472
FXUS63 KDTX 280738
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
338 AM EDT Mon Sep 28 2026

.KEY MESSAGES...

- Dry and pleasant weather conditions will persist into Wednesday.

- Areas of dense fog expected this morning and Tuesday morning.

- Rain chances increase during the latter half of next week with
  cooler temperatures expected.

&&

.DISCUSSION...

Fog development is following a similar temporal cadence to yesterday
as noted via Nighttime Microphysics RGB. The geographic footprint of
the fog plume, however, is taking on a more southerly drift given
the backed wind direction in comparison to yesterday while also
showing signs of mechanical turbulence. Nonetheless, likely to see
another localized area of dense fog for the Thumb areas and
northeast suburbs as winds go calmer toward daybreak. MOS guidance
is also still on track for another round of fog Tuesday morning, and
more bullish than the past few days as remnant moisture from the
deformation axis wraps around the high pressure center. This
coincides with the high pressure center moving overhead which will
minimize gradient flow for optimized radiative cooling/fog
potential. Fog lifts and mixes out by mid-morning both today and
Tuesday, extending the stretch of dry and seasonable fall weather
for SE Michigan. Daytime highs both days expected to peak in the low-
mid 70s under plenty of sunshine.

A pattern shift begins Tuesday on the western flank of the high
noted by a wind shift to the southwest. This leads to modest thermal
advection that peaks Tuesday night, boosting h8 temperatures from 10
C to 15 C by Wednesday morning. The first round of mid-level height
falls approaches early Wednesday to bring thickening mid-level cloud
to the region. By this point the east coast system will be dislodged
and the low levels will be characterized by the western flank of
broad eastern CONUS high pressure. This will be quite effective in
stalling low level moisture transport to our west through much of
the day Wednesday, keeping the majority of SE Michigan dry but
cloudy with virga. The trend toward a drier forecast Wednesday also
boosts the temperature forecast for Wednesday, with highs expected
to climb into the mid-upper 70s.

Rain chances then increase Wednesday night and persist through at
least Thursday as northern stream troughing phases with the broad
deformation/trough axis over central CONUS. The low level height
field tightens quickly Wednesday night as the trough approaches,
leading to strengthening LLJ winds to about 50 knots by Thursday
morning. On its own this causes breezy SW flow across SE Michigan
Thursday where gusts to 25 mph are possible. The enhanced SW flow
will also enhanced moisture transport into lower Michigan, which
will be engaged by the deformation and approaching frontal forcing
to bring rain to the region Thursday. Forcing will be defined
primarily by deformation and WAA while lapse rates stay moist
adiabatic, so expecting a light-moderate stratiform nature to
Thursday`s rain chances. That said, the impressive moisture axis
(PWAT nearly 2.0") will take most of the day to sink south across
Lower Michigan which could grind out 0.50-0.75" when all is said and
done. That said, preceding dry weather and long duration rainfall
limits flooding concerns with this rain.

A meaningful cool down is then expected Friday into the weekend post-
front, with showers tapering off Friday. There is still some
uncertainty as to how aggressively high pressure pushes in behind
the fropa, which keeps low rain chances going through Friday.
Temperature prospects for the weekend carry higher confidence, with
highs only reaching the mid 60s and lows back into the 40s to start
October.

&&

.MARINE...

High pressure to hold over the Great Lakes through tomorrow. This
will cap wind gusts to or below 15 knots for most locations. Wind
direction will mainly hold from the north to northwest today but
will back to the south to southwest tomorrow after the passage of a
warm front. The next chance for rain and possible some thunderstorms
will return Wednesday and Thursday ahead of and along a cold front.

&&

.PREV DISCUSSION...
Issued at 1156 PM EDT Sun Sep 27 2026

AVIATION...

High amplitude H3 to H5 ridging will remain in place across the
central Great Lakes throughout the taf period. The high pressure
will be immediately upstream as a dipole to the closed Northeast
United States upper level low. Active subsidence between 2.0 and
10.0 kft agl will help facilitate deep stability. Persistent north
northeasterly flow trajectories off of Lake Huron will bring the
potential for fog again Monday morning. Well agreed upon signal for
br/fg with NAMnest and HRRR surface condensation pressure deficits
and MOS guidance.

D21/DTW Convection...No thunderstorms forecast through the TAF
period.

DTW THRESHOLD PROBABILITIES...

* None


&&

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

$$

DISCUSSION...MV
MARINE.......AM
AVIATION.....CB


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at www.weather.gov/detroit.