Storm Prediction Center Mesoscale Discussion 1639

   Mesoscale Discussion 1639
   NWS Storm Prediction Center Norman OK
   1244 AM CDT Fri Jul 11 2025

   Areas affected...east-central and eastern Iowa

   Concerning...Severe Thunderstorm Watch 503...

   Valid 110544Z - 110715Z

   The severe weather threat for Severe Thunderstorm Watch 503
   continues.

   SUMMARY...A downstream severe thunderstorm watch may be needed soon
   across portions of eastern Iowa.

   DISCUSSION...A well-established bowing cluster with a history of
   severe wind gusts is currently moving across central Iowa. The KDMX
   VWP suggests this cluster has started to outrun the stronger
   low-level jet which could limit its intensity as it moves farther
   east. However, 2000 to 2500 J/kg MUCAPE is present across all of
   central and eastern Iowa which could maintain this cluster with some
   severe weather threat across eastern Iowa through the early morning
   hours. This threat would likely be maximized along the frontal zone
   (apparent by lead convection across eastern Iowa and far western
   Illinois). Confidence in this cluster of storms moving farther east
   into Illinois is low given the weaker instability, ongoing
   convection along the boundary, and a weaker low-level jet with
   eastward extent. However, there may be sufficient
   instability/forcing to necessitate a small downstream watch across
   eastern Iowa to address this threat. Convective trends will continue
   to be monitored.

   ..Bentley/Guyer.. 07/11/2025

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

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

   LAT...LON   41859412 41969294 41919166 41889065 41659027 41199055
               40859096 40899157 40929208 40909244 40949361 41059404
               41859412 

   MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH
   MOST PROBABLE PEAK WIND GUST...55-70 MPH
   MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN