636
FXUS63 KDTX 050701
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
301 AM EDT Fri Sep 5 2025

.KEY MESSAGES...

- Becoming windy today with southwest-west wind gusts up around 40
  mph.

- Cold this weekend with highs in the 60s and lows in the 40s.

- Isolated showers possible over the weekend, especially north of M-
46.

&&

.DISCUSSION...

Large upper level low/trough centered over Northern Ontario will
direct a series of shortwaves/cold shots into the Great Lakes region
through the weekend. 00z raob out of International Falls Minnesota
revealed an 850 MB temp of 0 C, with this cold air arriving tonight
into Saturday, modified by the mild waters of the Great Lakes
region.

Today`s max temp forecast is a bit tricky as the strong cold front
crosses southeast Michigan around noon, with good low level cold
advection behind the front. 925 MB temps of 15+ C along an Adrian-
Pontiac-Port Huron line (blend of regional GEM/NAM/RAP/HRRR)
supports highs in the lower 70s east, with upper 60s west.

Mixing depths increasing to 850 MB level along/behind the front will
support windy conditions, with gusts of 35-40 MPH. Isolated gusts to
45 mph are possible with in any convective rolls as the 50 knot low
level jet slowly wanes/exists east.

850 MB temps in the lower single numbers through the weekend and
sbcapes of 50-100 J/kg intersecting the freezing level will bring a
chance of lake enhanced activity, particularly across the northern
third of the CWA with a Lake Superior-Michigan connection setting up
as low level winds trend to the northwest by the second half of the
Weekend. Min temps will be dependent on the amount of clouds around,
but 40s are expected either way. Lower 40s would be no problem if
skies remain mostly clear to partly cloudy, but confidence is low,
as there are signs of troughing and isolated showers around for
Saturday night as the mid level cold pool of -7 of -8 C at 700 MB
moves overhead. Potential to dip aob 40 degrees Sunday night as
winds die off and surface dew pts slip into upper 30s to around 40
degrees.

Building heights and a strong warm advection pattern develops early
next week, as 850 MB temps push into the lower teens late Tuesday
ahead of yet another cold front, which looks to slowly track through
on Wednesday. Bulk of Euro ensemble members pushing temps into the
upper 70s for much of southeast Michigan on Wednesday, with a dry or
mostly dry frontal passage due to the limited upper level support
and moisture.

&&

.MARINE...

Wind event across the Great Lakes commences this morning as the
surface low governing the wind is beginning to pass over the eastern
U.P. at press time. Winds organize out of the south through the
early morning as the mature low brings a tight pressure gradient
across Lake Huron and points southward. Sustained winds around 30kts
are expected across the bulk of Lake Huron by mid morning as gusts
increase towards 35kts. Low slides northeast towards northern
Ontario through the day while dragging a cold front across the
region resulting in winds shifting towards the west-southwest by
late morning. As this occurs, a 40-50kt low level jet is set to
expand over the central Great Lakes supporting a further uptick in
wind gusts towards 40kts over Lake Huron. A few gusts approaching
45kts with sustained winds near 34kts not out of the question for
central Lake Huron late morning-early afternoon (~10a-2p). All of
Lake Huron is under a Gale Warning through this evening as a result.
Lakes St Clair and Erie expected to see weaker winds given their
displacement southward from the low with gusts holding more in the
lower 30kt range. Small craft advisories are in effect for both of
these bodies of waters but will be watching observations for the
potential upgrade to Gale warning if need be. With the current wind
forecast, water levels in both the Saginaw Bay and western Lake Erie
near or fall below low water advisory criteria this morning. These
trends will be monitored and with issuance of an advisory
potentially needed in coming forecast updates. With a cooler airmass
expanding back over the lakes, waterspouts will again be possible
today into this weekend. Cooler, unsettled weather lingers into
early next week as the upper trough settles over the Great Lakes.

&&

.PREV DISCUSSION...
Issued at 1156 PM EDT Thu Sep 4 2025

AVIATION...

Steady increase in southerly flow commences tonight, downstream of
strengthening low pressure lifting into the northern great lakes.
VFR conditions with limited cloud coverage through the early morning
hours as greater low level stability holds. Thickening mid cloud for
the mid-late morning period, as the noted uptick in wind speed off
the surface supports a low level wind shear mention. Brief window
for shower development mainly at MBS during this time. Emerging
gustiness to southwest wind for the afternoon hours, peaking around
30 knots.

For DTW/D21 Convection... No thunderstorms expected through the
period.

THRESHOLD PROBABILITIES...

* Low for cigs at 5000 feet or less Friday.


&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement from 8 AM EDT this morning through this
     evening for MIZ049-055-063-083.

Lake Huron...Gale Warning until 10 PM EDT this evening for LHZ361>363-421-422-
     441>443-462>464.

Lake St Clair...Small Craft Advisory until 10 PM EDT this evening for LCZ460.

Michigan waters of Lake Erie...Small Craft Advisory until 10 PM EDT this evening for LEZ444.

&&

$$

DISCUSSION...SF
MARINE.......DRK
AVIATION.....MR


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