MESOSCALE DISCUSSION 1028
   NWS STORM PREDICTION CENTER NORMAN OK
   0318 PM CDT WED JUN 10 2009
   
   AREAS AFFECTED...SRN IL AND SWRN IND
   
   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 
   
   VALID 102018Z - 102145Z
   
   CORRECTED FOR INCORRECT PHRASE
   
   AN ISOLATED THREAT OF LARGE HAIL AND DAMAGING WINDS WILL EXIST
   ACROSS SRN IL AND SWRN IND DURING THE REMAINDER OF THE
   AFTERNOON/EARLY EVENING. AT THIS TIME...COVERAGE DOES NOT APPEAR TO
   BE GREAT ENOUGH TO SUPPORT A WW.
   
   AN ISOLATED CLUSTER OF QUASI DISCRETE THUNDERSTORMS HAS INITIATED
   OVER S-CENTRAL IL DURING THE LAST HOUR...FOCUSED WITHIN A ZONE OF
   LOW LEVEL CONVERGENCE INVOF A POSSIBLE OUTFLOW BOUNDARY. FAVORABLE
   DESTABILIZATION HAS OCCURRED IN THE WAKE OF SHOWERS/STORMS MOVING E
   ACROSS OH/WV/ERN KY...WITH SURFACE TEMPERATURES RISING INTO THE
   LOW-MID 80S. SURFACE DEWPOINTS ALONG AND SOUTH OF A STATIONARY FRONT
   LOCATED JUST N OF THE REGION ARE GENERALLY IN THE UPPER 60S TO NEAR
   70...AND ARE CONTRIBUTING TO MLCAPE VALUES OF 2500 J/KG. AREA VWP/S
   AND RUC FORECAST SOUNDINGS INDICATE EFFECTIVE BULK SHEAR VALUES ON
   THE ORDER OF 40-50 KT...SUPPORTIVE OF ORGANIZED MULTICELLS AND
   POSSIBLE SUPERCELL STORM STRUCTURES. HI RES RADAR DATA FROM KVWX
   INDICATES REFLECTIVITY FEATURES SUGGESTIVE OF LARGE HAIL WITH THE
   STRONGEST UPDRAFT CORES CROSSING THE IL/IND BORDER...BUT THIS
   ACTIVITY IS MOVING TOWARD A SLIGHTLY MORE STABLE AIRMASS.
   HOWEVER...OTHER ISOLATED STORMS ARE FORMING IMMEDIATELY E OF
   STL...AND MAY STRENGTHEN AS THEY MOVE ACROSS THE REMAINDER OF IL
   POSING A RISK OF LARGE HAIL/DAMAGING WINDS. AT THIS TIME...IT
   APPEARS THAT INCREASING SHORT WAVE RIDGING WILL PREVENT SUFFICIENT
   STORM COVERAGE FOR A WW...BUT CONVECTIVE TRENDS WILL CONTINUE TO BE
   MONITORED.
   
   ..GARNER.. 06/10/2009
   
   
   ATTN...WFO...LMK...IND...PAH...ILX...LSX...
   
   LAT...LON   37988790 38048902 38338997 39149012 39548925 39438748
               38858661 38348669 38088722 37988790