MESOSCALE DISCUSSION 0999
   NWS STORM PREDICTION CENTER NORMAN OK
   0220 PM CDT THU MAY 15 2003
   
   AREAS AFFECTED...IN...KY...OH...TN...VA
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 378...379...
   
   VALID 151920Z - 152045Z
   
   SCATTERED TSTM ACTIVITY CONTINUES IN AREAS OF WW #378 AND #379. WW
   #378 WILL LIKELY BE ALLOWED TO EXPIRE AS SCHEDULED AT 15/21Z WITH
   #379 TO CONTINUE TO REMAIN IN EFFECT THRU 15/23Z.
   
   RECENT WV IMAGERY SHOWS THE THE MID-UPPER LVL CIRCULATION ALONG THE
   MI/IN BORDER REGION WITH A SURGE OF SUBSIDENCE...LIKELY AN NVA
   REGION...OBSERVABLE FROM NCNTRL IL SEWD TO SRN IN/NWRN KY. SOME
   CLEARING VIA VISIBLE IMAGERY FROM NCNTRL TN NNEWD INTO ERN KY WILL
   ALLOW SOME ADDITIONAL DESTABILIZATION OVER THE NEXT FEW HOURS AHEAD
   OF DEVELOPING MCS. EXPECT SURFACE TEMPERATURES AND DEWPOINT VALUES
   TO RISE OVER THE NEXT FEW HOURS INTO THE MID 60S TO LOW 70S AND THE
   LOW 60S RESPECTIVELY...LIKELY YIELDING 100MB MIXED CAPE VALUES
   BETWEEN 1000-1500 J/KG. EXPECT PRIMARY SEVERE THREATS OF LARGE HAIL
   AND DAMAGING WINDS...BUT AREAS OF VERY HEAVY RAINFALL ALSO ARE
   POSSIBLE GIVEN FCST SOUNDING PW VALUES OVER AN INCH AND CONSTANT
   MERGING OF CELL STRUCTURES. 
   
   ..NADEN.. 05/15/2003
   
   
   ATTN...WFO...RNK...RLX...MRX...JKL...ILN...LMK...OHX...PAH...
   
   35628471 35758546 36588726 37888660 39168481 40088294
   38058168 36528183