textproduct: Detroit/Pontiac

KEY MESSAGES

- Pockets of light rain or drizzle possible late tonight through early Friday morning, moreso for the Tri-Cities and Thumb areas.

- Mainly dry conditions again this weekend with a warming trend by Sunday.

- Increased precipitation chances arrive during the first half of next week.

AVIATION

Expansive area of low stratus entrenched across the area late this evening, solidified by a brief period of meaningful low level warming and moistening ahead of a cold front. This process leading to a gradual decline in cloud base with time, while offering some pockets of drizzle with an associated dip in visibility into MVFR. Observational trends suggest an increasing probability for ceilings to dip into IFR overnight. Inbound cold front on pace to move through mid-late morning, effectively lifting ceiling heights back into MVFR. A drying post-frontal environment could offer greater clearing potential into the afternoon hours particularly from PTK northward. Uncertainty in scale and timing of clearing remains high and precludes a more aggressive stance at this stage.

DTW THRESHOLD PROBABILITIES...

* High in cigs aob 5kft through Friday morning. Medium confidence Friday afternoon.

PREV DISCUSSION

Issued at 257 PM EST Thu Nov 20 2025

DISCUSSION...

Warmer air filters into Lower Michigan this afternoon due to return flow from surface high pressure approaching the Mid-Atlantic. Surface winds veer WSW this evening and overnight, reflecting 925 mb flow trends. Temperatures should level off by midnight due to warm advection. Meanwhile, a low pressure system deepens and tracks east into southern Hudson Bay. The system's cold front gets shoved across the region early Friday morning as shortwave troughing within the base of the polar jet deamplifies after interference due to spill- over mid-level ridging exiting The Plains. Local precipitation response appears marginal given an abundance of dry air aloft. However, sufficient low-level saturation may promote a more favorable environment for light rain/sprinkles before the front clears out, around 13Z Friday. QPF shouldn't exceed a hundredth for most areas, more likely for the Tri-Cities and the tip of The Thumb.

Southeast Michigan remains positioned along the interface between thermal troughing over Ontario and greater thicknesses encompassing The Southeast, including portions of the Ohio Valley on Friday. 850 mb temperatures should generally reside in the low to mid single digits within a south to north thermal gradient. Expect highs above climatological normals for most areas, ranging from the upper 40s to low 50s. Surface ridge expands from The Dakotas, centering over The Upper Midwest by Friday evening. This veers gradient flow NNW Friday night as 1021 mb surface high centers over central Wisconsin. Just to the south, a low amplitude shortwave slides through the northern reaches of the Ohio Valley leading to shower development. Latest model consensus affords higher confidence in the dry continental airmass winning out for all of southern Lower, therefore dry PoPs were included for almost the entire CWA. The one exception resides along the immediate MI/OH border, with a thin stripe of Slight Chance.

A more seasonable airmass settles returns on Saturday with highs in the mid 40s. Broader anticyclonic influence ensures dry conditions. Flow flips southerly for the second half of the weekend as the oscillatory pattern in temperature trends persists. Low-level thetaE advection then surges into the Great Lakes on Sunday. Not expecting much in the way of rainfall with the passing trough given the lack of deeper column moisture, marked by PWATs of around 0.25 inches. Next opportunity for meaningful precipitation comes early next week after a stalled southern stream Pacific closed low ejects into central CONUS, possibly phasing with a northern stream wave as the synoptic pattern becomes more progressive. The milder airmass likely lingers through mid-week.

MARINE...

Southwesterly winds continue to gradually increase through the evening in response to low pressure tracking over northern Ontario. Strongest winds develop late evening-early tonight when gusts peak around 20-25kts across northern/central portions of Lake Huron. Winds over the southern half of the region hold closer the 15-20kts. Associated cold front crosses the region late tonight offering scattered rain shower chances as well as ushering in renewed colder NW flow. With the region residing on the fringe of this system, only modest cold advection follows keeping gusts sub 30kts across the northern and central portions of Lake Huron with the southern half of the region peaking closer to 20kts. Some higher wave action clips the tip of the Thumb Friday night warranting the need for Small Craft Advisories. High pressure then briefly works in by Friday night bringing light winds to start the weekend.

DTX WATCHES/WARNINGS/ADVISORIES

MI...None. Lake Huron...Small Craft Advisory from 7 PM Friday to 4 AM EST Saturday for LHZ441.

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