555
FXUS63 KDTX 160803
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
303 AM EST Sun Nov 16 2025

.KEY MESSAGES...

- Colder and brisk today. Wind gusts in excess of 30 MPH at times.

- There is a chance for rain and snow on Tuesday, mainly south of
the I 69 corridor.

&&

.DISCUSSION...

Deep layer northwest flow will sustain cold air advection across Se
Mi into the afternoon. A mid level axis of positive vorticity will
cross Lower Mi early this morning, an extension of a developing mid
level low forecast to race into nrn New England today. Mid level
confluence in the wake of this feature will support broad subsidence
in the mid levels across Lower Mi today. The degree of cold air now
advecting across the lakes, with 850mb temps plunging into the
negative single digits, will activate the lake effect. There is a
strong signal among the 00Z suite in showing an impressive dominate
mid Lake Huron band. The northwest flow will keep this well offshore
of the thumb. However, some Lake Mi preconditioning should support
scattered snow showers off Saginaw Bay and into portions of the
thumb considering equilibrium levels are projected to rise above 8k
feet. This will remain supportive of scattered snow showers with
little accumulations expected given the short fetch off the bay.
Mixing depths through the day will be quite good (around 6k feet)
within the sustained cold air advection. This will keep daytime
temps largely in the 40s while winds of 25 to 30 knots will reside
well within the mixed layer, leading to rather brisk conditions.

Mid level subsidence will hold through Monday. While the lake
instability will support occasional clouds, the degree of dry air
will certainly open the door to intervals of clearing. A continued
northwest gradient through tonight will limit nocturnal cooling,
however the ambient airmass will be so cold and dry that temps will
still drop into the mid/upper 20s. The subsidence will suppress
mixing depths a little more Monday, which will hold afternoon
highs around 40 to the low 40s.

A compact mid level low forecast to emerge from the lee of the
central Rockies Monday is shown to dampen as it translates across
the nrn Ohio Valley and srn Great Lakes within the mid level
confluence. There is a strong mid level fgen signal among the 00Z
model suite forecast to track across srn Lower Mi, aided by left
exit region upper jet support. North of the mid level frontal
circulation, the degree of deep layer dry air suggests a fairly
tight cut off gradient to the precip shield. As a result of model
variations in the placement of the expected fgen region, the blended
model solutions will paint a broad chance type pop over the southern
half of the forecast area Tuesday. Taking both wet bulb cooling
potential and above freezing daytime boundary layer temps, a
rain/snow mix or wet/melting snow with minimal accumulations will be
forecast at this time.

&&

.MARINE...

Gale event is well underway this morning as a much colder airmass
and northwest flow settle into the Great Lakes region. Sustained
winds in excess of 30 knots with gusts up to 40 knots will persist
throughout the day on the back side of a strong, occluding low over
New England. Weak upper level disturbances moving overhead this
morning initiate lake effect snow bands across Lake Huron, which in
combination with gusty winds will be capable of causing squally
conditions and visibility reductions below one nautical mile.
Northwest winds begin to subside late tonight as the low departs and
high pressure starts to fill in, allowing Gale Warnings to be
replaced by Small Craft Advisories along the Lake Huron shoreline.
Waves remain elevated through Monday in the lingering northwest
flow, although winds continue to subside through the day. High
pressure briefly takes residence to start to the week, followed by
the next Pacific wave which glances across the Ohio Valley mid-week.
Minimal wind and/or wave response with this system, but there will
be potential for wintry precipitation.

&&

.PREV DISCUSSION...
Issued at 1153 PM EST Sat Nov 15 2025

AVIATION...

Colder NW flow between New England low pressure and Plains high
pressure governs conditions across Lower Mi late tonight through
Sunday. Pockets of mid level clouds start off the late night period
followed by streamers of sub 5000 ft VFR stratocu off the Great
Lakes later in the night most favored toward the MBS and FNT areas.
Inbound colder air activates the lakes and also maintains a mixed
boundary layer sufficient to keep wind gusts elevated as direction
becomes steady from the NW. Probability of greater stratocu coverage
remains higher toward MBS, especially with a boost from daytime
instability, while rain/snow showers set up east of the terminal
corridor during the afternoon into Sunday evening.

For DTW... Scattered to broken coverage of mid and high clouds
decrease late tonight. Probability of ceiling 5000 ft or less then
relies on lower predictability lake effect cloud streamers reaching
down into the DTW area as wind direction settles into a 300
direction tonight through Sunday.

DTW THRESHOLD PROBABILITIES...

* Low for ceiling 5000 feet late tonight through Sunday.

* Low for exceeding crosswind threshold from 300 direction late
  tonight through Sunday.


&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...Gale Warning until 10 PM EST this evening for LHZ361>363-421-422-
     441-462>464.

     Small Craft Advisory until 4 AM EST Monday for LHZ442-443.

Lake St Clair...Small Craft Advisory until 10 PM EST this evening for LCZ460.

Michigan waters of Lake Erie...Small Craft Advisory until 10 PM EST this evening for LEZ444.

&&

$$

DISCUSSION...SC
MARINE.......MV
AVIATION.....BT


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