MESOSCALE DISCUSSION 0846
   NWS STORM PREDICTION CENTER NORMAN OK
   0855 PM CDT SAT MAY 21 2011
   
   AREAS AFFECTED...ERN NEB...WRN/CNTRL IA
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 317...
   
   VALID 220155Z - 220300Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 317
   CONTINUES.
   
   AT 0145Z...REGIONAL RADAR IMAGERY SHOWED A LARGE AREA OF STORMS
   ARCING NEWD ACROSS PORTIONS OF SWRN INTO CNTRL IA...POSSIBLY AIDED
   BY ASCENT OCCURRING AHEAD OF UPPER IMPULSE ROTATING ACROSS NEB/KS.
   OBJECTIVE ANALYSIS AND 00Z OAX RAOB CONTINUES TO INDICATE THE
   PRESENCE OF MODERATE INSTABILITY /MLCAPE VALUES AROUND 1000-2000 J
   PER KG/ ACROSS ERN NEB AND WRN/CNTRL IA...WHICH MAY AID STORM
   PERSISTENCE PAST THE 03Z EXPIRATION TIME OF WW 317. THIS MAY REQUIRE
   EITHER A SPATIAL/TEMPORAL EXPANSION OF WW 317...OR ISSUANCE OF A NEW
   WATCH OVER IA.
   
   OTHERWISE...COOLING/STABILIZING BOUNDARY LAYER OVER SERN NEB HAS
   LIKELY REDUCED THE SVR WEATHER THREAT SUBSTANTIALLY...WHICH SUGGESTS
   COUNTIES MAY BE CLEARED BEHIND NERN NEB-SWRN/CNTRL IA THUNDERSTORM
   ACTIVITY.
   
   ..GARNER.. 05/22/2011
   
   
   ATTN...WFO...DVN...ARX...MPX...DMX...EAX...FSD...OAX...GID...
   
   LAT...LON   43519605 43499207 40609218 40579400 40589529 40019559
               40029764 43519605