MESOSCALE DISCUSSION 1311
   NWS STORM PREDICTION CENTER NORMAN OK
   0327 AM CDT MON JUN 20 2011
   
   AREAS AFFECTED...ERN NEB/WRN AND CENTRAL IA
   
   CONCERNING...TORNADO WATCH 518...
   
   VALID 200827Z - 200900Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 518 CONTINUES.
   
   A NEW WW MAY BE NEEDED ACROSS ERN NEB INTO PARTS OF WRN AND CENTRAL
   IA...GIVEN ONGOING STRONG TO SEVERE STORMS ACROSS THIS REGION WHICH
   ARE EXPECTED TO PERSIST BEYOND 09Z AS THIS LARGE TSTM COMPLEX MOVES
   SLOWLY EWD. 
   
   TRENDS IN REGIONAL RADAR AND SATELLITE IMAGERY INDICATED THE ONGOING
   MCS ACROSS ERN NEB INTO WRN IA WAS MOVING SLOWLY EWD AS THE VERY
   STRONG LLJ TO 80 KT HAS VEERED TO SWLY.  THIS ACTIVITY WAS LOCATED
   NORTH OF A WARM FRONT THAT EXTENDED EWD FROM NRN KS INTO NRN
   MO...WITH PERSISTENT LOW LEVEL WAA EXPECTED TO MAINTAIN THIS MCS AS
   IT ADVANCES EWD.  EFFECTIVE BULK SHEAR OF 50+ KT AND A RESERVOIR OF
   MODERATE-VERY STRONG INSTABILITY /MUCAPE 2000-3500 J PER KG/
   EXTENDING FROM SRN-SERN NEB INTO SRN IA/NRN MO WILL PROVIDE
   SUFFICIENT FUEL TO SUPPORT ADDITIONAL ELEVATED STORMS.  GIVEN THE
   DEGREE OF INSTABILITY...BULK SHEAR AND STEEP MIDLEVEL /7.5-8.5 C PER
   KM/...STRONGER/PERSISTENT UPDRAFTS WILL BE CAPABLE OF PRODUCING
   LARGE HAIL.
   
   ..PETERS.. 06/20/2011
   
   
   ATTN...WFO...DMX...EAX...FSD...OAX...GID...
   
   LAT...LON   41589766 42039756 42379609 42289406 42029270 41169266
               40719278 40569442 40499579 40569752 41589766