MESOSCALE DISCUSSION 0736
   NWS STORM PREDICTION CENTER NORMAN OK
   0218 PM CDT WED MAY 11 2011
   
   AREAS AFFECTED...CNTRL IL...FAR ERN MO
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 111918Z - 112015Z
   
   THE THREAT FOR SVR STORMS WITH DMGG WINDS AND LARGE HAIL IS
   INCREASING. A SVR TSTM WATCH MAY BE REQUIRED SOUTH OF WW 281...OR WW
   281 MAY NEED TO BE EXPANDED SWD.
   
   THE IMPACTS OF A SUBTLE MID-LEVEL IMPULSE SWINGING THROUGH THE
   MID-MISSISSIPPI VALLEY REGION CONTINUE TO BE MANIFESTED AS
   CONVECTION DEVELOPING NEAR AND NORTH OF THE SAINT LOUIS AREA. MLCAPE
   VALUES AOA 2500 J/KG WILL RESULT IN DEEP/VIGOROUS UPDRAFTS. SWLY
   FLOW AROUND 50 KT AT 5 KM AGL PER STL VWP...LIKELY ASSOCIATED WITH
   THE IMPULSE...WILL PROVIDE SOME SUSTENANCE TO THE MULTICELLULAR
   CONVECTION GIVEN EFFECTIVE BULK SHEAR MAGNITUDE VALUES OF 30-35 KT.
   DMGG WINDS AND LARGE HAIL WILL BE THE PRIMARY THREATS.
   
   ..COHEN.. 05/11/2011
   
   
   ATTN...WFO...LOT...ILX...LSX...DVN...
   
   LAT...LON   38639077 39359146 40159127 40309012 41068920 41058860
               40818797 39938815 38728867 38348966 38639077