868
FXUS63 KDTX 021743
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1243 PM EST Sun Nov 2 2025

.KEY MESSAGES...

- Breezy conditions Monday as a cold front crosses the region. There
  is a chance that peak gusts may fall into the 35 to 45 MPH range.
  Chances for rain favored toward the Tri Cities and northern Thumb.

&&

.AVIATION...

Increasing SW flow dominates conditions across SE Mi this afternoon
and evening as streamlines originate from mid MS valley high
pressure and associated low level dry air. The exception is a narrow
plume of residual Lake Michigan moisture that is adequate for
scattered to broken cumulus. VFR is otherwise maintained in this
setup under clear sky followed by gradually increasing high clouds
ahead of the Midwest cold front tonight. Also tonight, low level jet
development requires a mention of LLWS until the cold front sweeps
through the region Monday morning. A broken band of showers moves in
toward the MBS area by sunrise accompanied by MVFR ceiling within
and ahead of the front that collectively slide across SE Mi and exit
eastward by late morning. Clouds decrease while wind returns as the
weather highlight increasing to gusts around 30 knots post front
Monday afternoon.

For DTW/D21 Convection...No thunderstorms today through Monday.

DTW THRESHOLD PROBABILITIES...

*  Low for ceiling 5000 feet or less this afternoon and tonight.
   High Sunday morning.

&&

.PREV DISCUSSION...
Issued at 309 AM EST Sun Nov 2 2025

DISCUSSION...

Medium range guidance supports high index flow setting up across
much of central North America and Great Lakes throughout the upcoming
next 7 days. High periodicity of shortwaves is anticipated with
shorter duration weather events.

Quiet weather is the narrative today with differential anticyclonic
vorticity advection supporting synoptic scale subsidence over the
region. Deep downward vertical motion between 5.0 and 20.0 kft agl
is forecasted to lower significantly the latter half of today.
Pleasant early November weather with sunshine, modest southwest
wind, and temperatures well into the 50s.

Exit region to very strong, anticyclonically curved upper level jet
stream will bulldoze into the northern Great Lakes region tonight.
Models show a reorientation and organization to deep composite
trough at least into northern Lake Huron region by 12z Monday.
Geopotential height falls are not over the area for much of any
duration with greatest forcing flashing south and eastward rapidly.
Models do show some 850-700mb fgen over portions of northern and
central Lower Michigan this evening, but then falling apart. Best of
forcing appears to be lead shortwave energy firehosing across the
forecast area, particularly north. Given the depth of moisture,
coverage may be good but very brief across the Saginaw Bay region
and Thumb 09-13z, not much confidence in anything south of M 46/I
69. Daytime heating and steepening boundary layer lapse rates brings
potential for breezy west wind conditions Monday. Hires based mixing
based technique probabilities suggest 30 to 35 mph Monday afternoon
with the best potential for strongest winds downwind of Saginaw Bay
over the northern Thumb.

Very broad upper level and surface based ridging forecasted to
expand across Lower Michigan late Monday through early Wednesday.
Bottom line is dry weather with temperatures in the upper 50s.

Models are reasonably converging on a solution that brings a Clipper
System to the northern Great Lakes Wednesday and Thursday. Inbound
trajectory from the northwest into the area suggests a very short
residence time and short duration to any frontal forcing. Depending
on how the thermal fields align could be looking at breezy
conditions developing in the cold advection regime.

Continuing low amplitude high index flow suggests progressive
ridging on Thursday and Friday before the next exit region to upper
level jet impulse arrives sometime next weekend.

MARINE...

A diffuse high pressure system will hold across the Great Lakes
today which will maintain light winds through the first half of the
day. There remains a low chance for some isolated light shower
development across Lake Huron this morning, but otherwise most
locations are expected to remain dry. Attention will then turn to a
cold front which will bring unsettled conditions across Lake Huron
late tonight and through most of the day tomorrow. Ahead of this
front, winds back to the southwest through the late morning and
afternoon hours, with sustained winds speeds ramping up shortly
thereafter. Wind speeds increase to around 25 to 30 knots late
tonight, while gusts to gales become increasingly likely, initially
across north and central Lake Huron.

Expect wind direction to veer west-northwest tomorrow after the
passage of the cold front, where improved mixing depths will sustain
the chances for gust to gales through the day. A Gale Warning is now
in effect for the Saginaw Bay and greater portion of Lake Huron.
Small Craft Advisories are also in effect through a portion of the
forecast area. Last, scattered to numerous showers are likely with
the frontal passage.

A ridge of high pressure will build in Tuesday, bringing respite
from unsettled conditions. A second low pressure system may build
back in on Wednesday, bringing back elevated winds and gusts through
the midweek period.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...None.

Lake Huron...Small Craft Advisory from 10 PM this evening to 10 PM EST Monday
     for LHZ442-443.

     Gale Warning from 10 PM this evening to 10 PM EST Monday for
     LHZ361>363-421-441-462>464.

     Gale Warning from 10 PM this evening to 10 AM EST Monday for LHZ422.

Lake St Clair...Small Craft Advisory from 10 PM this evening to 10 PM EST Monday
     for LCZ460.

Michigan waters of Lake Erie...Small Craft Advisory from 10 PM this evening to 10 PM EST Monday
     for LEZ444.

&&

$$

AVIATION.....BT
DISCUSSION...CB
MARINE.......CB


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