MESOSCALE DISCUSSION 1338
   NWS STORM PREDICTION CENTER NORMAN OK
   1158 AM CDT TUE JUN 21 2011
   
   AREAS AFFECTED...CNTRL/NRN LA...MUCH OF MS
   
   CONCERNING...HEAVY RAINFALL 
   
   VALID 211658Z - 211800Z
   
   HEAVY RAINFALL WITH 1-2 INCH AN HOUR RATES WILL CONTINUE OVER
   PORTIONS OF LA...GRADUALLY PROGRESSING EWD WITH TIME INTO MUCH OF
   MS. 
   
   A VORTICITY MAX THAT SPAWNED SEVERE WEATHER NEAR THE DFW METROPLEX
   LAST EVENING AROUND THE BASE OF A LARGER SCALE UPPER TROUGH HAS
   PROGRESSED EWD TO SRN AR/NRN LA...PROVIDING FORCING FOR ASCENT FOR
   WIDESPREAD CONVECTION TO DEVELOP OVER PORTIONS OF THE GULF STATES.
   12Z SOUNDINGS INDICATE A VERY MOIST AIR MASS CHARACTERIZED BY PWAT
   VALUES GENERALLY AOA 2.10 INCH IN THE LA/MS AREA...WITH SATURATION
   PRIMARILY BELOW 500 MB. VAD WIND PROFILE DATA INDICATES MODEST
   UNIDIRECTIONAL SLY LOW LEVEL WINDS...WHICH WILL CONTINUE TO MAINTAIN
   MOIST INFLUX OF GULF AIR...WITH UPPER 70S DEW POINTS NOTED INTO SRN
   LA. AS THE UPPER LOW CENTERED ROUGHLY NEAR THE NERN NEB/SERN SD
   BORDER SLOWLY PROGRESSES EWD...WLY FLOW ALOFT WILL ALLOW CURRENT
   CONVECTION TO GRADUALLY BE SHUNTED EWD INTO MS. GREATER THAN 2 INCH
   AN HOUR RATES WILL BE POSSIBLE IN MORE STRONGLY ORGANIZED
   MULTICELLULAR CLUSTERS.
   
   ..HURLBUT.. 06/21/2011
   
   
   ATTN...WFO...MEG...JAN...LIX...LCH...SHV...
   
   LAT...LON   34008833 32738861 31389025 30839216 31179307 31739233
               32729125 32979104 34079008 34368888 34008833