MESOSCALE DISCUSSION 2305
   NWS STORM PREDICTION CENTER NORMAN OK
   0353 PM CST TUE NOV 08 2011
   
   AREAS AFFECTED...SOUTHEAST TEXAS
   
   CONCERNING...TORNADO WATCH 876...
   
   VALID 082153Z - 090000Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 876 CONTINUES.
   
   ISOLATED TORNADO THREAT CONTINUES ACROSS WW 876. THE THREAT IS
   LIKELY TO PERSIST FOR AT LEAST THE NEXT 2-3 HRS...WITH A SLOW
   DECREASING TREND WITH TIME. 
   
   AT 2130Z...A CLUSTER OF SUPERCELLS IS ONGOING ACROSS LIBERTY AND
   HARDIN COUNTY...WITH SCATTERED NON-SEVERE CONVECTION ACROSS THE
   REMAINDER OF THE WATCH. MODERATE CAPE OF AROUND 1000-1500 J/KG
   REMAINS ACROSS THE WATCH AREA PER SFC MESOANALYSIS...WITH SUFFICIENT
   EFFECTIVE SHEAR /AROUND 40 KTS/ TO SUPPORT SUPERCELL STRUCTURES. 0-1
   KM SHEAR OF 20-25 KTS CONTINUES TO SUPPORT A THREAT OF ISOLATED
   TORNADOES...ESPECIALLY ACROSS ERN PARTS OF THE WATCH. THERE IS SOME
   THREAT OF SEVERE WIND AS WELL...ESPECIALLY WHERE CELL MERGERS RESULT
   IN SMALL BOWING STRUCTURES. 
   
   WHILE DEEP-LAYER SHEAR WILL CONTINUE TO SUPPORT OCCASIONAL SUPERCELL
   STRUCTURES...LOW-LEVEL SHEAR IS LIKELY TO WEAKEN WITH TIME AS A
   MIDLEVEL TROUGH CURRENTLY OVER OKLAHOMA EJECTS ENE AWAY FROM THE
   AREA...WITH A DECREASING TORNADO THREAT ACROSS THE WATCH FROM WEST
   TO EAST. CURRENT ACTIVITY MAY PERSIST FOR THE NEXT 2-3 HRS BEFORE
   COVERAGE BEGINS TO DECREASE. A COLD FRONT MOVING INTO THE WESTERN
   PART OF THE WATCH MAY TRIGGER A MORE LINEAR MODE OF CONVECTION WITH
   A LOW-END WIND THREAT EARLY THIS EVENING...BUT THIS SCENARIO IS
   UNCERTAIN GIVEN WEAKENING UPPER SUPPORT.
   
   ..DEAN.. 11/08/2011
   
   
   ATTN...WFO...LCH...SHV...HGX...FWD...
   
   LAT...LON   30749609 31229575 31289477 31249399 30819378 30429373
               30099390 29939468 29869507 29839553 30059590 30309606
               30749609