MESOSCALE DISCUSSION 1685
   NWS STORM PREDICTION CENTER NORMAN OK
   1020 AM CDT FRI JUL 22 2011
   
   AREAS AFFECTED...SRN LOWER MICHIGAN...NRN/CENTRAL INDIANA AND NWRN
   OHIO.
   
   CONCERNING...OUTLOOK UPGRADE 
   
   VALID 221520Z - 221615Z
   
   ...PORTIONS OF SRN LOWER MICHIGAN...NRN/CENTRAL INDIANA AND NWRN
   OHIO WILL BE UPGRADED TO A SLIGHT RISK ON THE 1630Z DAY 1 OUTLOOK. 
   
   AT 1510Z...A LINE OF THUNDERSTORMS...WITH GUSTS MAINLY IN THE 35 TO
   55 MPH RANGE...WAS MOVING EAST AT 35 KT THROUGH NERN IL... INCLUDING
   THE CHICAGO METRO AREA. THE ACCOMPANYING COLD POOL COMBINED WITH THE
   WARMING AND DESTABILIZING BOUNDARY LAYER MAY SUSTAIN STORMS
   EWD...THOUGH MOST STORM SCALE MODELS SUGGEST STORMS WILL WEAKEN BY
   17Z. IF THESE STORMS DO NOT DISSIPATE...THE INCREASING INSTABILITY
   AND 25-30 KT SHEAR WOULD BE SUFFICIENT FOR AT LEAST AN ISOLATED
   DAMAGING WIND THREAT THIS AFTERNOON.
   
   ALSO...STORM SCALE MODELS INDICATE STORMS ARE LIKELY TO DEVELOP
   ACROSS PORTIONS OF INDIANA AND OHIO...ALONG AND AHEAD OF AN OUTFLOW
   BOUNDARY THAT IS MOVING EWD THROUGH EAST CENTRAL ILLINOIS. THIS AREA
   IS UNDER THE NRN INFLUENCE OF THE UPPER RIDGE WITH WEAK FLOW ALOFT
   AND POOR LAPSE RATES. HOWEVER...STRONG WARMING OF VERY MOIST
   BOUNDARY LAYER...DEWPOINTS IN THE MID/UPPER 70S AND MLCAPES AROUND
   4000 J/KG...MAY SUPPORT PULSE STORMS WITH A FEW WET MICROBURSTS.
   
   ..IMY.. 07/22/2011
   
   
   ATTN...WFO...RLX...CLE...ILN...DTX...IWX...GRR...IND...LOT...
   
   LAT...LON   41158589 42278475 42208308 41298223 39898245 39448440
               39518609 39758719 40288722 40758700 41158589