MESOSCALE DISCUSSION 1561
   NWS STORM PREDICTION CENTER NORMAN OK
   0741 PM CDT THU AUG 18 2016

   AREAS AFFECTED...SRN WI...NERN IA...NWRN IL

   CONCERNING...SEVERE THUNDERSTORM WATCH 450...451...

   VALID 190041Z - 190215Z

   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH
   450...451...CONTINUES.

   SUMMARY...AN ISOLATED DAMAGING WIND RISK CONTINUES WITH THE
   CONVECTIVE SYSTEM MOVING INTO SOUTHERN WI/NORTHEAST IA. OTHER
   ISOLATED STORMS ACROSS NORTHWEST IL WILL BE CAPABLE OF LOCALLY
   SEVERE HAIL. ADDITIONAL WATCH ISSUANCE BEYOND THE CONFINES OF WW
   450/451 IS NOT ANTICIPATED.

   DISCUSSION...AT 0030Z...A BOWING THUNDERSTORM CLUSTER CONTINUES
   MOVING ESEWD ACROSS NERN IA/SWRN WI. SOME WEAKENING HAS BEEN
   NOTED...LIKELY DUE TO INCREASINGLY WEAK VERTICAL SHEAR /AS NOTED IN
   00Z DVN SOUNDING/ AND THE ONSET OF DIURNAL BOUNDARY-LAYER
   DESTABILIZATION. HOWEVER...A LOCAL DAMAGING WIND RISK WILL CONTINUE
   FOR ANOTHER 1-2 HOURS IN AREAS ALONG THE LEADING EDGE OF THE COLD
   POOL WHERE VIGOROUS CONVECTION REMAINS. 

   AN ADDITIONAL STRONG ISOLATED STORM HAS DEVELOPED ACROSS NWRN IL.
   WEAK VERTICAL SHEAR SHOULD LIMIT THE LONGEVITY OF THIS STORM...BUT A
   LOCALIZED HAIL AND DOWNBURST RISK WILL EXIST WITH THIS STORM AND ANY
   OTHER CELLS THAT DEVELOP AHEAD OF THE MAIN CONVECTIVE SYSTEM...GIVEN
   STRONG BUOYANCY THAT IS IN PLACE. IN ADDITION...THE WEAKENING
   CONVECTIVE SYSTEM TO THE NORTH WILL MOVE INTO PORTIONS OF ERN
   IA/NWRN IL SOUTH OF WW 450/451 BETWEEN 01-02Z...WITH SOME POTENTIAL
   FOR LOCALLY STRONG WIND GUSTS. HOWEVER...ADDITIONAL WATCH ISSUANCE
   IS NOT CURRENTLY ANTICIPATED GIVEN THE INCREASINGLY MARGINAL NATURE
   OF THE THREAT.

   ..DEAN/GRAMS.. 08/19/2016


   ATTN...WFO...GRB...LOT...MKX...DVN...ARX...DMX...

   LAT...LON   43009276 43369162 43479113 44019125 44119067 44198982
               43888932 43028895 42498902 42168916 41918964 42019045
               42409213 42659268 43009276