MESOSCALE DISCUSSION 2157
   NWS STORM PREDICTION CENTER NORMAN OK
   0733 PM CST WED NOV 21 2007
   
   AREAS AFFECTED...WRN TN/NRN AND WRN MS/SERN AR/PARTS OF ERN AND SRN
   LA
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 735...736...
   
   VALID 220133Z - 220300Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH
   735...736...CONTINUES.
   
   MOIST/UNSTABLE PRE-FRONTAL AIR MASS ACROSS THE LOWER MS VALLEY AND
   EFFECTIVE BULK SHEAR OF 30-40 KT ARE EXPECTED TO MAINTAIN TSTM
   DEVELOPMENT ALONG THE PROGRESSIVE COLD FRONT FOR THE NEXT SEVERAL
   HOURS.  
   
   TSTM DEVELOPMENT ALONG THE COLD FRONT IN SWRN LA HAS DECREASED IN
   INTENSITY AS THIS ACTIVITY MOVES INTO A CONVECTIVELY OVERTURNED
   ENVIRONMENT IN THE WAKE OF PRE-FRONTAL TSTM CLUSTER NOW MOVING
   THROUGH SWRN LA TO FAR SWRN MS.  THIS LEADING TSTM CLUSTER MAY HAVE
   AN ENHANCED WIND THREAT GIVEN UNSATURATED MID LEVEL ENVIRONMENT PER
   00Z SOUNDINGS AT LCH/JAN AND SOME COLD POOL DEVELOPMENT ACROSS
   SWRN/CENTRAL LA.
   
   FARTHER N...EARLY EVENING OBJECTIVE ANALYSES INDICATED DECREASING
   INSTABILITY ACROSS NRN PART OF WW 736 IN WRN TN/NRN MS...GIVEN LOSS
   OF DAY TIME HEATING.  THIS SHOULD RESULT IN A DIMINISHING SEVERE
   WEATHER THREAT AS ACTIVITY MOVES EWD.
   
   ..PETERS.. 11/22/2007
   
   
   ATTN...WFO...OHX...BMX...HUN...PAH...MEG...JAN...LIX...LZK...LCH...SHV...HGX...
   
   30119500 30769360 31439246 32519228 34109078 34908981
   36538832 36478797 35068793 33738825 32888888 31428994
   30249025 29879127