MESOSCALE DISCUSSION 1887
   NWS STORM PREDICTION CENTER NORMAN OK
   0114 AM CDT WED SEP 05 2012
   
   AREAS AFFECTED...SERN MN...SRN WI...NRN IA
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 617...618...
   
   VALID 050614Z - 050745Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH
   617...618...CONTINUES.
   
   SUMMARY...RISK FOR DAMAGING WIND GUSTS CONTINUES...BUT MAY BEGIN TO
   DIMINISH WITH THE LEAD STORM CLUSTER NOW SPREADING ACROSS THE UPPER
   MISSISSIPPI VALLEY INTO SOUTHERN WISCONSIN WITHIN THE NEXT COUPLE OF
   HOURS.
   
   DISCUSSION...INTENSE CONVECTION CONTINUES ALONG THE LEADING EDGE OF
   THE SIGNIFICANT EASTWARD PROPAGATING SURFACE COLD POOL...AND WITHIN
   A ZONE OF LOW-LEVEL WARM ADVECTION DOWNSTREAM...ALONG THE STALLED
   WESTERN FLANK OF THE COLD POOL ASSOCIATED WITH THE DISSIPATING STORM
   CLUSTER NOW SOUTH OF LAKE MICHIGAN.  THROUGH 07-08Z...AIDED BY
   FORCING ASSOCIATED WITH A SUPPORTING MID-LEVEL JET STREAK...ACTIVITY
   APPEARS LIKELY TO CONTINUE EASTWARD ACROSS THE UPPER MISSISSIPPI
   VALLEY INTO SOUTHERN WISCONSIN...WHERE THE LOW-LEVEL ENVIRONMENT HAS
   BEEN COOLED AND STABILIZED BY PRIOR CONVECTION.  AS THIS OCCURS...
   DAMAGING WIND POTENTIAL SEEMS MORE LIMITED...AND THREAT SHOULD
   DIMINISH FURTHER AS INFLOW OF MORE STABLE AIR WEAKENS CONVECTION.
   
   MODELS DO INDICATE THAT A MODERATE LOW-LEVEL JET WILL PERSIST TO THE
   WEST OF THIS ACTIVITY THROUGH THE NIGHT...WHERE INFLOW AND LIFT OF
   MOIST AND MODERATELY UNSTABLE AIR MAY MAINTAIN VIGOROUS CONVECTIVE
   DEVELOPMENT ABOVE THE TRAILING SURFACE COLD POOL... ACROSS PARTS OF
   NORTH CENTRAL INTO EASTERN IOWA.  HEAVY RAINFALL ...FREQUENT
   LIGHTNING AND LOCALLY STRONG SURFACE GUSTS MAY NOT BE OUT OF THE
   QUESTION WITH THIS ACTIVITY.
   
   ..KERR.. 09/05/2012
   
   
   ATTN...WFO...GRB...LOT...MKX...DVN...ARX...MPX...DMX...FSD...
   OAX...
   
   LAT...LON   44259191 44278994 43628920 42668883 41318995 41209118
               41309300 41489480 41769574 42439574 43069467 43949382
               44259191