MESOSCALE DISCUSSION 1807
   NWS STORM PREDICTION CENTER NORMAN OK
   0625 PM CDT SUN AUG 19 2007
   
   AREAS AFFECTED...E CNTRL MO...CNTRL IL...PARTS OF NW IND
   
   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 
   
   VALID 192325Z - 200130Z
   
   DOWNSTREAM OF THICKER CLOUD COVER ASSOCIATED WITH THE REMNANTS OF
   ERIN...BREAKS IN CLOUD COVER ALLOWED FOR CONSIDERABLE SURFACE
   HEATING THIS AFTERNOON...TO THE SOUTH OF SURFACE FRONT ACROSS
   NORTHERN ILLINOIS/INDIANA.  THIS OCCURRED BENEATH A RELATIVELY COLD
   MID-LEVEL TROUGH...EXTENDING FROM THE MID MISSISSIPPI VALLEY EAST
   NORTHEASTWARD THROUGH THE LOWER OHIO VALLEY...AND ALLOWED A MOIST
   BOUNDARY LAYER WITH 70F+ DEW POINTS TO BECOME MODERATELY UNSTABLE
   WITH CAPE UP TO AROUND 2000 J/KG.  ALTHOUGH LOW-LEVEL FLOW IS WEAK
   IN CONFLUENT REGIME ACROSS EAST CENTRAL MISSOURI THROUGH PARTS OF
   NORTHWEST INDIANA...30+ KT SOUTHWESTERLY 500 MB WINDS HAVE
   CONTRIBUTED TO MODERATE DEEP LAYER SHEAR...WHICH APPEARS TO HAVE
   ENHANCED MARGINAL SEVERE HAIL PRODUCTION IN STRONGER ONGOING STORMS.
    THIS MAY CONTINUE ANOTHER COUPLE OF HOURS...MAINLY EAST OF
   SPRINGFIELD IL INTO THE LAFAYETTE IND AREA...BUT STORMS ARE EXPECTED
   TO BEGIN TO WEAKEN BY 01-02Z AS BOUNDARY LAYER COOLS/STABILIZES WITH
   LOSS OF DAYTIME HEATING.
   
   ..KERR.. 08/19/2007
   
   
   ATTN...WFO...IWX...IND...LOT...ILX...LSX...DVN...
   
   39159137 40269078 40678945 40948883 40878690 40258629
   39488713 39188841 38398983 38719113