MESOSCALE DISCUSSION 1085
   NWS STORM PREDICTION CENTER NORMAN OK
   0127 PM CDT SAT JUN 04 2011
   
   AREAS AFFECTED...NRN IL...NRN IND
   
   CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 
   
   VALID 041827Z - 041930Z
   
   UPPER RIDGE IS EXPECTED TO GRADUALLY FLATTEN ACROSS THE NRN OH
   VALLEY PERHAPS IN RESPONSE TO SRN INFLUENCE OF UPPER GREAT LAKES
   SHORTWAVE TROUGH.  THIS FLATTENING PROCESS SHOULD LEAD TO A ZONE OF
   MORE FAVORABLE LOW LEVEL CONFLUENCE SHIFTING INTO NRN IL/IND WHICH
   WILL BE ENHANCED BY LAKE MI BREEZE.  STRONG SUNSHINE HAS STEEPENED
   LOW LEVEL LAPSE RATES ACROSS THIS REGION AND A DEEPENING BOUNDARY
   LAYER IS NOW MORE CONDUCIVE FOR CU DEVELOPMENT ALONG LAKE
   BREEZE...PER LATEST VIS IMAGERY.  ADDITIONALLY...SHOWERS ARE
   GRADUALLY INCREASING ACROSS SERN IA INTO NWRN IL WITH ISOLATED
   LIGHTNING NOW OBSERVED WITH STRONGER UPDRAFTS.  RECENT HRRR MODEL
   SUPPORTS ROBUST CONVECTIVE INITIATION ACROSS NRN IL/IND BY 19Z...AND
   ALTHOUGH THIS MAY BE A BIT EARLY IT WOULD SEEM TO BE SUPPORTED BY
   LATEST OBSERVATIONAL TRENDS.  FOR THIS REASON A SEVERE THUNDERSTORM
   WATCH MAY BE WARRANTED SOON.
   
   ..DARROW.. 06/04/2011
   
   
   ATTN...WFO...IWX...IND...LOT...ILX...DVN...
   
   LAT...LON   42188914 42078792 41538706 41718528 40618509 40518780
               41489005 42188914