MESOSCALE DISCUSSION 1859
   NWS STORM PREDICTION CENTER NORMAN OK
   0853 AM CDT MON JUL 25 2005
   
   AREAS AFFECTED...NERN IL...EXTREME SRN LWR MI...NRN IND AND NRN OH
   
   CONCERNING...SEVERE THUNDERSTORM POTENTIAL 
   
   VALID 251353Z - 251530Z
   
   PLAN VIEW PROFILERS/VWPS INDICATE THAT THE LLJ HAS VEERED TO WSWLY
   WITH THE NOSE OF THE JET IMPINGING ON THE FRONT SITUATED FROM THE
   CHICAGO AREA EWD INTO NRN OH.  RESULTANT WARM ADVECTION HAS LIKELY
   BEEN THE IMPETUS FOR INCREASING TSTMS FROM NRN IL INTO NCNTRL IND
   SINCE 13Z.
   
   VSBL SATL SHOWS THAT THE DOWNSTREAM AIR MASS WAS ESSENTIALLY
   CLOUD-FREE AND THE BOUNDARY LAYER WILL WARM RAPIDLY THROUGH EARLY
   AFTN ALONG/S OF THE FRONT.  12Z SOUNDINGS CONTINUE TO SHOW VERY
   STEEP MID-LEVEL LAPSE RATES AND GIVEN MAGNITUDE OF HEATING AND
   LOW-LEVEL MOISTURE IN PLACE...TSTMS SHOULD CONTINUE TO GROW
   UPSCALE/ROOT INTO THE BOUNDARY LAYER AS THEY MOVE EWD. 
   
   PRESENCE OF 30-35 KTS OF FLOW IN THE 4-6KM LAYER AND UNIDIRECTIONAL
   WSWLY FLOW REGIME THROUGH THE COLUMN WILL BE FAVORABLE FOR STORMS TO
   POSSIBLY EVOLVE INTO A BOW ECHO AND PRODUCE DAMAGING WINDS.  LARGE
   HAIL WILL ALSO BE LIKELY GIVEN THE STEEP LAPSE RATE ENVIRONMENT. 
   
   TSTMS WILL LIKELY DEVELOP/MOVE EWD FROM NRN IL/NRN IND INTO EXTREME
   SRN LWR MI AND NRN OH THROUGH LATE MORNING.  A WW MAY BE REQUIRED
   SOON.
   
   ..RACY.. 07/25/2005
   
   
   ATTN...WFO...PBZ...CLE...ILN...DTX...IWX...GRR...IND...LOT...ILX...DVN...
   
   40778846 41218938 42018893 42378667 42308487 42148328
   41888176 41368086 40838116 40388210 40398268 40438352
   40458515 40538701