textproduct: Detroit/Pontiac

KEY MESSAGES

- Lake effect snow showers impact the eastern Thumb region tonight into Saturday morning with localized 1 to 3 inch accumulations.

- Cold tonight/Saturday morning and Saturday night/Sunday morning with wind chill ranging between 0 and 15 below.

- Sunshine on Sunday leads to temps climbing into the lower 20s, with high temperatures in the 20s persisting next week.

AVIATION

A surface trough will move from north to south across the area over the next couple hours, the passage of which will be marked by a wind shift to the north. Enhanced low level convergence within ongoing moisture advection is supporting widespread MVFR based clouds. Recent model trends are also suggesting a lower trend in ceilings into the day Saturday as some moisture flux off Lake Huron advances into portions of Se Mi. Model soundings suggest lowering inversion height during the day, which will likely hold low clouds in place well into the afternoon before drier air advects in from the north. In short, while there will likely be intervals of variability in ceiling heights Sat morning, prevailing MVFR will be carried.

For DTW...Nothing more than a few flurries are expected through the morning.

DTW THRESHOLD PROBABILITIES...

* Moderate in ceilings aob 5000 feet Saturday.

PREV DISCUSSION

Issued at 338 PM EST Fri Jan 30 2026

DISCUSSION...

A zonally oriented upper shear axis is passing southward toward the stateline with a trailing bubble of subsidence offering a window of sunny skies for much of the area this afternoon. Mid-level clouds are already arriving across the Thumb and Mid MI behind this dry pocket as deeper moisture accompanies the next weak shortwave impulse that tracks south tonight. Temperatures currently in the teens are forecast to drop to around zero by late evening for areas that stay cloud free - mainly south of M-59. The inbound cloud then helps insulate and hold temps mainly in the single digits overnight. Steady but light northwest gradient wind is projected to hold wind chill in the -5 to -10 range tonight, so no Cold Weather Advisory was issued. REFS hourly probabilities indicate <10% chance for wind chill at or below -15. HREF is slightly more aggressive with wind magnitude, and shows a 20% chance for those clear areas late this evening, and up to 40% chance pre-dawn Saturday morning as the wind picks up slightly.

As a surface trough sinks south across the region overnight, northeast wind over Lake Huron will cause the stalled lake effect snow band to migrate toward the eastern Thumb. Despite significant ice coverage in the nearshore area, the bulk of model guidance does brush the coast with this band, so kept high PoPs tonight. Convective depth is modeled to be near or below 5 kft and favorable wind direction lasts into early Saturday afternoon, supportive of several inches of accumulation. Model 925mb omega fields generally target the Huron City/Port Hope/Harbor Beach vicinity around and after midnight, then spread south toward the Port Sanilac/Lexington area early Saturday morning where the forcing stalls before weakening during the afternoon.

Highest confidence in accumulation up to 2 to 3 inches is positioned along the shoreline between Harbor Beach and Lexington, per the 12z REFS guidance. This ensemble also suggests potential for several inches of snow for the Port Huron area on Saturday, but this carries lower confidence as most guidance is more transient with any banding that far south. REFS also offers a 10% probability for localized totals up to 4 inches in the aforementioned area by Saturday night, with spotty coverage indicating a very localized instance should it occur. Elsewhere across southeast MI, mainly just flurries and light snow showers expected overnight. Some areas may see a dusting, and highest potential for around a half inch will be inland areas of the Thumb.

A period of height rises Saturday into Sunday allows a surface ridge to build into the area, promoting dry conditions apart from any lake effect snow along the eastern Thumb on Saturday. Lake effect clouds will remain pervasive even inland much of the day Saturday before clearing out Saturday night, setting the area up for another cold night. Lows are projected to range between 5 and -5, and a light gradient results in wind chill in the -5 to -15 degree range early Sunday morning. Burgeoning warm advection on Sunday with a boost from abundant sunshine within the ridge axis will send temps into the 20s by Sunday afternoon - for the first time since Jan 22 for most of the area.

A shearing shortwave brings a chance of light snow on Monday, though models have generally trended drier over the past 24 hours. With weak ascent associated with this wave, areas that see snow would be most likely to receive less than a half inch. Colder air builds back in Monday night into Tuesday as arctic high pressure spreads across the Midwest, but highs in the 20s remain favored through the week. There is growing confidence for widespread accumulating snow Friday and Friday night, with latest NBM showing a 30 to 50% chance for over 2 inches of snow across the area.

MARINE...

The Great Lakes remain under broad upper troughing allowing another mid-upper wave to dive through the region this evening. Result of which is a shift in winds from northwesterly to north-northeast by tonight with minimal weakening as sustained winds hold 15-20kts and gusts 20-25kts. Northern edge of Plains high pressure then expands over the central Great Lakes Sunday bringing light (<15kt) winds. A weak clipper arrives late day Monday but aside for scattered light snow showers, brings minimal marine impacts with accompanying winds holding at or below 20kts. Another high dropping out of the upper Midwest then follows for midweek.

DTX WATCHES/WARNINGS/ADVISORIES

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