MESOSCALE DISCUSSION 2201
   NWS STORM PREDICTION CENTER NORMAN OK
   0610 PM CDT SUN SEP 25 2011
   
   AREAS AFFECTED...PARTS OF SERN AR...WRN TN...NWRN MS
   
   CONCERNING...TORNADO WATCH 855...
   
   VALID 252310Z - 260045Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 855 CONTINUES.
   
   VIGOROUS CONVECTIVE DEVELOPMENT AND SLOW SOUTHEASTWARD PROGRESSION
   OF THE COLD FRONT IS BEGINNING TO STABILIZE THE NARROW PRE-FRONTAL
   INSTABILITY AXIS...WHERE STRONGEST DAYTIME HEATING OCCURRED...ACROSS
   NORTHEAST AND EAST CENTRAL ARKANSAS.  STORMS APPEAR TO BE GENERALLY
   WEAKENING AS THEY PROGRESS EASTWARD AND INGEST MORE STABLE BOUNDARY
   LAYER AIR OVER WESTERN TENNESSEE.  SIMILAR TRENDS SEEM PROBABLE WITH
   STORMS EAST AND NORTHEAST OF PINE BLUFF AS THEY CROSS THE
   MISSISSIPPI RIVER INTO NORTHWEST MISSISSIPPI.  HOWEVER...A RESIDUAL
   FOCUSED AREA OF STRONGER WARM ADVECTION...ON THE NOSE OF THE
   PRE-FRONTAL LOW-LEVEL THERMAL RIDGE EXTENDING EAST NORTHEASTWARD OUT
   OF CENTRAL TEXAS...APPEARS LIKELY TO REMAIN A FOCUS FOR ADDITIONAL
   STRONG/SEVERE STORM DEVELOPMENT NEAR/NORTH OF MONTICELLO AR INTO THE
   GREENVILLE MS AREA THROUGH THE 00-03Z TIME FRAME.  SUPERCELLS ARE
   POSSIBLE...PRIMARILY WITH THE RISK FOR LARGE HAIL...PERHAPS LOCALLY
   DAMAGING WIND GUSTS.  BUT EVEN WITH FAIRLY SIZABLE SUB-CLOUD
   TEMPERATURE/DEW POINT SPREADS... CLOCKWISE CURVED LOW-LEVEL
   HODOGRAPHS ARE LARGE ENOUGH TO SUPPORT POTENTIAL FOR AN ISOLATED
   TORNADO.
   
   ..KERR.. 09/25/2011
   
   
   ATTN...WFO...MEG...JAN...LZK...
   
   LAT...LON   34019199 34819089 35339023 35458950 35048914 34089033
               33499066 32899089 32919172 33249192 34019199