Expert Forecast Opinion

994
FXUS63 KDTX 060758
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
358 AM EDT Wed May 6 2026

.KEY MESSAGES...

- Cool today and Thursday with daytime highs in the 50s and overnight
lows in the 30s; some morning frost is possible on Thursday.

- Mainly dry today and Thursday, but isolated late afternoon and/or
evening showers are possible.

- Temperatures recover over the weekend with additional rain chances;
potential exists for thunderstorms Sunday.

&&

.DISCUSSION...

The final round of light showers is finally winding down along the
Michigan/Ohio border as persistent 800-750 mb system-relative ascent
and axis of ThetaE advection drift eastward and exit. Several
continental wave mergers are underway early this morning, but the
most significant is occurring with the northern and southern stream
longwave troughs over the Mississippi Valley. As the day progresses,
the resultant unified jet axis will extend an impressive distance,
some 3,000 miles between the Baja Peninsula and Labrador Sea.
Southeast Michigan will be situated adjacent to the western edge of
the jet streak, and between associated lobes of vorticity. Governing
barotropic low slowly retrogrades over Hudson Bay today which helps
direct colder air aloft into the Great Lakes region. Benign
conditions are favored with this configuration at least through the
midday hours. A packet of mid-level height falls along a shortwave
trough positioned within the mean flow is directed into Lower
Michigan. No meaningful precipitation response is expected with this
feature as a more zonal orientation to tropospheric flow ushers in
drier Canadian air throughout the day. Diurnal mixed-layer will be
fairly developed, extending to the 7-9 kft AGL layer, but capping
above ensures nil instability. At most, could see some virga in some
vertically mature cumuliform clouds. Nocturnal cloud fraction aloft
will dictate frost potential late tonight into Thursday morning.

Anticyclonically curved surface pressure gradient extends into
southern Lower on Thursday while the next embedded shortwave trough
takes aim at the Tri-State area. Non-zero chance for some pop-up
diurnal showers as a ribbon of 850-700 mb moisture spills into the
lower peninsula during the afternoon heating cycle. Both coarse and
high resolution 06.00Z solutions include isolated to scattered
showers/QPF. Thursday is also shaping up to be the coolest day of
the week marked by 850 mb temperatures of -3C to -6C. Highs should
struggle to break out of the mid 50s. Late-day gustiness arises as
lower column flow increases amidst favorable mixing profiles, but
nocturnal cooling should outpace advective cooling after low veers
northwesterly, ending 20-25 knot gusts by late evening.

The unified jet axis orients equatorially through the Tennessee
Valley on Friday, modified by the next shortwave digging into the
Mid-Mississippi Valley. Weak surface reflection is noted in NWP with
precipitation shield clipping the southern forecast area Friday, and
into the overnight hours. Thermal moderation with upward trend in
PWATs aligns with NBM guidance of Chance PoPs at this juncture.
Warmer Saturday with southwest flow ahead of a late weekend cold
front. A period of showers and thunderstorms is probable in relation
to the frontal passage.

&&

.MARINE...

Winds are expected to stay on the light side (under 20 knots) for
the rest of the work week as a weak pressure gradient lingers. This
is despite a cooler airmass in place, with sub zero 850 MB temps.

A pattern of weak clipper systems brings periodic chances for
showers which will continue into the weekend as milder air and
higher moisture levels arrive. As it stands now, this leads to
Saturday night being the primary window for showers and isolated
thunderstorms as a cold front slowly moves through the region.

&&

.PREV DISCUSSION...
Issued at 1148 PM EDT Tue May 5 2026

AVIATION...

Maintenance of dry low level conditions ensures VFR through the taf
period. Expansive area of mid level cloud will persist north of a
frontal boundary overnight. A brief window of clearing may emerge
early Wednesday, before high based diurnal cu development and
expansion occurs for the afternoon and evening periods. Prevailing
winds from the west to northwest.

D21/DTW Convection...No thunderstorms expected through Thursday.

DTW THRESHOLD PROBABILITIES...

* None


&&

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

$$

DISCUSSION...KGK
MARINE.......SF
AVIATION.....MR


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