MESOSCALE DISCUSSION 2244
   NWS STORM PREDICTION CENTER NORMAN OK
   0330 AM CST THU DEC 20 2007
   
   AREAS AFFECTED...UPR TX COAST...SABINE RVR VLY...SWRN LA
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 200930Z - 201100Z
   
   A WEAK LEAD MID-LEVEL WAVE WAS EVIDENT IN WATER VAPOR IMAGERY
   EJECTING NEWD AHEAD OF THE PARENT SRN PLAINS IMPULSE.  THIS FEATURE
   WILL CONTINUE ENEWD INTO THE AR OZARKS THROUGH 12Z.  ATTENDANT 1011
   MB SFC LOW WAS LOCATED OVER ECNTRL TX WITH TEMPORAL VEERING OF THE
   LOW/MID-LVL WIND PROFILES SWWD IN AREAS EAST OF THE ESCARPMENT.  THE
   LOW WILL LIKELY RECONSOLIDATE OVER THE ARKLATEX BY 12Z WHERE CURRENT
   MAX IN PRESSURE FALLS ARE LOCATED.  AS THIS OCCURS...MID-UPR 60S SFC
   DEW POINTS WILL SURGE NWD ALONG THE UPR TX COAST INTO THE SABINE VLY
   AND SWRN LA THE NEXT SEVERAL HOURS AS THE CORE OF THE LLJ FOCUSES
   FROM NEAR/E OF HOUSTON NEWD INTO THE MID-SOUTH.
   
   CURRENT TSTMS DEVELOPING VCNTY KLFK SEEM TO BE LOCATED ALONG THE NWD
   MOVING WARM FRONT AND MAY BE ROOTED SUFFICIENTLY CLOSE TO THE SFC TO
   ATTAIN MAXIMUM SRH IN AN ENVIRONMENT CHARACTERIZED BY MODEST VEERING
   FROM SFC THROUGH 3 KM.  THIS KINEMATIC ENVIRONMENT APPEARS TO BE
   LIMITED TEMPORALLY AND SPATIALLY AS THE LOW/MID-LVL FLOW CONTINUES
   TO VEER WITH TIME THROUGH DAYBREAK. THUS...ANY TORNADO THREAT WILL
   LIKELY BE LIMITED TO THE SABINE RVR VLY.
   
   OTHERWISE...DEEP LAYER SHEAR WILL REMAIN SUFFICIENT FOR OTHER
   ELEVATED STORMS TO ATTAIN SUPERCELLULAR CHARACTERISTICS OVER THE
   REMAINDER OF ERN TX AND CNTRL/NRN LA.  THESE STORMS WILL LIKELY BE
   MAINLY A LARGE HAIL THREAT.  BUT...STORMS THROUGH CNTRL LA MAY
   PRODUCE DMGG WIND GUSTS AS THE WARMER BOUNDARY LAYER WORKS NWD WITH
   TIME THIS MORNING.
   
   ..RACY.. 12/20/2007
   
   
   ATTN...WFO...LCH...SHV...HGX...FWD...
   
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