MESOSCALE DISCUSSION 0470
   NWS STORM PREDICTION CENTER NORMAN OK
   0322 PM CDT MON APR 13 2009
   
   AREAS AFFECTED...FAR SRN IND...CNTRL KY...MIDDLE TN...FAR NRN AL
   
   CONCERNING...TORNADO WATCH 151...
   
   VALID 132022Z - 132115Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 151 CONTINUES.
   
   SEVERE THUNDERSTORMS CAPABLE OF LARGE HAIL AND DMGG WINDS WILL
   CONTINUE ACROSS MAINLY THE ERN HALF OF WW151. ISOLD TORNADOES REMAIN
   POSSIBLE...ESPECIALLY NEAR THE WARM FRONT ACROSS THE FAR NRN PORTION
   OF THE WATCH. 
   
   CONVECTIVE DEVELOPMENT HAS BECOME MORE WIDESPREAD ACROSS THE WATCH
   AREA UNDER STRONGLY DIFFLUENT FLOW ALOFT AND AHEAD OF A MID LEVEL
   SHORT WAVE NOTED ON WV IMAGERY APPROACHING CNTRL KY/MIDDLE TN. 20Z
   SURFACE ANALYSIS PLACES A LOW IN CNTRL IL...WITH A MESOLOW IN SRN
   IND. A WARM FRONT EXTENDS EWD ROUGHLY ALONG THE OH RIVER...WHILE A
   COLD FRONT EXTENDS SWD THROUGH CNTRL KY/MIDDLE TN. ALTHOUGH STORMS
   ON THE SRN EXTENT ARE GENERALLY MERGING INTO FORCED LINEAR
   CONVECTION ALONG THE COLD FRONT...STORMS TO THE N ARE MAINTAINING
   DISCRETE/SUPERCELLULAR STRUCTURES IN AN ENVIRONMENT CHARACTERIZED BY
   50 TO 60 KT OF 0-6 KM BULK SHEAR AND MODERATE INSTABILITY. CLOSER TO
   THE WARM FRONT...TORNADIC SUPERCELLS REMAIN POSSIBLE...SUPPORTED BY
   RECENT PROFILER DATA IN SWRN OH WHERE CONSIDERABLE DIRECTIONAL SHEAR
   IS NOTED IN LOW LEVELS. A LOCAL EXTENSION OR A NEW WW EAST OF THE
   CURRENT WATCH MAY BE NEEDED.
   
   ..HURLBUT.. 04/13/2009
   
   
   ATTN...WFO...JKL...ILN...LMK...OHX...IND...HUN...PAH...
   
   LAT...LON   36358529 34828650 34858733 35488703 36648634 38288692
               38868672 39138573 38608467 37048494 36358529