MESOSCALE DISCUSSION 0636
   NWS STORM PREDICTION CENTER NORMAN OK
   1209 PM CDT TUE MAY 01 2007
   
   AREAS AFFECTED...NERN IL...NRN IND...SRN LWR MI...NW OH
   
   CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 
   
   VALID 011709Z - 011915Z
   
   A WW PROBABLY WILL BE NEEDED BY 20-21Z...IF NOT BEFORE.
   
   STRONG SURFACE HEATING IS ALREADY WELL UNDERWAY IN CONFLUENT
   LOW-LEVEL FLOW TO THE SOUTH OF WEAK SURFACE LOW NEAR CHICAGO...
   EASTWARD ALONG WARM FRONTAL ZONE THROUGH THE SOUTHERN LOWER MICHIGAN
   BORDER AREA INTO NORTHERN OHIO.  TEMPERATURES HAVE ALREADY EXCEEDED
   80F...AND SURFACE DEW POINTS ARE RISING TO AROUND 60F...CONTRIBUTING
   TO THE DEVELOPMENT OF MIXED BOUNDARY LAYER CAPE AROUND 1000 J/KG. 
   FURTHER DESTABILIZATION IS LIKELY INTO THE PEAK AFTERNOON HEATING
   HOURS...AND MIXED LAYER CAPE MAY LOCALLY APPROACH 2000 J/KG.
   
   MID-LEVEL INHIBITION IS IN THE PROCESS OF WEAKENING...AND MOST MODEL
   GUIDANCE SUGGESTS THAT RAPID DEVELOPMENT OF STORMS WILL OCCUR ALONG
   FRONTAL ZONE BY THE 20-21Z TIME FRAME.  HOWEVER... THERE IS SOME
   CONCERN THAT INITIATION OF AT LEAST ISOLATED BOUNDARY BASED STORMS
   COULD OCCUR A BIT EARLIER.  THIS SEEMS MOST PROBABLE NEAR LAKE
   BREEZE ACROSS NORTHWESTERN INDIANA.  IF THIS OCCURS...A MODERATELY
   SHEARED DEEP LAYER WESTERLY FLOW REGIME WILL BE SUFFICIENT FOR
   SUPERCELLS.  
   
   INITIATION/INTENSIFICATION OF ADDITIONAL ISOLATED STORMS ALSO
   APPEARS POSSIBLE ABOVE WARM FRONTAL INVERSION LAYER FARTHER TO THE
   EAST...ACROSS SOUTHERN MICHIGAN INTO THE VICINITY OF LAKE ERIE. 
   MID-LEVEL FORCING FOR UPWARD VERTICAL MOTION WILL BE A BIT BETTER
   ACROSS THIS REGION...ASSOCIATED WITH GLANCING INFLUENCE OF SHORT
   WAVE TROUGH PROGRESSING THROUGH THE UPPER GREAT LAKES REGION.
   
   ..KERR.. 05/01/2007
   
   
   ATTN...WFO...CLE...DTX...IWX...GRR...LOT...
   
   41958738 42358612 42428477 42258375 42178273 42088185
   41348190 40968297 40908433 41088587 41158666 41158761
   41318837 41578787