941
FXUS63 KDTX 081748
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1248 PM EST Sat Nov 8 2025

.KEY MESSAGES...

- Seasonably cool with drier conditions expected tonight and
Saturday.

- Precipitation arrives Saturday night as a mix of rain and snow.
Significant melting of any snow expected, but some accumulation will
be possible mainly on unpaved surfaces overnight through early
Sunday.

- Potential for additional snow showers Sunday thru Monday as
conditions turn much colder. Some accumulation possible, with a
particular focus across the thumb within bands of lake effect snow.

- Coldest conditions Monday morning, with wind chill dropping into
the teens.

&&

.AVIATION...

Weak area of high pressure over the northern great lakes will
maintain a drier northerly low level flow through this evening. Some
pockets of lower VFR or brief MVFR cigs may emerge across the
Detroit corridor as a mid level frontal zone lingers, but otherwise
simply a higher coverage of higher based cloud through sunset.
Moisture quality improves tonight north of a low pressure system
tracking across the Ohio valley. This will bring a widespread area
of light precipitation from Detroit up through Flint, with an onset
within the 04-06z window. Initial precipitation type of a rain/snow
mix likely given projected above freezing temperatures, with a
transition toward melting/wet snow through the early morning Monday.
Highest probability for a peak in snowfall intensity with an
accompany dip in conditions to IFR will exist mid-late morning
Sunday /11z-16z/.

For DTW...A few patches of MVFR stratus may yet develop this
afternoon. Lower confidence in occurrence precludes a more
definitive mention. A light mix of rain and melting snow arrives
overnight, with an onset of 04z-06z. Transition toward mainly
wet/melting snow through the morning period as temperatures lower.
Peak in snowfall intensity 11z-16z bringing IFR conditions and a
possibility for some minor slushy accumulation.

DTW THRESHOLD PROBABILITIES...

* Low in ceiling aob 5000 prior to midnight. High overnight through
  Sunday.

* Medium for precipitation type as a mix of rain and snow overnight,
  with a transition toward mainly snow Sunday morning.

* Low for ceilings 200 feet or less and visibility to 1/2 mile or
  less with snowfall late tonight.

&&

.PREV DISCUSSION...
Issued at 335 AM EST Sat Nov 8 2025

DISCUSSION...

Water vapor imagery currently highlights a potent upper-level
shortwave over eastern Montana, which will progress through the
northern Plains before rounding into the northern Ohio River Valley.
The associated low pressure clipper system will track with the wave
and will center over southern Indiana and Ohio between 06Z-12Z
tomorrow. This will initially bring a combination of rain and wintry
weather to SE MI late tonight through early Sunday morning. The
initial precipitation footprint will expand through southern
Michigan, initially up through the M59 corridor, driven by lead
isentropic ascent. Some lower end chances will be included north
with some east flow lake enhancement possibilities. Initial
precipitation arrives with temperatures ranging from just above
freezing across the Irish Hills, to closer to 36-37 degrees through
the border into the southern Metro region. This brings initial p-
types ranging from rain for these warmer locations, to a rain/snow
mix where temperatures near the freezing mark.

Progress of low pressure into Ohio then brings increasing chances
for a frontogenetic forcing within the northwest quadrant of the
low, which has potential to clip portions of southern Michigan
through the mid and late morning hours. Any type of frontogenetic
response would be highly sensitive to the final track of the low
pressure system along with the transient rain/snow line given the
shallow wet bulb zero temperatures and surface temperatures near to
just above 32Z. Any strong ageostrophic response along the
deformation zone would quickly erode static stability and would
exude a quick transition to all snow, which can lead to some
accumulation snowfall. Highest probability for this occurrence will
reside from roughly Adrian up through Howell and into portions of
the northern Metro region, where a slushy 1-2" will be possible. One
caveat noted in a small subset of models, is if fgen lights up just
south of the state line, which would significantly hamper moisture
transport through Michigan, cutting into this accumulation
potential. Early November warm soil temperatures will also aid in
melting of snowfall leading into the afternoon.

Departure of this low pressure system in conjunction with a
secondary shortwave shearing off of a parent low over the James Bay
into the Great Lakes will greatly amplify the longwave trough
structure through the Midwest and will pull down anomalously cold
air starting tomorrow afternoon, which will fully entrench the
Great Lakes through Monday. 500MB temperatures drop to or below
-36C through the Ohio River Valley, which if verified would fall
outside of all climatological values, while 500mb heights fall to or
below the .5th percentile. The large delta t off the warmer lakes
will enhance over-lake instability and will result in efficient
transport of lake moisture inland starting in the afternoon hours
initially downwind of the Saginaw Bay and Lake Huron. Even with
projected temperatures in the mid 30s during daylight hours, strong
low-level potential instability and convergence along the lakeshore
can produce pockets of dynamic cooling which can support all snow,
before temperatures fall to and below the freezing mark in the
evening and overnight hours.

While predictability regarding location of lake bands or squall like
features is low at this time, this setup is not to be overlooked for
some impactful accumulating snowfall off the Saginaw Bay, through
portions of the Tri-Cities and with Lake Huron across the Thumb,
especially along the Lake Huron shoreline through Monday. The
updated snowfall forecast will highlight the potential for highly
localized 2-5" of accumulation through Monday morning, noting low
end potential for higher amounts along the Lake Huron shoreline
given any favorable prolonged north-northwest fetch that can last
through Monday. Adjustments to the lake effect portion of the
forecast will be necessary through the subsequent forecast updates.
Locations away from the lakeshore can still see isolated to
scattered snow showers leading into Monday morning, but will see
diminishing chances through the day once north flow takes hold,
which will advect dry air into the region. Cold temperatures will be
realized during the early week period under the strong thermal
trough. Expect highs in the 30s with lows in the 20s. Wind chills
drop in the teens both Monday and Tuesday morning as wind gusts
range around 15 to 20 mph.

MARINE...

Northwest wind subsides through the morning as a weak high pressure
settles in across the region today. This allows wave heights to
diminish as well. A low pressure system then tracks through the Ohio
Valley and southern Great Lakes late tonight into Sunday, bringing
the next round of more active weather. Wind becomes organized out of
the east and northeast tonight, becoming gusty to around 20 to 25 kt
from the north to northeast through the day Sunday. This will
necessitate the next round of Small Craft Advisories as waves build
in excess of 4 ft across southern Lake Huron. This system will also
bring a swath of rain and snow which could become briefly heavier at
times across the southern lakes.

Much colder air arrives across the region as the system departs
Sunday night into Monday. This sustains gusty northwest wind with
additional snow showers. Flow then flips to southwest on Tuesday and
remains gusty as milder air returns. Another cold front mid-week
perpetuates the active westerly flow pattern with chances for
showers.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.
&&

$$

AVIATION.....MR
DISCUSSION...AM
MARINE.......TF


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