Expert Forecast Opinion

120
FXUS63 KDTX 270345
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1145 PM EDT Wed Aug 26 2026

.KEY MESSAGES...

- An isolated shower is possible Thursday afternoon, then drier and
less humid conditions are expected through Friday and Saturday.

- A warming trend brings above normal temperatures early next week.

&&

.AVIATION...

Subtle moisture influx Thursday morning within the post cold frontal
environment may lead to some MVFR and/or VFR based strato cu with
the onset of daytime heating during the mid-late morning. Diurnal
boundary layer growth will then support a lifting of cloud bases
Thurs afternoon along with light WNW winds.

D21/DTW Convection...No convection is forecast through the TAF
period.

.DTW THRESHOLD PROBABILITIES...

* None.

&&

.PREV DISCUSSION...
Issued at 313 PM EDT Wed Aug 26 2026

DISCUSSION...

A couple of thunderstorm clusters have developed over western Lower
Michigan this afternoon along a continuous line of agitated cumulus
that stretches from northern MI back toward central Illinois. The
trend so far has been for cells to be short-lived as they move off
the boundary and away from the instability axis, which is anchored
closely to the cold front itself. Local cloud trends are quite
stable still, reflecting remnants of the 850-600mb stable layer that
was sampled in the 12z KDTX sounding.

Expectations for the afternoon-evening are still largely on track
where coverage increases to become a broken line of showers and
storms. Any deeper convective growth is likely confined to a window
of about 4pm-9pm as moisture convergence sweeps through ahead of the
front and overlaps with weakening shear profiles. The lack of deep
layer shear favors a pulsey/multicellular nature rather than strong
cold pool organization, meaning isolated downburst and hail
potential as cores collapse. Given the environment, higher
confidence in a strong-severe storm exists near the Ohio border
where instability is greatest although all of SE MI is in at least a
Marginal Risk for severe weather. Veered south/southwest flow is
generally less favorable for the streamwise vorticity needed for
tornadoes with a west-east mean wind. That said, there has been weak
mid-level rotation noted upstream so cannot rule out supercellular
structures, mainly early on as shear is at its peak.

The cold front sweeps through late this evening, bringing an end to
thunderstorm chances overnight. A quieter pattern then develops
Thursday into the weekend as surface high pressure fills in post
cold front. Northwest flow and return of thermal troughing take
advantage of warmer lake temperatures to generate partial coverage
of stratocumulus Thursday, which could squeeze out low-topped shower
activity. Moisture availability then wanes Friday into the weekend
as the high drifts overhead, with winds then shifting to the
southwest by Saturday in response. Dry conditions thus expected.
Coolest high temperatures of the period expected Thursday-Friday as
h8 temperatures drop into the lower teens across Lower MI, equating
to highs in the upper 70s and lows in the 50s.

The emergence of SW flow Saturday then kicks off a warming trend
that peaks early next week. GFS and Euro MOS guidance are in line
with the extended NBM, projecting high temperatures near 90 degrees
Monday-Tuesday. This pairs with a gulf connection where moisture
transport is accelerated Sunday through Tuesday as low level jet
winds increase to 30-35 knots. This establishes breezy southwest
flow (~25 to 30 mph) during peak heating each day, as well as an
increase in shower and thunderstorm chances across the Great Lakes.

MARINE...

Scattered showers and thunderstorms work across the area this
evening in advance of an approaching cold front. An isolated strong
wind gust is possible particularly towards the southern Great Lakes.
Cold front eventually crosses the region late evening-tonight
flipping around winds to the NW for Thursday. Moderate cool
advection follows with peak gusts between 20-25kts over the northern
portions of Lake Huron daytime Thursday before high pressure begins
to build in. Said high then drifts overhead Friday and Saturday.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.
&&

$$

AVIATION.....SC
DISCUSSION...MV
MARINE.......KDK


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