436
FXUS63 KDTX 201047
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
547 AM EST Thu Nov 20 2025

.KEY MESSAGES...

- Dry and cloudy today with highs mainly in the 40s.

- A low chance for rain or drizzle Thursday night along and behind a
cold front.

- High pressure will move into the region for the beginning of the
weekend with highs in the low 50s.

&&

.AVIATION...

South-southwest low level flow has developed early this morning
within return flow of departing sfc high pressure and in advance of
a weakening cold front advancing into Minnesota. This return flow is
driving the region of MVFR based stratus upstream across Se Mi. This
moisture is being ducted under a deep inversion. The persistence of
this evening will ensure low clouds hold through the day. Ceilings
upstream have dropped below 2000 feet. These lower based clouds have
been struggling to a degree to reach the Se Mi terminals as it the
moisture feed is interacting with some lingering dry air. In light
of upstream observations, this dry air is likely to be overcome this
morning, warranting at least a prob group for some sub 2k feet
clouds. Some slight diurnal mixing this afternoon is expected to
support prevailing MVFR clouds based just above 2k feet. The surface
gradient will still remain weak, which will maintain light winds
below 8 knots.

DTW THRESHOLD PROBABILITIES...

* High in cigs aob 5kft today and tonight.

&&

.PREV DISCUSSION...
Issued at 334 AM EST Thu Nov 20 2025

DISCUSSION...

Western edge of an area of high pressure is holding on over SE MI to
start the day as we sit in between a strong low pressure system
passing over northern Ontario and a southern stream low stringing
out across the the Ohio Valley. A warm front is being pulled
northward through lower MI today, already draping itself from MKG to
ADG early this morning as evident in the low stratus field over that
area and dewpoints in the upper 30s. Expansive cloud field on
satellite extends to our south through the Ohio Valley and northwest
through WI/MN back toward the cold front which will lift northeast
through the area through the day. A stout inversion will help keep
this cloud field in tack through the cold frontal passage which will
not occur until around 12Z Friday for Saginaw Valley and a few hours
later for Detroit. Models continue the trend of bringing the cold
front through dry tonight with the HRRR now keeping the moisture in
the sub 5kft layer with PWATs increasing to around 0.5 to 0.75
inches. Not much support for precip with a weaken band of EPV, a
narrow ridge of theta e, and not much surface convergence to speak
of. The soundings suggest at best we might squeeze out a few hours
of drizzle/mist overnight tonight out of the thick low stratus.

Models have also continued to pull pops southward later Friday as a
weak wave rippling along the stalled front to our south tries to
activate some elevated frontal surface. Looks like the cold front
and high pressure building to the south should largely hold any
northward advances off, keeping the bulk of the rain to the south of
the area. Zonal confluent flow will keep some warmer air around
Friday though allowing temps to rebound back to around 50 before the
colder thermal trough swings through on Saturday. 850mb temps will
drop to around -5C by Saturday morning keeping highs in the low-mid
40s.

We remain dry through the weekend with only a passing shortwave
advancing through the Northern Great Lakes, but that should stay
north of the area. Next chance of rain will come Monday night and
Tuesday as a pair of lows target the area. How the northern stream
and southern stream systems phase will determine how things play out
locally, but the longer range models have been offering some
semblance of this for a few cycles now. After a week of temps around
50, this system looks to offer a big cool down with 850mb temps
falling to -10C on Thanksgiving.

MARINE...

Southwesterly winds slowly increase through the day in response to
low pressure tracking over northern Ontario. Strongest winds develop
by the latter half of the evening when gusts peak around 20-25kts
across northern/central portions of Lake Huron. Winds over the
southern half of the region hold closer the 15-20kts which would
preclude the need for any Small Craft Advisories. Associated cold
front crosses the region late tonight offering scattered rain shower
chances as well as ushering in renewed colder NW flow. With the
region residing on the fringe of this system, only modest cold
advection follows which keeps gusts sub 30kts across the northern
and central portions of Lake Huron with the southern half of the
region peaking closer to 20kts. High pressure then briefly works in
by Friday night bringing light winds to start the weekend.

&&

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

$$

AVIATION.....SC
DISCUSSION...DRK
MARINE.......KDK


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