SPC AC 121957
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0157 PM CST FRI DEC 12 2003
   
   VALID 122000Z - 131200Z
   
   THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 60 N
   BRO 35 NW NIR 30 SE AUS 15 SSE CLL 50 WNW BPT 30 ESE BPT.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 10 W MFE 30 SW HDO 45
   E SJT 15 NE ABI 30 SW END 20 ENE BVO 45 W UNO 55 WSW GLH 20 S MCB 20
   SE BVE.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 20 N CVS 30 NNW GDP
   40 ESE DMN 20 WSW TCS 45 SE GNT 10 WSW 4SL 35 SW ALS 15 N RTN 20 N
   CVS.
   
   ...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE MIDDLE AND
   UPPER TX GULF COAST...
   
   ...SYNOPSIS...
   SHORT WAVE TROUGH...CURRENTLY OVER SRN NM/FAR W TX PER WV IMAGERY...
   WILL TRACK EWD ACROSS THE SRN PLAINS TONIGHT.  INCREASING LARGE
   SCALE ASCENT AHEAD OF THIS TROUGH IS AIDING IN CONVECTIVE
   DEVELOPMENT FROM THE MIDDLE TX COAST NWD TO NRN TX/SRN OK.  THIS
   ACTIVITY WILL INCREASE IN COVERAGE AND SPREAD ENEWD TO WRN AR/LA
   OVERNIGHT.  MOST OF THESE THUNDERSTORMS WILL BE ELEVATED ABOVE A
   SHALLOW BOUNDARY LAYER...WHICH IS BEING SUSTAINED BY LOW-LEVEL ELY
   WINDS ADVECTING A COOL/DRY CP AIR MASS ACROSS ERN PORTIONS OF THE
   SRN PLAINS.  A FEW ELEVATED STORMS OVER ERN TX MAY POSE A RISK OF
   HAIL THIS AFTERNOON AND EVENING.  A GREATER THREAT FOR SEVERE STORMS
   WILL BE CONFINED TO ALONG/JUST INLAND OF THE MID TO UPPER TX COAST
   THROUGH THE REST OF THE FORECAST PERIOD.
   
   ...MID TO UPPER TX COAST...
   EARLY AFTERNOON SURFACE ANALYSIS INDICATED A COASTAL BOUNDARY
   EXTENDED FROM BRO TO NIR AND THEN EWD TO THE TX COAST AROUND 35 SW
   PSX.  BOUNDARY LAYER WITHIN THE WARM SECTOR CONTINUES TO MOISTEN PER
   18Z SOUNDING AT CRP WITH SURFACE DEWPOINTS IN THE UPPER 60S TO
   AROUND 70 F.  THIS COMBINED WITH INCREASING ASCENT IS WEAKENING THE
   CAP AT CRP AND SUGGESTS CONVECTION WILL CONTINUE TO TRY AND DEVELOP
   ALONG THE MIDDLE TX COAST THIS AFTERNOON.  DESPITE A MARGINALLY
   UNSTABLE AIR MASS...STRONG DEEP LAYER AND LOW-LEVEL SHEAR WILL FAVOR
   ROTATING UPDRAFTS WITH THREAT OF ISOLATED DAMAGING WINDS AND PERHAPS
   A TORNADO.
   
   THE DESTABILIZATION OF THE AIR MASS ACROSS THE UPPER TX COAST WILL
   BE A SLOW PROCESS THROUGH THE REST OF THE FORECAST PERIOD...AS ELY
   LOW-LEVEL TRAJECTORIES TRY TO STABILIZE THE BOUNDARY LAYER WITH
   COOL/DRY CP AIR.  MODELS SUGGEST...HOWEVER...THE SEVERE THREAT
   SHOULD DEVELOP NEWD ALONG THE UPPER TX COAST INTO THE EVENING AS A
   MARGINALLY UNSTABLE AIR MASS EVENTUALLY DEVELOPS OVER THIS
   AREA...WITH A CONTINUED THREAT FOR ISOLATED DAMAGING WINDS OR
   PERHAPS A TORNADO.
   
   ..PETERS.. 12/12/2003
   
   ...NOTICE...
   FOR USERS DECODING THE POINTS PARAGRAPH HEREIN...LATITUDE AND
   LONGITUDE POINTS FOR THE CATEGORICAL AND PROBABILISTIC OUTLOOK
   GRAPHICS ALSO ARE LOCATED IN A SEPARATE PRODUCT UNDER THE WMO
   HEADINGS WUUS01 PTSDY1...WUUS02 PTSDY2...AND WUUS03 PTSDY3.  THE
   INCLUSION OF POINTS IN THIS PRODUCT WILL EVENTUALLY BE DISCONTINUED.
   
   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED FOR 0100Z