MESOSCALE DISCUSSION 0158
   NWS STORM PREDICTION CENTER NORMAN OK
   0335 PM CST TUE FEB 12 2013
   
   AREAS AFFECTED...S-CNTRL/ERN LA THROUGH SERN MS INTO SWRN AL AND THE
   WRN FL PNHDL
   
   CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 
   
   VALID 122135Z - 122300Z
   
   PROBABILITY OF WATCH ISSUANCE...80 PERCENT
   
   SUMMARY...THE THREAT FOR SUPERCELLS CAPABLE OF TORNADOES WILL
   INCREASE LATE THIS AFTERNOON INTO EVENING AND A TORNADO WATCH WILL
   LIKELY BE REQUIRED PRIOR TO 00Z.
   
   DISCUSSION...21Z SURFACE ANALYSIS SHOWED A SURFACE LOW SW OF HEZ
   WITH AN ASSOCIATED WARM FRONT EXTENDING SEWD TO NEAR BTR/MSY AND
   THEN EWD ACROSS THE SHELF WATERS S OF MOB BEFORE CURVING ENEWD ONTO
   THE FL PNHDL /N OF AAF/.  A COLD FRONT TRAILED THE SURFACE LOW SWD
   TO E OF LCH.  OVER THE PAST HOUR...TSTMS HAVE GENERALLY DIMINISHED
   IN AREAL COVERAGE ACROSS THE DISCUSSION AREA...PERHAPS IN RESPONSE
   TO THE PASSAGE OF A LEAD SHORT-WAVE TROUGH TO THE N OF THE REGION. 
   THIS HAS RESULTED IN THE MOST WIDESPREAD TSTMS DEVELOPMENT BECOMING
   FOCUSED WELL TO THE N OF THE SURFACE WARM FRONT OVER CNTRL PARTS OF
   MS AND AL.  MOREOVER...RAPID-REFRESH AND 18Z NAM-DERIVED SOUNDINGS
   INDICATE A WARM NOSE IN THE 700-550-MB LAYER WHICH MAY BE
   PROHIBITING MORE ROBUST UPDRAFT GROWTH WITHIN THE WARM SECTOR.
   
   IT STILL APPEARS PROBABLE THAT RENEWED HEIGHT FALLS AHEAD OF THE
   PRIMARY MIDLEVEL TROUGH OVER THE SRN PLAINS IN CONJUNCTION WITH
   LOW-LEVEL UPLIFT ALONG THE WARM AND COLD FRONTS WILL FOSTER AT LEAST
   WIDELY SCATTERED TSTM DEVELOPMENT BY 00Z FROM S-CNTRL LA EWD INTO
   FAR SRN PARTS OF MS/AL AND THE FL PNHDL.  GIVEN THE PRESENCE OF A
   MOIST AND AT LEAST MARGINALLY UNSTABLE WARM SECTOR AIR MASS AND
   MODERATELY STRONG LOW-LEVEL AND DEEP-LAYER SHEAR...THE POTENTIAL
   WILL EXIST FOR SUPERCELLS CAPABLE OF A FEW TORNADOES AND LOCALLY
   DAMAGING WINDS.
   
   ..MEAD.. 02/12/2013
   
   
   ATTN...WFO...TAE...MOB...JAN...LIX...LCH...
   
   LAT...LON   30009129 30829128 31388988 31568741 31408653 30438626
               29878678 29568779 29499000 29579109 30009129