St. Clair Shores, Michigan 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

625
FXUS63 KDTX 221426
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
926 AM EST Mon Dec 22 2025

.KEY MESSAGES...

- Light snow with a brief period of wintry mix possible this morning
and early afternoon. A dusting to a few tenths of  accumulating
snowfall possible.

- There is a low chance for freezing drizzle tonight into Tuesday
morning  before temperatures climb above freezing by daybreak. Only
trace   amounts of ice will be possible.

- Above normal temperatures through the mid and late week period.

&&

.UPDATE...

No update needed in the gridded forecast and messaging for the today
period with the 22.12z KDTX raob capturing a very dry air mass in
the lowest 8kft agl. A considerable amount of moistening will be
needed for hydrometeors to reach the ground, with surface
observations supporting virga and evaporation clear back to
Wisconsin. Initial system relative isentropic ascent will increase
modestly in the 15-20Z time window in response to a time tendency
change towards less anticyclonic/more cyclonic flow. Weak upglide
centered at a relatively high 8-12kft suggests ice nucleation will
occur and any precipitation rate will favor snow as ptype
particularly north of M 59 and east of I 75. Less confidence exists
in measurable precipitation reaching the ground in Metro Detroit
early today.

&&

.PREV DISCUSSION...
Issued at 541 AM EST Mon Dec 22 2025

AVIATION...

Mid-cloud (10kft) is currently overspreading the region at the start
of the new forecast period marking the lead edge of moisture tied to
a developing warm front. Precip begins to work into the area by mid-
morning (~13-14Z) however the dry resident low level airmass keeps
intensities light and ceilings VFR. Main p-type during this period
expected to be snow given the temperatures, though increasing mid-
level warm advection affords a shot to see some snow-wintry mix
through the morning. Only minor accumulations of a trace to couple
tenths of snow possible with only a trace of ice if wintry mix fully
manifests. A secondary push of lower level moisture arrives this
evening supporting a light rain/drizzle chance. For the first few
hours of precip onset, this could fall as freezing drizzle before
surface temperatures sufficiently warm. Again only trace ice amounts
forecast.

For DTW...Light snow, potentially with a period of snow-wintry mix
this morning. Only trace snow/ice amounts forecast. A lull in precip
expected this afternoon before light rain/drizzle develops in the
evening. With temperatures within a degree or two of freezing,
initial rain could fall as freezing drizzle before temps warm
sufficiently. Only trace ice possible in this window as well.

DTW THRESHOLD PROBABILITIES...

* Low in ceilings aob 5000 feet this morning and afternoon, high by
  tonight.

* High for p-type of snow this morning with moderate probability to
  see a period of light wintry mix. Low to moderate for a couple
  hour period this evening for light freezing drizzle.

PREV DISCUSSION...
Issued at 433 AM EST Mon Dec 22 2025

DISCUSSION...

Return flow is starting to kick in this morning as the surface high
pressure moves toward the Mid Atlantic. Meager moisture within this
flow and weak isentropic ascent along a mid level warm frontal zone
will be responsible for an area of predominately light snow
spreading across southeast Michigan this morning. This is already
noted by the area of clouds and light radar returns moving in from
the west at press time. Resident airmass is rather dry with PWs at
less than a quarter inch noted on the 00Z DTX RAOB last evening and
most surface dewpoints observed this morning are in the teens to 10
degrees. This dry airmass will keep overall accumulations and QPF in
check as precipitation spreads across the area through the morning
and early afternoon. The better of the weak, more persistent forcing
will be focused east of I-75 and north of the M-59 corridor. Latest
temperatures trends this morning highlight a slight increase in
chances for a wintry mix to result from stronger push of warm air
aloft before surface temperatures can climb above freezing. This
comes from the HRRR trending slightly more towards the NAM
solutions. This does bring potential for a brief period of wintry
mix of an hour or two between 9 am to 1 pm for areas along and south
of I-69.

Bulk of hi-res models draw the forcing north of the area bringing a
period of dry conditions during the afternoon with the FV3 being one
of the more aggressive models at holding light precipitation across
the area after 2 pm. Any lingering precipitation, if it does occur,
would be across the northern half of the CWA and would be mostly snow
or a rain/snow mix as surface temperatures should warm just above
during the afternoon. A secondary push of moisture in the low levels
is then expected after 7 pm this evening at a time when mid- upper
level moisture is beginning to dry out. This will work to strip
moisture from the DGZ, preventing ice, and warm advection aloft will
transition any snow occurring across the north to rain during the
night. Moisture depth in the evening will also be decreasing
resulting in transition to more of drizzle/mist scenario. The
challenge with this part of the forecast will be the surface
temperatures. A slightly slower arrival of warm/moist advection with
wet bulb temperatures at or below 0C will open the door for low
chance of freezing drizzle for a period of time overnight before
temperatures eventually climb above 32 degree F and chances for
precipitation ends before daybreak. QPF will be very light and any
occurrence would likely only lead to trace amounts. In regards to
snow, most locations will see a dusting to a few tenths of an inch
with isolated spots in the Thumb possibly reaching a half inch over
the course of the day into the evening before the transition occurs
tonight.

High pressure will build across the Great Lakes leading to a dry
Tuesday and Wednesday period. Warm advection brings highs for
Tuesday up into the 40s with the high pressure drawing in a slightly
cooler airmass for Wednesday bringing highs back into the 30s. A
warm up remains in the cards for Christmas Day and through the rest
of the week with daytime highs ranging in the 40s to low 50s. A
baroclinic zone hovering around the region will be a focal point for
a couple of waves rounding the ridge; a weaker system Wednesday
night and stronger wave Friday. Warmer temperatures should keep any
precipitation as rain through this period.

MARINE...

High pressure across the eastern Ohio River Valley will depart into
the Carolinas this morning, which will reinforce southwest flow
across the Great Lakes. This will bring some localized stronger
gusts towards 25 knots across central Lake Huron given the favorable
fetch. Light snow showers will also be likely this morning and
afternoon with the passage of a warm front. Otherwise, generally
light winds for winter standards holds until tomorrow evening, where
a glancing area of cold air briefly drops down across Lake Huron.
This will bring the potential for gusts around 30 knots for northern
Lake Huron as well as elevated wave heights into the outer Saginaw
Bay and northern Thumb, which may briefly breach Small Craft
Advisory thresholds.

&&

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

$$

UPDATE.......CB
AVIATION.....KDK
DISCUSSION...AA
MARINE.......AM


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