740
FXUS63 KDTX 201957
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
257 PM EST Thu Nov 20 2025

.KEY MESSAGES...

- Mainly dry and cloudy the rest of today with temperatures holding
  near-steady overnight.

- Pockets of light rain or drizzle possible late tonight through
  early Friday morning, moreso for the Tri-Cities and Thumb areas.

- Mainly dry conditions again this weekend with a warming trend by
  Sunday.

- Increased precipitation chances arrive during the first half of
  next week.

&&

.DISCUSSION...

Warmer air filters into Lower Michigan this afternoon due to return
flow from surface high pressure approaching the Mid-Atlantic.
Surface winds veer WSW this evening and overnight, reflecting 925 mb
flow trends. Temperatures should level off by midnight due to warm
advection.  Meanwhile, a low pressure system deepens and tracks east
into southern Hudson Bay. The system`s cold front gets shoved across
the region early Friday morning as shortwave troughing within the
base of the polar jet deamplifies after interference due to spill-
over mid-level ridging exiting The Plains. Local precipitation
response appears marginal given an abundance of dry air aloft.
However, sufficient low-level saturation may promote a more
favorable environment for light rain/sprinkles before the front
clears out, around 13Z Friday. QPF shouldn`t exceed a hundredth for
most areas, more likely for the Tri-Cities and the tip of The Thumb.

Southeast Michigan remains positioned along the interface between
thermal troughing over Ontario and greater thicknesses encompassing
The Southeast, including portions of the Ohio Valley on Friday. 850
mb temperatures should generally reside in the low to mid single
digits within a south to north thermal gradient. Expect highs above
climatological normals for most areas, ranging from the upper 40s to
low 50s. Surface ridge expands from The Dakotas, centering over The
Upper Midwest by Friday evening. This veers gradient flow NNW Friday
night as 1021 mb surface high centers over central Wisconsin. Just
to the south, a low amplitude shortwave slides through the northern
reaches of the Ohio Valley leading to shower development. Latest
model consensus affords higher confidence in the dry continental
airmass winning out for all of southern Lower, therefore dry PoPs
were included for almost the entire CWA. The one exception resides
along the immediate MI/OH border, with a thin stripe of Slight
Chance.

A more seasonable airmass settles returns on Saturday with highs in
the mid 40s. Broader anticyclonic influence ensures dry conditions.
Flow flips southerly for the second half of the weekend as the
oscillatory pattern in temperature trends persists. Low-level thetaE
advection then surges into the Great Lakes on Sunday. Not expecting
much in the way of rainfall with the passing trough given the lack
of deeper column moisture, marked by PWATs of around 0.25 inches.
Next opportunity for meaningful precipitation comes early next week
after a stalled southern stream Pacific closed low ejects into
central CONUS, possibly phasing with a northern stream wave as the
synoptic pattern becomes more progressive. The milder airmass likely
lingers through mid-week.

&&

.MARINE...

Southwesterly winds continue to gradually increase through the
evening in response to low pressure tracking over northern Ontario.
Strongest winds develop late evening-early tonight 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.
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 keeping gusts sub 30kts across the
northern and central portions of Lake Huron with the southern half
of the region peaking closer to 20kts. Some higher wave action clips
the tip of the Thumb Friday night warranting the need for Small
Craft Advisories. High pressure then briefly works in by Friday
night bringing light winds to start the weekend.

&&

.PREV DISCUSSION...
Issued at 1234 PM EST Thu Nov 20 2025

AVIATION...

Surface high pressure retreating out of the area with an increase in
westerly kinematics has resulted in return flow and deep saturation
within the lowest 4-5 kft agl. Prevailing MVFR ceilings are in place
across much of the area with a few brief exceptions. Based on
satellite trends will prefer MVFR conditions to hold throughout the
day into tonight. Midlevel thetae advection is forecasted this
evening in advance of the cold front which will only bolster the
ceilings tonight. The cold front is forecasted to pass through MBS
at approximately 12Z, then through the Detroit terminals sometime
between 15-18Z. Lower confidence does exist at the end of the period
and beyond as moisture could become too shallow to maintain a cloud
deck. However, some slowing of the front is expected across far
southern Lower Michigan and prefer prevailing ceilings for the
Detroit terminals.

DTW THRESHOLD PROBABILITIES...

* High in cigs aob 5kft today and tonight. Medium confidence Friday
  afternoon.


&&

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

$$

DISCUSSION...KGK
MARINE.......KDK
AVIATION.....CB


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