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