Mesoscale Discussion 1340 NWS Storm Prediction Center Norman OK 0121 PM CDT Sat Jul 24 2021 Areas affected...Much of central and southern lower Michigan into adjacent portions of northwestern Ohio and northern Indiana Concerning...Severe potential...Watch possible Valid 241821Z - 242015Z Probability of Watch Issuance...60 percent SUMMARY...At least scattered thunderstorm development still appears probable, now mostly likely around 4-6 PM EDT, with the potential to organize into clusters capable of producing damaging wind gusts. Trends continue to be monitored for the possibility of a severe weather watch. DISCUSSION...Initial attempts at intensifying thunderstorm development across/east of the Houghton Lake vicinity appear to be waning, perhaps due to weakening of the trailing mid-level cyclonic vorticity center. However, the boundary layer across much of central and southern lower Michigan remains moist, modestly unstable and weakly inhibited, to the south of the effective warm frontal zone, and ahead of conglomerate convective outflow trailing across northern Lake Michigan through southern Wisconsin. Although the mid-level trough axis is in the process of shifting across and northeast of the Lake Huron/Georgian Bay vicinity, moderately strong (40+ kt around 500 mb) west-northwesterly mid-level flow will maintain strong deep-layer shear across the region into this evening. Beneath this regime, it still appears that continuing daytime heating will support the initiation of at least scattered thunderstorm activity, perhaps focused on the lake breeze advancing inland off Lake Michigan. Aided by the shear, this activity may tend to grow upscale, with organizing clusters posing a risk for potentially damaging wind gusts.