171
FXUS63 KDTX 152034
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
334 PM EST Sat Nov 15 2025

.KEY MESSAGES...

- Lingering light rain chances ending this evening as a cold front
  sweeps across the area.

- Cold and brisk conditions Sunday. Wind gusts in excess of 30 mph
  at times.

- A few light snow showers possible mainly across the Saginaw Bay
  area and thumb region through the latter half of the weekend.

- Temperatures will remain below normal into early next week.

&&

.DISCUSSION...

Shortwave zipping across the northern great lakes will mark the lead
edge of more meaningful height falls and colder conditions expected
to overtake the region in the coming days. Warmest profile over at
least the next 7 days now entrenched locally, as sufficient
residence time within a gusty pre-cold frontal environment allow
temps to push 60 degrees or greater in many locales. Cold front on
pace to sweep across the area over the next several hours. Little
evidence per latest radar trends or hi res model guidance to suggest
a greater potential for shower production, leaving simply a
lingering low end chance through the evening window as the advective
process strengthens. Peak in wind gust potential within the
immediate wake of the fropa as improved mixing taps 30 knots at 925
mb. Some gustiness into the 35 mph range still plausible early
tonight.

Pronounced period of cold air advection will encapsulate the region
overnight into Sunday, as a stronger lobe of vorticity breaks off
the parent Hudson Bay low and digs southeast. Associated brief
increase in synoptic moisture quality boosted by improving lake
moisture flux off lake Superior and northern lake Huron as overlake
instability increases within the cold northwest flow. While the most
focused and intense bands of corresponding lake augmented snow
shower activity will remain to the northwest or offshore over
northern lake Huron given the trajectory, some pockets of light snow
showers will be possible mainly around Saginaw Bay and the thumb
region. Outgoing forecast will simply introduce a low end mention
for this corridor with little to no accumulation expected attm. Lows
Sunday morning arriving in the low to mid 30s. Modest diurnal
recovery with the low level thermal trough in residence for the
daylight period, keeping highs below average in the low to mid 40s.
Continued gustines out of the northwest with the overall wind
magnitude still elevated within a firm pressure gradient.

Cold, deep layer northwest flow maintains control through Monday.
Predominant lake Huron LES band(s) likely to hold just north of the
tip of the thumb given current wind projection, but worth monitoring
for Monday morning as the convergence axis pivots south before
releasing eastward through the day. Otherwise, minimal thermal
advection as surface ridging builds into the region ensures
continued below average temps with dry conditions.

Remnant pv feature left behind from the closed low now churning off
the California coast will eject to the east/northeast during the
early week period. Standard level of uncertainty yet in the forecast
detail locally Monday night and Tuesday, as usual variation in model
projection of system track and magnitude exists associated with this
feature as it lifts across the Ohio valley. Potential for a light
precip event to emerge over portions of lower Michigan within the
elevated warm air advection wing and trailing system dynamics
assuming a favorable trajectory. Latest NBM output still highlights
modest potential for roughly the southern half of the forecast area.
Further forecast refinement assured, as drying low level easterly
flow associated with high pressure to the north will remain a
factor.

&&

.MARINE...

Surface low pressure now centered over Georgian Bay will deepen as
it slides east this evening. A quick shift in winds from SW to NW
occurs late this afternoon as a cold front sweeps across the area,
followed by a ramp up in winds to 30-35 knots and gusts toward gale
force overnight. With this magnitude of wind speeds, wave heights in
excess of 12-15 feet will be plausible, while wind direction directs
the peak wave heights across the open waters while clipping the tip
of the Thumb. Air-lake temperature differences peak around 20 C by
Sunday morning to support well-mixed/unstable profiles, with the
lingering wind field keeping gale force gusts going through Sunday
night. Main forecast update today is the inclusion of the
southernmost Lake Huron zone to the Gale Warning, where local and
operational guidance alike carry high probabilities for gusts to
exceed 34 knots over the next 24 hours. Otherwise, Gale Warnings
remain unchanged. Multiple lake effect snowbands develop on Sunday,
which will also be impactful mainly to visibility across the
waterways. High pressure drifts into the Ohio Valley and Upper
Midwest Monday to ease wind concerns and reduce precipitation
chances, although elevated wave heights will lag. The next low to
impact the area arrives Tuesday, but mostly presents concern for a
wintry mix while winds/waves remain below headline thresholds.

&&

.PREV DISCUSSION...
Issued at 142 PM EST Sat Nov 15 2025

AVIATION...

The terminals remain warm sectored today as a low pressure system
tracks across Lake Superior. This has led to a large swath of MVFR
ceilings, and gusty SW winds of 20-25 knots. The system`s cold front
lags behind, currently approaching the eastern shores of Lake
Michigan. The expectation is that once the front clears though,
ceilings should scatter out and winds veer WNW. As far as
precipitation goes, column saturation and upstream radar trends
suggest insufficient moisture to produce meaningful rainfall. Some
sprinkles are possible, but in the absence of preceding surface obs,
no mention was added this TAF cycle. The highest probability for any
rainfall is generally confined to MBS and/or FNT. The front should
clear through shortly after 21Z this afternoon. Push of drier air
moves in this evening and overnight into Sunday leading to clearer
skies. Model signal exists for some lake-effect cloud to stream in
from the northwest as low-level trajectories improve. It is unclear
whether or not this lake cloud makes it to any TAF site, although
MBS would be the more probable target. Strong pressure gradient
lingers tonight into Sunday, therefore winds remain above 10 knots
through the end of the cycle.

For DTW...Gusty SW flow turns WNW behind a passing cold front later
this afternoon. Sub-2 kft AGL clouds lift and scatter out as MVFR
restrictions fade by after 21Z. Probability of ceilings will be low
tonight and Sunday.

DTW THRESHOLD PROBABILITIES...

* High for ceiling 5000 feet this afternoon, then low through Sunday
  morning.

* Low for exceeding crosswind threshold from 300 direction this
  afternoon and tonight.


&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...Gale Warning until 10 PM EST Sunday for LHZ361>363.

     Small Craft Advisory until 9 AM EST Sunday for LHZ421-422.

     Gale Warning from 9 AM to 10 PM EST Sunday for LHZ421-422.

     Gale Warning from 8 PM this evening to 10 PM EST Sunday for LHZ441-
     462>464.

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

Lake St Clair...Small Craft Advisory from 7 PM this evening to 10 PM EST Sunday for
     LCZ460.

Michigan waters of Lake Erie...Small Craft Advisory from 7 PM this evening to 10 PM EST Sunday for
     LEZ444.

&&

$$

DISCUSSION...MR
MARINE.......MV
AVIATION.....KGK

You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.