Storm Prediction Center Mesoscale Discussion 1912

   Mesoscale Discussion 1912
   NWS Storm Prediction Center Norman OK
   0907 PM CDT Mon Aug 10 2026

   Areas affected...Eastern Iowa into northern Illinois

   Concerning...Severe potential...Watch possible 

   Valid 110207Z - 110400Z

   Probability of Watch Issuance...60 percent

   SUMMARY...Convection developing in eastern Iowa will likely
   intensify in the coming hours and could pose some severe threat for
   portions of eastern Iowa into northern Illinois. Confidence in exact
   evolution is limited, but watch issuance may need to be considered.

   DISCUSSION...Latest regional reflectivity and GOES IR imagery shows
   steady deepening of nascent convection across eastern IA along a
   diffuse warm frontal zone. A recent 00 UTC DVN RAOB sampled weak
   mixed-layer inhibition that is evidently being overcome by ascent
   within the frontal zone as a nocturnal jet slowly strengthens. This
   sounding also sampled extreme buoyancy and adequate deep-layer wind
   shear for organized convection. Consequently, it seems likely that
   further intensification will occur over the next 1-2 hours. 

   Moderate veering through the lowest 3 km is also noted in the
   observed hodograph, which should support the potential for a
   supercell or two capable of producing large hail and perhaps brief
   tornadoes. The primary uncertainty regarding this potential is the
   possibility of destructive storm interactions and clustering given
   forecast storm motions largely along the zone of initiation. This
   potential is hinted by recent solutions of the HRRR and RRFS, which
   show initially semi-discrete cells growing upscale into northern IL
   later this evening. Convective trends will continue to be monitored,
   and watch issuance may be needed if robust supercells become more
   imminent.

   ..Moore/Mosier.. 08/11/2026

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

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

   LAT...LON   41879229 41999275 42309288 42609273 42789230 42508890
               42228873 41928879 41718893 41568910 41408941 41879229 

   MOST PROBABLE PEAK TORNADO INTENSITY...85-110 MPH
   MOST PROBABLE PEAK WIND GUST...55-70 MPH
   MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN