ACUS11 KWNS 121928
SWOMCD
SPC MCD 121928
MIZ000-122130-

Mesoscale Discussion 1955
NWS Storm Prediction Center Norman OK
0228 PM CDT Wed Aug 12 2026

Areas affected...portions of central and eastern lower Michigan

Concerning...Severe potential...Watch unlikely

Valid 121928Z - 122130Z

Probability of Watch Issuance...20 percent

SUMMARY...Isolated severe storms capable of marginally severe hail
and/or damaging wind gusts appear possible late this afternoon. A
watch is not currently expected due to the limited areal coverage of
the severe weather threat.

DISCUSSION...Recent visible satellite imagery shows areas of
deepening cumulus within a broadly confluent zone stretching through
central lower MI, from KLDM to KD95. While multilevel clouds have
slowed diabatic heating and resultant air mass destabilization,
modification of the 15Z DTX sounding for current surface conditions
yields MLCAPE of 1000-1500 J/kg. Water vapor imagery suggests that
stronger forcing for ascent associated with a weak mid-level
disturbance is currently shifting to the east of the region with
low-level convergence and modest warm advection serving as the
primary sources for widely scattered storm development by late
afternoon. Additionally, surface observations and visible satellite
suggest convective outflow from ongoing storms over IN and OH
surging north, which may also focus storm development.

Regional VWPs are sampling 40-50+ kt west-northwest winds generally
above 4 km AGL, which are yielding sufficient deep-layer shear for
some storm organization, including episodic supercell structures.
Poor mid-level lapse rates of less than 7 C/km should limit hail
sizes, though some marginally severe hail appears possible with the
strongest storms. Damaging wind potential will be contingent on
storms merging into clusters, leading to some cold pool
organization.

..Mead/Thompson.. 08/12/2026

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fjg!6YwSAYD463a5LIEVdKHLrPh0Fj7zlqDQBRcGpZS0RDc7HAhD_dLDSQzW02csaVAwv407eeSJTdXoOgrV5H60dsMFVcs$ for graphic product...

ATTN...WFO...DTX...APX...GRR...

LAT...LON 42588287 42928372 43608533 44068546 44388481 44088400
43768301 43508243 42938221 42628243 42588287

MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN


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