MESOSCALE DISCUSSION 0279
   NWS STORM PREDICTION CENTER NORMAN OK
   0227 PM CDT SAT MAR 26 2011
   
   AREAS AFFECTED...SRN AR...NRN LA...CNTRL MS...EXTREME NERN TX
   
   CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY 
   
   VALID 261927Z - 262030Z
   
   LATEST SATELLITE IMAGERY INDICATES TOWERING CU FIELD OVER EXTREME
   SERN OK HAS DEEPENED OVER THE PAST HOUR OR SO IN THE VICINITY OF
   SUBJECTIVELY ANALYZED SFC LOW PRESSURE CENTER. A WARM FRONT
   PROTRUDES EWD FROM THE SFC LOW ACROSS SRN AR INTO CNTRL MS...WITH
   SHALLOW CU FIELD EVIDENT ON VIS SATELLITE IMAGERY INDICATING ITS
   APPROXIMATE POSITION. S OF THE WARM FRONT...TEMPERATURES HAVE HEATED
   INTO THE LOW 80S /WITH SFC DEWPOINTS IN THE LOW 60S/...YIELDING
   MLCAPE VALUES UP TO 2500 J/KG. 
   
   SOME UNCERTAINTY REMAINS REGARDING THE TIMING OF CONVECTIVE
   INITIATION OVER THE REGION. LOW-LEVEL CONVERGENCE IS MAXIMIZED NEAR
   THE SFC LOW AND SWD ALONG THE DRYLINE/COLD FRONT. AN ADDITIONAL
   FOCUS FOR INITIATION MAY ALSO OCCUR ALONG THE WARM FRONT ACROSS SRN
   AR. GIVEN WEAKLY INHIBITED THERMODYNAMIC PROFILES...IT APPEARS THAT
   CONVECTIVE INITIATION WILL BE PROBABLE WITHIN THE NEXT 1-2 HRS...AND
   THIS SCENARIO IS SUPPORTED BY THE 26.1700 EXPERIMENTAL WRF-HRRR
   MODEL RUN. WITH EFFECTIVE SHEAR VALUES NEAR 50 KTS ACROSS THE
   REGION...THE POTENTIAL WILL EXIST FOR SPLITTING SUPERCELLS CAPABLE
   OF PRODUCING LARGE HAIL AND STRONG WIND GUSTS /GIVEN NEARLY
   UNIDIRECTIONAL VERTICAL SHEAR PROFILES/. AN ENHANCED THREAT FOR
   POSSIBLE TORNADOES WILL EXIST IN THE VICINITY OF THE WARM FRONT
   /WHERE LOW-LEVEL SHEAR WILL BE MAXIMIZED/.
   
   ..ROGERS.. 03/26/2011
   
   
   ATTN...WFO...MEG...JAN...LZK...SHV...
   
   LAT...LON   33859308 33899172 33968825 32428845 32479169 32609357
               32619429 34019438 33859308