945
FXUS63 KDTX 031915
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
315 PM EDT Fri Oct 3 2025

.KEY MESSAGES...

- Dry with near record warmth this weekend.

- The next chance of rain arrives late Monday into Tuesday.

- More seasonable temperatures are expected mid next week.

&&

.DISCUSSION...

A longwave ridge slowly migrates over the Great Lakes and eastern
CONUS through the weekend, ensuring summer-like warmth remains
entrenched over the region. 500mb heights and 850mb temps hold
near/above the 90th percentile through this period, at ~585 dam and
14 to 16 C respectively. The pressure gradient strengthens between a
surface high parked over the Mid-Atlantic and a deepening
trough/frontal zone over the northern Plains. This produces enough
southwesterly wind for deep mixing into the anomalously warm air
mass to result in high temps well into the 80s each day. A slight
uptick in low to mid-level moisture on Saturday should result in a
more robust coverage of diurnal cu, but prospects for any
precipitation are slim given high stability with the warm mid-
levels. High temps will reach the mid 80s Saturday with high 80s not
out of the question in the Saginaw Valley where downsloping plays a
role. Similar conditions on Sunday but with slightly lower humidity
levels. Lows will dip into the 50s and lower 60s each night.

Another hot day in the 80s on Monday with the last vestiges of the
ridge easing out of the area through the day. Stable conditions hold
through the early part of the day but the gradual height falls and
weak embedded shortwave activity will induce mid-level cooling that
may result in some marginal late day instability. There will be a
chance of showers and thunderstorms, mainly across the north, late
Monday into Monday night as the aforementioned frontal zone works in
from the west. Moisture transport and prefrontal convergence will be
relatively weak this far east through this period, so widespread
precipitation is not anticipated.

The better chance for showers and thunderstorms will arrive on
Tuesday as a strong shortwave dropping out of Manitoba/NW Ontario
sends the cold front across the state. Still room for timing
adjustment of highest shower coverage (Tuesday morning vs evening)
as medium range guidance differs on when the best ascent and fgen
tied to the right entrance region of the jet rolls through. Ensemble
mean QPF through this period is on the order of 0.25" to 0.50", but
interquartile range of LREF and NBM guidance showcases a high amount
of uncertainty - ranging from 0.10" to around 1.00". If frontal
timing is on the slower end of guidance, marginal instability and
increasing bulk wind shear may support some gusty convection Tuesday
afternoon/evening. High pressure then builds in behind the front
from Wednesday into Thursday with cooler air bringing weather more
typical of October.

&&

.MARINE...

Western periphery of high pressure continues to promote dry
conditions and light winds through the day. A series of low pressure
systems will then travel from the northern Plains into the James Bay
through the weekend. While this will not result in any significant
changes across the Great Lakes, this will strengthen the pressure
gradient slightly, reinforcing southerly flow across Lake Huron with
gust potential ranging between 15 to 20 knots. Much bigger changes
will move in on Monday as a strong cold front sweeps across the
Great Lakes. Prior the passage of the front, south flow wind speeds
will increase, with frontal passage then quickly veering wind
direction to north-northwest. Intrusion of cooler air Tuesday will
bring continuation of breezy conditions, but exact magnitude of gust
potential remains uncertain at this time.

&&

.CLIMATE...

The record highs for Saturday, October 4th.

Detroit: 89 Degrees (Set in 1951)
Flint:   88 Degrees (Set in 1951)
Saginaw: 87 Degrees (Set in 1967)

The record highs for Sunday, October 5th.

Detroit: 88 Degrees (Set in 1951)
Flint:   88 Degrees (Set in 1922)
Saginaw: 86 Degrees (Set in 2007)

&&

.PREV DISCUSSION...
Issued at 146 PM EDT Fri Oct 3 2025

AVIATION...

Extended stretch of VFR conditions continue throughout this taf
period, as persistent high pressure maintains a dry and stable
environment. Limited high based diurnal cumulus development each
day. Combination of dry conditions and light southerly wind will
again limit fog potential late tonight.

For DTW/D21 Convection... Thunderstorms will not occur through the
forecast period.

DTW THRESHOLD PROBABILITIES...

* None.


&&

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

$$

DISCUSSION...TF
MARINE.......AM
CLIMATE......MV
AVIATION.....MR


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