MESOSCALE DISCUSSION 0725
   NWS STORM PREDICTION CENTER NORMAN OK
   0226 AM CDT WED MAY 06 2009
   
   AREAS AFFECTED...PORTIONS WRN/NRN AR...SWRN TN...EXTREME NRN MS.
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 248...
   
   VALID 060726Z - 060930Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 248
   CONTINUES.
   
   SRN PORTIONS ORIGINAL WW HAVE BEEN REPLACED BY WW 250.
   
   AS OF 715Z...CLUSTER OF TSTMS FROM MEM AREA SSWWD OVER MS RIVER --
   ANCHORED BY POTENTIALLY TORNADIC SUPERCELL -- WILL POSE MOST
   CRITICAL SEVERE WEATHER THREAT AS IT MOVES ENEWD OVER PORTIONS NRN
   MS AND EXTREME SWRN TN.  SUPERCELL WILL MOVE ACROSS PORTIONS
   TUNICA/TATE/DESOTO COUNTIES IN NW MS...WITH DAMAGING HAIL AND A
   TORNADO OR TWO POSSIBLE.  THEN ENTIRE LEADING CLUSTER SHOULD CROSS
   OVER GRADUALLY MORE STABLE SFC-BASED PARCELS WITH TIME...BASED ON
   OBSERVATIONALLY MODIFIED RUC SOUNDINGS IN PROSPECTIVE PATH. 
   STILL...LARGE HAIL AND ISOLATED STG/DAMAGING GUSTS WILL REMAIN
   POSSIBLE WITH THIS ACTIVITY EVEN AFTER TORNADO THREAT BEGINS TO
   DIMINISH.
   
   BEHIND THIS ACTIVITY...AND BEHIND LARGE MCS NOW MOVING THROUGH WW
   350...SVR THREAT IS FCST TO BECOME MRGL...HAIL BEING MAIN CONCERN
   FROM ELEVATED CONVECTION DEVELOPING ATOP OUTFLOW POOL.  BROAD SHEET
   OF VERY MOIST AIR WILL BE LIFTED OVER STABLE NEAR-SFC AIR TO LFC. 
   EXPECT MUCAPE DECREASING FROM AROUND 1500 J/KG OVER CENTRAL/SWRN AR
   TO 500 J/KG OVER MOST OF OZARKS...AMIDST 40-50 KT EFFECTIVE SHEAR
   THAT SUPPORTS POTENTIAL ORGANIZATION OF ELEVATED TSTMS.  SVR THREAT
   SHOULD LESSEN WITH EWD EXTENT ACROSS NERN AR BEHIND INITIAL
   ACTIVITY...WHERE AIR MASS ALOFT IS MORE RECENTLY/STRONGLY STABILIZED
   AND WILL TAKE LONGER TO RECOVER SUFFICIENTLY...IF AT ALL.
   
   ..EDWARDS.. 05/06/2009
   
   
   ATTN...WFO...OHX...HUN...MEG...LZK...SHV...TSA...
   
   LAT...LON   34448815 34498871 34598869 34549022 34429026 34449040
               34659059 34639110 34369106 34589128 34599161 34499171
               34489240 34449270 34529286 34389299 34379423 34169429
               34199441 34899432 35379364 35729353 35679177 35929167
               35889091 35999071 35998973 35868933 35688902 35808884
               35858799 35038798 35028822 34888810 34448815