394
FXUS63 KDTX 042303
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
703 PM EDT Sat Oct 4 2025

.KEY MESSAGES...

- Dry with near record warmth this weekend.

- The next chance of rain arrives late Monday into Tuesday.

- More seasonable temperatures the latter half of the week.

&&

.AVIATION...

Little change occurs in the large scale weather pattern across the
Great Lakes tonight and Sunday. Surface high pressure remains
anchored off the Atlantic coast reaching into the SE States while
low pressure and its cold front move slowly across central Canada
and the Plains. VFR in a mix of high based cumulus and cirrus is the
result across the SE Mi terminal corridor as SW wind between these
systems reinforces record warmth across the Great Lakes. Hints of
elevated instability regenerates pockets of mid level clouds late
tonight, mainly toward MBS, leading into another round of scattered
high based cumulus Sunday afternoon. Conditions by then are still
deeply mixed but with less cloud moisture available compared to the
more robust cumulus development with a stray radar return this
afternoon. SW wind gusting around 25 knots becomes the weather
highlight, mainly north of the DTW corridor, by early afternoon into
Sunday evening.

For DTW/D21 Convection... Thunderstorms will not occur through the
forecast period.

DTW THRESHOLD PROBABILITIES...

* None.

&&

.PREV DISCUSSION...
Issued at 243 PM EDT Sat Oct 4 2025

DISCUSSION...

Conditions for the first weekend in October marked by near record
breaking warmth, as Southeast Michigan holds position within the
northern expanse of a sprawling 588 dm upper ridge. A well mixed
profile within light southerly flow and full insolation sending
temperature into the mid-upper 80s areawide late this afternoon.
There remains a remote opportunity for a shower or two to manifest
through the evening hours as a narrow theta-e gradient works to
engage existing weak boundary layer instability. Near term hi res
output still suggestive of this potential, mainly north/west of
Flint. Any activity limited in scale, duration and magnitude, thanks
to a well capped environment lacking in greater forced ascent.

Upper ridge axis anchors over the east coast Sunday and Monday, as
greater height falls take shape over the plains. Net result locally
remains continued high magnitude warmth, reinforced by improving
depth and magnitude to existing southwest flow. This will continue
to support afternoon temperatures well in the 80s both days. A
sufficiently capped, stable profile ensures dry conditions to finish
the weekend period. As upstream height falls begin to impinge on the
great lakes, a frontal boundary will ease into northern lower Mi by
Monday. A smaller subset of the model solution space introduces some
lower end potential for convection during the daylight period Monday
as pre-frontal moisture quality improves with time. NBM output and
the concurrent outgoing forecast maintain lower end potential mid
afternoon onward, but could certainly see rainfall chances holding
off until after 00z should meaningful forced ascent fail to
materialize within the warm sector to overcome lingering capping.

Southeastward sagging cold frontal boundary becomes the focus Monday
night and Tuesday, as greater height falls slowly commence within
the southern expanse of a deeper mid level wave pivoting across
Ontario. High probability of rainfall this period given the degree
of frontal convergence, pockets of heighted dcva and likelihood for
enhancement within the right entrance region of associated upper jet
core. A period of stronger fgen plausible should the upper jet
forcing more favorably intersect the advancing frontal boundary.
Forecast will highlight a broad qpf swath of generally one quarter
to one half inch of total rainfall at this stage, acknowledging the
75th percentile resides closer to three quarters of an inch within
grand ensemble solution space. Temperatures edge slightly below
normal within the post-frontal environment Wednesday and Thursday,
as building high pressure brings another stretch of dry conditions.

MARINE...

A series of low pressure systems will travel from the northern
Plains into the James Bay late tonight through tomorrow. While this
will not result in any significant changes across the Great Lakes,
this will strengthen the pressure gradient slightly, reinforcing
southerly flow across Great Lakes with gust potential ranging
between 15 to 20 knots, favored across Lake Huron.

Much bigger changes arrive Monday as a strong cold front sweeps
across the Great Lakes. Prior the passage of the front, south flow
wind speeds will increase tomorrow night, bringing gust potential up
to 25 knots over Lake Huron. Intrusion of cooler air Tuesday will
bring continuation of breezy conditions, with sustained winds of 20
to 25 knots and gusts up to 30 knots for Lake Huron given the more
favorable north to northwest fetch.

CLIMATE...

The record highs for Saturday, October 4th.

Detroit: 89 Degrees (Set in 1951)
Flint:   88 Degrees (Set in 1951)
Saginaw: 87 Degrees (Set in 1967)

The record highs for Sunday, October 5th.

Detroit: 88 Degrees (Set in 1951)
Flint:   88 Degrees (Set in 1922)
Saginaw: 86 Degrees (Set in 2007)

&&

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

$$

AVIATION.....BT
DISCUSSION...MR
MARINE.......AM
CLIMATE......MV


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