MESOSCALE DISCUSSION 0587
   NWS STORM PREDICTION CENTER NORMAN OK
   1226 PM CDT TUE APR 26 2011
   
   AREAS AFFECTED...EASTERN IL INTO MUCH OF INDIANA/WESTERN OH AND
   SOUTHERN LOWER MI
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 261726Z - 261900Z
   
   THE SEVERE THREAT IS EXPECTED TO GRADUALLY INCREASE THROUGH THE
   AFTERNOON FROM EASTERN IL INTO MUCH OF INDIANA/SOUTHERN LOWER MI AND
   EVENTUALLY WESTERN OH. A WATCH MAY BE NEEDED FOR AT LEAST PORTIONS
   OF THE REGION.
   
   AS THE BRUNT OF A LEAD SHORTWAVE TROUGH CONTINUES TO PIVOT
   NORTHEASTWARD TOWARD THE UPPER GREAT LAKES REGION...MIDDAY  SURFACE
   ANALYSIS REFLECTS A SURFACE LOW OVER THE UPPER MS VALLEY...WITH AN
   ASSOCIATED COLD FRONT EXTENDING SOUTH-SOUTHWESTWARD INTO THE MIDDLE
   MS VALLEY. ALONG/EAST OF A COLD FRONT AMID A REGION OF LOW LEVEL
   CONFLUENCE...TSTMS ARE EXPECTED TO CONTINUE TO DEVELOP WITHIN AN
   INCREASINGLY UNSTABLE/WEAKLY CAPPED BOUNDARY FROM EASTERN IL INTO
   MUCH OF INDIANA/WESTERN OH AND SOUTHERN LOWER MI...WHERE MODEST
   CLOUD BREAKS ARE OCCURRING COINCIDENT WITH UPPER 50S F SURFACE
   DEWPOINTS. AS STORMS MATURE...STRONG LOW-MID TROPOSPHERIC
   SOUTHWESTERLY FLOW WILL YIELD FAST NORTHEASTWARD-MOVING
   TSTMS...INCLUDING A FEW SUPERCELLS/ORGANIZED LINE SEGMENTS...CAPABLE
   OF DAMAGING WINDS/SEVERE HAIL AND PERHAPS A TORNADO. CONVECTIVE
   TRENDS WILL CONTINUE TO BE MONITORED FOR THE POSSIBILITY OF A WATCH.
   
   ..GUYER.. 04/26/2011
   
   
   ATTN...WFO...CLE...ILN...DTX...IWX...GRR...IND...LOT...ILX...
   
   LAT...LON   39028813 40498840 41428708 42508592 43338535 42958335
               41298337 38988492 39028813