MESOSCALE DISCUSSION 0745
   NWS STORM PREDICTION CENTER NORMAN OK
   0238 PM CDT TUE MAY 18 2004
   
   AREAS AFFECTED...CNTRL IL
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 215...
   
   VALID 181938Z - 182145Z
   
   CONTINUE REMAINING VALID PORTION OF WW.
   
   2-HOUR SURFACE PRESSURE FALLS ARE CURRENTLY CENTERED IN THE VICINITY
   OF WEAK CIRCULATION EVIDENT IN 19Z SURFACE DATA NEAR/EAST OF
   SPRINGFIELD IL.  ONGOING CONVECTIVE DEVELOPMENT...NEAR PRE-FRONTAL
   CONFLUENT ZONE ACROSS CENTRAL ILLINOIS...AND NEAR CONVECTIVELY
   GENERATED COLD POOL SHIFTING NORTH OF ST. LOUIS...APPEARS LIKELY TO
   CONSOLIDATE INTO LARGER CONVECTIVE CLUSTER THROUGH 21-22Z.  BOUNDARY
   LAYER ACROSS CENTRAL ILLINOIS IS MOIST AND MODERATELY UNSTABLE WITH
   MEAN MIXED LAYER CAPE AT OR ABOVE 1500 J/KG.  THIS WILL SUPPORT
   VIGOROUS UPDRAFTS WITH HAIL/HEAVY RAIN...AND NEW SURFACE COLD
   POOL/MESO HIGH MAY DEVELOP NORTHEAST OF ST. LOUIS INTO THE DECATUR
   IL AREA.
   
   ..KERR.. 05/18/2004
   
   
   ATTN...WFO...IND...PAH...LOT...ILX...LSX...
   
   39829003 40188934 40568778 39148750 38338908 38209059
   39249036