887
FXUS63 KDTX 021332
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
832 AM EST Tue Dec 2 2025

.KEY MESSAGES...

- Temperatures will remain well below normal throughout the week.
The coldest conditions arrive Thursday and Friday with wind chill
values bottoming out at or below zero.

- Arctic front will bring the potential for snow showers late
Wednesday, with some minor accumulation possible.

&&

.UPDATE...

Lingering synoptic snowfall has largely ended across Se Mi. There
continues to be some fog across the Saginaw Valley and northern thumb
region. Weak flow and a low December sun angle with snow cover
supports the current forecast in maintaining fog across the northern
sections of the forecast area through the rest of the morning.
Developing westerly flow this afternoon and a lowering subsidence
inversion suggests the upstream cloud cover will slowly filter back
into Se Mi during the afternoon and evening. There will be still be
peaks of sun within an overall variably cloud day.

&&

.PREV DISCUSSION...
Issued at 600 AM EST Tue Dec 2 2025

AVIATION...

Light snow near Detroit comes to an end over the next 1 to 2 hours
as Ohio Valley low pressure passes east and high pressure begins to
ease in from the west. The pressure gradient will remain weak this
morning, keeping abundant low level moisture in place. An area of
LIFR fog/stratus is likely to linger across the Saginaw Valley while
MVFR visibility in mist lingers elsewhere. Weak flow then begins to
organize out of the west to southwest this afternoon, allowing any
visibility restrictions to mix out. Ceilings will be variable and
carry a high amount of uncertainty today, but overall MVFR stratus
is the dominant signal in model guidance. May see some periods of
VFR at times this morning and afternoon. Predominant MVFR is favored
overnight.

For DTW...Snow exits east early in the forecast with MVFR conditions
likely through mid morning. Low confidence on timing of any periods
of VFR today.

DTW THRESHOLD PROBABILITIES...

* High for ceiling at or below 5000 ft through the forecast.

* High for precipitation type as snow this morning.

PREV DISCUSSION...
Issued at 300 AM EST Tue Dec 2 2025

DISCUSSION...

Area of light accumulating snow impacting mainly areas from M-59
southward early this morning on pace to vacate from west to east
over the next 2-4 hours. Trailing lower amplitude mid level trough
will track through during the morning period. Satellite trends
confirm recent sounding data in maintaining a higher degree of low
level saturation anchored to this feature beneath a strengthening
inversion. Shallow convective depth with neutral thermal advection
suggests limited potential for additional snow shower or flurry
activity going forward today. Given no meaningful adjustment in the
resident thermal profile, expectation remains for highs to arrive
around 30 degrees again today. Forecast will remain pessimistic on
cloud cover into tonight, noting greater likelihood for emerging
westerly flow to draw the residual lake Michigan moist plume back
into the area. A few inconsequential flurries around as moisture
depth improves. Magnitude of this cold airmass will again support
lows in the teens many locations despite a lower probability of
witnessing open sky.

Polar low anchored over Hudson Bay will remain influential in local
conditions through the latter half of the week. Stronger vorticity
lobe pivoting through the cyclonic periphery will dig southeast and
across the great lakes Wednesday night. Brisk conditions develop
Wednesday as the southwest gradient strengthens ahead of the inbound
attendant arctic front. Gust potential muted by low inversion
heights as modest warming commences atop the shallow mixed layer.
Probability of snow showers will increase from northwest to
southeast from late afternoon into the evening hours, focused
primarily along the advancing convergence axis. Accumulation
potential from a dusting to half inch. Greater signal for snow
squall potential remains to the north and across lake Huron based on
projection of low level cape and fgen collocated with the stronger
frontal convergence. With that, a few bursts of higher intensity
snow showers will remain possible through this time.

High magnitude cold defined by temperature readings near 20 degrees
below average will mark the Thursday and Friday periods as the
arctic airmass takes firm residence. This will translate into single
digit wind chill during the daylight hours, with a minimum in wind
chill sub-zero for many locations both Thursday and Friday mornings.
Little change in the overall pattern ensures well below average cold
sticks around this weekend and likely well into the following week.
A series of shortwaves cascading over the prevalent central Pacific
ridge will dive into the mean trough. Pattern still subject to
higher degrees of uncertainty in time and space for defining
additional snowfall chances as these waves migrate downstream from
Friday night onward. Assessment of recent ensemble guidance points
to lower end but equal chances for meaningful forcing to enter the
area anytime within the Friday night through Monday window. Synoptic
scale moisture quality will remain on the lean side given the
Pacific origin within a predominant mid level west-northwest flow.
Forecast will continue to simply highlight a broader, low chance
with further refinement likely as greater consensus on track and
magnitude materialize with time.

MARINE...

High pressure will continue to push off towards the New England
region with lighter winds prevailing over Southern portions of the
Great Lakes. Over the northern Great Lakes, persistent southwest
flow will continue as a broad low pressure system continues to
reside over the Hudson Bay region. Next significant system arrives
Wednesday as a strong arctic cold front drops out of northern
Ontario resulting in both strong preceding southwest winds and
trailing northwesterly winds as the coldest air of the season thus
far moves over the Great Lakes. Limited potential for a brief period
of gales within the southwest flow Wednesday precludes a gale watch
at this time. Increasing wave action will bring an extended period
of small craft conditions across Saginaw Bay and the nearshore
waters of Lake Huron

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...Small Craft Advisory from 9 PM this evening to 4 PM EST Thursday
     for LHZ421-422-441.

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

$$

UPDATE.......SC
AVIATION.....TF
DISCUSSION...MR
MARINE.......SS


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