537
FXUS63 KDTX 040458
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1158 PM EST Wed Dec 3 2025

.KEY MESSAGES...

- Temperatures will remain well below normal Thursday through the
weekend. The coldest conditions arrive Thursday and Friday mornings
with wind chill values bottoming out near or below zero.

- Arctic front will bring scattered snow showers this afternoon and
evening, with accumulations from a dusting to a half inch. Some
patchy freezing drizzle is possible early this evening.

&&

.AVIATION...

The cold front is timed to push south of the Detroit terminals
between 5-6z this evening. There could be some isolated snow shower
activity immediately behind the front as convergence and initial
cold advection leads to steeper lapse rates. However, models are
adamant in dry advection within the lowest 4.0 kft agl behind the
cold front. This will result in improving conditions with flight
categories improving to VFR. West winds will veer to the northwest
and gust up to 20 knots overnight. There is lower confidence that
skies will clear out late tonight with moisture fluxing off the
Great Lakes upstream. Boundary layer growth on Thursday should
continue to help sky conditions with some breaks anticipated after
19z.

For DTW...VFR conditions developing after the cold front pushes
southward with just an isolated brief snow shower possible.

DTW THRESHOLD PROBABILITIES...

* High for ceiling at or below 5000 ft through tonight. Low after
  18Z Thursday.

&&

.PREV DISCUSSION...
Issued at 907 PM EST Wed Dec 3 2025

UPDATE...

Satellite and radar trends suggest that midlevel moisture between 5.0
and 12.0 kft agl is now peeling eastward away from Southeast
Michigan. This is expected to cease the seeder-feeder mechanism,
largely ending the widespread light snowfall observed over much of
Southeast Michigan this evening. The potential does exist for a few
isolated snow showers as cold advection begins behind a surface cold
front. The wind shift is now just north of the Tri Cities and will
settle southward through 5z.

PREV DISCUSSION...
Issued at 320 PM EST Wed Dec 3 2025

DISCUSSION...

The much advertised arctic cold front is now moving across nrn Lower
Mi. Aggressive mid level height falls preceding the mid level trough
over nrn Ontario will continue to drive the front southward, taking
it across Se Mi during the first half of tonight. Radar/satellite
composite indicate mid/upper level moisture advancing into the srn
portions of the area from the southwest. The front is also picking
up some added low level moisture from Lake Michigan. The moisture
off Lake Michigan has been quite shallow, resulting in some freezing
drizzle reports to the west. Rap soundings suggest moisture depth
increasing to the level for ice nucleation during the late
afternoon. This should mitigate freezing drizzle over Se Mi. The
exception to this will be across the Saginaw Valley to perhaps the
northern portions of the Flint/Owosso areas where mid level moisture
will be a little leaner.

The expected brevity of adequate moisture depth and relatively weak
and shallow low level frontal forcing will keep accumulations with
any late afternoon/evening snow showers to less than a half inch.
Post frontal arctic air will arrive overnight within gusty northwest
winds, with model soundings showing 20 knots within the mixed layer.
925mb temps are forecast to plunge to -13 to -15C by Thurs morning,
with 850mb temps of -20C across the thumb. This will drop sfc temps
into the teens and low 20s by Thurs morning, with minimal rebound in
afternoon temps. The gusty winds will hold wind chill readings in
the single digits through the day.

High pressure will expand across the srn lakes on Thursday beneath
respectable large scale subsidence courtesy of mid level
anticyclonic vorticity advection. The subsidence and more shallow
layer of arctic air into the southern lakes will keep inversion
heights low. This and the very dry will will inhibit any lake effect
activity into Se Mi Thursday. The low level flow will back southwest
Thurs night into Friday within the return flow of the departing sfc
high. Low level warm air advection will bring temps into the upper
20s Friday afternoon. A solid 20 knots within the shallow mixed
layer will however keep afternoon wind chills in the teens. A weak
short wave impulse forecast to rotate across the northern lakes Fri
night into Saturday will drive another cold front across Se Mi
Saturday, offering a slight reinforcing shot of cold air by Sunday.
Continued limited moisture and weak forcing supports nothing more
than low chance type pops with the front.

Although there is considerable timing variability, the medium range
model suite suggest at least a couple short wave impulses
originating from the Gulf of Alaska and tracking along the baroclinic
zone over the Great Lakes in the Tues to Wednesday time frame next
week. These features will provide the next chance for more
widespread snowfall.

MARINE...

A strong low pressure system well to the north over Hudson Bay is
pulling a cold front through the Great Lakes this afternoon and
evening. Observations ahead of the front, currently passing through
the straits at press time, are showing gusts up to around 30 knots
in the southwesterly flow. There will be a brief weakening of the
wind field as the front passes before winds quickly ramp back up
from the northwest for tonight into Thursday as high pressure ushers
in possibly the coldest arctic airmasses of the season thus far.
Guidance has been consistent with showing gusts reaching 30 to 35
knots Thursday morning. With upstream observations over Superior
slow to ramp up and consistency of the forecast to hold gusts just
below gales, will continue to mention a few gusts to gales and hold
off on a headline.  Small Craft Advisories are in effect for the
Lake Huron shoreline for winds to 30 knots and increased wave
heights. Looking ahead, there will be another round of increased
southwesterly winds on Friday ahead of the next system passing
through Ontario with the cold front swinging through early Saturday.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...Small Craft Advisory until 4 PM EST Thursday for LHZ421-422-441>443.

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

$$

AVIATION.....CB
UPDATE.......CB
DISCUSSION...SC
MARINE.......DRK


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at www.weather.gov/detroit.