010
FXUS63 KDTX 010952
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
552 AM EDT Mon Sep 1 2025

.KEY MESSAGES...

- Dry with seasonal temperatures into Wednesday.

- Showers Wednesday night will give way to much cooler temperatures
  late week through the weekend. Additional shower chances late week.

&&

.AVIATION...

Broad area of high pressure remains in-place today offering stable
and dry conditions. Expect a similar diurnal cumulus response to
that of previous days with predominantly FEW-SCT coverage around 5
kft AGL. A brief period of BKN sky is possible as peak heating
approaches and lake moisture augments low-level hygrometric
profiles. Given the vicinity of the Southeast Michigan terminals to
aggregate ridge center (migrating into northern Lake Huron),
gradient flow will be rather weak. This keeps easterly winds below
10 knots. Did keep the TEMPOs for MVFR fog potential late tonight
into Tuesday as dewpoints inch upward and nocturnal cooling occurs
with little outgoing inhibition.

For DTW/D21 Convection...No thunderstorms expected during the
forecast period.

THRESHOLD PROBABILITIES...

* None

&&

.PREV DISCUSSION...
Issued at 303 AM EDT Mon Sep 1 2025

DISCUSSION...

Weak mid level low pressure over the Mid Atlantic will lift across
the eastern Great Lakes tonight into Tuesday. This system will not
be able to dislodge the mid level ridge axis over Lower Mi or make
much impact on the expansive sfc high pressure that stretches across
the eastern and southern Lakes region. Deep columnar subsidence will
therefore persist today and Tuesday and will remain supportive of
dry conditions. While light easterly winds will persist at the
surface today, model soundings show mixing depths that are a bit
higher than yesterday by at least 1500 feet. This will support a
little warmer afternoon highs; upper 70s to around 80. The low level
flow will will veer more southerly on Tuesday, driving slightly
warmer air into Se Mi and warranting highs around 80. The overall
dry ambient airmass, light winds and clear skies will still promote
optimal radiational cooling conditions, allowing nighttime mins to
drop back into the 50s.

The 00Z model suite remain consistent in showcasing a potent short
wave dropping into nrn Minnesota from northern Canada on Wednesday,
transitioning to a deep closed mid level low which meanders across
nrn Ontario into the weekend. Southwest flow will increase across
srn Mi on Wednesday as this wave and associated cold front advance
into the northern and western Great Lakes. Although there are some
model indications of prefrontal troughing over Se Mi Wednesday
afternoon, mid level capping and weak forcing will inhibit
convective initiation ahead of the main cold front. 15 to 20 knots
of flow within the deep daytime mixed layer will push Wed highs into
the low 80s. Strong mid level positive PV advection along a deep
layer theta e axis will then bring widespread showers along/behind
the cold front associated with the aforementioned upper low. Model
solutions and probabilistic guidance generally suggests a 5 to 7 hour
window of strong ascent. Timing uncertainty at this stage will
spread forecast pops out from Wednesday afternoon through early
Thursday morning. The strenght of the ascent may compensate to a
degree for weak instability, thus support a chance for thunderstorms.

The airmass in the wake of the front will be quite cool for early
September as 850mb temps drop into the single digits. This will
result in temperatures being a solid 10 to 20 degrees below normal
late week into next weekend. Cool air aloft combined with potential
short wave impulses will support additional chances for showers,
especially on Friday.

MARINE...

Sprawling high pressure over the Great Lakes region providing light
and variable winds, which looks to continue through Tuesday with dry
conditions. There is a low chance for some fog to develop late at
night into the early morning hours due to the warm waters.  A
pattern shift mid week will be characterized by strengthening low
pressure across the northern Great Lakes resulting in the passage of
a strong cold front late Wednesday. This will drive much colder air
across the lakes for Thursday, ushered in by strong northwest winds.
The forecast for Friday is a bit in flux, as there have been varied
model solutions with the strength and location of the next low
pressure system diving southeast from Central Canada. Outgoing
forecast for Friday suggests strong southwest winds ahead of the low
before winds swing to the west-northwest for Friday evening/night.
Enough cold air in behind this system for the weekend to bring the
potential for waterspouts.

&&

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

$$

AVIATION.....KGK
DISCUSSION...SC
MARINE.......SF


You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.