Expert Forecast Opinion

592
FXUS63 KDTX 091835
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
235 PM EDT Wed Sep 9 2026

.KEY MESSAGES...

- Dry weather with near-normal, pleasant temperatures returns for
Thursday and Friday.

- Mainly dry weather continues through the weekend, accompanied
by slightly above-normal temperatures.

&&

.DISCUSSION...

A moist airmass in place, as the 12z DTX RAOB checked in with a PW
value of 1.99 inches. Thick cloud cover and numerous to widespread
showers tracking through southeast Michigan have limited
instability, and thus thunderstorm development has been hard to come
by. Do not expect any severe storms as MLcape remains under 1000
J/kg through the remainder of the day, and SPC Day 1 has adjusted
the marginal risk south.

Showers end by early this evening as the 850-700 MB Theta-E ridge is
on track to drop south of the border this evening, with much drier
air advecting in through Friday morning, when PW Values bottom out
around 0.5 inch. With this drier air mass and a 1018 MB surface high
over southeast Michigan, efficient radiational cooling areas will
likely see min temps aoa 50 degrees, warming into the upper 70s
during the day under mostly sunny skies.

The large anti-cyclone in place on Friday will be slow to exit east,
and associated 850-700 MB Theta-E trough looks to hold through
Saturday morning before a weak cold front and moisture axis
approaches from the western Great Lakes. Warm mid levels (up to 9 C
at 700 MB) and weak low level convergence certainly could support a
mainly dry frontal passage Saturday evening/night, or even a washing
out boundary that promotes some fog development. Outgoing NBM pops
are under 15 percent Saturday through Sunday.

&&

.MARINE...

Cold front gradually crosses the central Great Lakes this evening
ending further shower/storm chances. Moderate northwesterly flow
follows for Thursday however only a glancing shot of cold advection
and a rapidly diminishing gradient has high pressure builds in caps
winds below 30kts. High pressure then drifts overhead through Friday
night leading to benign marine conditions to close the work week.

&&

.PREV DISCUSSION...
Issued at 149 PM EDT Wed Sep 9 2026

AVIATION...

Edge of upper level Pacific jet streak has carved out a developing
frontal zone over Southeast Michigan this afternoon. Widespread VFR
to MVFR shower activity is in place over the forecast area the first
couple/few hours of the period. A lot of uncertainty whether or not
MVFR ceilings will develop southward into the Detroit terminals.
Based on ceiling height trends at KMBS and KFNT kept 2.5kft agl
ceilings at DTW late this afternoon. Building high pressure tonight
will cause winds to weaken and may bring some light br/hz at
daybreak Thursday.

D21/DTW Convection...Low chance for a thunderstorm this afternoon.

DTW THRESHOLD PROBABILITIES...

* Moderate in ceilings aob 5000 feet today.

* Low for thunderstorms today.


&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...Small Craft Advisory until 10 PM EDT this evening for LHZ421-422-
441.

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

$$

DISCUSSION...SF
MARINE.......KDK
AVIATION.....CB


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