MESOSCALE DISCUSSION 1086
   NWS STORM PREDICTION CENTER NORMAN OK
   0447 PM CDT SAT JUN 04 2011
   
   AREAS AFFECTED...MUCH OF CENTRAL IL INTO NERN MO
   
   CONCERNING...SEVERE POTENTIAL...SEVERE THUNDERSTORM WATCH LIKELY 
   
   VALID 042147Z - 042215Z
   
   SEVERE THUNDERSTORM WATCH WILL BE ISSUED SHORTLY ACROSS PARTS OF
   CENTRAL IL INTO NERN MO.
   
   21Z SURFACE ANALYSIS SHOWED A FRONT EXTENDING WSWWD FROM NWRN OH
   THROUGH NRN IND...CENTRAL IL...AND FAR NRN MO NEAR THE IA BORDER.
   AIR MASS INVOF THIS BOUNDARY IS MOIST /PW VALUES 1.3-1.5 INCH/ WITH
   SURFACE DEWPOINTS IN THE MID 60S-AROUND 70 F.  THIS COMBINED WITH
   STRONG SURFACE HEATING AT THE SRN EXTENT OF STEEPER MIDLEVEL LAPSE
   RATES IS RESULTING IN MODERATE TO VERY STRONG INSTABILITY /MLCAPE
   2000-3500 J PER KG/.  ALTHOUGH MIDLEVEL WLY FLOW IS NOT TOO
   STRONG...THIS REGION IS LOCATED ALONG THE SRN EXTENT OF STEERING
   FLOW WITH EFFECTIVE BULK SHEAR OF 20-30 KT SUPPORTING MULTICELLS
   WITH THE POTENTIAL FOR ONE OR TWO CLUSTERS TO ORGANIZE INTO THE
   EVENING.  PRIMARY THREATS WILL BE LARGE HAIL AND DAMAGING WINDS.
   
   ..PETERS.. 06/04/2011
   
   
   ATTN...WFO...LOT...ILX...LSX...DVN...DMX...EAX...
   
   LAT...LON   40639268 40949131 41138957 41048902 40428842 40078841
               40068939 40079078 40189213 40639268