336
FXUS63 KDTX 072047
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
347 PM EST Fri Nov 7 2025

.KEY MESSAGES...

- Seasonably cool with drier conditions expected tonight and
Saturday.

- Precipitation arrives Saturday night as a mix of rain and snow.
Significant melting of any snow expected, but some accumulation will
be possible mainly on unpaved surfaces overnight through early
Sunday.

- Potential for additional snow showers Sunday thru Monday as
conditions turn much colder. Some accumulation possible, with a
particular focus across the thumb within bands of lake effect snow.

- Coldest conditions Monday morning, with wind chill dropping into
the teens.

&&

.DISCUSSION...

Broader mid level troughing left in the wake of a lead shortwave
allows a cold front to sweep across the area this evening. A drying
and gusty westerly wind will emerge, bringing a period of clearing
sky for the evening period.  Expectation remains for a secondary and
stronger cold frontal passage to commence overnight, governed by
more pronounced height falls associated with a vorticity lobe
pivoting through the base of the closed low centered over Hudson
Bay. Profile remains generally stable overall, but a brief uptick in
forced ascent could generate a few scattered showers mainly across
the thumb. Broad distribution in lows, ranging from lower 30s north
to upper 30s south.

Dry and seasonably cool conditions locally Saturday as weak high
pressure briefly gains control north of the frontal boundary now
anchored over the northern Ohio valley. Attention then turns to the
behavior of a clipper system set to arrive Saturday night and early
Sunday, followed by the intrusion of arctic air into early next week
as the aforementioned closed low digs southward and across the great
lakes. Surface low projected to track east-northeast across the Ohio
Valley, with a noted trend toward a more southerly trajectory within
the model solution space over the last 24 hours. Strong model
consensus exists in depicting a defined axis of deeper forced ascent
along the north/northwest flank of the low, with a signal for
meaningful fgen to emerge as the elevated frontal zone shifts back
northward into lower Michigan to some degree. This offers high
confidence for a precipitation event featuring wet/melting snow
and/or rain over a good portion of lower Michigan within roughly a 9-
12 hour period centered between 02z-14z. Expectation for a
significant component of melting of any snow to exist within areas
that lack greater precipitation rate, owing to a marginal thermal
profile still featuring above freezing air temperature and the early
season warmer ground/pavement condition. The placement and scale of
a narrower axis of higher precipitation rates still carries greater
uncertainty, with some variance yet with positioning anywhere
between the M-59/I-96 corridor and south of the Ohio border. Where
rates prove sufficient, then a smaller footprint of an inch or two
of accumulation remain possible by mid morning Sunday mainly on
grassy/unpaved surfaces.

System peels east early Sunday, leaving cold low level northerly
flow for the latter half of the day immediately downstream of the
inbound polar upper low. Low level flow veered just enough over lake
Huron to offer a window for greater moisture flux into the thumb.
This occurs as ongoing height falls draw the lake aggregate trough
southward with time. This will maintain a higher probability for a
mix of rain and snow showers during the day, with a particular focus
over the thumb region. Higher magnitude deep layer cold air
advection will then mark the Sunday night and Monday periods as the
upper low pivots through, with 850 mb temps dipping below -10C. Wind
chill Monday morning projected in the teens, with modest recovery
into the 20s during the day. Lake effect potential remains through
this period, conditional on yet defined wind trajectory and overall
moisture quality relative to any lingering overlake troughing.
Otherwise, some pockets of light snow showers or flurries plausible
at times within the cold cyclonic flow. Eastern thumb region most
susceptible to accumulation within this pattern, but pockets of
minor accumulation plausible at any location. High amplitude
troughing slow to relinquish control next week, ensuring well below
normal temperatures hold through at least midweek.

&&

.MARINE...

Low pressure departs the northern Great Lakes into Ontario and
Quebec, sending a cold front across the region this evening. Gusty
northwest winds will accompany this frontal passage, with northern
and central Lake Huron seeing a brief period of gusts to around 30
kt. Elsewhere, gusts to 20 to 25 kt can be expected this evening
before winds begin to subside overnight. Small Craft Advisories
remain in effect around the Lake Huron nearshore through this
period. A weaker pressure pattern will dominate the area on Saturday
with lighter winds and waves.

The next low pressure system will track through the southern Great
Lakes Saturday night into Sunday. This system will produce gusty
northerly winds and rain/snowfall on Sunday, then pull a much colder
air mass across the region for the early week. Latest guidance
continues to hold wind magnitude below gales - mainly around 25 kt.
However, the gusty winds and building wave action across southern
Lake Huron will necessitate another round of Small Craft Advisories.
Gusty northwest wind is expected to persist through Monday with
additional snow showers at times. Flow then flips to southwest on
Tuesday and remains gusty.

&&

.PREV DISCUSSION...
Issued at 1255 PM EST Fri Nov 7 2025

AVIATION...

Borderline MVFR/IFR ceiling remains behind across Lower Mi for this
afternoon after the morning showers exited into Ontario. The leading
cold front is on track to sweep these clouds eastward mid to late
afternoon followed by a clearing trend and renewed west wind gusting
near 30 knots until around sunset. A reinforcing cold front then
brings MVFR clouds back into the area from north to south tonight
which last into Saturday morning. Fragile high pressure promotes
lighter wind and scattered VFR cumulus under a surge of high clouds
Saturday afternoon ahead of the next low pressure system.

For DTW... Wind gusts briefly approach crosswind threshold from 280
direction and from about 22Z-02Z.

DTW THRESHOLD PROBABILITIES...

* High for ceiling 5000 ft or less early this afternoon. Moderate
  late tonight and Saturday morning.


&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...Small Craft Advisory until 10 AM EST Saturday for LHZ421-441-442.

     Small Craft Advisory until 4 AM EST Saturday for LHZ422-443.

Lake St Clair...Small Craft Advisory until 4 PM EST this afternoon for LCZ460.

Michigan waters of Lake Erie...Small Craft Advisory until 4 PM EST this afternoon for LEZ444.

&&

$$

DISCUSSION...MR
MARINE.......TF
AVIATION.....BT

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