661
FXUS63 KDTX 252021
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
321 PM EST Tue Nov 25 2025

.KEY MESSAGES...

- A Wind Advisory is in effect from 10AM Wednesday to 4AM Thursday.

-  Sustained southwest turning west winds of 20 to 30 mph with gusts
40 to 45 mph expected.

- Lake effect snow showers ramp up Wednesday evening through
Thanksgiving Day and will linger into Thursday night. Snowfall
accumulation totals will be highly variable across SE MI, ranging
from a half inch, up to 3 inches.

- Wind chills drop into the teens Thursday morning and only increases
  into the 20s by Thursday afternoon.

&&

.DISCUSSION...

For the remainder of the evening... Widespread stratus with periodic
pockets of drizzle/mist will persist noting RH aoa 95% through
700mb. Moisture depths truncate into the overnight period but 0-1km
RH will continue to support overcast skies, periodic drizzle, and
patchy fog. Copious cloud cover will help mute and diurnal
temperature response overnight, holding overnight lows in the mid 40s
overnight. Attention will then quickly turn to the next low pressure
system, progged to travel over and strengthen across the northern
Great Lakes tomorrow morning and afternoon, which will bring windy
conditions, accumulating snowfall potential/holiday travel impacts,
and wind chills in the teens, centered tomorrow afternoon through
early Friday morning.

Water vapor imagery highlights the strong upper-level wave now
leaving the Dakotas and the subsequent low pressure system just
downstream of the wave. Both features will path through the Midwest
and will arrive over the Great Lakes by tomorrow morning, with the
center of the low moving across the Straights. As the shortwave digs
into the Midwest, the developing trough will deepens and take on a
negative tilt and will initially push a strong cold front across SE
MI from roughly 11Z-15Z. This will maintain a line of broken showers
that will be capable of producing wind gusts up to 40 mph through
the mid to late morning hours.

Within the wake of the front, a dry slot will move in, bringing a
brief period of dry conditions. Cold air advection will also boost
mixing depths while a strong 50 knots wind field builds in over the
greater portion of southern Michigan, all while broader subsidence
increases. This will bring for efficient downward momentum transfer,
producing wind gusts on the order of 40 to 45 mph through the day,
initially across the northern Ohio Valley and southern Michigan by
the late morning hours, and expanding northward through the remainder
of the cwa into the afternoon and evening hours as the
aforementioned low strengthens and then occludes. A Wind Advisory is
now in effect for all of SE MI from 10AM tomorrow until 4AM Thursday.

Wrap around moisture from the departing low and strong moisture flux
off of Lake Michigan will then assist in the development and
advection of lake effect snow showers starting in the late afternoon
hours. Despite temperatures in the mid-30s with the onset of any
precipitation, this synoptic setup characterized by strong cyclonic
flow and under the greater trough with stronger pva tends to
increase fall velocity and reduce residence time, easily overcoming
the shallow above freezing temperatures. As temperatures drop to and
below freezing late tomorrow night into Thursday morning, this
ensures all snow as the p-type. Snowfall totals will be highly
variable pending where and snow banding or repeated snow showers set
up, ranging between a half inch up to 3 inches. Two locations of
interest for these higher end amounts will be around I-696 down to
or south of I-94, aligned where better convergence and potential
instability resides. A secondary area of interest will be portions
of the northern Tri-Cities into the Thumb, where banding or
convectively enhanced snow showers could clip, mostly derived from
the northern Lake Michigan basin. Even for locations that experience
lower-end snow amounts, residual moisture on untreated roadways has
the potential to freeze as temperatures drop below freezing Thursday
morning. Last, cold temperatures and windy conditions drop wind
chills in the teens Thursday morning.

Thursday afternoon and evening again brings continued snow chances,
and while convergent signals are not as robust, latest model output
suggests along or south of I-94 as a potential spot for renewed
accumulation up to an inch, along with the northern Thumb.
Regardless, 0-3 km lapse rates will be strong across the cwa during
daylight hours, bringing the chance for snow shower potential through
the day. Windy conditions continue Thursday with gusts around 40
mph, bringing wind chills in the 20s by the day and back down into
the teens into Friday morning. Subsidence increases through the day
Friday, ending lake effect snow chances.

Active conditions look to continue into the weekend as low pressure
develops and moves into the Great Lakes late Saturday into Sunday
morning. Ensembles show moderate to strong convergence regarding the
track of the low, but uncertainties still exist surrounding the
degree of warm advection and forcing, which have implications on p-
type/snow amounts/snow ratios. Regardless, accumulating snow
potential across the Great Lakes region is looking increasingly
likely to end the holiday weekend.

&&

.MARINE...

Strong low pressure brings deteriorating marine conditions across
the Great Lakes tonight into the late week period. The center of the
system will track across the Straits near peak strength Wednesday
evening before continuing into Ontario/Quebec and pulling an arctic
air mass into the region. A strong cold front will sweep across the
region early Wednesday with long duration of gales expected
Wednesday through Thursday and into early Friday for some areas.
Gale Warnings are in effect for all marine zones through the period,
and Low Water Advisories are in effect for western Lake Erie and
inner Saginaw Bay during the peak of the event Wednesday into
Wednesday night.

The strongest gusts are expected across Saginaw Bay and
central/southern Lake Huron Wednesday afternoon through Thursday,
peaking between 40 and 45 kt. The gales will be from the SW behind
the Wednesday cold front, then gradually veer to W early Thursday
and NW Thursday evening. There is high confidence for gales during
this period and low probability for gusts to storm force.

For Lake St. Clair and western Lake Erie, SW gales are expected in
the wake of the front by midday Wednesday, reaching a peak near 40
kt through the evening and overnight. Wind direction gradually veers
to W on Thursday while gales slowly subside.

For northern Lake Huron, gales will be relatively slower to start as
a weaker gradient exists with the center of the low passing in the
vicinity. However, NW wind will quickly ramp up Wednesday evening as
the low departs and NW gales of 35 to 40 kt are expected there
through the day Thursday.

Rain showers will change over to snow showers Wednesday evening and
snow squalls are likely through Thursday into Thursday night. Gales
gradually subside on Friday but wind remains gusty out of the
northwest with additional snow showers. Winds weaken further on
Saturday as narrow high pressure works in ahead of the next system
set to track through on Sunday.

&&

.PREV DISCUSSION...
Issued at 1129 AM EST Tue Nov 25 2025

AVIATION...

The ongoing influx of low level moisture is driving ceilings down to
IFR and LIFR. The region of higher intensity rain will largely lift
northeast of terminals around or shortly after 18Z as mid level dry
air overspreads srn Lower Mi. However, continued low level moisture
advection will sustain areas of drizzle into the evening. Upstream
observations are supportive of LIFR conditions during much of the
afternoon and evening hours. Southerly flow will increase during the
night, adding some subtle mixing to the boundary layer. This will
likely trend conditions to prevailing IFR. A strong cold front will
traverse the terminals around 12Z. A line of showers, shallow
convection, will accompany the frontal passage. Strong post frontal
cold air advection within a strengthening low level wind field will
result in post frontal wind gusts over 30 knots by late Wed morning.

For DTW...Upstream observations are supportive prevailing IFR and
LIFR conditions in drizzle into late evening. The cold front is
forecast move across metro around 12Z Wednesday. A rapid increase
in SW winds is forecast thereafter.

DTW THRESHOLD PROBABILITIES...

* High for ceiling 5000 feet or less this afternoon through
  Wednesday afternoon.

* Low for ceiling below 200 ft or visibility below 1/2 sm this
  evening.

* Moderate for precip as snow Wednesday afternoon.


&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...Wind Advisory from 10 AM Wednesday to 4 AM EST Thursday for
     MIZ047>049-053>055-060>063-068>070-075-076-082-083.

Lake Huron...Gale Warning from noon Wednesday to 7 AM EST Friday for LHZ361-362.

     Gale Warning from 7 AM Wednesday to 10 AM EST Friday for LHZ363-421-
     422-441>443-462>464.

     Low Water Advisory from 7 AM Wednesday to midnight EST Wednesday
     night for LHZ422.

Lake St Clair...Gale Warning from 7 AM Wednesday to 4 AM EST Friday for LCZ460.

Michigan waters of Lake Erie...Gale Warning from 7 AM Wednesday to 4 AM EST Friday for LEZ444.

     Low Water Advisory from 7 AM Wednesday to 4 AM EST Friday for
     LEZ444.

&&

$$

DISCUSSION...AM
MARINE.......TF
AVIATION.....SC


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