MESOSCALE DISCUSSION 2442
   NWS STORM PREDICTION CENTER NORMAN OK
   1129 PM CST WED DEC 10 2008
   
   AREAS AFFECTED...FAR SOUTHEAST TX AND WESTERN/CENTRAL LA
   
   CONCERNING...WINTER MIXED PRECIPITATION 
   
   VALID 110529Z - 111030Z
   
   MAINLY LIGHT SNOW/SOME SLEET IS EXPECTED TO DEVELOP EASTWARD ACROSS
   PORTIONS OF FAR SOUTHEAST TX INTO WESTERN/CENTRAL LA OVERNIGHT.
   
   LATEST WATER VAPOR IMAGERY FEATURES A CLOSED/LOW-LATITUDE UPPER LOW
   SHIFTING EASTWARD TOWARD THE SABINE RIVER VICINITY OF FAR SOUTHEAST
   TX/SOUTHWEST LA LATE THIS EVENING. UNUSUALLY COLD EARLY-SEASON
   THERMAL PROFILES WILL BE CONDUCIVE FOR MAINLY LIGHT SNOW/SOME SLEET
   ACROSS FAR SOUTHEAST TX INTO WESTERN/CENTRAL LA THROUGH THE EARLY
   MORNING HOURS. 05Z OBSERVED SURFACE WET BULB 32F LINE...LOCATED FROM
   NEAR LONGVIEW TX SOUTHWARD TO BETWEEN LUFKIN/JASPER TX TO NEAR/WEST
   OF BEAUMONT TX...WILL CONTINUE A SLOW BUT STEADY EASTWARD
   PROGRESSION INTO WESTERN LA OVERNIGHT AS COLD ADVECTION INCREASES IN
   THE WAKE OF THE EASTWARD-SHIFTING UPPER TROUGH. MARGINAL THERMAL
   PROFILES/MODEST UVV THROUGH THE ICE BEARING LAYER AND INITIALLY WARM
   TERRESTRIAL TEMPERATURES WILL TEND TO KEEP SNOW ACCUMULATIONS LIGHT.
   EVEN SO...A GRADUALLY COOLING COLUMN AND A NEARLY ISOTHERMAL LAYER
   BETWEEN 1-3 KM...PER RUC FORECAST SOUNDINGS AND OBSERVED ACARS DATA
   FROM NEAR HOUSTON...WILL FAVOR BOUTS OF STEADY LIGHT SNOW/SOME SLEET
   ACROSS FAR SOUTHEAST TX INTO WESTERN/CENTRAL LA THROUGH THE EARLY
   MORNING HOURS.
   
   ..GUYER.. 12/11/2008
   
   
   ...NOTICE...
   SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A
   SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR
   TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC
   FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS.
   
   ATTN...WFO...LCH...SHV...HGX...
   
   LAT...LON   29979452 30809488 31959381 31869266 30849210 30119262
               29979452