MESOSCALE DISCUSSION 0842
   NWS STORM PREDICTION CENTER NORMAN OK
   0607 PM CDT SAT MAY 21 2011
   
   AREAS AFFECTED...ERN NEB...WRN/CNTRL IA
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 317...
   
   VALID 212307Z - 220000Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 317
   CONTINUES.
   
   AT 23Z...MIXTURE OF STORM CLUSTERS AND DISCRETE CELLS...SOME SHOWING
   MIDLEVEL UPDRAFT ROTATION...WERE LOCATED MAINLY ACROSS ERN
   NEB...MOVING NEWD AT AROUND 20-30 KT. OTHER STORMS WERE LOCATED OVER
   NERN KS...AND ARE EXPECTED TO MOVE ACROSS NWRN MO INTO SWRN/S-CNTRL
   IA DURING THE NEXT FEW HRS. OBJECTIVE ANALYSIS GUIDANCE INDICATES
   AIRMASS ACROSS WW 317 IS CHARACTERIZED BY MLCAPE VALUES AROUND 2000
   J/KG...WHILE AREA VWP/S AND RUC FORECAST SOUNDINGS SHOW WIND
   PROFILES FAVORABLE FOR SUPERCELL DEVELOPMENT. THIS ENVIRONMENT
   SUPPORTS CONTINUED THREAT OF LARGE HAIL/DAMAGING WINDS AND PERHAPS A
   TORNADO INTO THE EVENING HRS.
   
   AS STORMS CONTINUE TO MOVE DOWNSTREAM INTO IA...WW 317 MAY NEED TO
   BE EXTENDED EWD INTO PORTIONS OF CNTRL/S-CNTRL IA.
   
   ..GARNER.. 05/21/2011
   
   
   ATTN...WFO...ARX...MPX...DMX...EAX...FSD...OAX...GID...
   
   LAT...LON   43509605 43489302 41879381 40579372 40589531 39999559
               40009763 43509605