MESOSCALE DISCUSSION 1836
   NWS STORM PREDICTION CENTER NORMAN OK
   0955 AM CDT SUN AUG 09 2009
   
   AREAS AFFECTED...CENTRAL/ERN IA INTO SRN WI/NRN IL
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 681...
   
   VALID 091455Z - 091530Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 681
   CONTINUES.
   
   NEW WATCH WILL BE NEEDED BY 1530Z OVER ERN IA INTO SRN WI/NRN IL.
   
   LATEST STORM REPORTS OF DAMAGING WINDS OVER CENTRAL IA SUGGEST AN
   INCREASING THREAT FOR ADDITIONAL DAMAGING WINDS AS ACTIVITY SPREADS
   EWD INTO DESTABILIZING AIR MASS OVER ERN IA/NRN IL AND SRN WI LATE
   THIS MORNING INTO THE AFTERNOON.  DOWNSTREAM AIR MASS FROM WW 681 IS
   ALREADY MODERATELY UNSTABLE /MLCAPE 2000-2500 J/KG/...GIVEN STRONG
   SURFACE HEATING WITHIN VERY MOIST ENVIRONMENT /SURFACE DEWPOINTS
   LOWER 70S/ AND BENEATH PLUME OF STEEP MID LEVEL LAPSE RATES.  RECENT
   RADAR TRENDS INDICATED THE STRONG TO SEVERE STORMS OVER CENTRAL IA
   ARE TRACKING ENEWD AT 35 KT AND WILL EXIT THE ERN EXTENT OF WW 681
   BY 16-1630Z.  RECENT OBJECTIVE ANALYSES SHOWED SURFACE BASED
   INHIBITION WEAKENING FROM NERN IA INTO SRN /ERN WI WITH FURTHER
   WEAKENING EXPECTED.  THIS WILL AID IN SUPPORTING AN INCREASING
   THREAT FOR DAMAGING WINDS AS STORMS BECOME SURFACE BASED.
   
   ..PETERS.. 08/09/2009
   
   
   ATTN...WFO...LOT...MKX...DVN...ARX...DMX...FSD...OAX...
   
   LAT...LON   42279628 42899568 43099461 43249295 43639056 43628904
               42538842 41698909 41279021 41029140 40789302 40749516
               40829655 40669701 40729733 41309728 42279628