Storm Prediction Center Mesoscale Discussion 1676

   Mesoscale Discussion 1676
   NWS Storm Prediction Center Norman OK
   0434 PM CDT Mon Jul 20 2026

   Areas affected...central and eastern Iowa

   Concerning...Tornado Watch 500...

   Valid 202134Z - 202330Z

   The severe weather threat for Tornado Watch 500 continues.

   SUMMARY...A corridor of enhanced damaging wind potential with gusts
   of 70-80 mph appears to be evolving from the Waterloo vicinity
   towards Iowa City. A few tornadoes and isolated occurrences of large
   hail are also possible.

   DISCUSSION...Initial more discrete supercells have evolved into a
   bowing complex with embedded HP supercells near and southwest of
   Waterloo as of 2125Z. The storm complex is largely situated on the
   immediate cool side of a north-south-oriented outflow boundary
   within a zone of locally backed near-surface winds, which are
   enhancing both low-level and deep-layer shear. Extrapolation of
   current storm motion and latest WoFS forecasts suggest that a
   corridor of enhanced damaging wind potential and some tornado risk
   will spread southeast toward Iowa City over the next 1-1.5 hours.
   Isolated occurrences of large hail will also be possible given the
   embedded supercell structures.

   ..Mead.. 07/20/2026

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

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

   LAT...LON   41199253 41769301 42289323 42669330 42899283 42869225
               42269147 41559131 41169119 40909149 40949218 41199253 

   MOST PROBABLE PEAK TORNADO INTENSITY...120-145 MPH
   MOST PROBABLE PEAK WIND GUST...65-80 MPH
   MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN