Expert Forecast Opinion

365
FXUS63 KDTX 072023
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
323 PM EST Sun Dec 7 2025

.KEY MESSAGES...

- Below normal temperatures continue this week, with the coldest air
expected Monday morning when wind chills drop to or below zero.

- Active weather pattern returns Tuesday with additional
opportunities for accumulating snow, and even some rain by Wednesday
morning.

- Abnormally cold conditions settle back in by Thursday with lake
effect snow chances through the end of the week.

&&

.DISCUSSION...

Synoptic snowfall has ended across SE MI this afternoon as the Ohio
Valley shortwave is supplanted by a new surface low developing
across the eastern Great Lakes. In its wake, north-northwest winds
draw in a renewed push of arctic air into the region and initiating
lake effect snow showers. While some of these flurries/light snow
showers push into SE MI, increasingly dry airmass as well as
increasing subsidence limits infiltration this far removed from the
lake source. As such, the most of SE MI will see dry conditions and
gradually clearing skies through the evening into early tonight. Only
potential exception is the far eastern Thumb who will reside on the
fringe of any lake effect bands over southern Lake Huron tonight.
Combination of the ongoing cold advection and scattering cloud
promotes a very cold night with areas outside of the lakeshores and
Metro Detroit (who stay in the teens) falling into the single digits.
Morning wind chills hover in the lower single digits with periods
dropping subzero even with the lighter winds under the high.

Arctic high pressure is fully established for Monday bringing a
brief reprieve in the active pattern though not wrt the much below
average temperatures. With the ridge axis not crossing the state
until Monday night, thermal recovery is minimal as daytime highs
Monday only top out in the mid 20s and Monday night lows falling to
lower teens-upper single digits.

A baroclinic zone is set to linger over lower MI through next week
following the departure of high pressure late Monday allowing a
series of clippers to track near or over the region almost everyday
into next weekend. First of these arrives Tuesday morning with model
trends favoring a more southerly track over northern lower MI which
brings associated precip further south offering chances for all of
SE MI. Shift south also puts parent vort max over southern lower MI
resulting in stronger ascent and a higher potential snowfall rates
(towards 0.3"/hr). Fast moving nature of this wave is the main
limiting factor however with this period of enhanced ascent/rates
only occuring over a specific location for 2-3hrs. Should current
trends hold, end result would be another 1-2" type snowfall across
most of SE MI, save for the southern third. Is worth noting, a brief
transition to freezing drizzle at the tail-end of precip late
Tuesday morning is possible with forecast soundings advertising rapid
mid-level drying de-saturating the DGZ and reducing overall ice
nuclei for the still saturated low levels and sub-freezing surface
layer. Given the prior snowfall, light QPF (by that point), and
afternoon temps climbing to around/just over freezing, impacts should
be minimal.

A stronger, more dynamic shortwave is then progged to sweep out of
the northern Plains and directly over southern MI Wednesday. This
current track allows a degree of milder air to be partially advected
into lower MI which would support initial lead snow Tuesday night to
transition to rain-snow mix (northern areas) or all rain (southern
areas) by Wednesday morning. Finer detail on potential snow totals
will depend on the strength of lead ascent Tuesday night, speed at
which the warm front lifts north, and exact track of the low center
determining the northward extent of warmer air/mixed precip, all of
which are too sensitive to be able to speak with certainty on this
far out.

&&

.MARINE...

Cold air rushing into the Central Great Lakes this evening, with the
deepest and coldest air over northern Lake Huron, with 850 MB temps
aob -16 C. Good mixing depths will lead to wind gusts 20-30 knots
over much of Lake Huron before the strong surface high over the
Midwest builds east tonight, reaching the region Monday morning.
Winds veer around to the north tonight will lead to large waves (>4
feet) building over the south Lake Huron basin, and small craft
advisories will continue through 10 AM Monday morning.

Still looking at brief southwest gales possible on Tuesday as low
pressure tracks through the northern Great Lakes. The strongest
winds looking to be over Saginaw Bay/Central Lake Huron. Snow will
likely cause some precip drag, which should help limit the magnitude
and duration of any gales that develop.

A larger and stronger low pressure system is then on track to move
through Lower Michigan Tuesday night into Wednesday producing
widespread snow and even rain over Lake
St. Clair and Lake Erie. The southwest low level jet ahead of the
looks to be very strong, and low level profiles do not appear to
warm quick enough to stabilize the near water surface. Thus, it is
looking like increasing chance of gales of western Lake Erie, with
potential to briefly reach aoa 40 knots.

Rush of cold air behind the passage of the low will then support
strong northwest winds late Wednesday and Wednesday evening.
Isolated, brief gusts to gales will be possible,
but the pressure gradient quickly relaxes by Thursday morning.

&&

.PREV DISCUSSION...
Issued at 1149 AM EST Sun Dec 7 2025

AVIATION...

The region of light snow will exit southeast of the area by 18Z.
Colder and drier air will then advect across Se Mi during the
afternoon within NNW winds of 8 to 15 knots. Model guidance suggests
some lingering and/or redevelopment of MVFR strato cu in the wake of
the region of light snow due to some remnant moisture under the low
level inversion. As cold air deepens during the afternoon/evening,
lifting inversion heights will trend ceilings to VFR. North flow and
continued low level cold and dry air advection is likely to support
partial to full clearing this evening into the overnight.

For DTW...Ongoing radar trends are showing a rapid degrease in snow
coverage and intensity. Nothing more than a few flurries is expected
after 18Z.

DTW THRESHOLD PROBABILITIES...

* High for ceiling at or below 5000 ft today. Low tonight. Moderate
Monday.


&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...Small Craft Advisory until 10 AM EST Monday for LHZ421-441>443.

Lake St Clair...None.
Michigan waters of Lake Erie...None.
&&

$$

DISCUSSION...KDK
MARINE.......SF
AVIATION.....SC


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