textproduct: Detroit/Pontiac

KEY MESSAGES

- Dry weather with cool to seasonable temperatures lasts through the weekend and the first half of next week.

- The next chance of rain arrives with a low pressure system and cold front projected to reach the region by Wednesday.

DTW THRESHOLD PROBABILITIES

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

PREV DISCUSSION

Issued at 421 AM EDT Fri Sep 25 2026

DISCUSSION...

The large-scale pattern will be governed by varying forms of vicinity ridging through the weekend, and into the first half of next week. At present, the prior Rex Block has unlocked and is being replaced by a weak mid-level shortwave trough getting pushed downstream of Upper Midwest ridging. This should provide ambient ascent over Lower Michigan, generating healthy coverage of clouds aloft. Thermal fields remain intact, with 850 mb temperatures holding near 10C which keeps highs at least 5F below climatological normals. Strong stability within the lower half of the column, positioned within a well-established anticyclone ensures subsidence and limited boundary-layer cloud.

Rain-free weather extends through the weekend with a warming trend lifting readings toward early Fall averages. An elongated ridge axis extending from the Gulf into Ontario, subdivided by southern and northern stream components, will move eastward by Saturday. The northern stream shorter wavelength feature displaces the residual troughing, and centers over the western Great Lakes. High pressure will lock in at the surface, centering between southwest Lower and Quebec, offering light winds from the northeast quadrant. Meanwhile, a strong Atlantic coast quasi-tropical system/nor'easter will meander between Chesapeake Bay and Cape Cod over the next 3+ days. The upper levels of this system and the stationary mature low are what will prevent much movement from the composite ridge axis over the Great Lakes region. A strong positively-tilted Pacific longwave trough eventually digs across CONUS mid-week, kicking out the Atlantic wave. High confidence in a dry forecast prior to the arrival of this system, once pre-frontal winds flip southerly and top-down column saturation gets underway closer to Wednesday.

MARINE...

The expansion of a strong Canadian high pressure system derived from Quebec and Ontario into the Great Lakes will provide an extended period of light winds and dry weather through early next week. Some periodic wind gust potential around 20 knots will be possible across southern Lake Huron through this extended time frame, but otherwise, wind gust potential at or below 15 knots is expected. Wind direction will mainly hold from the northeast as high pressure fills in across Michigan.

DTX WATCHES/WARNINGS/ADVISORIES

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