MESOSCALE DISCUSSION 0780
   NWS STORM PREDICTION CENTER NORMAN OK
   0503 PM CDT FRI MAY 13 2011
   
   AREAS AFFECTED...LOWER TN VALLEY / NWRN AL
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 132203Z - 132300Z
   
   SOME SEVERE THREAT MAY CONTINUE E OF ONGOING SEVERE WATCH 298 AS THE
   AIR MASS OVER THE LOWER TN VALLEY AND NWRN AL SLOWLY RECOVERS IN
   WAKE OF THE EARLIER MCS.  A WW IS POSSIBLE.
   
   21Z SURFACE ANALYSIS PLACES AN OUTFLOW BOUNDARY DRAPED FROM CNTRL AL
   INTO E-CNTRL MS AND THEN EXTENDING NWD TOWARDS THE TN/MS/AL BORDER
   REGION.  VISIBLE SATELLITE IMAGERY SHOWS AN ABSENCE OF CU OVER NWRN
   AL AND WRN MIDDLE TN OWING TO THE STABILIZING INFLUENCE OF THE
   EARLIER MCS.  THE UPPER LOW OVER MO IS SHIFTING EWD FOCUSING LARGE
   SCALE FORCING FOR ASCENT TOWARDS THE REGION.
   
   INCREASING FORCING FOR ASCENT AND AN IMPROVING TROPOSPHERIC WIND
   PROFILE /SUPPORTIVE OF ORGANIZED STORMS INCLUDING SUPERCELLS/ MAY
   ACT TO IMPROVE STRONG-SEVERE POTENTIAL ACROSS THE AREA.  DESPITE
   THESE POSITIVES...SUBSTANTIAL SURFACE-BASED CINH /TEMPS ONLY IN THE
   UPPER 60S-LOWER 70S/ SHOULD FAVOR A TENDENCY FOR STORMS TO BECOME
   ELEVATED AND ROOTED ABOVE THE RELATIVELY COOL/STABLE BOUNDARY LAYER
   AS THEY MOVE INTO THE DISCUSSION AREA.  THEREFORE...DMGG WIND
   POTENTIAL SHOULD LESSEN AS STORMS MOVE EWD FROM WW 298 INTO THE WRN
   PARTS OF THE DISCUSSION AREA...WITH LARGE HAIL BECOMING THE PRIMARY
   THREAT WITH TIME FOR STORMS THAT ARE ABLE TO REMAIN ROBUST INTO THE
   EARLY EVENING HOURS.
   
   ..SMITH.. 05/13/2011
   
   
   ATTN...WFO...LMK...OHX...BMX...HUN...PAH...MEG...
   
   LAT...LON   33378827 35168809 36298803 37088791 37368747 37198682
               36398651 35108663 33708694 33388719 33098759 33098795
               33378827