MESOSCALE DISCUSSION 0444
   NWS STORM PREDICTION CENTER NORMAN OK
   1259 PM CDT THU APR 11 2013
   
   AREAS AFFECTED...SWRN AL...FAR NW FL PANHANDLE
   
   CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY 
   
   VALID 111759Z - 111930Z
   
   PROBABILITY OF WATCH ISSUANCE...95 PERCENT
   
   SUMMARY...TORNADO WATCH NEEDED DOWNSTREAM OF ONGOING LINE OF STORMS
   ENTERING FAR SRN MS. WATCH ISSUANCE EXPECTED BY 19Z.
   
   DISCUSSION...LINE OF TSTMS ACROSS SERN LA AND FAR SRN MS HAS
   GRADUALLY INTENSIFIED OVER THE PAST SEVERAL HOURS. A WARM...TROPICAL
   AIRMASS...CHARACTERIZED BY DEWPOINTS IN THE LOW 70S...CONTINUES TO
   ADVECT NWD INTO THE CNTRL GULF COAST. 16Z LIX SOUNDING REVEALS THE
   CAPPING INVERSION PRESENT ON THE 12Z SOUNDING HAS ERODED WITH
   ABUNDANT DEEP MOISTURE AND STEEP LOW-LEVEL LAPSE RATES FAVORING
   STRONG INSTABILITY. VAD PROFILES AT LIX AND MOB SHOW STRONG
   LOW-LEVEL SHEAR WITH 0-1 KM SRH VALUES AROUND 250 M2/S2.
   MESOANALYSIS SHOWS EFFECTIVE SRH IN EXCESS OF 200 M2/S2 ACROSS
   COASTAL MS AND AL. GIVEN THE MOIST LOW-LEVEL PROFILES...AMPLE
   LOW-LEVEL INSTABILITY...AND STRONG LOW-LEVEL SHEAR...A FEW TORNADOES
   APPEAR POSSIBLE WITHIN THE LINE AND ANY DISCRETE DEVELOPMENT AHEAD
   OF IT. ALL OF THESE FACTORS CONFIRM A TORNADO WATCH IS NEEDED AND
   ONE WILL BE ISSUED BY 19Z.
   
   ..MOSIER/THOMPSON.. 04/11/2013
   
   
   ATTN...WFO...TAE...BMX...MOB...
   
   LAT...LON   30528651 30418672 30308728 30218793 30728839 32098839
               32098750 32108690 31848638 31288627 30528651