964
FXUS63 KDTX 030914
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
414 AM EST Wed Dec 3 2025

.KEY MESSAGES...

- Temperatures will remain well below normal throughout the week.
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 under an inch.

&&

.DISCUSSION...

Persistent anomalous upper troughing over Hudson Bay will maintain
influence over the Great Lakes this forecast period, with prolonged
well below normal temperatures expected through the rest of the week
and into next week. A lobe of vorticity will swing around the upper
low tonight, sending a reinforcing shot of arctic air across the
region behind a strong cold front. Ahead of the front, brisk
southwest flow will develop today as a LLJ passes overhead. The warm
air advection associated with this jet will remain elevated and the
resultant 15-25mph breeze will hold wind chills in the teens and
lower 20s today even as temperatures peak in the lower 30s.

The front will reach the Saginaw Valley in the afternoon and track
southeast through the evening hours. Model guidance continues to be
very lean on QPF as there will be a lot of mid-level dry air to
overcome before deeper saturation occurs, and most of the inbound
sfc-700mb moisture will be pooling out ahead of the front where
ascent is disorganized and shallow. A few light pre-frontal snow
showers or flurries will be possible, then a quick round of trailing
post-frontal snow showers follows later this evening as a brief
intersection of steepening low-level lapse rates, boundary layer
moisture, and frontal forcing occurs. A few hi-res runs produce
around 30-50 J/KG of SBCAPE in the Saginaw Valley which would
support a brief heavier burst of snow as a higher end scenario, but
the overwhelming model signal is for a muted response with these
showers. A dusting to a half inch of accumulation will be the most
likely outcome through tonight. Additional flurries may continue
overnight as the inbound cold air mass sends the DGZ down into the
boundary layer with any lingering clouds capable of producing a few
flakes.

Strong cold advection will keep the boundary layer well mixed
tonight with northwest wind of 10-15mph sending wind chill below
zero Thursday morning as temps plummet into the teens. High pressure
spreading across the southern lakes will ease the wind and bring
some sunshine on Thursday, but 925mb temps bottoming out near -14C
will maintain biting cold conditions with highs topping out near 20.
This is some 20 degrees below average highs and actually lower than
our average lows for early December. The degree of dry air will hold
any lake effect close to Lake Michigan and out of the local area.

The next lobe of arctic PV is slated to pivot across northern
Ontario Friday night, sending a cold front across the northern lakes
on Saturday. Ahead of this front, flow emerges once again out of the
southwest which will force the thermal trough away and offer a
warming trend from Friday into Saturday. A weak shortwave passing
across the Great Lakes Friday night will bring a slight chance of
snow, but the deeper moisture and ascent with this wave will be
focused north of the local area. The trailing portion of the front
will pass through later this weekend keeping below normal temps
around well into next week. The upper pattern holds a stronger jet
across the SE CONUS which leaves the Great Lakes in a relative lull
pattern void of stronger systems. Ensemble guidance breaks down this
pattern and brings in a more active storm track during the middle of
next week.

&&

.MARINE...

High pressure will finish sliding to the east coast today with the
next system set to move through today. Strong southwesterly winds
ahead of a cold front will have gusts reaching 25 to 30 knots into
the afternoon across central Lake Huron. A Small Craft Advisory is
in effect for Sagainw Bay and around to Harbor Beach for these
winds. A strong low pressure system over Hudson Bay will send the
cold front through this afternoon into the evening with very cold
arctic air entering the region in the wake of the front. The front
will flip the winds around to the northwest while the arctic air
increases the winds gusts of 30 to 35 knots possible Thursday
morning. Most guidance still offers little support for wind gusts to
reach gales for any notable amount of time during this period so
will continue to hold off on any gale headlines and mention the
potential for a few gusts to gales instead.

&&

.PREV DISCUSSION...
Issued at 1150 PM EST Tue Dec 2 2025

AVIATION...

Large scale forcing supports shortwave ridging aloft and high
pressure at the surface tonight across Southeast Michigan. Forecast
soundings continue to suggest a substantial lowering of the
inversion with time tonight which helps to dry the lower troposphere
out. Extensive MVFR stratus deck has been slow to move north and
east into the Detroit terminals this evening. Flow will eventually
become more organized out of the southwest which will help advect
moisture below the inversion and cloud to the northeast into all of
the taf sites. Developing pseudo warm sector ahead of the cold front
should aid in a lifting ceiling and breaks Wednesday. The potential
does exist for scattered snow showers along the cold front 21z-02Z
Wednesday. Included a TEMPO at all taf sites for snow showers. MVFR
ceilings are expected Wednesday night.

For DTW...Expecting prevailing MVFR ceilings to develop and then
hold through the morning. Warm sector development will support VFR
ceilings Wednesday. Maintained MVFR snow shower potential after 23z
Wednesday.
DTW THRESHOLD PROBABILITIES...

* High for ceiling at or below 5000 ft tonight and Wednesday.


&&

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

     Small Craft Advisory from 10 PM this evening to 4 PM EST Thursday
     for LHZ442-443.

Lake St Clair...None.
Michigan waters of Lake Erie...Low Water Advisory from 10 AM this morning to 10 PM EST this
     evening for LEZ444.

&&

$$

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


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