MESOSCALE DISCUSSION 1448
   NWS STORM PREDICTION CENTER NORMAN OK
   1247 PM CDT THU JUN 30 2011
   
   AREAS AFFECTED...ERN OK...WRN AR...NWRN LA...NERN TX
   
   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 
   
   VALID 301747Z - 302015Z
   
   A FEW STORMS COULD CONTAIN DMGG WIND GUSTS THIS AFTERNOON.
   
   WITH STEEPENING LOW-LEVEL LAPSE RATES OWING TO SFC TEMPERATURES
   ALREADY HAVING CLIMBED INTO THE LOWER TO MIDDLE 90S...OROGRAPHIC
   INFLUENCES OVER THE OUACHITA MOUNTAINS HAVE RESULTED IN THE RECENT
   DEVELOPMENT OF A CUMULUS FIELD OVER PARTS OF W-CNTRL AR AND E-CNTRL
   OK. ADDITIONAL CUMULUS DEVELOPMENT HAS BEEN NOTED OVER THE BOSTON
   MOUNTAINS AND OZARK PLATEAU IN NWRN AR. MODIFICATIONS TO THE 12Z
   LITTLE ROCK SOUNDING FOR CURRENT SFC OBSERVATIONS CONFIRM THAT
   SURFACE-BASED CINH HAS BEEN SUBSTANTIALLY ERODED. WITH A VERY
   UNSTABLE AIR MASS ALREADY IN PLACE ACROSS THE REGION...SUPPORTED BY
   AMPLE BOUNDARY-LAYER MOISTURE /SFC DEWPOINTS IN THE UPPER 60S TO
   LOWER 70S/ ADDITIONAL CONVECTION MAY DEVELOP INVOF HIGHER TERRAIN
   AND AN AXIS OF CONFLUENCE JUXTAPOSED WITH A BAROCLINIC ZONE DRAPED
   NEAR THE OK-AR BORDER THAT EXTENDS SEWD INTO THE LOWER MS VALLEY.
   THIS DEVELOPMENT IS SUPPORTED BY THE CONSENSUS AMONGST
   CONVECTION-ALLOWING MODEL GUIDANCE...WHICH DEPICTS THE GREATEST
   THREAT FOR CONVECTION DEVELOPING BETWEEN 19Z AND 21Z. WEAK
   DEEP-LAYER SHEAR WILL FOSTER A PRIMARY PULSE CONVECTIVE MODE. THE
   THREAT FOR MICROBURSTS PRODUCING DMGG WIND GUSTS WILL OCCUR GIVEN
   DCAPE VALUES OF 1300 TO 1600 J/KG...AS STORMS MOVE WWD/WSWWD OVER
   THE SRN PERIPHERY OF A MID-LEVEL RIDGE CENTERED OVER THE CNTRL
   PLAINS. THE ISOLATED NATURE OF THE SVR THREAT WILL PRECLUDE THE NEED
   FOR A WW.
   
   ..COHEN.. 06/30/2011
   
   
   ATTN...WFO...LZK...SHV...TSA...FWD...OUN...
   
   LAT...LON   33189531 33909590 34889595 35969557 36379482 36469426
               36469339 36269304 35939294 35529300 34849287 34339270
               33489254 32859257 32419301 32499386 32679440 33189531