St. Clair Shores, Michigan 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

606
FXUS63 KDTX 041625
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1225 PM EDT Mon May 4 2026

.KEY MESSAGES...

- Mild and breezy today.

- A chance of thunderstorms this evening into tonight. Some storms
may be strong or severe south of the I-69 corridor.

- Much cooler temperatures return Tuesday and last through the end
of the week.

&&

.AVIATION...

Well-mixed boundary layer allowing for southwest winds to gust AOA
25 knots this afternoon. Despite the moderate southwest winds, low-
level moisture is slow to advect into the state, and a cap should
hold through 20Z, limiting low cloud development. A chance of
showers and storms develop over the southern TAFs during the evening
hours. A cold front slowly tracking through tonight brings a chance
of showers and low VFR/borderline MVFR ceilings, with embedded
thunder not out of the question.

D21/DTW Convection...Inherited timing of 23Z-03Z for thunderstorms
looks good, but confidence in a direct impact is still not high
enough to upgrade from PROB30. Strong wind gusts and hail are
possible should a strong or severe storm intersect the airfield.
Heavy downpours could result in brief IFR reductions. Additional
showers are expected overnight into Tuesday morning as a cold front
tracks through, some of which could include embedded thunder. Winds
will shift to the northwest mid-to-late Tuesday morning.

.DTW THRESHOLD PROBABILITIES...

* Low for thunderstorms this evening and tonight.

* Low for ceiling at or below 5000 feet this evening and tonight;
  medium tomorrow.

&&

.PREV DISCUSSION...
Issued at 300 AM EDT Mon May 4 2026

DISCUSSION...

Subtle mid level height rises and warming in the 900 to 700mb layer
today will result in a formidable mid level cap by afternoon. There
will be a good deal of sunshine through much of the day given the
subsidence and dry air. Deep layer mixing up to 7k feet with 850mb
temps forecast to rise to +10 to +11C this afternoon will support
high temps in the mid 70s across much of the forecast area today.
While not as windy as yesterday, model soundings still indicate a
solid core of southwest winds of 25 to 30 knots in the mixed layer,
which will support peak gusts in the 30-35 MPH range.

The gradual northward advection of a little higher boundary layer
moisture (characterized by sfc dewpoints in the 50s) from the Ohio
Valley into the southern portions of the forecast area late this
afternoon and evening is shown by the 00Z model suite. This will
support modest instability with 0-1km ML CAPE forecast to reach 1k
J/kg per latest HRRR. SREF Surface based CAPE actually ranges from
1500 to 2000 J/kg in the far south. Forecast strengthening of the
low to mid level SW wind fields across the nrn Ohio Vally this
evening may support enough forced ascent across the srn portions of
the area this evening to initiate convection. 0-6km bulk shear values
during the evening are forecast to be a modest 20 to 30 knots. Model
soundings do however indicate ample mid level dry air, suggestive of
the potential for localized damaging winds and large hail. The HRRR
and 3km NAM do indicate a localized axis of increased 0-3km helicity
along the lead edge of the northward advancing boundary layer
moisture axis during the evening, which may be supportive of a few
supercells.

A surface cold front will be driven into Se Mi overnight courtesy of
long wave trough amplification/mid level height falls across the
Upper Midwest and northern Great Lakes. An influx of deep layer
moisture will advect into Se Mi along and ahead of this front, with
the surface based instability forecast to transition to elevated
instability. This will support high chances for showers and
thunderstorms. There is some variation among the hi res suite as to
the available elevated instability, ranging from very little up to
1500 J/kg, with HREF around 500 J/kg. Given increasing deep layer
shear profiles, lingering strong to possibly severe storms into the
overnight are at least possible predicated on enough available
instability.

The surface cold front is forecast to slowly move east of the
forecast area on Tuesday. Favorable upper jet dynamics and potential
short wave impulses lifting northeastward along the mid level
baroclinic zone is forecast to increase frontogenesis along the
elevated portions of the frontal zone Tuesday, possibly into Tuesday
night. Recent 00Z model runs have trended a little more
southeastward with the axis of forcing over southeast Michigan, in
line with recent trends in the ensemble members. This will place the
better chances for rain generally southeast of a Bad Axe to Owosso
line, with the chances for heavy rain (over and inch) now more
probable just east of the forecast area. Shallow post frontal cold
air will lead to notably cooler temperatures on Tuesday. The long
wave trough is forecast to hold across the upper Midwest and Great
Lakes region through the end of the week, leading to seasonally cool
temperatures with daytime highs in the 50s and nighttime lows in the
30s and 40s.

MARINE...

A brief lull in the slightly more elevated wind speeds will be
likely through the late morning to early afternoon hours, outside of
the Saginaw Bay where the southwest fetch remains favorable for
localized higher winds. Some gust potential around 20 knots also
remains possible across Lake Erie and Saginaw Bay given the brief
reduction in stability through the morning hours. This lull in
breezy conditions will be supported by increasing stability through
the day as much warmer air surges over the Great Lakes. Isolated to
scattered showers and embedded thunderstorms will be possible within
the warm sector later this afternoon and evening, most favorable
across Lake Erie and Lake St. Clair. Any stronger storm development
will be capable of producing gusts aoa 34 knots. A broken line of
showers will be possible with the cold front, with wind direction
veering northwest in the wake of the front. Small Craft Advisories
remain in effect through the Saginaw Bay as wave heights build
towards the 4 ft mark, with the stronger wind potential favored for
this evening through early tomorrow morning.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...Small Craft Advisory until 10 PM EDT this evening for LHZ421-422.

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

$$

AVIATION.....SF
DISCUSSION...SC
MARINE.......AM


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