244
FXUS63 KDTX 141903
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
303 PM EDT Tue Oct 14 2025

.KEY MESSAGES...

- There is a low chance for light rain tonight into early Wednesday
morning.

- Dry weather and normal mid October temperatures resume Wednesday
afternoon through Thursday.

- Warmer air but a more active rain pattern is expected Friday
through this weekend.

&&

.DISCUSSION...

Expansive sfc high pressure centered over the Minnesota boundary
waters region will drift east to Lake Superior by Wed morning. This
will sustain a feed of low level dry air across Se Mi within
persistent north-northeast winds. Ongoing mid level moisture
convergence is however resulting in an expanding area of rain across
the upper Midwest. The ageostrophic response associated with an
upper jet streak interacting with the mid tropospheric front is
driving this region of forcing. Recent adjustments among the 12Z hi
res guidance suggests the higher based frontogenetical forcing will
track across the Saginaw Valley and thumb region during the first
half of the night, with the frontal forcing becoming more focused
farther south late tonight through daybreak Wednesday. The very
elevated and somewhat brief duration of the better forcing will be
offset by the formidable layer of dry air in the low levels. These
factors, with support of latest probabilistic guidance, warrants low
chance pops tonight with QPF ranging from a trace to a few
hundredths of an inch at best.

High pressure will gradually expand across Lower Mi Wednesday into
Thursday as high amplitude ridging builds across the western Great
Lakes. Expansive clouds are expected Wednesday morning, both a
result of mid/high level clouds associated with the elevated frontal
system and some lower clouds resulting from the moisture flux off
Lake Huron. Deep layer dry air advection through the afternoon will
clear skies out by late day. This will at least open the door to
some late day diurnal mixing, allowing temps to rebound into the low
60s after early morning readings in the 40s. Optimal radiational
cooling conditions Wed night/Thurs morning will support low temps in
the 30s outside the metro Detroit heat island (40s in Detroit).
Sunny and seasonally cool temps will prevail through Thursday with
the sfc high overhead.

Amplification of the long wave trough over the Upper Midwest is
forecast Friday into Saturday. This will force deep layer southwest
flow to take hold across Lower Mi, advecting a warmer and more
moisture laden airmass into the forecast area. The Medium range
model suite all suggest additional amplification within the base of
the long wave trough over the Ohio Valley during the latter half of
the weekend. The has the potential to be a stronger and more dynamic
system, potentially bringing a more widespread region of rain to the
forecast area. At this stage in the forecast, there is still ample
variability on timing and strength. Generally mild with high rain
chances will remain warranted through the weekend at this time.

&&

.MARINE...

A cold front will move across the Great Lakes late tonight through
tomorrow morning which will veer wind direction from northwest to
northeast. Sustained winds around 20 knots with gusts up to 25 knots
across Lake Huron will increase wave heights into the outer Saginaw
Bay and along the Lake Huron through the morning, where Small Craft
Advisories are in place. Rain showers will also be possible with the
passage of the front. High pressure will then quickly fill in
tomorrow and will hold through Thursday, which will bring light
winds and dry weather.

&&

.PREV DISCUSSION...
Issued at 1237 PM EDT Tue Oct 14 2025

AVIATION...

Low level moisture pooling along a cold front will continue to sink
south this afternoon with just enough moisture to support a period
of sct-bkn low clouds (1.5-5 kft). Otherwise, drier air and
clear/mostly clear skies work in from north to south late this
afternooon into early evening. Mid/high clouds ramp up the rest of
the evening and especially tonight, with some high based
showers/sprinkles possible as elevated warm front lifts into the
western Great Lakes. Any light rain activity surviving the trip east
is not expected to impact visibility very much, and with the
uncertainty on location, no tafs will mention rain at this time. Mid
deck of clouds will hold through Wednesday morning with light north-
northeast winds at the surface.

For DTW/D21 Convection...No thunderstorms through the TAF period.

DTW THRESHOLD PROBABILITIES...

*  Medium for ceilings at or below 5000 ft this afternoon.


&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...Small Craft Advisory until 5 PM EDT Wednesday for LHZ421-441.

     Small Craft Advisory until 5 PM EDT Wednesday for LHZ442-443.

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

$$

DISCUSSION...SC
MARINE.......AM
AVIATION.....SF


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at www.weather.gov/detroit.