631
FXUS63 KDTX 071945
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
345 PM EDT Mon Sep 7 2026

.KEY MESSAGES...

- Dry and warm today and tomorrow.

- Showers with a chance of thunderstorms tomorrow night and
  Wednesday.

&&

.DISCUSSION...

High pressure and inbound ridge axis will control the weather today
into tomorrow. Surface high pressure expected to slide to the
eastern Great Lakes tonight while ridge axis ridge axis begins to
slide into the central Great Lakes. The general southeast flow today
is helping support a healthy cumulus field across most of southeast
Michigan. Lack of deeper moisture and stability will keep the
forecast free of precipitation through the remainder of today and
through tonight. Lows tonight down into the 50s tonight. The
increasingly south to southwest flow tomorrow with the ridge axis and
eventually passage of it will lead. This will result in warm/moist
advection that will allow daytime highs on Tuesday to reach the low
80s and surface dewpoints to climb above 60 degrees.

Helping drive this warm/moist airmass into the region will be a
Pacific trough that is forecast to eject across the northern
plains and central Canada. Low-mid level jet forcing along with the
systems associated cold front will lead to the next chance of
widespread rain and scattered thunderstorms Tuesday night through
Wednesday. Within the theta-e ridge will be a plume of deep moisture
that has PWAT values to around 2 inches and be the corridor of
focused convection. The southwest to northeast orientation of this
corridor will lead to PoPs increasing across the Saginaw Valley
first on Tuesday night before greater upscale growth occurs through
Wednesday morning as the system propagates downstream into southeast
Michigan over the course of Wednesday. Less favorable early day
timing and the potential for cloud cover may temper a stronger
instability response. Towards the southern Michigan border would be
the favored locations that greater instability may be able to
develop. While shear will be favorable, mid-level lapse rates do not
appear to be very steep. At this time, the severe threat appears
limited and held south of the state with general thunderstorms more
likely across southeast Michigan. Given the degree of moisture
though, locally heavy rainfall will certainly be possible. Current
QPF guidance is to around a half inch across the Saginaw Valley with
lesser amounts with southeast extent. In addition, winds will be
elevated on Wednesday with increasing pressure gradient and gusts of
25 to 30 mph will be possible.

A trailing trough will help push the cold front out of the area by
Thursday morning. Post frontal airmass will bring cooler and less
humid conditions for Thursday and Friday. Temperatures back into the
70s and dewpoints down in the 50s. Over the weekend, temperatures
look to rebound back to around 80 degrees within quasi zonal flow.
Passing shortwaves to the north offer low end PoPs at this stage.

&&

.MARINE...

High pressure drifts over the region through Tuesday maintaining
benign marine conditions. South turning southwesterly winds
strengthen Tuesday night into Wednesday as seasonably strong low
pressure system tracks across southern Canada into Hudson Bay. While
a gust or two two could reach entry-level gales over central Lake
Huron, winds are expected to peak around 30kts. Return of a humid
airmass back to the region will support shower and thunderstorm
chances for much of the day Wednesday before the attendant cold
front crosses late evening. Moderate northwesterly flow follows for
Thursday however only a glancing shot of cold advection and a
rapidly diminishing gradient has high pressure builds caps winds aob
30kts.

&&

.PREV DISCUSSION...
Issued at 123 PM EDT Mon Sep 7 2026

AVIATION...

VFR conditions are maintained across the area as high pressure
currently over Lake Huron gradually migrates toward the Mid-Atlantic
region by Tuesday morning. Cumulus will wane with the loss of
daytime heating this evening, leaving clear skies below 20 kft and
just increasing coverage of higher cirrus tonight. Light easterly
wind persists into tonight before veering to south and southeast
during the day Tuesday. Despite weak onshore flow, near-surface
moisture flux off Lake Erie is not particularly strong in model
guidance so will hold off on an early morning fog/mist mention in
the Metro Detroit TAFs.

D21/DTW Convection...Thunderstorms are not forecast today or tonight.

DTW THRESHOLD PROBABILITIES...

* Medium for ceiling at or below 5000 ft early this afternoon.


&&

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

$$

DISCUSSION...AA
MARINE.......KGK
AVIATION.....TF


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