MESOSCALE DISCUSSION 0026
   NWS STORM PREDICTION CENTER NORMAN OK
   0345 PM CST TUE JAN 17 2012
   
   AREAS AFFECTED...PARTS OF CENTRAL/SRN LA AND SRN MS
   
   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 
   
   VALID 172145Z - 172245Z
   
   THE POTENTIAL FOR ISOLATED STRONG TO SEVERE STORMS WILL PERSIST
   ACROSS THE LOWER MS VALLEY /CENTRAL AND SRN LA TO SRN MS/ LATE THIS
   AFTERNOON.  IN ADDITION TO SOME SEVERE WEATHER THREAT...STORMS
   DEVELOPING OVER CENTRAL/SWRN LA WILL TEND TO TRACK ENEWD INTO FAR
   SRN MS WHERE STORMS ARE ALREADY IN PROGRESS.  HEAVIER RAINFALL RATES
   WILL BE POSSIBLE WITH THESE TRAINING STORMS.
   
   MID-AFTERNOON SURFACE ANALYSES SHOWED A COLD FRONT STEADILY
   ADVANCING EWD THROUGH THE LOWER MS VALLEY AND TOWARD THE TX COAST. 
   STORMS OVER CENTRAL LA WERE LOCATED ALONG AND E OF THE FRONT...WHILE
   THE STORMS OVER FAR SRN MS WERE LOCATED ALONG AN APPARENT
   DIFFERENTIAL HEATING BOUNDARY.  DESPITE SURFACE DEWPOINTS IN THE 60S
   AND STEEP MIDLEVEL LAPSE RATES...EXTENSIVE CLOUDINESS HAS CONTINUED
   TO INHIBIT GREATER SURFACE HEATING AND THUS MAINTAINING WEAK
   INSTABILITY /MLCAPE 500-1000 J PER KG/.  STRONG EFFECTIVE BULK SHEAR
   /AROUND 50 KT/ IS SUPPORTIVE FOR ORGANIZED STORMS...BUT VEERED
   PRE-FRONTAL LOW LEVEL WINDS WILL CONTINUE TO LIMIT CONVERGENCE AND
   OVERALL TSTM COVERAGE.  GIVEN STEEP MIDLEVEL LAPSE RATES AND DEEP
   LAYER SHEAR...HAIL AND STRONG WIND GUSTS WILL BE POSSIBLE WITH THE
   MORE SUSTAINED UPDRAFTS.  
   
   CONCERN ALSO EXISTS FOR HEAVY RAINFALL RATES...AS STORMS TRAIN ENEWD
   FROM CENTRAL LA THROUGH EXTREME SRN MS...WITH THE GREATEST THREAT
   AREA EXTENDING WSW-ENE WITHIN A 30-40 MILE WIDE CORRIDOR FROM NRN
   EVANGELINE PARISH LA TO LAMAR COUNTY MS.  PRECIPITABLE WATER VALUES
   TO AROUND 1.5 INCH WILL SUPPORT THIS THREAT.
   
   ..PETERS.. 01/17/2012
   
   
   ATTN...WFO...JAN...LIX...LCH...SHV...
   
   LAT...LON   30619347 31479216 31879144 31919007 31468922 30938971
               30709100 30379241 30329316 30619347