261
FXUS63 KDTX 130750
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
350 AM EDT Mon Oct 13 2025

.KEY MESSAGES...

- Dry weather to start the week with temperatures 5 to 10 degrees
  above normal.

- A dry cold front moves through the area Tuesday leading to cooler
  temperatures Wednesday.

- There is also an increasing probability of rain Wednesday morning,
  currently at about 30 percent.

- Dry weather and normal mid October temperatures resume during the
  late week.

&&

.DISCUSSION...

Late night/early morning observations show mild air entrenched
across the central Great Lakes that is heavily augmented by moisture
from Lake Huron, Erie, and also Lake Ontario given the easterly wind
trajectories. This means another round of fog and stratus across
Lower Mi with varying coverage depending on surface wind resilience.
Cirrus inbound from the Midwest frontal zone does little to disrupt
the otherwise standard mid October daytime heating influence on fog
and stratus trends during the morning. The boundary layer moisture
then mixes into a cumulus field just as clouds from the Midwest cold
front approach from western Lower Mi this afternoon. Upstream
observations at press time support model initializations of a broken
band of rain showers within the leading theta-e ridge. Model
agreement also remains overwhelming on dissipation of the showers as
the front moves into Lower Mi well to the south and east of mid
level short wave and upper jet support in Canada. The 500 mb ridge
is actually shown to build over the central Great Lakes today until
getting nudged eastward which allows the front to finish moving
through SE Mi Tuesday morning. Until then, temperatures continue a
run of 5 to 10 degrees above normal today and Tuesday before low
level cold advection gains traction Tuesday night.

Wednesday is set to be the coolest day of the week as Canadian high
pressure builds into Lower Mi dropping high temperatures back into
the upper 50s to lower 60s. Clouds will also be a factor along with
increasing probability for rain as elevated sections of the Tuesday
front linger overhead. The surface front is well south toward the
Ohio valley while the 850-700 mb theta-e gradient sets up across
Lower Mi late Tuesday night and Wednesday morning. Consensus of
deterministic models is trending upward on rain probability during
this time as the upper jet and a low amplitude 500 mb wave activate
the mid level frontal zone until driving the pattern south of the
IN/OH border by afternoon.

The larger scale mid and upper level flow amplifies considerably
during late week resulting in a ridge centered on the Midwest by
Thursday. This supports dry weather and a broad area of surface high
pressure across the central Great Lakes. Extended range/global model
solutions are then in general agreement on slow eastward progression
of the ridge across Lower Mi through Friday. Solutions are mixed on
the eastward extent of precipitation by then as a large low pressure
and frontal system organize from central Canada down through the
Plains heading into next weekend.

&&

.MARINE...

Influence of ridging gradually wanes today as winds turn more
southeasterly. Low pressure lifting out over the Hudson Bay allows
the local gradient to slacken resulting in winds falling below 15kts
by this afternoon and persisting through most of tonight. Associated
cold front eventually pivots across the central Great Lakes ushering
in moderate northwesterly flow Tuesday with peak gusts reaching
between 20-30kts- strongest over the open water zones of Lake Huron.
Small craft advisories will likely be needed around the Thumb due to
the favorable wind direction bringing higher wave action into the
nearshore waters. A few light showers are also possible along this
front late Tuesday however the bulk of the region remains dry. High
pressure sinking out of the Canadian Prairie then builds across the
region midweek.

&&

.PREV DISCUSSION...
Issued at 1153 PM EDT Sun Oct 12 2025

AVIATION...

Surface ridging will hold over Southeast Michigan throughout the
period. Uptick in surface moisture with dewpoints in the lower 50s
brings the prospects for a persistence forecast and br/fg at
daybreak. Did maintain BKN IFR ceilings with the TEMPO group for
fog. Conditional to fog development, stratus is anticipated for a
portion of Monday. Maintained MVFR ceilings mid morning Monday.

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

DTW THRESHOLD PROBABILITIES...

*  Medium for ceilings aob 5000 ft agl after 10Z Monday.

*  Medium for visibilities aob 1/2 sm or ceilings aob 200 ft 09z-13z
   Monday morning.


&&

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

$$

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


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