MESOSCALE DISCUSSION 2125
   NWS STORM PREDICTION CENTER NORMAN OK
   0644 PM CST MON NOV 26 2012
   
   AREAS AFFECTED...ERN TX...NRN/CNTRL/WRN LA...FAR SRN
   AR...SWRN/W-CNTRL MS
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 270044Z - 270215Z
   
   PROBABILITY OF WATCH ISSUANCE...60 PERCENT
   
   SUMMARY...CONVECTIVE DEVELOPMENT IS UNDERWAY ACROSS PARTS OF NERN TX
   AND NWRN LA...AND THE ISSUANCE OF A SVR TSTM WATCH IS POSSIBLE.
   
   DISCUSSION...OBSERVED SOUNDINGS FROM SHREVEPORT INDICATE COOLING
   WITHIN THE 730-600-MB LAYER FROM 18Z TO 00Z...POTENTIALLY INDICATING
   THE INCREASE IN LARGE-SCALE ASCENT DOWNSTREAM OF A MID-LEVEL VORT
   MAX SOON TO EMERGE OVER CNTRL/SRN TX. THE ASCENT/COOLING HAS
   CONTRIBUTED TO DESTABILIZATION...WITH THE 00Z SHREVEPORT RAOB
   INDICATING AROUND 1100 J/KG OF MLCAPE WITH AROUND 20 J/KG MLCIN.
   RADAR RETURNS HAVE BEEN NOTED FROM RUSK COUNTY TX TO BOSSIER PARISH
   LA...WHICH IS THE MANIFESTATION OF ONGOING CONVECTIVE INITIATION AS
   A COLD FRONT APPROACHES FROM THE NW...WITH MESOSCALE ASCENT ENHANCED
   BY CONVERGENCE AROUND A WEAK SUB-SYNOPTIC-SCALE CYCLONE POSITIONED
   NEAR SHREVEPORT. STORMS WILL LIKELY INCREASE IN NUMBER AND INTENSITY
   DURING THE NEXT HOUR OR TWO...POTENTIALLY EVOLVING INTO ONE OR MORE
   SQUALL LINES NEAR/JUST AHEAD OF THE FRONT AMIDST 20-35 KT OF
   EFFECTIVE BULK SHEAR. SVR WINDS/HAIL WILL BE THE MAIN CONCERN WITH
   THIS ACTIVITY...MAINLY TO THE W OF A NNW/SSE-ORIENTED CONFLUENCE
   AXIS/WARM FRONT ACROSS THE WRN HALF OF LA. WEAKER INSTABILITY
   FARTHER E TOWARD THE MS RIVER INTO WRN MS AND N INTO FAR SRN AR MAY
   MITIGATE THE THREAT WITH TIME...WHERE WW ISSUANCE IS RELATIVELY LESS
   LIKELY.
   
   ..COHEN/DARROW.. 11/27/2012
   
   
   ATTN...WFO...JAN...LIX...LZK...LCH...SHV...HGX...
   
   LAT...LON   29849303 29549484 30929543 32149468 33189347 33289272
               33159198 32819123 31989096 31139139 30359203 29849303