602
FXUS63 KDTX 080700
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
300 AM EDT Tue Sep 8 2026

.KEY MESSAGES...

- A little warmer today.

- Showers with a chance of thunderstorms tonight and Wednesday.

- Dry Thursday and Friday.

&&

.DISCUSSION...

A compact mid level low will track from southern Saskatchewan to
northern Ontario today while the mid level ridge axis over Lower Mi
exits east of the region. East-southeasterly low level wind fields
across Se Mi early this morning will veer toward the south as a
broad low to mid level anticyclone departs east. This will
correspond to an influx of warmer air into the forecast area today.
Increased cloud cover through the day associated with moisture
advection around 850mb and increasing mid/high clouds from the west
will result in overall increasing cloud trends, likely capping
afternoon highs to the lower 80s.

Latest water vapor imagery across North America this morning shows a
plume of moisture off the Pacific advecting into the Upper Midwest
while Gulf moisture in the lower levels feeds into this same region.
This is leading to a pool of very deep moisture; latest SPC meso
analysis indicates precipitable water values of 1.7 to 2.1 inches
extending across the central plains to upper Midwest. This deep layer
moist axis will advance across Lower Mi tonight as the ridge axis
flattens and the mean flow upstream turns more westerly. The
corresponding increase in mid level moisture will support increasing
shower chances during the night, mainly across the Saginaw Valley and
thumb.

Forecast strengthening of an upper jet streak across the northern
lakes Wednesday will support an expanding region of upper divergence
and weak mid level frontal forcing across northern and central Lower
Mi. The forcing within the deep moist axis will sustain rain chances
through Wednesday as the mid level frontal boundary sinks southward
into srn Lower Mi. One point of uncertainty to the Wednesday forecast
involves the remnants of a potential convective complex expected to
develop over ern Iowa/nrn Illinois tonight. An MCV from this feature
would certainly enhance precip chances across srn Mi if it were to
materialize. A deeper/slower mid level wave may also support a better
influx of instability into the far southern portions of the forecast
area Wed afternoon, supported by a few high res solutions. This in
turn has allowed Wed CAPE probabilities to trend upward south of the
I-94 corridor. The SPC Day2 convective outlook has thus nudged the
area of Marginal Risk into Monroe County. Given the degree of deep
layer moisture overhead Wednesday, if deep convection does
materialize, intense rainfall rates will be of concern.

There is strong agreement that the deep layer moist axis and mid
level frontal boundary will remain progressive as mid level west-
northwest flow expands across the northern Great Lakes by Thursday,
advecting a much drier airmass across Se Mi. Model soundings
indicate subtle cold air advection will be offset by steep low level
lapse rates to boost Thurs highs well into the 70s. Mid level
ridging and associated surface high pressure will then build across
the region, supporting dry conditions to end the work week.

&&

.MARINE...

High pressure drifts over the region through this morning
maintaining benign marine conditions. South turning southwesterly
winds strengthen tonight 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 1147 PM EDT Mon Sep 7 2026

AVIATION...

VFR under broken cirrus with light easterly wind continue as surface
high pressure drifts eastward tonight. Wind direction off Lake Erie
will be monitored for signs of stratocu, however recent guidance
remains weak on cloud moisture generation off the lake. There is a
stream of higher RH moving in from the Ohio valley around 850 mb
which could lead to a few pockets of VFR stratocu early in the
morning. Otherwise, this moisture axis leads into a scattered to
broken cumulus field in the afternoon under continued cirrus
coverage into Tuesday evening.

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

DTW THRESHOLD PROBABILITIES...

* Low for ceiling 5000 ft or less late tonight through Tuesday
  evening.


&&

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

$$

DISCUSSION...SC
MARINE.......KGK
AVIATION.....BT


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