826
FXUS63 KDTX 200334
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1134 PM EDT Tue Aug 19 2025

.KEY MESSAGES...

- Seasonable temperatures and dry weather move in and hold Wednesday
through Friday.

&&

.AVIATION...

Ongoing shallow cool air advection and ample low level moisture has
led to a widespread low stratus. Observational trends and recent
model guidance suggest a prevailing low end MVFR and IFR ceilings
through daybreak. The northern gradient flow will sustain winds
around 10 knots and will be a limiting factor for much if any fog.
Some brief minor visibility restriction may however be possible
within any areas of early morning drizzle. Low level dry air
advection and diurnal heating/mixing will result in a steady
improving trend in ceiling heights during the day Wednesday. Some
veering of the low level winds fields toward the north-northeast Wed
afternoon and evening may sustain a strato field across portions of
Se Mi into Wed night given the added moisture flux off the lakes.

For DTW/D21 Convection...No thunderstorms are forecast through the
TAF period.

THRESHOLD PROBABILITIES...

* High for ceilings aob 5000 feet tonight and Wednesday.

&&

.PREV DISCUSSION...
Issued at 314 PM EDT Tue Aug 19 2025

DISCUSSION...

Strong upper level anticyclonic wave break over the Canadian Prairie
provinces combined with weak entrance region dynamics over
Ontario/Quebec is resulting in the amplification and digging of a
trough over the Great Lakes region today. The greatest area of the
height falls and synoptic scale ascent has now been squeezed
immediately south and east of the cwa. Will still have to work
through an axis of showers and convergence that is now pushing into
northern Metro Detroit. Radar data supports warm cloud/small droplet
distribution in the showers. No thunderstorms are expected, but
rainfall rates could prove to be surprisingly efficient the couple
of hours. Model data the past 24 hours or so has steadily converged
on a solution that is much drier for the evening hours. Will continue
chance PoPs.

The midlevel trough is forecasted to be progressive, opening the
doors to differential geopotential height rises tonight. While the
large scale upper level pattern supports blocking over the Southwest
United States, tilting of the  upper level ridge into the Great
Lakes is anticipated. The net result will be a uniform expansion of
surface high pressure into Southeast Michigan with the anticyclone
then persisting through the early portion of Saturday. More
comfortable weather is expected with highs generally in the lower
80s (around normal) with surface dewpoints in the 50/60s.

The next chance of rainfall is expected to be late Saturday and
Sunday. There has been a strong consensus amongst the global models
in amplifying a large wavelength upper level low pressure system as
it pushes east of he Rocky Mountains. Current forecast suggests
daytime high temperatures in the low 70s Next Monday and Tuesday,
approximately  8 to 10 degrees below normal.

MARINE...

Low pressure reaches western Lake Erie late this afternoon and
continues to track east toward Lake Ontario tonight. Showers with
embedded thunderstorms will wane in coverage through the evening
while wind over Lake Huron backs from east to northeast, increasing
to around 15 to 20 knots with gusts to 25 knots on Wednesday. Small
Craft Advisories are in effect for all southern Lake Huron nearshore
zones through Wednesday evening. High pressure builds in from the
northern Great Lakes through Thursday causing northeast wind to
become light. Wind then shifts to southwest on Friday ahead of the
next cold front set to arrive on Saturday.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement from 8 AM EDT Wednesday through Wednesday
     evening for MIZ049-055-063.

Lake Huron...Small Craft Advisory from 8 AM to 10 PM EDT Wednesday for LHZ421-
     422-441>443.

Lake St Clair...None.
Michigan waters of Lake Erie...None.
&&

$$

AVIATION.....SC
DISCUSSION...CB
MARINE.......TF


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