textproduct: Detroit/Pontiac

KEY MESSAGES

- Low chance for patchy fog overnight.

- Increasing rain chances through tomorrow.

- A much colder airmass arrives Thursday, triggering lake effect rain and snow showers late Thursday through Saturday.

DTW THRESHOLD PROBABILITIES

* None.

PREV DISCUSSION

Issued at 347 PM EST Tue Nov 10 2026

DISCUSSION...

Diffuse high pressure expands over the Great Lakes under zonal flow aloft which will bring about the continuation of dry weather overnight. The forecasted clear skies for the start of the night brings minor consideration for fog overnight, however the overall potential remains on the lower side. Deep mixing this afternoon have brought dew points down into the low to mid 30s. West boundary layer flow keep low-levels mixed tonight with high-based clouds then expected to move in overhead as winds start to decouple. So from a radiational cooling perspective probabilities remain low for robust fog potential, but some haze closer to sunrise cannot be ruled out. There is a signal for moisture advection off the southern Lake Michigan basin to spread inland given the west flow. Low-stratus or fog will likely expand across western Michigan, but there is low confidence in regards the degree of expansion inland, especially through the western fringe of the cwa. Locations across or near Howell, Owosso, and possibly up through the southern Tri-Cities may see some degree of fog and visibility restrictions pending the strength of moisture advection.

Tomorrow, the combination of low pressure progressing across the Ohio Valley in conjunction with an upper-level shortwave and trailing cold front will likely produce light rain showers across SE MI. The two areas of interest will far southern Michigan where forcing will be predominately derived from isentropic ascent just ahead of the progressing low, and a secondary area across across northern lower Michigan into the Tri-Cities tied to the wave and cold front. Some localized higher rainfall rates will be possible with any frontogenetic forcing but overall no local impacts expected given a stable environment.

Cyclonic flow behind the departing low, reinforced from a stronger upper-level closed low that will retrograde across Quebec and Ontario will usher in cooler Canadian air, will activate lake effect precipitation for both Thursday and Friday. The combination of north to northwest flow off the lake and the boost in 0-1 km instability over the lake will bring about efficient moisture advection, further supported by secondary vorticity lobes that will swing around the parent upper-level closed low. This will bring about lake effect rain showers on Thursday, with increasing coverage Friday as cooler air is advected in. As low-level flow backs NNW, the Thumb and Lake Huron shoreline becomes more susceptible for sustained lake effect activity on Friday and Saturday. By Friday, a fully saturated dgz wrt to ice and freezing levels between 1-2 kft bring the possibility to see a rain/snow mix or melting snow flakes. Otherwise cool starting Thursday and through the weekend with highs in the 40s and lows in the 20s to 30s.

Lake effect precipitation chances greatly diminish on Sunday once high pressure builds in from the west, shrinking moisture heights and stripping moisture from the column. High pressure to expand and hold into the midweek period, bringing an extended window for dry weather.

MARINE...

Post-frontal gradient winds decline this evening and through the overnight hours as a low pressure system continues to exit into the St. Lawrence seaway. Fleeting high pressure brushes the central Great Lakes overnight before the next system ejects across the Upper Mississippi Valley late tonight. This wave is expected to deepen as it sweeps over the Ohio Valley Wednesday evening. Winds pick up considerably Wednesday night and Thursday with the waterways positioned within the northern half of the system. This leads to strong norht-norhteasterly flow, with a heightened wind and wave response. Latest model data continues to advertise gusts to gales by Thursday morning. This could be more prevalent across the southern waterways, especially western Erie, St. Clair, and maybe Saginaw Bay. Small Crafts will likely be needed for the remaining nearshore waters. Persistent troughing keeps winds elevated Friday, albeit with lower chances for gales. Potential exists for a waterspout or two during this time-frame as shower activity arises.

DTX WATCHES/WARNINGS/ADVISORIES

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