Expert Forecast Opinion

965
FXUS63 KDTX 072239
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
639 PM EDT Wed Oct 7 2026

.KEY MESSAGES...

- Dry conditions with cool to seasonable temperatures Thursday and
Friday; chilly Thursday night with lows in the upper 30s to lower
40s.

- Much warmer Saturday with temperatures in the upper 70s to around
80 degrees.

- Next significant chance of rain arrives for the second half of the
weekend.

&&

.AVIATION...

The cluster of showers and isolated thunderstorms now advancing
across northern Lower Mi will remain north of the Se Mi terminals
this evening as the main mid level forcing driving this will track
across northern Lake Huron. This will leave clear skies across the Se
Mi terminals tonight. Ongoing weak cold air advection within the
west- northwest gradient will keep winds slightly elevated this
evening. Shallow nocturnal boundary layer cooling suggests a likely
drop in wind speeds below 7 knots overnight. Sustained WNW gradient
flow will allow a modest uptick in winds with diurnal heating Thurs
afternoon.

D21/DTW Convection...No thunderstorms forecast during the period.

.DTW THRESHOLD PROBABILITIES...

* None

&&

.PREV DISCUSSION...
Issued at 336 PM EDT Wed Oct 7 2026

DISCUSSION...

Pretty quiet forecast heading through the end of the work week as
the energetic jet stream resides mostly across Canada. Stacked low
centered over Hudson Bay today will send a trough down through the
Great Lakes on the nose of a mid level jet streak tonight. This
opens the door for broad troughing to encompass a portion of the
northern Great Lakes while high pressure slides through the Midwest
into the Ohio Valley building a stable airmass across the southern
Great Lakes. For tonight, northwesterly cool flow over the
relatively warm lakes will provide a boost to instability and though
moisture is weak, PWATs roughly 0.6 inches, there could be enough
concentrated moisture in the region of steeper low/mid level lapse
rates to allow some scattered showers or even a thunderstorm over
the north half of Lake Huron. Further south into the Thumb, moisture
is even thinner and forcing weaker, but the cool airmass and low
level jet could be enough to touch off some scattered showers over
the Thumb this evening into tonight. Current radar over the U.P.
does have thunderstorms present adding to the confidence of weak
storms over northern Huron later.

High pressure then expands back northward across the region ending
any rain chances Thursday into Friday. Cool air within the trough
will drop 850mb temps into the single digits above 0C leading to
cool highs in the 60s to end the week. Clearing skies under the
ridge with the cool airmass in place could allow some low temps to
fall into the upper 30s Thursday night in some of the cooler spots,
otherwise low 40s could be in store for most locations.

Brief but strong warm up on Saturday as strong ridging over the
Plains advances eastward over the Great Lakes. ECMWF is a touch
warmer (~18C at 850mb) than GFS (-16C) Saturday with strong
southwesterly flow into the region. Current forecast is for temps to
touch 80F in the Saginaw Valley with upper 70s for most other
locations. The warm front leading the way could touch off a few
showers after 00Z Saturday with the bubble of stronger theta e
lifting through the area. Though model output is not strong in
producing rain, we`ve see these leading theta e gradients on
elevated warm fronts produce narrow brief areas of showers many
times. For now, we`ll note it and see if we need to add POPs later.

This warmup will be brief as attention the turns to TS Isaias which
is set to make landfall over MS Friday evening then getting drawn
northward into the Ohio Valley before getting caught in the
westerlies and forced to the east coast. This brings the rain shield
into Lower MI Saturday night and/or Sunday. Details will come
together in the coming days, but for now expect a gradient of rain
from south to north with the highest totals over southern lower MI.
Abundant moisture with a tropical system will lead to efficient rain
production for any areas that get clipped by the rain shield.

MARINE...

Moderate southwesterly winds gradually weaken this evening as a cold
front extending from low pressure near James Bay crosses the central
Great Lakes. The lighter gradient winds also veer west-northwesterly
behind the front early tonight. However, an uptick in speeds returns
late tonight or early Wednesday as the upper level jet deepens over
the region. Stability trends lower with the slightly cooler airmass,
and given the rejuvenated low-level jet winds, mixing likely
delivers some elevated gusts. Potential exists for gusts to around
30 knots over portions of Lake Huron Thursday afternoon, with
marginal gusts to gales possible for northern Huron. A Small Craft
Advisory may be needed over The Thumb should confidence rise in the
frequency of 25+ knot gusts, but any higher end gusts further north
should be infrequent enough to preclude a Gale Warning. Mid/Upper
Mississippi Valley high pressure then expands into the area Thursday
night and Friday offering weaker winds with a southerly shift.

&&

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

$$

AVIATION.....SC
DISCUSSION...DRK
MARINE.......KGK


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