Expert Forecast Opinion

903
FXUS63 KDTX 040904
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
404 AM EST Thu Dec 4 2025

.KEY MESSAGES...

- Near record cold conditions today and Friday with wind chills
ranging between -5 and 10F until Friday afternoon.

- Below normal temperatures persist this weekend and into next week.

- The next chances for light snow will be Friday night and Sunday with
only a 10 to 40% chance to exceed 1 inch.

&&

.DISCUSSION...

Longwave troughing over the Great Lakes and NE CONUS is reinforced
by the amplified upper wave passing overhead this morning. Frigid
conditions are settling in this morning with 925mb temps falling to
the -13 to -15C range. Sfc temps in the teens at daybreak will only
recover a few degrees by this afternoon as cold advection continues
through the day. Current forecast highs in the lower 20s will
challenge record low max temps across the area. Persistent northwest
wind around 15 to 20 mph caps wind chills in the single digits.
Meanwhile, post- frontal drying and subsidence will offer increasing
potential for periods of sun for most of the area. The exception
will be the Thumb, downwind of the Superior-Michigan- Saginaw Bay
connection that will likely maintain a degree of lake cloud and some
flurries. Very cold conditions tonight as wind weakens, allowing for
lows in the single digits.

Southwest return flow behind departing high pressure ensues Friday
to boost temperatures slightly, with highs reaching the mid 20s.
However, 15 to 20 mph wind will again keep the wind chill lower in
the teens. The next shortwave in the active pattern passes through
the region Friday night offering the next opportunity for light snow.
The bulk of the ageostrophic response and ascent with the associated
jetlet aloft will be focused north of the area. Guidance is also
lean with moisture depth and there will be a fair amount of low
level dry air to overcome to see measurable snow. Latest guidance
does suggest a light dusting up to an inch possible north of I-69.

The early Saturday period bears monitoring as boundary layer
moisture pools ahead of an inbound cold front, but upper moisture
begins to strip out. Model solutions offer tenuous presence or even
loss of ice nuclei - so patchy freezing drizzle is not out of the
question before the front passes through during the day. This
potential is currently less than 20% for any location. Post-frontal
dry air then brings decreasing potential for any precip during the
evening. The Saturday front brings the next bout of cold air that
extends the below-normal stretch into next week with highs in the
20s and lows in the teens/single digits Sunday and Monday. A
northern stream wave will track through the northern Great Lakes on
Sunday bringing the next opportunity for light snow. Any
accumulations would likely be minor. At this stage moisture depth
doesn`t look to be a concern with this wave and snow should be the
ptype.

High pressure easing directly over the Great Lakes offers benign but
cold weather to start the week. The Tuesday and Wednesday period
remains a focus for a series of waves to track overhead within the
energetic northwest flow around the Hudson Bay upper low. Ensemble
guidance continues to exhibit relatively high agreement for
widespread snowfall, with early system strength and moisture progs
suggestive of potential for several inches during this time period.

&&

.MARINE...

With the cold front now to our east, winds have flipped around to
the northwest across the region ushering an arctic airmass across
the waters. Observations behind the front over Lake Superior show
what was expected thus far with gusts into the low 30 knot range
with sporadic gusts to 35 knots. Winds will peak over the next few
hours and then will start to decrease through the rest of the
morning hours. Small Craft Advisories remain in effect for the Lake
Huron shoreline for winds to 30 knots and increased wave heights.
After weakening to around 20 knots early tonight, 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. Another round of Small Craft Advisories for
Saginaw Bay may be needed and a few gusts to 35 knot gales can`t be
ruled out over northern and central Lake Huron.

&&

.CLIMATE...

The record low max temps for Thursday, December 4th.

Detroit: 23 Degrees (Set in 1895)
Flint: 23 Degrees (Set in 1935)
Saginaw: 22 Degrees (Set in 1991)

The record low min temps for Friday, December 5th.

Detroit: 6 Degrees (Set in 1974)
Flint: 6 Degrees (Set in 1991)
Saginaw: 6 Degrees (Set in 1991)

&&

.PREV DISCUSSION...
Issued at 1158 PM EST Wed Dec 3 2025

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.


&&

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

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

$$

DISCUSSION...TF
MARINE.......DRK
CLIMATE......TF
AVIATION.....CB


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