Storm Prediction Center Mesoscale Discussion 1966

   Mesoscale Discussion 1966
   NWS Storm Prediction Center Norman OK
   0727 AM CDT Thu Aug 13 2026

   Areas affected...parts of central/southeastern Iowa and adjacent
   Illinois

   Concerning...Severe Thunderstorm Watch 581...

   Valid 131227Z - 131430Z

   The severe weather threat for Severe Thunderstorm Watch 581
   continues.

   SUMMARY...The cluster of storms has undergone general weakening, but
   could still pose a risk for strong to severe wind gusts along and
   south of the I-80 corridor, east of Des Moines toward the
   Mississippi River, through 9-10 AM CDT.

   DISCUSSION...Coldest cloud tops in infrared satellite imagery and
   peak lightning flash rates have generally been maintained into the
   Des Moines vicinity, but the convective system has become less
   organized looking in radar loops.  The primary MCV and westerly rear
   inflow to its southwest have undergone recent weakening.  However,
   another notable cyclonic circulation has developed to the
   east-southeast (now to the northeast of Des Moines), within
   continuing stronger thunderstorm development focused near/above the
   leading edge of a developing area of 2-hourly surface pressure rises
   on the order of 2 mb.  This may continue pose the most prominent
   risk for a swath of strong to severe surface gusts near the I-80
   corridor east of Des Moines through 14-15Z.  It does not appear out
   of the question that another similar circulation could still evolve
   within trailing convection now to the southwest through south of Des
   Moines.

   ..Kerr.. 08/13/2026

   ...Please see www.spc.noaa.gov for graphic product...

   ATTN...WFO...DVN...DMX...

   LAT...LON   42189285 42199165 41779088 41429074 40889130 40659186
               40809275 40769373 41139402 41709281 42189285 

   MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
   MOST PROBABLE PEAK WIND GUST...55-70 MPH
   MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN