786
FXUS63 KDTX 051924
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
324 PM EDT Sun Oct 5 2025

.KEY MESSAGES...

- Summer-like warmth continues into Monday.

- Rain expected Monday night into Tuesday.

- Cooler conditions Tuesday through the end of the week.

&&

.DISCUSSION...

High pressure over the Mid-Atlantic and a deepening low zipping
poleward across northwestern Ontario are responsible for the
southerly breeze extending our stretch of summer-like weather today.
A pocket of dry air above 800mb precludes a precip mention through
the rest of the day into tonight with the persistent gradient wind
keeping conditions very mild into tonight. Forecast lows Monday
morning in the upper 50s to lower 60s are more characteristic of
early August.

The low quickly tracks toward northern Quebec on Monday, leaving us
within the warm sector another day as its cold front is left behind
within nearly boundary-parallel flow. The front will slowly ease
eastward across the western Great Lakes with humidity gradually
increasing with time. This should reduce mixing to keep highs a
touch lower than today but still very warm for early October, in the
mid 80s. Chances for rain during the daylight hours remain very slim
as there will be a good amount of dry air to overcome. By Monday
evening the front will be inching into Mid MI and the Thumb, with
enough moisture and frontal lift to generate an expanding coverage
of showers across the north around or after sunset.

Showers spread south and east through the course of the night as the
front works in and Gulf moisture arrives ahead of it. PVA and
divergence within the upper jet right entrance region along with the
abundant moisture warrant high PoPs overnight. Weak instability also
brings a chance for some embedded rumbles of thunder, but weak lapse
rates of 6 C/km or preclude stronger convection. PWAT reaches 1.25
to 1.50" which gives higher confidence for moderate rainfall rates
at times. Rain is likely to continue into the first half of Tuesday
as the mid-level front passes over, then probabilities taper off
through the afternoon as mid-level dry air arrives from the west.
The past few cycles of ensemble QPF guidance have remained
relatively stable with highest probabilities for most locations to
receive 0.25 to 0.50" of rainfall. A few totals of 1"+ are not out
of the question where any convection or training occurs. These
amounts may help stabilize drought conditions in a few areas but
will need plenty more rain to start to see improvement.

The surface cold front passes through Tuesday morning with cold
advection ensuing through the day, keeping clouds around and
resulting in significantly cooler temps with highs in the 60s. High
pressure builds in across the Midwest and Great Lakes from Wednesday
into Thursday, sustaining dry conditions with seasonably cool
temperatures - highs in the lower 60s. Mornings will be crisp as we
near climatological first freeze, but as of now temps look to hold
above 32F. Thursday morning stands the best chance to see some frost
across the area with the current forecast offering nearly calm winds
and allowing lows to reach the mid 30s outside of urban areas.
Return flow around the departing high brings the return of slightly
warmer conditions by late week.

&&

.MARINE...

Low pressure tracking through northern Ontario this afternoon and
into James Bay tonight will maintain south-southwest flow into
tomorrow. Winds looks to be mostly in the 15 to 20 knot range, but a
few gusts up to 25 knots will be possible over Lake Huron as cold
front approaches. The continued progression of low pressure into
Quebec will then push a strong cold front across the region late
tomorrow into Tuesday morning. Wind direction will veer to the north
after the passage of the front. Post frontal cold air advection will
sustain breezy conditions across Lake Huron Tuesday as 850 MB temps
fall into the low to mid single numbers. A period of wind gusts in
the 25 to 30 knot range are expected before winds diminish on
Wednesday as expansive high pressure arrives.

&&

.PREV DISCUSSION...
Issued at 132 PM EDT Sun Oct 5 2025

AVIATION...

High amplitude upper level ridging will remain in place over
Southeast Michigan through Monday afternoon. A dry airmass and
strong static stability between 4.0 and 17.0 kft agl will result in
VFR conditions. South winds today will trend to the southwest today
and MOnday.

For DTW/D21 Convection... Thunderstorms will not occur through the
forecast period.

DTW THRESHOLD PROBABILITIES...

* None.


&&

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

$$

DISCUSSION...TF
MARINE.......sf
AVIATION.....CB


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