616
FXUS63 KDTX 250335
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1135 PM EDT Sun Aug 24 2025

.KEY MESSAGES...

- Cooler weather persists through much of the week.

- Chance for scattered light showers through this evening and
tomorrow.

- Mostly dry mid to late week with the exception of Thursday.

&&

.AVIATION...

A few VFR based clouds with perhaps a stray shower will impact Se Mi
through the night under persistent low level cool air advection
aiding enhanced moisture flux off Lake Michigan. Daytime heating
late Mon morning will again lead to an expansion of VFR based strato
cu and scattered to possibly numerous brief afternoon showers. The
westerly winds will also increase slightly courtesy of daytime
mixing.

For DTW/D21 Convection...No thunderstorms are expected at this time.

THRESHOLD PROBABILITIES...

* Low in ceilings aob 5000 feet tonight and Monday.

&&

.PREV DISCUSSION...
Issued at 305 PM EDT Sun Aug 24 2025

DISCUSSION...

This afternoon into early evening, expect hit or miss showers and a
few isolated thunderstorms as a broader upper-level trough continues
to move over lower Michigan. While a few isolated storms are
possible, especially across the Tri-Cities and Thumb regions, the
environment is much more supportive for lightning production across
northern lower Michigan where mid-level lapse rates are better and a
more prominent vort max is tracking. As the evening hours progress,
lingering convection will gradually wane as we lose daytime heating.
We will also see clouds thin overnight, favoring a cool night, with
lows in the 40s and 50s.

The above mentioned upper-level trough will continue to move east
across the Great Lakes region through Tuesday night, with a number
of embedded shortwaves expected to track across the region. This
trough will continue to usher in a much cooler, fall-like airmass.
Overnight lows through Tuesday night will be in the 40s and lower
50s. Daytime highs will generally be in the mid/upper 60s, flirting
with the 70 degree mark in a few areas. The cooler airmass over the
region will continue to support lake-effect rain showers downwind
from the Great Lakes, with a west to northwest fetch favored through
the region. Inland from the Great Lakes, diurnal flare ups of
afternoon/evening showers are expected. On Monday afternoon, daytime
heating coincident with a vort max rotating through the region
should favor an uptick in the coverage of showers during the
afternoon hours. Sounding profiles are quite impressive regarding
the degree of mixing in the boundary layer, mixing to nearly 6-8kft.
With impressive inverted-v profiles, more robust showers or isolated
thunderstorms may be capable of producing gusty winds. By Tuesday,
the broad upper-level trough begins to crest the region, providing
one last day of isolated to scattered shower potential. Upon
coordination with neighboring offices, did introduce low-end PoPs
for Tuesday afternoon. Profiles look quite similar to Monday
afternoon, with perhaps a slightly deeper pocket of elevated
instability for showers to work with.

High pressure then builds into the region Tuesday night into
Wednesday, bringing back a slight warm up and limiting the diurnal
development of shower activity. However, as a backdoor cold front
drops south across the area on Thursday, showers and the potential
for a few thunderstorms returns. The timing of the front will
greatly influence how warm it gets on Thursday, for now have kept
mentions of mid 70s. The Tri-Cities and Thumb regions will feel the
influence of this backdoor cold front first, and thus have the
greater uncertainty regarding how warm it gets. Did keep mentions of
thunder in the forecast, but conditions do not look favorable for
organized severe weather. After the cold front moves through, high
pressure looks to help maintain a mostly dry forecast as we head
into next weekend.

MARINE...

Cooler conditions are in-place today as a temperate Canadian airmass
filters in and lingers over the central Great Lakes for the next
several days. Shortwave forcing aloft has been sufficient in
producing scattered showers with some isolated lightning strikes.
This activity will mainly hold over Lake Huron before waning through
the evening hours. Improved mixing profiles are expected Monday
afternoon amid steeper low-level lapse rates, thus generating higher
gusts. The strongest gusts should remain over northern Lake Huron
(east of The Straits) where gusts could occasionally approach gale-
force Monday afternoon. LLJ winds are not impressively strong
tomorrow, briefly marked by lower 30 knot values at the 850 mb level
(4 kft AWL). Further south, issued Small Craft Advisories from Outer
Bay through the tip of The Thumb as occasional waves exceed 5 feet.
Additional shower and thunderstorm chances exist Monday with some
isolated waterspouts possible, mainly for Lake Huron. A stray shower
or two will be possible again Tuesday before drier conditions settle
in mid-week. Daytime gusts generally peak in the 20-25 knot range
Tuesday through Thursday. Additional Small Craft Advisories may be
needed.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...Small Craft Advisory from 10 PM Monday to 10 AM EDT Tuesday for
     LHZ421-442.

     Small Craft Advisory from 10 AM Monday to 10 AM EDT Tuesday for
     LHZ441.

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

$$

AVIATION.....SC
DISCUSSION...JA
MARINE.......KGK


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