Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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371
FXUS63 KDTX 061901
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
301 PM EDT Mon Oct 6 2025

.KEY MESSAGES...

- Showers and scattered thunderstorms tonight and overnight, with
showers lingering into tomorrow afternoon.

- Much cooler conditions Tuesday through the end of the week.

&&

.DISCUSSION...

Last day of the anomalously warmer temperatures is underway under
brisk southwest flow which have propelled temperatures back into the
80s this afternoon. A stark change in temperatures will arrive by
tomorrow after the passage of a cold front, which also brings shower
and thunderstorm chances.

A strong shortwave impulse will round into western Ontario through
the day today and will amplify the greater trough feature through
the northern Plains, aiding in the continued progression of a strong
cold front that now extends through northern lower Michigan. Slow
progression of the front will continue through the morning hours
tomorrow as deep-layer steering flow remains largely parallel to the
boundary. As the front arrives within the vicinity of and over SE
MI, numerous showers with embedded thunderstorms will move in, aided
from the efficient deep transport of high theta-e moisture coupled
with elevated instability.

Hi-res models continue to pick up on the potential for prefrontal
development late tonight through Midnight favored across the Tri-
Cities and Thumb. Unidirectional wind direction could promote some
isl to sct pulse or linear segmented convection. Some pockets of
localized gusty winds will be possible with this activity, but the
overall elevated nature precludes any stronger wording of damaging
gust potential. Frontal progression will then pick up through the mid
to late morning hours as flow aloft veers, enhancing the
frontogenetic response, especially across the Tri-Cities and Thumb.
The cold front and subsequent rain chances clear the cwa entirely in
the afternoon hours.

An anomalously strong surface high pressure system is then set to
build into the area through the midweek period, with central SLP
values expected to reach of exceed the 99.5th percentile of the
climatological distribution for this time of year. The extreme
strength is amplified by a synergistic dynamic setup. Specifically,
the Great Lakes will be situated beneath the right exit region of the
nnw-sse jet over Ontario which will maximize upper-level confluent
flow. Coupled with cold air advection in the low levels through 850mb
which increases density of the column, SLP increases and peaks by
Thursday morning. The passage of the cold front and thermal trough
brings stark temperature changes Tues-Thurs afternoon with highs in
the low to mid 60s and lows 30s (Wed-Fri morning). The coolest night
will likely be Thursday morning as lows drop into the low to mid 30s,
which will bring frost and freeze concerns. Otherwise, this
aforementioned setup brings dry weather and clear skies through the
midweek period.

&&

.MARINE...

A cold front will continue to slowly track south through the Central
Great Lakes this evening and tonight, with blossoming showers and
embedded thunderstorms expected. Stronger thunderstorms will be
capable of producing wind gusts of 35+ knots.

Post frontal cold air advection through tomorrow as 850 MB temps
fall into the low single numbers to near zero. A period of wind
gusts up to 30 knots is expected across northern Lake Huron Tuesday
evening with the increased boundary layer before winds slowly
diminish and veer north-northeast on Wednesday as expansive high
pressure arrives. Despite winds diminishing, the northerly flow will
lead to larger waves over the southern Lake Huron basin Tuesday
evening into Wednesday, with small craft advisories needed during
this time for the nearshore waters as the cold airmass leads to
unstable low level profiles conducive to good wave growth with the
long north-northeast fetch.

&&

.HYDROLOGY...

A cold front will bring numerous showers with embedded thunderstorms
to SE MI late tonight through tomorrow morning. Basin averaged
rainfall totals are expected to range between a quarter-inch to a
half-inch of rainfall, with some localized higher amounts likely
with any repeated shower or thunderstorm activity. The most likely
location for repeated activity will reside along or north of I-69,
through the Tri-Cities and Thumb, where totals closer to an inch or
more will be possible. Given the antecedent dry conditions,
localized flooding is not expected.

&&

.PREV DISCUSSION...
Issued at 143 PM EDT Mon Oct 6 2025

AVIATION...

VFR conditions will prevail through the remainder of the daylight
hours with scattered clouds at 5-10 kft. Southwest winds gusting to
to 15-20 knots this afternoon will also ease towards 00Z this
evening. Increasing moisture tonight ahead of a cold front will bring
rain/thunderstorms chances along with lowering cigs/vsbys. MVFR to
periodic IFR ceilings can be expected as precipitation rolls through.
Showers and thunderstorms taper off from north to south, clearing
east of the southern metro terminals by around 18Z tomorrow
afternoon. A wind shift from southwesterly to northerly post front
will occur at MBS after 06Z with eventual passage south of DTW by
around 16-17Z tomorrow. Post frontal environment will also see
ceilings lift back to VFR.

For DTW/D21 Convection...Thunderstorm activity late today/tonight
stays north of DTW. There is then a low chance (30%) for
thunderstorms to impact the airspace tomorrow morning as early as
07z, but more likely between 10z and 14z.

DTW THRESHOLD PROBABILITIES...

* Low for ceiling 5000 ft or less through this evening, increasing
  to high by early tomorrow morning.

* Low for thunderstorms tomorrow morning between 10z and 14z.


&&

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

$$

DISCUSSION...AM
MARINE.......AM
HYDROLOGY....AM
AVIATION.....AA


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at www.weather.gov/detroit.