Storm Prediction Center Mesoscale Discussion 1475

   Mesoscale Discussion 1475
   NWS Storm Prediction Center Norman OK
   0505 PM CDT Fri Jul 03 2026

   Areas affected...Eastern Iowa into southern Wisconsin and northern
   Illinois

   Concerning...Severe potential...Watch possible 

   Valid 032205Z - 040000Z

   Probability of Watch Issuance...40 percent

   SUMMARY...Convective trends are being monitored across eastern Iowa
   into southern Wisconsin and northern Illinois. Watch issuance is
   possible if further convective intensification and clustering can
   occur in the coming hours.

   DISCUSSION...Weak convection has been percolating along a residual
   outflow boundary across eastern IA and into southern WI/northwest IL
   over the past hour. Despite temperatures warming back into the 80s
   and dewpoints recovering into the 70s, prior convective overturning
   appears to be limiting the overall thermodynamic environment across
   this region, resulting in the anemic convective development observed
   so far. 

   Further south, a more diffuse outflow boundary associated with a
   weak MCS currently over Lower MI is beginning to advance northward.
   Convective development in proximity to the boundary as well as
   notable boundary-layer cumulus along/south of the boundary hint that
   this demarcates the northern extent of the more buoyant/unstable air
   mass (characterized by MLCAPE values of 2000-3000 J/kg). It remains
   unclear how far north this boundary will progress through
   mid-evening, but it is conceivable that the more buoyant air mass
   will continue to spread north, eventually reaching the boundary
   draped across eastern IA and the IL/WI border. If this occurs,
   further intensification of convection will be possible, and
   downstream propagation across northern IL may occur. It is also
   possible that developing convection along the southern boundary
   continues to intensify and could pose a more transient and localized
   hail/wind risk in the coming hours. Confidence in either scenario is
   relatively limited, but trends are being monitored for the need for
   watch issuance this evening.

   ..Moore/Gleason.. 07/03/2026

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

   ATTN...WFO...LOT...ILX...MKX...DVN...ARX...

   LAT...LON   41088825 41078973 41179094 41489178 41769188 42279196
               42659190 43009168 43149140 43189071 43138795 43018777
               42768776 42338776 42068761 41808743 41738743 41558740
               41258749 41108776 41088825 

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