895
FXUS63 KDTX 190724
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
324 AM EDT Wed Aug 19 2026

.KEY MESSAGES...

- Low chance of a shower or thunderstorm today near the Ohio border;
dry conditions prevail elsewhere today and Thursday.

- Showers and thunderstorms return Friday night, with the highest
coverage and best chances on Saturday.

- Temperatures remain near normal through the period.

&&

.DISCUSSION...

A large and seasonably strong upper level low (544 DAM at 500 MB) is
centered over James Bay early this morning and looks to exert its
influence through the rest of the workweek. Respectable height falls
this morning supported light showers with the slowly advancing cold
front, although thunderstorms were hard pressed to materialize, as
expected with the limited instability. The front looks to wash out
close to the southern Michigan border as a weak PV filament breaks
off from trailing shortwave over the Midwest and tracks through
southern Lower Michigan late today. A secondary 850-750 MB Theta-E
ridge is expected to track south of Eight Mile Road this afternoon,
bringing enough instability near the southern Michigan border to
offer up a low chance of shower or thunderstorm.

Otherwise, upper level confluent flow sets in, strong subsidence/mid
level drying will allow for dry conditions tonight and Thursday as
high pressure (1018 MB) translates east through the Central Great
Lakes. A series of shortwaves is then on track to reinforce
troughing over the Great Lakes region.  The first one arrives Friday
evening/night, with a second, stronger shortwave arriving Saturday
that has the potential to cut off over the central/eastern Great
Lakes Saturday night into Sunday. Numerous Showers and a few
thunderstorms are likely on Saturday. A lower chance of showers
continues into Sunday under cool cyclonic flow around as 850 MB
temps drop below 10 C.

Temperatures look to remain near normal through the forecast period.
High temperatures will generally hover within a few degrees of 80
degrees depending on the day, with overnight lows dropping into the
50s most nights.

&&

.MARINE...

Northwest flow takes hold this morning in the wake of a departing
cold front. High pressure will fill in through the day which will
promote light winds and dry weather, and will bring some more
variable wind direction by the afternoon before veering winds east
for portions of the southern Great Lakes. High pressure holds
through Friday morning before departing east across the continental
northeast. Active weather returns Friday afternoon and into the
weekend as a cold front moves through the region. Rain showers and
thunderstorms will become increasingly likely ahead of and along the
cold front.

&&

.PREV DISCUSSION...
Issued at 1201 AM EDT Wed Aug 19 2026

AVIATION...

A weak frontal boundary moving across the region is leading to
increasing coverage of showers through the early morning hours.
Isolated thunderstorm chances exist, but low probability will
continue to preclude mention at this time as observations have also
shown decreasing lightning potential as activity moves through. There
will be a chance for lower stratus in the immediate wake of the
frontal passage which may bring intervals of MVFR ceilings roughly
between 08-13Z. Ceilings currently expected to lift into VFR by late
tomorrow morning or early afternoon with post frontal northwesterly
winds that will eventually turn out of the N-NE in the evening.

D21/DTW Convection...Very limited chance of an isolated thunderstorm
through 10Z.

DTW THRESHOLD PROBABILITIES...

* Medium for ceiling at or below 5000 feet tonight, and high
  later this morning.

* Very low for thunderstorms through the early morning hours.


&&

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

$$

DISCUSSION...SF
MARINE.......AM
AVIATION.....AA


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at www.weather.gov/detroit.