MESOSCALE DISCUSSION 1059
   NWS STORM PREDICTION CENTER NORMAN OK
   0410 PM CDT MON JUN 21 2010
   
   AREAS AFFECTED...CENTRAL/WRN IL...CENTRAL/NRN MO...SRN IA INTO NERN
   KS
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 366...
   
   VALID 212110Z - 212145Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 366
   CONTINUES.
   
   OBJECTIVE ANALYSES INDICATED VERY STRONG INSTABILITY /MLCAPE
   2500-4000 J PER KG/ EXTENDING FROM CENTRAL/SRN IL WWD THROUGH MO AND
   SRN IA INTO KS/SERN NEB.  STRONGEST EFFECTIVE BULK SHEAR /40-50 KT/
   EXTENDED FROM NERN KS THROUGH NRN MO/SRN IA TO CENTRAL IL.  
   
   GREATEST LOW LEVEL CONVERGENCE EXTENDED FROM NERN KS INTO NRN MO
   /MAINLY N OF WW 366/ INTO SERN IA.  VISIBLE IMAGERY SHOWED CU FIELD
   WITH TCU ACROSS FAR NRN MO AND TSTMS DEVELOPING OVER FAR SERN IA IN
   VICINITY OF THE BOUNDARY.  FORCING FOR ASCENT ATTENDANT TO NERN IA
   MCV AND CO-LOCATION OF STRONGER SHEAR AND NRN EXTENT OF STRONG
   INSTABILITY MAY BE SUPPORTING THE MORE RECENT DEVELOPMENT IN SERN
   IA.  FARTHER SW...TOP 20Z SPECIAL SOUNDING SHOWED STEEP LAPSE RATES
   AND MINIMAL SBCINH.  RECENT VISIBLE IMAGERY INDICATED SOME CU
   FORMING ALONG THE BOUNDARY IN NERN KS...BUT STRONGER DEVELOPMENT MAY
   BE IN AN HOUR OR TWO.
   
   FARTHER S...THE LACK OF LOW LEVEL CONVERGENCE ACROSS THE SRN EXTENT
   OF WW 366 APPEARS TO BE LIMITING THE DEVELOPMENT OF TSTMS...DESPITE
   THE AVAILABILITY OF FAVORABLE INSTABILITY/SHEAR VALUES THAT WOULD
   SUPPORT SEVERE STORMS.  THUS...SRN AND SERN EXTENT OF THIS WATCH CAN
   BE CANCELLED EARLY.
   
   ..PETERS.. 06/21/2010
   
   
   ATTN...WFO...LOT...ILX...LSX...DVN...SGF...DMX...EAX...OAX...
   TOP...
   
   LAT...LON   38208986 38309173 38669290 38749408 39189436 39239529
               39009780 39639789 40739564 40969400 41149169 40938900
               40668847 39958865 38208986