762
FXUS63 KDTX 132348
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
648 PM EST Sat Dec 13 2025

.KEY MESSAGES...

- Bitter cold temperatures for the weekend into Monday. The coldest
period will be tonight and Sunday morning when actual air
temperatures bottom out at zero to 5F above. Expect wind chills to
range between -15F to -10F by Sunday morning.

- Snow showers along the eastern Thumb shoreline on Sunday with
accumulations of 1 to 2 inches possible.

- A dramatic warmup is forecast Tuesday to Thursday next week with
temps rising over 40 degrees Thursday, setting the stage for rain.

&&

.AVIATION...

A few pockets of MVFR ceilings are holding on this evening along and
north of I-69. Greater clearing is anticipated tonight as clouds try
and scatter out in the 03-07Z window tonight. Very cold airmass
moving across Michigan this morning will allow coverage of lake
clouds to expand tomorrow morning. Ceilings look like they will be
on the border of MVFR and low VFR for tomorrow. Winds will become
gusty out of the northwest to 20-25 knots during the mid morning
through the early afternoon while a few lake effect light snow
showers/flurries also be possible. PTK to MBS is the corridor that
is most likely to see this activity and have introduced a PROB30
group starting shortly after 12Z tomorrow morning. Any snow shower
activity should end mid afternoon. Winds ease towards the late
afternoon and early evening.

For DTW...Low clouds have become scattered across DTW this evening
and expect this to hold through tonight. BKN to OVC ceilings expand
across metro by late tomorrow morning/early afternoon supported by
the very cold airmass. May see occasional flurries, but chances too
low to include mention at this time.

DTW THRESHOLD PROBABILITIES...

*   Low in ceilings below 5000 feet tonight, Medium tomorrow morning
    and afternoon.

&&

.PREV DISCUSSION...
Issued at 347 PM EST Sat Dec 13 2025

DISCUSSION...

A shortwave pivoting around the base of the upper low sinking into
the northern Great Lakes is driving a region of frontal ascent and
widespread snow across the Ohio Valley this afternoon. The high-
based northern reach of the snow shield is currently pivoting along
the stateline where up to a dusting of accumulation will be possible
before light snow tapers off this evening. 925mb temps are analyzed
at -14 to -16C and will continue to fall toward -18C through tonight
as a surge of Arctic air overtakes the Great Lakes. The cold
advection will keep the gradient wind active and prevent the surface
layer from fully decoupling, resulting in lows between 0 and 5F
Sunday morning. With the persistent wind around 10 to 15 mph, wind
chill dips as low as -10 to -15F for a few hours overnight.

The core of the coldest air will pass to the south Sunday morning
with temperatures rebounding into the lower 20s by Sunday afternoon,
though wind chills will remain very cold in the single digits. DCVA
attendant to the inbound upper low sends a surface trough north to
south across the state during the morning. Models show enough
shallow ascent and supersaturation along this feature to warrant 20-
30% PoPs north of M-59. Just a dusting of fluffy accumulation is
favored with this activity. Included a localized 40-60% PoP along
the eastern shoreline of the Thumb where there is moderate
confidence in the trough sending the Lake Huron convergence
axis/snow band inland during the day. If this occurs, snow
accumulation of 1 to 2 inches is likely there. Another cold night
Sunday night with lows around 10F and wind chill near 0F.

The next shortwave passes overhead on Monday within energetic
northwest flow, with model trends over the past 24 hours showing a
southwestward shift in forcing, sufficient for light snowfall mainly
during the morning. Highest PoPs are over northern and eastern areas
where the wave and isentropic ascent engage with the NNW-SSE
oriented elevated frontal slope. There are some differences among
guidance regarding strength of 700-850mb flow/warming, which will
affect the depth/integrity of the DGZ and resultant SLRs.
Accumulations on the order of 1 to 2 inches in the Thumb and a
dusting elsewhere are supported by the bulk of ensemble guidance.
Despite rising temps aloft, the low-level thermal trough looks to be
locked in place Monday with highs still struggling to break 20F.

A substantial warming trend ensues Tuesday into Thursday as
pervasive eastern North America troughing gives way to zonal flow
aloft. The next shortwave tracks over the northern Great Lakes early
Wednesday, sending a surface low well north of SE MI and inducing a
strong positive thickness trend Tuesday into Tuesday night. A
trailing cold front passes through on Wednesday offering a very low
chance for showers and only weak and short-lived cold advection. A
stronger low dropping in from the Canadian Prairie then produces an
even stronger warm advective response with high confidence in temps
into the 40s on Thursday. Widespread showers are likely to accompany
this system.

MARINE...

The arctic front is now east of the area which has let the cold air
begin to filter into the region through the day. The coldest of the
arctic air will arrive overnight into Sunday morning with a
secondary front turning winds a bit more to the northwest from west.
Wind speeds will continue to be in the mid 20 knot range with gusts
up to around 30 knots. The northwesterly flow will push the higher
waves along the Lake Huron shoreline of the Thumb resulting in Small
Craft Advisories the rest of the day through Sunday night. The cold
airmass and elevated winds will also lead to potential snow squalls
and freezing spray as well during this time. Monday will again
feature elevated wind speeds as the next system tracking through
southern Canada runs up against a high pressure system centered over
much of the eastern conus. The tightening of the prefrontal gradient
along with cold unstable air will lead to another period of wind
gusts nearing gale force. Currently there is a large spread in the
model guidance solutions as to what max gusts will be achievable but
several hours of gales may be possible Monday afternoon.

CLIMATE...

The record low min temps for Sunday, December 14th.

Detroit:  -1 Degrees (Set in 1914)
Flint:     0 Degrees (Set in 1944)
Saginaw:  -7 Degrees (Set in 1917)

&&

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

     Small Craft Advisory from 7 AM Sunday to 4 AM EST Monday for LHZ442-
     443.

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

$$

AVIATION.....AA
DISCUSSION...TF
MARINE.......DRK
CLIMATE......SF


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