MESOSCALE DISCUSSION 1287
   NWS STORM PREDICTION CENTER NORMAN OK
   1131 AM CDT TUE JUN 23 2009
   
   AREAS AFFECTED...SRN MN...NRN/CNTRL IA
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 496...
   
   VALID 231631Z - 231800Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 496
   CONTINUES.
   
   N/S BAND OF STRONG/SEVERE STORMS FROM EXTREME SWRN MN INTO NWRN IA
   IS MOVING EWD 25 KT.  LINEAR EXTRAPOLATION INDICATES STORMS WILL
   MOVE TO THE EAST EDGE OF WW 496 BY 1730Z...AND A NEW WW WILL LIKELY
   BE ISSUED WITHIN THE NEXT HOUR FOR PARTS OF SRN MN AND NRN/CNTRL IA.
   
   
   ENVIRONMENT OVER THE AREA IS VERY UNSTABLE WITH MLCAPE OF 2000-4000
   J/KG...AND LATEST OBJECTIVE RUC-BASED GUIDANCE INDICATES THE CAP IS
   WEAKENING OVER NRN IA IN ADVANCE OF THE AFOREMENTIONED STORMS. 
   ALTHOUGH AREA IS ALONG THE SRN EDGE OF STRONGER WINDS ALOFT AND
   VERTICAL SHEAR...SUFFICIENT SHEAR /30 KT IN LOWEST 6 KM AGL/ IS
   PRESENT TO MAINTAIN ORGANIZED CONVECTIVE STRUCTURES.  DAMAGING WIND
   GUSTS AND LARGE HAIL ARE EXPECTED TO BE THE PRIMARY THREATS.
   
   ..WEISS.. 06/23/2009
   
   
   ATTN...WFO...DVN...ARX...MPX...DMX...FSD...OAX...
   
   LAT...LON   44079650 44479600 44449521 44059330 43839203 43099175
               42079223 41729311 41779453 41819603 41959667 42499673
               44079650