NWS Forecast Discussion

786
FXUS63 KDTX 090442
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1142 PM EST Sun Nov 8 2026

.KEY MESSAGES...

-Dry and Warm early week: Temperatures reach well into the 50s
Monday through Wednesday, with lower 60s likely on Tuesday.

-Mid-week uncertainty: Rain chances increase late Wednesday into
Thursday, but models disagree on exact locations and coverage.

-Cold shift late week: A much colder airmass moves in Thursday,
holding highs in the 40s into the weekend. The drop in temperature
over the warm lake waters brings the season`s first solid chance for
lake-effect rain and snow showers late Thursday through Saturday.

&&

.AVIATION...

Invigorated absolute vorticity is sliding due southward within the
upper level troughing to the tip of the Thumb. The differential
vorticity advection has resulted in an added component favorable for
synoptic lift. Moisture remains very limited with saturation shown
to be shallow. The potential for rain showers and/or virga is
expected to remain greater for areas to the north and east of MBS.
Have included a VFR ceiling for the northern taf sites across the
south. Height rises with warm advection aloft is expected to result
in a high cloud ceiling on Monday.


.DTW THRESHOLD PROBABILITIES...

* Moderate for ceiling at or below 5000 ft tonight.

&&

.PREV DISCUSSION...
Issued at 331 PM EST Sun Nov 8 2026

DISCUSSION...

The upcoming 7-day period is defined by a distinct two-phase
evolution of the hemispheric upper-air pattern across North America:
an initial fast, low-amplitude pseudo-zonal/progressive regime
through Wednesday, followed by a major amplification into a deep
Eastern CONUS longwave trough late week.

(Monday through Wednesday) An energetic Pacific jet stream will
maintain broad west-northwesterly to quasi-zonal flow across the
central and eastern United States to start the work week. A
shortwave trough passing north across Ontario on Monday will push a
moisture-starved cold front through lower Michigan, followed by
brief shortwave ridging into early Wednesday. Subsequent Pacific-
origin shortwave impulses traversing the northern plains will build
500mb heights aloft, reinforcing strong low-level warm air advection
(WAA). As such, Tuesday/Wednesday could end up a bit warmer than
currently forecast depending on the timing and track of upstream
shortwaves traversing the Midwest. Excellent ensemble clustering
yields high confidence for Tuesday, with expected high temperatures
climbing into the upper 50s to lower 60s supported by 925 mb
temperatures in the upper single digits to near +10C under westerly
low-level flow.

Model guidance and ensemble members begin to diverge on the position
and phasing of cyclogenesis developing over the Ohio Valley on
Wednesday and tracking into the Central Appalachians by Thursday. In
fact, current solutions (e.g., 12z Canadian/UKMET/ICON/Euro) keep
the northern and southern stream branches separated longer, keeping
the primary low pressure and bulk of moisture suppressed through the
southeastern United States.

(Thursday night through Sunday) Strong cold air advection (CAA)
behind the departing surface system will scour out the mild Pacific
airmass on Thursday. Southeast Michigan will reside firmly in the
core of the cyclonic upper-level trough by Friday. Steepened low-
and mid-level lapse rates combined with thermal contrast (850 mb
temps dropping to -6C to -8C) over the warm Great Lakes waters will
setup robust lake-effect precipitation structures. This brings the
first legitimate potential for lake-effect rain and snow showers
across the CWA. High temperatures will fall back into the 40s,
slightly below Mid-November climatological normals.

MARINE...

Ontario low pressure is on-track to cross into western Quebec this
evening, with its cold front draped southwestward. As the front
works across the central Great Lakes during the overnight hours,
post-frontal gradient winds veer northwesterly. The ensuing cold
advection promotes favorable mixing depths above relatively warm
lake waters, allowing gusts to reach gale-force for the northern
half of Lake Huron. Given that low-level winds should be bound
between 35 and 40 knots, gusts likely hold within a similar range.
Higher winds and waves are also expected for all nearshore zones,
supporting the continuation of Small Craft Advisories through
tonight. Expect periods of gusts at/above 25 knots and waves in
excess of 4 feet. The pattern quickly shifts and becomes more stable
as high pressure briefly builds in Monday, leading to weaker winds
backing southwesterly. Troughing returns Tuesday as the next clipper
brushes the northern shores of Lake Superior, with its attendant
cold front passing through and shifting winds toward the WNW. Note
that the frontal passage is expected to be mainly dry. Some
potential exists for additional Small Craft Advisories. High
pressure then returns Tuesday night into Wednesday with weaker winds
and lower wave heights.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...Gale Warning until 4 AM EST Monday for LHZ361-362.

     Small Craft Advisory until 10 AM EST Monday for LHZ421.

     Small Craft Advisory until 4 AM EST Monday for LHZ422.

     Small Craft Advisory until 4 PM EST Monday for LHZ441>443.

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

$$

AVIATION.....CB
DISCUSSION...SF
MARINE.......KGK


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NWS DTX Office Area Forecast Discussion