209
ACUS11 KWNS 121406
SWOMCD
SPC MCD 121406
MIZ000-121630-

Mesoscale Discussion 1654
NWS Storm Prediction Center Norman OK
0906 AM CDT Sat Jul 12 2025

Areas affected...Parts of Lower MI

Concerning...Severe potential...Watch possible

Valid 121406Z - 121630Z

Probability of Watch Issuance...40 percent

SUMMARY...Strong to locally severe storms may increase in coverage
later today.

DISCUSSION...A convectively enhanced midlevel shortwave trough is
moving across the Great Lakes this morning, in advance of a deeper
mid/upper-level trough moving from the Dakotas into MN. Morning
elevated convection has helped to reinforce an east-west oriented
baroclinic zone across central Lower MI, while a cold front is
moving eastward across western lower MI. Midlevel lapse rates are
weak, but rich low-level moisture is currently supporting MLCAPE of
500-1500 J/kg, with a further increase expected with time as
prefrontal temperatures warm into the 80s F near/south of the
baroclinic zone.

The KAPX VWP is currently favorable for supercells, with low-level
veering with height and 50+ kt of southwesterly midlevel flow.
However, wind profiles may tend to become less favorable with time,
as low-level flow veers, and wind profiles become more
unidirectional. There may be a window of opportunity later this
morning into the early afternoon for supercell development
along/ahead of the front, especially across northeast lower MI. Any
such development would pose a threat of damaging wind, isolated
hail, and possibly a tornado. Otherwise, multicell clusters and
perhaps a transient supercell or two will become increasingly
possible into this afternoon, with a primary threat of damaging
wind.

Guidance varies regarding the timing and coverage of storm
development along/ahead of the front later today, but watch issuance
is possible if trends support an organized severe threat.

..Dean/Mosier.. 07/12/2025

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

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

LAT...LON   41818556 44058496 44728523 45938412 45738357 45418300
            43978265 42668242 42148301 41808347 41778463 41818556

MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN