MESOSCALE DISCUSSION 0629
   NWS STORM PREDICTION CENTER NORMAN OK
   0256 PM CDT WED APR 27 2011
   
   AREAS AFFECTED...MUCH OF MS/AL INTO SOUTHERN TN AND NORTHWEST GA
   
   CONCERNING...TORNADO WATCH 232...235...
   
   VALID 271956Z - 272200Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 232...235...CONTINUES.
   
   PARTICULARLY DANGEROUS SITUATION /PDS/ TORNADO WATCHES 232/235
   CONTINUE UNTIL 00Z/03Z RESPECTIVELY. THIS INCLUDES THE POTENTIAL FOR
   LONG-TRACK STRONG/PERHAPS VIOLENT TORNADOES INTO THIS EVENING AS A
   SEVERE WEATHER OUTBREAK ONLY INCREASES IN MAGNITUDE/RISK.
   
   AN EXTREMELY DANGEROUS/LIFE-THREATENING SITUATION CONTINUES TO
   UNFOLD THIS AFTERNOON ACROSS A LARGE PART OF MS/AL...WITH ADJACENT
   PORTIONS OF TN/NORTHWEST GA ALSO EXPECTED TO BECOME A CONCERN LATE
   THIS AFTERNOON/EVENING. CURRENT OBSERVATIONAL TRENDS...REASONABLY
   SUPPORTED BY EXPERIMENTAL HRRR GUIDANCE...IMPLY THAT SCATTERED
   SUPERCELLS WILL CONTINUE TO FORM IN BROKEN NNE-SSW ORIENTED
   CORRIDORS OF SUBTLE CONFLUENCE AHEAD /EAST/ OF MORE
   STORMS/SUPERCELLS THAT ARE DEVELOPING ALONG A PRE-COLD FRONTAL
   TROUGH/DRYLINE GENERALLY NEARING I-55 IN MS. 
   
   THE WARM SECTOR AIRMASS HAS AGGRESSIVELY DESTABILIZED THIS AFTERNOON
   AMID NEAR 70F/LOWER 70S F SURFACE DEWPOINTS...REFERENCE SPECIAL 18Z
   OBSERVED RAOBS FROM JACKSON MS/BIRMINGHAM AL...WITH A WIDE/HIGHLY
   SHEARED MOIST SECTOR IN PLACE ALONG/SOUTH OF A MODIFYING WEST-EAST
   OUTFLOW BOUNDARY /NOW AN EFFECTIVE WARM FRONT/ ACROSS FAR NORTHERN
   PORTIONS OF AL/MS. EXTREME LOW LEVEL SHEAR...VIA LONG/CURVING LOW
   LEVEL HODOGRAPHS...WILL REMAIN HIGHLY CONDUCIVE FOR SUPERCELLS
   CAPABLE OF LONG-TRACK STRONG/VIOLENT TORNADOES INTO THIS EVENING
   AMID 0-1 KM SRH OF 300-500 M2/S2 OR GREATER /ESPECIALLY NEAR THE
   AFOREMENTIONED NORTHERN MS AND AL BOUNDARY/.
   
   ..GUYER.. 04/27/2011
   
   
   ATTN...WFO...MRX...FFC...OHX...BMX...HUN...MOB...MEG...JAN...
   
   LAT...LON   31419103 33129004 34948902 35258559 33928523 31558765
               31419103