MESOSCALE DISCUSSION 0699
   NWS STORM PREDICTION CENTER NORMAN OK
   0715 PM CDT SAT MAY 07 2011
   
   AREAS AFFECTED...ERN IL...CNTRL AND SRN IND
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 264...
   
   VALID 080015Z - 080145Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 264
   CONTINUES.
   
   THE SEVERE THREAT CURRENTLY IN ERN IL AND WRN IND WILL MOVE SEWD
   INTO SRN IND THIS EVENING. ALTHOUGH A BRIEF TORNADO WILL BE
   POSSIBLE...LARGE HAIL AND WIND DAMAGE SHOULD BE THE PRIMARY THREATS.
   WW ISSUANCE IS NOT EXPECTED DOWNSTREAM FROM WW 264 BUT A LOCAL
   EXTENSION MAY BE REQUIRED LATER THIS EVENING.
   
   A SMALL CLUSTER OF SEVERE STORMS IS ONGOING NEAR THE IL AND IND
   STATE-LINE ON THE NERN END OF AN AXIS OF INSTABILITY WHERE
   MESOANALYSIS ESTIMATES MLCAPE VALUES ARE 500 TO 1000 J/KG. THE
   STORMS ARE BEING SUPPORTED BY A SHORTWAVE TROUGH AND AN ASSOCIATED
   50 TO 60 KT MID-LEVEL JET. THE MID-LEVEL JET IS HELPING TO CREATE
   STRONG DEEP LAYER SHEAR WITH WSR-88D VWP IN INDIANAPOLIS SHOWING 60
   KT OF 0-6 KM SHEAR. THIS COMBINED WITH STEEP MID-LEVEL LAPSE RATES
   SHOULD CONTINUE TO SUPPORT A THREAT FOR SUPERCELLS AND LARGE HAIL.
   ISOLATED WIND DAMAGE MAY ALSO OCCUR ESPECIALLY AS THE STORMS BECOME
   MORE LINEAR. HOWEVER...THE SEVERE THREAT SHOULD BECOME INCREASINGLY
   ISOLATED AS INSTABILITY WEAKENS THIS EVENING.
   
   ..BROYLES.. 05/08/2011
   
   
   ATTN...WFO...ILN...LMK...IND...PAH...ILX...
   
   LAT...LON   38408699 38458589 38758531 39428532 39878624 39978730
               39698812 38918818 38408699