015
FXUS63 KDTX 050703
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
303 AM EDT Sun Oct 5 2025

.KEY MESSAGES...

- Near record highs today and continued warm Monday.

- Rain expected Monday night into Tuesday.

- Cooler temperatures Tuesday through the end of the week.

&&

.DISCUSSION...

An anomalously strong mid level ridge (500mb heights around 590dm)
centered over the Mid Atlantic will continue to influence Se Mi
today into Monday. Southerly return flow circulating around this
large anticyclone will maintain the feed of unseasonably warm air
into Se Mi. Model soundings suggest some slightly lower mixing
potential today compared to yesterday, indicating highs in the mid
80s. Euro ensemble members are fairly uniform in mid 80s for highs,
although a few members do have maxes into the upper 80s. A little
stronger southerly flow today with full sun will justify forecast
highs in the mid to upper 80s. Southwesterly gradient flow will
strengthen tonight, limiting nocturnal boundary layer cooling which
should hold min temps in the upper 50s to low 60s.

The increased gradient flow is in response to a cold front
approaching from the northwest. This cold front will be driven
across Se Mi late Monday into early Tues morning in response to a
mid level trough advancing across northern Ontario. Se Mi will
remain in the warm sector on Monday in which a deep afternoon mixed
layer will again drive highs into the 80s. Increased moisture on
Monday will be supportive of more cloud cover, which may keep highs
on the lower end of guidance range, lower to mid 80s.

As the mid level frontal boundary settles overhead Monday night into
Tuesday, model solutions indicate a plume of gulf moisture getting
transported into the frontal system. Mid level short wave features
and upper jet support will maintain some degree of deep layer
frontogenesis Monday night into Tuesday. This combined with weak
elevated instability will support high probabilities for rain, with
at least a chance for thunderstorms. Ensemble guidance has a fairly
large spread in forecast total QPF with this system. Overall, total
rainfall amounts of a quarter to half inch carry high probabilities
of occurrence. There are a few ensemble members who do have total
QPF a little over an inch, not terribly surprising given the weak
elevated convective component and slow movement of the frontal
forcing. Shallow post frontal cold air advection will advect a much
cooler airmass across Se Mi on Tuesday. Strong high pressure will
then expand across the Great Lakes region from the north on
Wednesday in the wake of the cold front. This will advect and cool
and very dry airmass into the region, supporting temperatures during
the latter half of the work week which are a little more in line
with seasonal averages.

&&

.MARINE...

A low pressure system will traverse from the northern Plains into
the James Bay today, which will strengthen the pressure gradient
across the Great Lakes. This will maintain southerly flow and will
result in some increasing wind speeds and gust potential late
tonight through tomorrow morning, especially across Lake Huron.
Winds speeds increase to 15-20 knots with gusts around 25 knots by
tonight. The continued progression of low pressure into Quebec will
then push a strong cold front across the region late tomorrow into
Tuesday morning. Wind direction will veer to the north after the
passage of the front. Post frontal cold air advection will sustain
breezy conditions across Lake Huron Tuesday, where gusts around 30
knots will be likely.

&&

.PREV DISCUSSION...
Issued at 1153 PM EDT Sat Oct 4 2025

AVIATION...

A slowly changing large scale weather pattern consists of surface
high pressure 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. The result is VFR in a mix of clear
sky and patchy mid level clouds across the SE Mi terminal corridor
as SW wind between these systems maintains record warmth across the
Great Lakes. Hints of elevated instability are only able to produce
a few pockets of mid level clouds late tonight, mainly toward MBS,
leading into another round of high based cumulus with scattered or
less coverage Sunday afternoon. Boundary layer conditions by then
are still deeply mixed but with less cloud moisture available
compared to the more robust cumulus development that produced a
stray radar return Saturday afternoon. SW wind gusting near 25 knots
becomes the weather highlight, again mainly toward MBS, by afternoon
into Sunday evening.

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

DTW THRESHOLD PROBABILITIES...

* None.


&&

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

$$

DISCUSSION...SC
MARINE.......AM
AVIATION.....BT


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