646
FXUS63 KDTX 102025
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
325 PM EST Mon Nov 10 2025

.KEY MESSAGES...

- Lake effect snow showers continue across the Eastern Thumb region
through this evening, winter weather advisory in effect for Huron
County.

- Light precipiation is possible Tuesday afternoon and evening with
little to no snow accumulation expected.

- Slow warming trend mid to late week.

&&

.DISCUSSION...

Due to the persistence of lake effect banding with multiple
observations of 1/4 +SN at Bad Axe this morning, temperatures in the
middle 20s and some reports of slow traffic for various spots around
the county, issued a Winter Weather Advisory earlier for Huron
County that will be in effect until Midnight. Highly variable
conditions are expected across the county, but moist/saturated
convective depths of up to 9.0 kft supports additional hours this
afternoon of multi-banded lake effect snow potential. Snowfall rates
have likely been in excess of 1 inch per hour at times. Forecast
soundings do show a significant drying of the low levels after the
wind switches to the northwest after 21z. The question outstanding
is how long it will take to the clear lake effect banding away from
the Huron County shoreline. There is some model guidance that keeps
the convergence fields over the tip of the Thumb during the evening
hours and a few NWP solutions that bring additional snow
accumulations to areas near/east of Port Austin to Harbor Beach. The
Winter Weather Advisory is in effect through this evening for the
potential additional snowfall and possible impacts to area roadways
with cold winterlike temperatures.

With longer wavelength eastern North America troughing, fast
northwest flow will drive the weather over the Upper Midwest and
Great Lakes during the middle of the week. Main feature to key on
for Tuesday is a cyclonically curved exit region to jet streak set
to push into Lake Michigan vicinity between 0-6z Wednesday. Tight
thermal gradient along the western periphery of the troughing will
provide an opportunity for some isentropic ascent/warm advection
lift already beginning late Tuesday afternoon and evening. This will
be collocated with the eastern fringe/edge of the low level jet axis.
Forecast soundings show a significant amount of dry air in the
lowest 10.0 kft agl through the mid to late afternoon with top down
moistening especially in the NAM by the evening. Did increase PoPs
for the 18-00z time period based on the latest NBM data.
Precipitation type is interesting as there could be a lack of ice
nucleation with saturation well below -10C. Not expecting much
accumulation potential of any snow. Steep lapse rate environment
brings southwest winds 20 to 25 mph early Tuesday with temperatures
trying to climb into the middle to upper 30s.

Shortwave parade then sets up over the region with one vort max
timed to dig southward Wednesday morning and another during the day
on Thursday. Low confidence exists on coverage of precipitation early
Wednesday with a lack of a QPF signal. Forecast soundings are again
showing the depth of moisture limited to 7.0 kft agl or less, below
the -10C isotherm. Differential geopotential height rises are then
anticipated late Wed early Thursday which leads to a lowering of
significant subsidence. Surface high pressure then builds into the
region for the end of the week. Temperatures will slowly moderate
with readings in the low 50s by Friday.

Low confidence exists for any sensible weather forecast next weekend
as timing and amplitude of upcoming wave pattern leads to a varying
envelope of solutions.

&&

.MARINE...

Northerly flow continues to generate organized bands of lake effect
snow across southern Lake Huron while also elevating wave heights to
7+ feet along the nearshore zones. Should be in the last 12 hours or
so of the lake effect response as winds are expected to shift
northwest overnight and eventually southwest Tuesday morning as
surface ridging briefly builds into the Great Lakes. Ridging will
quickly be dislodged by a progressive surface trough, anchored to
low pressure over Ontario. A core of 50-55 knot low level winds
remains just ahead of the trough, and will result in a quick ramp up
in SW winds Tuesday evening. Mixing efficiency will quickly
deteriorate as a warm/stable airmass moves in, limiting gale
potential in standard SW flow fashion. Nonetheless, a
localized/brief period of gale force gusts cannot be ruled out for
Saginaw Bay/western Lake Erie Tuesday evening.

Passage of the trough axis Wednesday affords a gradual shift to W/NW
flow, shifting concern for gales to the northern waters of Lake
Huron Wed afternoon-evening. Guidance is just on the cusp of Gale
Watch thresholds (both magnitude and duration), and would like to
see an upward trend before issuing any headlines. Small Craft
Advisories on the other hand have been extended through Thursday to
account for several episodes of elevated wind/wave potential for all
nearshore zones.

&&

.PREV DISCUSSION...
Issued at 312 PM EST Mon Nov 10 2025


&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...Winter Weather Advisory until midnight EST tonight for MIZ049.

Lake Huron...Small Craft Advisory until 4 AM EST Thursday for LHZ421-441>443.

     Small Craft Advisory from noon Tuesday to 4 AM EST Thursday for
     LHZ422.

Lake St Clair...Small Craft Advisory from noon Tuesday to 10 PM EST Wednesday for
     LCZ460.

Michigan waters of Lake Erie...Small Craft Advisory from noon Tuesday to 10 PM EST Wednesday for
     LEZ444.

&&

$$

DISCUSSION...CB
MARINE.......MV


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