MESOSCALE DISCUSSION 2216
   NWS STORM PREDICTION CENTER NORMAN OK
   0328 PM CDT THU SEP 29 2011
   
   AREAS AFFECTED...CNTRL/ERN IND...WRN OH...FAR NRN KY
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 292028Z - 292200Z
   
   NARROW LINE OF THUNDERSTORMS MAY DEVELOP DURING THE NEXT 1-2 HOURS
   OVER CNTRL/ERN IND...AND THEN MOVE QUICKLY EWD INTO PORTIONS OF WRN
   OH WHILE BACK BUILDING SWD TOWARD FAR NRN KY. DUE TO LIMITED
   INSTABILITY...IT IS UNCERTAIN WHETHER A WW WILL BE NEEDED...BUT
   CONVECTIVE TRENDS WILL CONTINUE TO BE MONITORED.
   
   AT 20Z...SURFACE CYCLONE WAS CENTERED OVER THE U.P. OF
   MI...IMMEDIATELY AHEAD OF POTENT MIDLEVEL SHORTWAVE TROUGH. OCCLUDED
   FRONTAL BOUNDARY EXTENDED SWD FROM THE LOW TOWARD WRN IND...WITH
   PLUME OF ASCENT AND ASSOCIATED SHOWERY ACTIVITY SPREADING EWD ACROSS
   THE FRONT OVER CNTRL IL INTO NRN IND...OCCURRING WITHIN THE EXIT
   REGION OF 90 KT MIDLEVEL JET. LATEST REGIONAL AND HI-RES RADAR
   IMAGERY SHOWS DEEPENING CONVECTION DEVELOPING OVER CNTRL
   IND...EXTENDING SWD FROM THE NRN IND PRECIP SHIELD. THIS CONVECTION
   IS BACK BUILDING INTO A CORRIDOR OF STRONGER BOUNDARY LAYER
   DESTABILIZATION AND AXIS OF MID 50S DEWPOINTS. RESULTANT AREA OF
   RELATIVELY HIGHER THETA-E AIR IS AIDING IN THE DEVELOPMENT OF MUCAPE
   VALUES NEAR 500 J/KG OVER CNTRL/SRN IND...AND IS FORECAST TO SHIFT
   EWD INTO WRN OH/FAR NRN KY BY EVENING. MOST RECENT RUN OF THE 3 KM
   HRRR SUGGESTS A NARROW LINE OF CONVECTION WILL DEVELOP WITHIN THE
   INSTABILITY AXIS DURING THE NEXT FEW HOURS...MOVING EWD TOWARD
   PORTIONS OF WRN OH AND FAR NRN KY WITH TIME. THOUGH INSTABILITY WILL
   BE LIMITED...STRONG DEEP LAYER WLY WIND FIELDS /MEAN FLOW OF 40+ KT/
   WILL FAVOR FAST DOWNSTREAM STORM MOTIONS AND THE POTENTIAL FOR
   MOMENTUM TRANSPORT TO THE SURFACE. THUS...A DAMAGING WIND THREAT MAY
   DEVELOP...AND THIS AREA WILL CONTINUE TO BE MONITORED FOR POSSIBLE
   WW.
   
   ..GARNER.. 09/29/2011
   
   
   ATTN...WFO...ILN...LMK...IWX...IND...
   
   LAT...LON   41238572 41098408 40178349 38908371 38528463 38698653
               40098687 41238572