Saint Clair Township, Michigan Weather Forecast Discussion

594
FXUS63 KDTX 071943
AFDDTX
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
343 PM EDT Sun Sep 7 2025
.KEY MESSAGES...
- Chilly with temps falling to near 40 overnight and highs around 70
tomorrow.
- Continued dry weather with a gradual warming trend through the
rest of the week.
&&
.DISCUSSION...
Upper trough axis passes overhead this afternoon with subsidence
beginning to further dry and warm the mid-levels. Ample boundary
layer moisture is still in place for a healthy diurnal cu flare-up,
and even some scattered light showers near Saginaw Bay. Loss of
daytime heating will cause skies to clear and a cold night is in
store as a 850mb thermal trough sits overhead at around 4C, or below
the 10th percentile for the date. Soundings show the boundary layer
decoupling as the center of surface high pressure builds in, which
favors nearly calm winds. Based on dew points, temps should have no
problem falling to the lower 40s by Monday morning. The typical
colder areas - inland/low-lying/rural - will likely dip into the
upper 30s. Some patchy frost will even be possible - highest
potential is in the Saginaw Valley where latest HREF guidance
indicates a 20-40% chance for lows below 37F and a 10-20% chance for
lows below 35F. Do not expect occurrence or impacts to be widespread
enough to warrant a Frost Advisory at this time. Some patchy fog is
also possible before sunrise.
Gradual height rises Monday into Tuesday offer continued benign
weather conditions. Given the chilly start and thermal trough
holding in place, Monday temps only look to rebound to around 70
degrees for a high despite nearly full sun. Surface high pressure
pushes to the east by Tuesday with return flow helping to boost
highs into the mid 70s. A weak cold front stalls across the northern
Great Lakes Wednesday into Thursday, but models fail to produce a
signal for precip locally as upper forcing and moisture transport
are absent. This allows temps to rise toward 80 on Wednesday. The
remnant front shifts winds from the north/northeast by Thursday
which cools the lakeshore areas down slightly, otherwise dry and
seasonable conditions persist through the end of the week. The next
opportunity for precipitation will become possible on Saturday as
the next trough drops across the area.
&&
.MARINE...
The upper level trough is drifting east today away from the Great
Lakes allowing for ridging to slowly build into the region for the
next couple days. Surface high pressure is also building into the
region from the south which has backed the winds to westerly today
and eventually the south for Monday. This will provide a break in
from the cooler pattern with warm advection to start the new week. A
cold front will drift into the northern Great Lakes Tuesday and
stall out and weaken through Wednesday. This could provide some
showers and gusty southwesterly winds across northern Lake Huron but
high pressure will dominate most of the region through mid week.
&&
.PREV DISCUSSION...
Issued at 124 PM EDT Sun Sep 7 2025
AVIATION...
Moderate 10-15kt west winds have drawn renewed moisture in from Lake
Michigan resulting in a healthy coverage of diurnal cu. This cloud
remains firmly VFR (at or above 5kft) through the early evening
before dissipating with sunset. Some areas of patchy fog are
possible late tonight as the center of high pressure reaches SE MI.
High drifts over the region Monday limiting cloud cover and keeping
winds light.
THRESHOLD PROBABILITIES...
* Low for cigs at or below 5000 ft today.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.
&&
$$
DISCUSSION...TF
MARINE.......DRK
AVIATION.....KDK
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at www.weather.gov/detroit.

NWS DTX Office Area Forecast Discussion