MESOSCALE DISCUSSION 0636
   NWS STORM PREDICTION CENTER NORMAN OK
   0538 PM CDT WED APR 27 2011
   
   AREAS AFFECTED...MIDDLE/EASTERN TN TO FAR WESTERN NC
   
   CONCERNING...TORNADO WATCH 238...
   
   VALID 272238Z - 280015Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 238 CONTINUES.
   
   PARTICULARLY DANGEROUS SITUATION /PDS/ TORNADO WATCH 238 CONTINUES
   UNTIL 05Z ACROSS MIDDLE/EASTERN TN. THE POTENTIAL FOR
   TORNADOES...INCLUDING STRONG TORNADOES...WILL ONLY INCREASE THROUGH
   EARLY/MID EVENING. THE RELATIVELY HIGHEST TORNADIC POTENTIAL
   INVOLVES SOUTHERN MIDDLE TN/SOUTHEAST TN INCLUDING THE CHATTANOOGA
   VICINITY AND I-24/I-75 CORRIDORS.
   
   A COMPLEX CONVECTIVE MODE INCLUDING EMBEDDED TORNADIC SUPERCELLS
   CONTINUE TO DEVELOP/QUICKLY SPREAD NORTHEASTWARD ACROSS PDS TORNADO
   WATCH 238. OF CONCERN...THE AIRMASS ALONG A PRIOR OUTFLOW BOUNDARY
   ALONG THE TN/AL BORDER CONTINUES TO RECOVER...WITH A CONTINUED
   LIKELY NORTHWARD ADVANCEMENT INTO THE SOUTHERN PART OF MIDDLE TN AS
   WELL AS MUCH OF EASTERN TN THIS EVENING. ACCORDINGLY...RICHER LOW
   LEVEL MOISTURE /LOWER-MIDDLE 60S F SURFACE DEWPOINTS/ WILL CONTINUE
   TO SURGE NORTH-NORTHEASTWARD...HEIGHTENING TORNADO POTENTIAL
   ESPECIALLY ACROSS SOUTHEAST TN. ADDITIONALLY...RAPID AIRMASS
   RECOVERY/DESTABILIZATION CONTINUES TO OCCUR UPSTREAM ACROSS WESTERN
   TN BENEATH THE MID LEVEL DRYSLOT...AND THIS WILL FURTHER AID
   DESTABILIZATION INTO MIDDLE TN THIS EVENING. WITH SUPERCELLS
   REMAINING LIKELY INTO THIS EVENING...EXTREME SHEAR/LOW LEVEL SHR
   WILL BE HIGHLY FAVORABLE FOR TORNADIC SUPERCELLS...INCLUDING THE
   POSSIBILITY OF STRONG TORNADOES.
   
   ..GUYER.. 04/27/2011
   
   
   ATTN...WFO...GSP...MRX...OHX...HUN...
   
   LAT...LON   35198736 36408668 36318268 35108437 35198736