433
ACUS11 KWNS 091803
SWOMCD
SPC MCD 091803
MIZ000-OHZ000-INZ000-092000-

Mesoscale Discussion 1616
NWS Storm Prediction Center Norman OK
0103 PM CDT Wed Jul 09 2025

Areas affected...Lower Michigan into far northwest Ohio

Concerning...Severe potential...Watch unlikely

Valid 091803Z - 092000Z

Probability of Watch Issuance...20 percent

SUMMARY...A couple of weak supercells may develop across parts of
lower Michigan through the afternoon with an attendant threat for
large hail and severe winds. Watch issuance is not anticipated given
the limited coverage of this threat.

DISCUSSION...Early thunderstorm development is underway across
central to southern lower MI as convection percolates along several
subtle boundaries over the region, including a weak cold front, a
lake-breeze boundary, and a weak surface trough. Despite somewhat
nebulous surface features and weak low-level winds, GOES-derived
winds suggest shear within the cloud-bearing layer is between 25-30
knots. This is slightly stronger than anticipated by morning
guidance, and hints that the kinematic environment is supportive of
organized convection. Similarly, a cold bias is noted in morning
guidance with observed temperatures running 2-4 F warmer than
anticipated. Consequently, surface-based CAPE estimates in recent
mesoanalyses may be more representative of the thermodynamic
environment and suggests around 2000-2500 J/kg SBCAPE is in place
across lower MI. Overall, these trends point towards a favorable
convective environment for weak supercells and/or organized
clusters. Meager forcing for ascent will likely limit severe storm
coverage, which should negate the need for watch issuance, but a few
instances of large hail/severe winds appear possible through late
afternoon.

..Moore/Mosier.. 07/09/2025

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

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

LAT...LON   41798533 42488561 42938563 43398545 43788504 44188345
            44178293 43958265 43488245 43198235 42868236 42478255
            41698297 41418318 41198351 41098376 41098409 41138453
            41238478 41798533

MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN