721
FXUS63 KDTX 052303
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
703 PM EDT Tue Aug 5 2025

.KEY MESSAGES...

- Temperatures gradually moderate into the mid/upper 80s through mid-
  week. By late week, upper 80s to 90 degrees with very humid
  conditions can be expected.

- Hazy skies again today due to Canadian wildfire smoke.

- A few pop-up showers possible late this afternoon-evening,
  scattered shower and an isolated thunderstorm chances Wednesday.

- Isolated shower chance Friday, otherwise dry weather develops for
  the late week/weekend timeframe.

&&

.AVIATION...

Late afternoon peak heating produced a few pop-up showers that are
quickly exhausting instability at forecast issuance. Observations
also indicate some improvement in near-surface smoke density that
carries through the evening. Visibility then drops back down into
MVFR as the boundary layer stabilizes late tonight through sunrise.
Surface wind becomes light with a lingering easterly component and
then picks up slightly by late morning, enough to support model
projections of more smoke filtering in from southern Ontario.
Otherwise, convective debris clouds fade this evening followed by
some mid cloud redevelopment during the late night. These clouds
lead into another round of cumulus building in a fashion similar to
this afternoon with a stray shower/thunder rumble once again
possible.

For DTW/D21 Convection... Low-end potential exists for an isolated
thunderstorm Wednesday afternoon, however with low predictability on
location and duration.

THRESHOLD PROBABILITIES...

* Low for thunder Wednesday afternoon.

&&

.PREV DISCUSSION...
Issued at 254 PM EDT Tue Aug 5 2025

DISCUSSION...

Lingering Canadian wildfire smoke has kept hazy skies in place again
today. With governing surface high pressure sliding into
northwestern Quebec, winds shift to the southeast later this
afternoon. This should aid in gradually clearing the worst of the
smoke out of the local areas however also draws in slightly richer
theta-e from Lake Erie/northern Ohio. Forcing mechanisms are limited
however areas of weak surface convergence offer a shot to see a few
pop-up showers late afternoon-evening. Best areas for potential
convergent wind are towards the southern Saginaw Valley/western I-69
corridor as wind funneling out the Bay hold more northeasterly amid
the broader wind shift and towards the I-94 corridor due to the
influence of Lake Erie.

Area of low amplitude mid-upper troughing slides across the central
Great Lakes daytime Wednesday setting up more organized southeast
flow into the area. Similar to today, this advects a hybrid Lake
Erie/northern OH richer theta-e airmass into southern lower MI,
particularly towards the central portions. CAMs still advertise a
healthy moisture gradient developing roughly near I-75/US-23 leading
this corridor being the favored area to see pop-up (thunder)showers,
especially if meaningful differential heating can manifest. Rain
chances quickly taper off near sunset with the loss of diurnal
heating and the trough vacating for the eastern Great Lakes.

Amplifying upper ridging across the central CONUS then becomes the
dominant factor for the late week into this weekend. Lower level
southwesterly flow renews advection of a hot, humid airmass confined
over the Plains towards the Great Lakes. While the core of this
airmass looks to stay well to our south/west, 850mb temps will reach
16-18C by Friday pushing highs to near or into the lower 90s as
surface dewpoints push toward the mid-upper 60s. Overall rain
potential during this timeframe is limited to the periphery of the
ridge leading in/out. Leading in Friday, the lead edge of the
accompanying theta-e plume is supportive of scattered shower/storm
development however with the main advective push directed toward
Lake Michigan, primary rain chances are largely confined to
western/northern lower MI. Ridge influence wanes Sunday before fully
breaking down Monday as broad upper troughing drifts over the Hudson
Bay. A weak associated cold front attempts to sink towards the Great
Lakes Monday offering the next chances for scattered rain over
portions of SE MI. Long range models do suggest this boundary
lingers/stalls near the central Great Lakes becoming the focal point
for additional unsettled weather through mid next week.

MARINE...

Area of high pressure to the north is continuing to drift eastward
across Canada through mid week before settling over far eastern
Canada and the New England states. Winds will veer from
northeasterly today, to easterly on Wednesday, before becoming
southeasterly for the latter half of the week once the high reaches
New England. Dry conditions through Wednesday with  some low end
chances for showers returning Thursday into Friday as a weak warm
front passes over northern Lake Huron.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.

&&

$$

AVIATION.....BT
DISCUSSION...KDK
MARINE.......DRK


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