Storm Prediction Center Mesoscale Discussion 2231

   Mesoscale Discussion 2231
   NWS Storm Prediction Center Norman OK
   0340 AM CDT Fri Sep 04 2026

   Areas affected...Portions of southern lower Michigan

   Concerning...Severe potential...Watch possible 

   Valid 040840Z - 041045Z

   Probability of Watch Issuance...40 percent

   SUMMARY...An organizing convective cluster/MCS may produce severe
   wind gusts or some hail overnight and continuing into the morning. A
   Watch is possible but uncertain.

   DISCUSSION...Recent radar trends with a convective cluster over
   eastern WI point toward organization into an MCS potentially capable
   of severe gusts and hail in the coming hours. Continued low-level
   warm air advection at the nose of a 30-40 kt low-level jet has
   supported an increase in convective coverage across eastern WI where
   cloud top cooling has been noted. This has likely strengthened a
   preexisting cold pool with the lead elements of this convective
   complex. These storms will cross the lake and move into lower MI in
   the next 1-2 hours. The air mass downstream remains moderately
   unstable and sheared aloft south of a warm front. Despite the
   buoyancy likely being elevated above the immediate surface stable
   layer, the environment is more than sufficient to maintain
   intensity/organization of the ongoing storms. This suggests severe
   wind gusts and some hail are possible as convection moves across the
   lake, into lower MI and eventually OH/IN later this morning.

   It remains unclear if the stronger gusts from this cluster will make
   it to the surface. The strengthening cold pool, more organized
   linear mode and recent CAM guidance suggest it's possible. Given the
   potential increase in severe threat, conditions are being closely
   monitored for a Severe Thunderstorm Watch.

   ..Lyons/Mosier.. 09/04/2026

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

   ATTN...WFO...CLE...DTX...IWX...GRR...

   LAT...LON   42038339 41908336 41758348 41708376 41678439 41688524
               41848593 42058645 42178672 42528707 42898733 43118731
               43338722 43608706 43688651 42258366 42038339 

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