textproduct: Detroit/Pontiac

KEY MESSAGES

- Dry conditions with cool to seasonable temperatures today and Friday; chilly tonight 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.

DISCUSSION

Longwave pattern consists of a ridge over the western half of the conus and troughing over the northeastern conus with the Great Lakes transitioning out of the trough tonight. Dry northwesterly flow and surface ridging will keep the area quiet tonight with the main question being how cold does it get with the thermal trough overhead dipping below 5C at 850mb? Center of the high will be to just to the south with gradient winds likely remaining in the 5 knot range overnight. There will also be some passing high cloud, but may not be enough to blanket the area to keep temps up. Afternoon min dewpoints have fallen into the upper 30s which shows the potential for low temps tonight which still look to fall to around 40.

Heights begin to rise Friday allow for a slight increase in temps, though they will likely remain in the 60s again. Low impact feature we continue to watch in the model space is a shortwave riding along the elevated warm front that will lift through Friday night. The shortwave looks to activate over IA and northern IL Friday afternoon with as the low level jet surges northward into it. As the wave drifts east though it separates from the jet which remains west of Lake MI so should see a weakening trend with any showers over lower MI, possibly no rain at all, but there is still a good theta e surge which could be enough to bring some showers along the state line after 00Z Saturday.

Still looking at a warm up on Saturday as southwesterly flow ramps up behind the warm front and the thermal ridge folds into the Great Lakes. ECMWF has cooled off a few degrees since yesterday with 850mb temps peaking around 15-16C instead of 18C that was advertised previously. GFS is still in the 16-17C range. So will keep highs in the upper 70s and we'll see if 80s will still be possible as we get closer.

Later in the weekend will be dictated by the track of the remnants of Hurricane Isaias which is forecast to lift northward toward the Ohio Valley through the weekend before getting shunted off to the east. Still indications that some degree of the outer portions of the northern precip shield will lift into southern MI before pealing off to the east, but now it appears the deeper plume of moisture will stay to the southeast limiting potential for heavier rainfall locally.

MARINE

Peak afternoon gustiness wanes into the evening hours as the boundary- layer collapses. Gusts have largely been kept in-check, therefore no marine headlines are planned through the near-term period. High pressure becomes firmly established in the vicinity of the central Great Lakes as a ridge spills eastward out of the Mid/Upper Mississippi Valley and the jet/trough overhead exits. Markedly lower gradient winds arrive Friday with the surface ridge axis oriented from Wisconsin to Virginia. Return flow eventually ensues with a southerly wind shift on Friday. The next forecast concern depends on the timing and track of the remnants of Hurricane Isaias. Winds are generally expected to hold below threshold criteria once the system lifts through the Ohio Valley. However, can't completely rule out a few gusts near gale-force over the northern Huron basin later on Saturday.

PREV DISCUSSION

Issued at 1220 PM EDT Thu Oct 8 2026

AVIATION...

High pressures slides into the Ohio Valley tonight-Friday, dislodging remnant troughing. The lingering gradient keeps westerly flow elevated this afternoon around 10-15 knots with gusts up to 25 knots before subsiding this evening. VFR and light winds then persist tonight-Friday, with winds backing to the SW by Friday morning.

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

DTW THRESHOLD PROBABILITIES...

* None

DTX WATCHES/WARNINGS/ADVISORIES

MI...None. Lake Huron...None. Lake St Clair...None. Michigan waters of Lake Erie...None.