Corunna, Michigan Weather Forecast Discussion

649
FXUS63 KDTX 111932
AFDDTX
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
332 PM EDT Thu Sep 11 2025
.KEY MESSAGES...
- Dry today and Friday with above normal high temperatures, but
areas of fog appear likely tonight.
- Chance of showers and slight chance of thunderstorms Saturday.
- Warm and dry Sunday through Wednesday.
&&
.DISCUSSION...
High pressure over Ontario will keep quiet weather over the region
through Friday. Diurnal cu will once again scour out this evening
leaving clear skies and light winds tonight. Good radiational
cooling setup with surface high in place with the lengthening
September night. In addition, the longwave ridge axis passes over
this evening, drawing in some of the better low level moisture
that`s been producing fog to our west each night and so expect a
period of fog early Friday morning. As the fog burns off, another
round of diurnal cu should develop with temps rising into the low
80s. Friday night lows will be a bit warmer as high clouds start
streaming in on elevated portions of a warm front that is developing
Friday.
Longwave ridge amplifies up through the Plains heading into the
weekend as the stalled trough over the western conus tightens up a
bit. A weak shortwave ejecting from the trough will excite lee
cyclogenesis over the northern Plains with a warm front extending
east through IA and northern IL. NAM and Canadian continues to show
the nocturnal low level jet flaring up over western WI igniting a
round of showers and storms that would fold over the ridge and dive
through SW lower MI in the morning Saturday while weakening without
the continued jet forcing. In addition, a stronger upper trough
diving through Hudson Bay will send a weak cold front southward into
the northern Great Lakes. This northern front may produce a round of
showers Friday night into Saturday across northern MI and Lake Huron
before reaching the CWA in the afternoon but with less coverage. The
trend in the forecast is to push back the chances of showers into
the afternoon Saturday as the northern front reaches the area during
peak heating. Overall chances are still low at less than 30 percent
but there may be some activity close by.
After Saturday the ridge expands further over the region keeping the
bulk of the jet energy well to the north supporting quiet weather
locally with dry and warm conditions heading into next week.
&&
.MARINE...
Light northeast flow is observed this afternoon with high pressure
just south of James Bay. Winds veer overnight as the high settles
toward New England, holding comfortably aob 10 knots. Increasing
stability aloft may generate patchy fog Friday morning close to
shore, but expect a more robust response on land due to more
favorable radiative cooling. Winds gain a southerly component by
Friday afternoon in between low pressure over Hudson Bay and another
low over the Plains. There is a chance for showers throughout the
day Saturday invof an upper wave in the morning and cold front that
tracks through Saturday night, although poor moisture depths limit
shower coverage and intensity. High pressure then fills in to
maintain quiet marine weather through early next week.
&&
.PREV DISCUSSION...
Issued at 206 PM EDT Thu Sep 11 2025
AVIATION...
High pressure over Ontario continues to dominate the region,
bringing light winds at or below 6 knots and fair weather cumulus.
The diurnal cumulus will dissipate this evening as we lose daytime
heating. With another night of clear skies and strong radiational
cooling, expect the potential for patchy fog. Did maintain the
TEMPO IFR mentions of BR between 09Z-13Z Friday morning.
For DTW/D21 Convection... No thunderstorms throughout the period.
THRESHOLD PROBABILITIES...
* None.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.
&&
$$
DISCUSSION...DRK
MARINE.......MV
AVIATION.....JA
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NWS DTX Office Area Forecast Discussion