textproduct: Detroit/Pontiac

KEY MESSAGES

- Dry weather persists through the weekend and into the first half of next week with temperatures near normal.

- The next chance for rainfall arrives ahead of a low pressure system and cold front on Wednesday.

DTW THRESHOLD PROBABILITIES

* Low in ceilings aob 5000 feet through the TAF period.

PREV DISCUSSION

Issued at 441 AM EDT Sat Sep 26 2026

DISCUSSION...

Noticeably warmer today amidst a decreasing cloud fraction and slowing northeasterly winds. The latter comes in response to the surface pressure gradient becoming more diffuse over the Great Lakes, positioned beneath the full-column Upper Midwest ridge that should build northeastward to center over Ontario/Quebec. This also aids in pushing out a meandering low-amplitude inverted shortwave trough responsible for lingering mid/high cloud. Overlaying 500 mb geopotential heights from the 00Z deterministic medium-range solutions, Southeast Michigan situates along the interface between vicinity ridging and the western extent of a broad warm-core nor'easter, expected to stall over the lower Hudson Valley until Monday. The net result will be the advection of cool and dry air from Canada, yielding a rain-free forecast through the weekend for the local area. The 26.00Z KDTX RAOB sampled this moisture-starved airmass between 20 kft AGL and yesterday's boundary-layer. With a measured PWAT of just 0.28 inches, a record low was observed for the date/time pairing. Forecast soundings do indicate slight recovery in tropospheric moisture, with periods of high cloud today, and perhaps a diurnal cumulus response Sunday afternoon.

The existing composite ridge axis extending from the Gulf into east- central Canada preserves surface high pressure into Monday and most of Tuesday next week. With little-to-no surface wind and 850 mb temperatures holding near 10C, highs should easily reach the lower 70s both days. The surface gradient could become reestablished as early as Tuesday afternoon, taking on a south-southwesterly vector ahead of the next precipitating system. A well-advertised, potent Pacific longwave trough eventually digs onshore over California, absorbing what becomes of eastern Pacific Hurricane Polo. This phased wave then ejects across The Plains, deflecting a lower amplitude embedded northern stream shortwave over Lower Michigan late Tuesday into Wednesday. Moisture advection from the southern system will lead to a marked uptick in ThetaE, eventually priming the column for a few rounds of showers Wednesday and perhaps Thursday. High variance exists amongst NWP QPF projections, affected by the differing track and evolution of the various competing synoptic waves. Several deterministic solutions suggest little to no rainfall south of I-69, even through 00Z Friday (e.g. 00Z GEM, ICON, and UKMET).

MARINE...

High pressure will hold over the Great Lakes through early next week. Some periodic wind gust potential around 20 knots will be possible across southern Lake Huron this today and tomorrow, but otherwise, wind gust potential to or below 15 knots is expected for most locations. Wind direction will mainly hold from the north to northeast with high pressure in place.

DTX WATCHES/WARNINGS/ADVISORIES

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