MESOSCALE DISCUSSION 1767
   NWS STORM PREDICTION CENTER NORMAN OK
   0654 PM CDT WED JUL 27 2011
   
   AREAS AFFECTED...NRN IL...FAR SRN WI...E-CNTRL IA
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 272354Z - 280100Z
   
   CONVECTIVE TRENDS ARE BEING MONITORED FOR A POSSIBLE WW...WITH A
   PRIMARY THREAT OF DMGG WINDS AND LARGE HAIL...AND PERHAPS AN
   ISOLATED TORNADO.
   
   CLUSTER OF STORMS HAS INTENSIFIED IN THE PAST HR NEAR KDBQ ALONG A
   SLOW-MOVING WARM FRONT AS A REMNANT MCV SHIFTS EWD ACROSS LAKE
   MICHIGAN. AREAL COVERAGE HAS PROBABLY BEEN LIMITED THUS FAR BY
   SHORTWAVE UPPER RIDGING OVERHEAD AND WARM MIDLEVEL TEMPERATURES.
   HOWEVER...PWAT VALUES IN EXCESS OF 2 INCHES /PER 00Z GPS-IPW DATA/
   AND VERY RICH BOUNDARY LAYER MOISTURE IN PLACE HAS AIDED IN EXTREME
   INSTABILITY WITH MLCAPE VALUES APPROACHING 4000 J/KG...AND SHOULD
   SUPPORT FURTHER CONVECTIVE DEVELOPMENT/MAINTENANCE THROUGH THE NEXT
   SEVERAL HRS. ALTHOUGH CONVECTIVE EVOLUTION IS SOMEWHAT UNCERTAIN DUE
   TO SUBTLE FORCING MECHANISMS IN PLACE...MODERATELY STRONG MIDLEVEL
   FLOW /E.G. 40 KTS AT 500 MB/ ALONG WITH VEERING LOW-LEVEL WIND
   PROFILES COULD SUPPORT AN ORGANIZED SVR THREAT ACROSS NRN IL SHOULD
   CONVECTIVE TRENDS CONTINUE TO INCREASE. PRIMARY THREATS ATTM APPEAR
   TO BE LARGE HAIL AND DMGG WINDS...THOUGH AN ISOLATED TORNADO CANNOT
   BE RULED OUT.
   
   ..ROGERS.. 07/27/2011
   
   
   ATTN...WFO...LOT...MKX...DVN...ARX...
   
   LAT...LON   41598811 41608922 41989122 42539163 42989124 42859025
               42788927 42488787 42468786 42108772 41598811