021
FXUS63 KDTX 251200
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
700 AM EST Tue Nov 25 2025

.KEY MESSAGES...

- Rain showers fill in across southern Lower Michigan during the
  morning and continue this afternoon until diminishing this evening.

- Passage of a strong cold front is on schedule for Wednesday
  morning. Westerly wind gusts of 35 to 40 mph are expected, with a
  chance of gusts around 45 mph by afternoon.

- The strong wind gusts continue Wednesday night into Thanksgiving
  day while also bringing a surge of colder temperatures. Wind chill
  in the teens is expected by Thanksgiving morning.

- Lake effect snow showers ramp up Wednesday night through
  Thanksgiving Day and linger into Thursday night. Travel will likely
  be affected by highly variable accumulation ranging from a half
  inch to around 2 inches.

- Snow showers diminish during Friday while cold air remains
  entrenched across the region.

&&

.AVIATION...

Low pressure over IL at sunrise moves across southern Lower Mi today
with a pattern of rain showers and deteriorating sky condition. An
abrupt drop of ceiling into LIFR across the SE Mi terminal corridor
is supported by observations upstream across the Midwest as of
forecast issuance this morning. The low clouds spread eastward and
then persist tonight even as rain mostly ends and the low pressure
center shifts eastward. The departing low leaves behind a mild and
moisture laden air mass within a diffuse surface pressure trough.
Nightfall and associated boundary layer cooling leads to a further
drop in visibility which then recovers late tonight as SW gradient
wind increases ahead of the powerful cold front due along the
terminal corridor by 12Z Wednesday.

For DTW... A rapid decrease in ceiling is on schedule to occur
during the late morning as rain showers increase coverage and
intensity across the area. Once in place, these conditions persist
through much of tonight.

DTW THRESHOLD PROBABILITIES...

* High for ceiling 5000 feet or less today and tonight.

* Low for ceiling below 200 ft or visibility below 1/2 sm this
  afternoon and tonight.

&&

.PREV DISCUSSION...
Issued at 403 AM EST Tue Nov 25 2025

DISCUSSION...

A few early morning pockets of sprinkles with temperatures in the
lower to mid 40s lead up to the rain event that is otherwise on
schedule for SE Mi today. The latest satellite and radar depictions
indicate the governing Mid MS valley short wave shearing
aggressively into the southern Great Lakes while forcing a plume of
moisture transport out ahead of its path. Showers spread SW to NE
across southern Lower Mi on the lead flank of DCVA and within the
northern fringe of the 850-700 mb theta-e ridge resulting in peak
coverage across SE Mi during the late morning and early afternoon.
The pattern gradually shifts eastward late in the day as the surface
pressure reflection occludes while grazing the area and the shifting
into Ontario by evening. Average rainfall totals hold around 0.25
inch with higher amounts located farther south/east in the upper
Ohio valley to mid Appalachians where peak low level jet driven
theta-e advection occurs with a boost from both the short wave and
favorable alignment of the upper jet.

Today`s system leaves behind a mild and moisture laden air mass
within a diffuse surface pressure trough tonight. It supports low
clouds, patchy drizzle, and fog as temperatures hover in the 40s
across SE Mi. There is also the chance for a stray rain shower as
the surface trough connects to the rapidly developing upper Midwest
low pressure system which remains on schedule to send a powerful
cold front across Lower Mi late tonight and Wednesday morning. Model
trends on this system show a slight southward adjustment on the
surface low center under a stronger negatively tilted 500 mb trough,
but remain rock solid on the frontal timing and strength across
Lower Mi. A broken line of rain showers sweep across the area with
the front and both the showers and wind shift could produce a pop of
40 mph wind gusts while moving rapidly across the area. The front is
followed by a textbook dry slot and low level thermal trough driving
across Lower Mi that organizes and longer duration wind concern
later in the day. Advisory level wind gusts are the primary concern
as strong downward momentum transport is set to occur within the
increasing wind field as the system strongly occludes to the north.
A survey of model soundings support the areal coverage detail in the
HREF mean 10 m wind gusts that show speed reaching toward 45 mph
first toward the Ohio border during the afternoon. Stronger winds
spread northward late in the day and Wednesday evening as the
gradient reorients into NW flow with eastward track of the surface
low center east of Lake Superior.

Strong wind gusts continue across the area Wednesday night while the
focus also shifts to continued refinement of lake effect snow
potential. While the wind ramps up, the temperature steadily drops
Wednesday afternoon on a pace for scattered rain showers becoming
mixed with snow showers late afternoon, and then all snow showers by
evening as freezing level drops and surface temperature falls into
the lower to mid 30s by sunset. Greater availability of hi-res model
data supports bulk wind, temperature, and RH fields in regional
models that focus on the I-94 corridor for the initial lake effect
activity. The higher wind speed and convective depth near 700 mb in
model soundings add confidence to expectations for coverage and
intensity capable of the initial 2 inch accumulation targets in the
going forecast Wednesday night into Thanksgiving morning with a
chance of travel impacts.

Thanksgiving Day conditions provide just incremental relief from the
wind while temperatures hover in the 30s with wind chill mainly in
the teens. Wind turning toward the NW with some mid level subsidence
drying around the west flank of the upper level low shifts greater
lake effect coverage from the I-94 corridor toward the Ohio border
while also shrinking coverage back toward Lake Michigan. The wind
trend refocuses lake effect potential toward the Thumb and Tri
Cities, especially if Lake Superior connection can be maintained.
Moisture quality then becomes an issue Thursday night as the parent
low pressure system migrates eastward, and stronger synoptic scale
subsidence brings an end to this lake effect event by Friday. The
lake effect diminishes, however winter weather conditions remain
active during the weekend as cold air remains entrenched ahead of
the next low pressure system. This system will be capable of another
round of snow accumulation Saturday and Sunday.

MARINE...

Southerly wind remains on the order of 10 kt today while backing to
the southeast as weak low pressure tracks into the southern Great
Lakes. An area of rain will accompany this system through the day.

A second, stronger low pressure system arrives from the Midwest
tonight, deepening considerably as it tracks across the northern
Great Lakes Wednesday into Wednesday night. This system will be
responsible for a long duration gale event and the arrival of the
coldest air of the season so far. A strong cold front will sweep
across the central lakes Wednesday morning with WSW gales in its
wake, then a secondary cold front will shift winds to WNW to NW by
Thursday into Friday. There is high confidence in gales during this
period and a Gale Watch remains in effect for all marine zones. The
peak of the event is expected Wednesday afternoon into Wednesday
night with sustained gales across most of the region. Gusts during
this period are forecast to occasionally reach 40 to 45 kt across
southern and central Lake Huron, including Saginaw Bay. Gales may be
slow to start across northern Lake Huron during the day Wednesday as
the center of the low tracks in the vicinity, but NW winds will
increase rapidly there Wednesday night after the low passes. 35 to
40 kt gales will continue through Thursday.

Rain showers on Wednesday change over to snow late in the day with
snow squalls likely on Thursday. 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 arrive by Sunday.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...None.

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.

Lake St Clair...Gale Warning from 7 AM Wednesday to 1 AM EST Friday for LCZ460.

Michigan waters of Lake Erie...Gale Warning from 7 AM Wednesday to 1 AM EST Friday for LEZ444.

&&

$$

AVIATION.....BT
DISCUSSION...BT
MARINE.......TF


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