MESOSCALE DISCUSSION 1159
   NWS STORM PREDICTION CENTER NORMAN OK
   0429 PM CDT THU JUN 09 2011
   
   AREAS AFFECTED...NE MO...SCNTRL IL
   
   CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 
   
   VALID 092129Z - 092230Z
   
   THE SEVERE THREAT MAY INCREASE ACROSS NE MO AND CNTRL IL LATE THIS
   AFTERNOON. LARGE HAIL AND WIND DAMAGE WILL BE POSSIBLE AND A TORNADO
   CAN NOT BE RULED OUT. WW ISSUANCE SHOULD BE NECESSARY OVER THE NEXT
   HOUR.
   
   AN ISOLATED SEVERE STORM IS CURRENTLY ONGOING IN NE MO LOCATED ALONG
   A GRADIENT OF MODERATE INSTABILITY WHERE MLCAPE VALUES ARE ESTIMATED
   IN 1500 TO 2500 J/KG RANGE. THE INSTABILITY COMBINED WITH 40 TO 50
   KT OF DEEP LAYER SHEAR EVIDENT ON REGIONAL WSR-88D VWPS WILL SUPPORT
   SUPERCELL DEVELOPMENT AS THE STORMS MOVE EWD INTO WCNTRL IL. STEEP
   MID-LEVEL LAPSE RATES SHOULD SUPPORT A POTENTIAL FOR LARGE HAIL. IN
   ADDITION...MESOANALYSIS SUGGESTS THE BOUNDARY LAYER IN ERN MO AND
   CNTRL IL HAS BECOME FAVORABLE FOR WIND DAMAGE WITH 0-3 KM LAPSE
   RATES ESTIMATED TO BE AROUND 8.0 C/KM. AS THE STORMS MOVE EWD INTO
   CNTRL IL EARLY THIS EVENING...THE DEEP LAYER SHEAR IS WEAKER
   SUGGESTING SOME UNCERTAINTY EXISTS CONCERNING THE DURATION OF THE
   SEVERE THREAT.
   
   ..BROYLES.. 06/09/2011
   
   
   ATTN...WFO...ILX...LSX...DVN...EAX...
   
   LAT...LON   40348918 40669127 40539203 40149233 39549220 39199101
               39148940 39578887 40348918