504
FXUS63 KDTX 011100
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
700 AM EDT Sat Nov 1 2025

.KEY MESSAGES...

- There is a chance for light rain showers to develop today, mainly
between I-94 and I-69.

- 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 towards northern half of the region.

&&

.AVIATION...

A midlevel convergence and deformation axis will become organized
over portions of Southeast Michigan today as upper level low
pressure digs into the Mid Mississippi River Valley. An increase in
moisture at the top of the boundary layer will bring a slight chance
for rain showers this afternoon particularly at the Detroit
terminals. Maintained a Prob30 group for the 18-22z window with VFR
ceilings. A stalled frontal boundary may lead to some low cloud/MVFR
ceilings after 09z tonight but confidence is low.

For DTW/D21 Convection...No thunderstorm activity this taf period.

DTW THRESHOLD PROBABILITIES...

*  Moderate in ceilings aob 5000 feet tonight through to tomorrow.

&&

.PREV DISCUSSION...
Issued at 335 AM EDT Sat Nov 1 2025

DISCUSSION...

Mid-upper trough continues to dive south along the Mississippi river
valley as its associated weak surface circulation forms over
southern Lake Michigan early this morning. As this occurs,
developing deformation axis aided by a subtle remnant surface
convergence boundary from Friday`s lake effect sets up near the I-94
corridor. This axis provides the best chances to generate scattered
light showers today as the background synoptic support is quite weak
due to the main mid-level shortwave/vort max remaining over IL and a
positively tilted upper trough sliding overhead. As a result
however, shower activity that does manage to develop will be
relatively narrow- roughly along/between the I-94/I-96 corridors
through late morning. A shift northward towards the M-59 corridor
looks to occur by early afternoon as the Lake Michigan circulation
pivots down towards the Chicagoland area, though coverage will begin
to steadily decrease through the afternoon-evening as isentropic
ascent wanes with the parent mid-level shortwave reaching the
southern Ohio Valley. Outside of these corridors, the majority of
remaining CWA likely doesn`t see any measurable rain today. Coolest
temperatures with highs struggling to break into the 50s expected
over the central portions of SE MI where greatest shower chances
reside as well as the tip of the Thumb due NNW flow off Lake Huron.
For the rest of the area, temps climb into the lower 50s.

Attention then turns to Monday when a 160kt jet across the northern
CONUS drives a Pacific Northwest originating shortwave across
northern Ontario. While the surface low is progged to track well to
our north over the James Bay, amplifying mid/upper troughing carves
south into the central Great Lakes. Mid-range models still in
disagreement wrt how far south this trough, and by extension rain,
reaches with outcomes ranging from only a glancing shot over the
Saginaw Valley/Thumb to reaching down to the M-59 corridor. There is
much more agreement on timing with the surface cold front crossing
the region the latter half of the day Monday tapering of any
potential showers by evening. Similar to uncertainty with potential
rain coverage, strength of the winds along/immediately following the
fropa is highly dependent on trough position as the strongest
low/mid level winds reside in its base. While a breezy day is likely
for all of SE MI regardless, areas along/north of I-69 stand the
greatest shot at seeing gusts at or above 35mph currently. Though if
the trough tracks further south, these chances to see stronger gusts
would likewise expand south towards Metro Detroit.

High pressure centered over the Tennessee valley then rapidly
expands into lower MI Monday night slackening winds. Influence of
this high holds through Tuesday maintaining lighter winds, dry
conditions, and a moderation in temps back to slightly above normal
in the mid-upper 50s.

MARINE...

Lake effect rain showers will remain possible through the day today
across the south-central and southern Lake Huron basin given the
northwest fetch and subtle cold air advection. There will be a very
low chance for a waterspout with any rain shower. Otherwise, high
pressure will continue to settle over the Great Lakes region today
and will hold for most of the day tomorrow. This will maintain
lighter wind speeds through the bulk of the weekend.

A cold front is then expected to move through on Monday which will
bring the next chance for showers along with breezy conditions. The
pressure gradient will strengthen ahead of the front which will
quickly ramp up southwest flow across the lake late Sunday. Gusts
around 30 knots will be possible prior to the frontal passage. The
subtle boost in cold air advection in the wake of the front elevates
mixing depths late Monday which brings the chance for gust potential
to gales, favored across north and central Lake Huron. Small Craft
Advisories will be likely for a greater portion of the forecast area
through early next week, and a Gale Watch may eventually be needed.

&&

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

$$

AVIATION.....CB
DISCUSSION...KDK
MARINE.......AM


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