVE OUTLOOK...REF AWIPS GRAPHIC PGWE46 KWNS.      VALID 231630Z - 241200Z    THERE IS A HIGH RISK OF SVR TSTMS TODAY AND TONIGHT OVER PARTS OF    SOUTHEAST TX...MUCH OF LA...AND SOUTHWEST MS...TO THE RIGHT OF A    LINE FROM 40 ENE PSX 50 NNW VCT AUS TPL GGG 30 SSW GLH 35 N MCB 15    ESE 7R4.      SURROUNDING THE HIGH RISK...THERE IS A MDT RISK OF SVR TSTMS OVER    PARTS OF CENTRAL TX...SOUTHERN AR...AND MUCH OF WESTERN/CENTRAL    MS...TO THE RIGHT OF A LINE FROM 20 SW PSX HDO JCT 50 SE BWD 50 SSE    DAL 20 N ELD UOX 20 NW CBM MEI 25 W BVE.    THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM    35 ENE CRP COT DRT SJT FTW TXK MEM MSL 0A8 30 SSE MOB.    GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 50 SW TUS PHX FMN    LVS PVW END JLN TBN MDH OWB CSV ABY AQQ.    ...OUTBREAK OF SEVERE THUNDERSTORMS INCLUDING THE POTENTIAL FOR    WIDESPREAD DAMAGING WINDS AND ISOLATED STRONG TORNADOES IS FORECAST    TODAY THROUGH TONIGHT...      LATEST SATELLITE IMAGERY SHOWS TWO WELL-DEFINED UPPER TROUGHS THAT    WILL AFFECT THE OUTLOOK AREA TODAY. THE INITIAL TROUGH IS NOW    MOVING INTO SOUTH TX...AND IS AIDING THE ONGOING SEVERE STORMS    ACROSS SOUTHEAST TX. THIS SYSTEM IS EXPECTED TO CONTINUE TO TRACK    EASTWARD...WITH SEVERE/SUPERCELL STORMS POSSIBLE THROUGH THE    AFTERNOON AND EVENING INTO PARTS OF CENTRAL/SOUTHERN LA. MODEL    FORECAST SOUNDINGS IN THIS ZONE INDICATE LIMITED INSTABILITY...BUT    VERY STRONG VERTICAL SHEAR PROFILES. ISOLATED TORNADOES /SOME    POTENTIALLY STRONG/ AND DAMAGING WINDS WOULD BE THE MAIN THREAT    WITH THIS ACTIVITY.      SECOND STRONG SHORTWAVE TROUGH IS NOW OVER NORTHERN MEXICO...AND IS    FORECAST TO MOVE INTO WEST TX THIS AFTERNOON/EVENING. MODEL    GUIDANCE SUGGESTS THAT STRONG INSTABILITY WILL REMAIN AS FAR WEST    AS DRT/JCT/TPL AROUND 18Z...WHERE RE-DEVELOPMENT OF STORMS IS    ANTICIPATED. THESE STORMS WILL BE STRONGLY LINEARLY FORCED...WITH    A RAPID EVOLUTION INTO A FAST-MOVING SQUALL LINE EXPECTED. DRY AIR    ALOFT...STEEP LAPSE RATES...AND 80-90 KNOT FLOW AT 500MB SUGGEST A    HIGH POTENTIAL FOR DAMAGING WINDS...LARGE HAIL...AND ISOLATED    TORNADOES...SOME POTENTIALLY STRONG. GREATER TORNADO THREAT WOULD    LIKELY BE ASSOCIATED WITH SUPERCELL STORMS THAT FORM AHEAD OF LINE    IN WEAKLY CAPPED AND MODERATELY UNSTABLE AIRMASS. FINALLY...TRACK    OF SURFACE MESOLOW ALONG EXISTING WARM FRONT OVER SOUTHEAST TX AND    NORTH CENTRAL LA COULD BE A FOCUS FOR SIGNIFICANT SEVERE WEATHER    FOR MUCH OF THE NIGHT. SEVERE STORMS ARE EXPECTED TO SPREAD INTO    WESTERN MS LATE TONIGHT...WITH A CONTINUED THREAT OF DAMAGING WINDS    AND ISOLATED TORNADOES.      ..HART.. 12/23/02       NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED FOR 2000Z