textproduct: Detroit/Pontiac

KEY MESSAGES

- Cold weather will persist through the weekend. Wind chills are forecast to fluctuate between the single digits and teens above zero.

- The next chance of light snow up to around an inch will come Saturday afternoon and evening, with highest chances across the Saginaw Valley and northern Thumb.

- The potential exists for accumulating snowfall over 1 inch Sunday night into Monday morning. The highest likelihood for impacts to the Monday morning commute is currently located north of M-59.

DISCUSSION

Remnants of a trough axis draped across lower MI has kept light snow showers grinding away all night with the connection to Lake MI moisture still present. Bulk of activity has held between I69 and M59 with a couple tenths through the overnight. All indications are for the mid level subsidence to increase through the early morning with RH fields drying out as high pressure stretches from the Midwest southeastward into the Ohio Valley. Will keep a chance of snow showers going a few more hours with a transition to flurries for the daytime hours. Though moisture will get stripped out of mid levels, subsidence will strengthen the low level inversion which will still be in the DGZ though only 3-4kft up. So will probably squeeze out some flurries before the high takes a greater hold later in the afternoon and thins the cloud field.

Before the northwesterly flow pattern breaks down to start the new week, there will be another opportunity for light snow accumulations Saturday afternoon and evening as the next clipper in the active pattern drops through northern MI. Track hasn't changed much this forecast cycle with the low tracking through the U.P. and northern Lake Huron with the mid level trough dropping across lower MI with the left exit region of the jet clipping Mid MI and the Thumb. Weak fgen and specific humidity only around 1 g/kg will offer some forcing and moisture to work with. QPF remains under a 0.1 inch and highest over the northern Thumb, tapering off quickly southward. NBM probabilities offer less than a 50 percent chance for PTK to accumulate a half inch of snow and 20 percent for Detroit. Most of the snow will fall between 21Z Sat and 03Z Sun.

Thermal trough still over the Great Lakes with 850mb temps down in the negative mid teens will warm slightly this weekend, but not enough to help highs out of the 20s through Sunday. Wind chills will largely stay below 20 through the weekend as well.

Ridge building over the west coast will drift eastward through the weekend reaching the Great Lakes Sunday. Riding the lead flank of the ridge will be yet another compact mid level system and attendant surface low which again is targeting northern MI. The left exit region will pass over southern MI with isentropic ascent forcing snow showers across the area Sunday night into Monday morning. Moisture will be better with this system but again focused north of I69. Local probabilistic guidance give this area a 50 to 70 percent chance of 1 inch of accumulation and 25 percent chance of 2 inches. Locations south of I69 are looking for up to an inch. This will be better defined as we get into the hires window.

As this wave passes and the ridge pushes farther east over the region, a warming trend is set to occur through the week. Temps will reach above freezing on Monday with 40s in the forecast creeping into the area as early as Tuesday, but more widespread for Thursday and Friday. There will be a chance of rain on Tuesday with the next system but then we may catch a few dry days through mid week.

MARINE

WNW winds continue to gust 20-25kts today with some lingering 30kts gusts possible over the northernmost portions of Lake Huron as the region is influenced by broad troughing over eastern Canada. Arctic airmass in place combined with these winds maintains areas of freezing spray in the open waters of Lake Huron through the day as well (especially in the north). The northeastern edge of Plains surface high pressure attempts to build into the region Saturday however is blunted by a weak clipper dropping out of the Canadian Prairie into the northern Great Lakes. This does however set up a weaker overall gradient, relative to these past few days, allowing for 20kt or less NW turning W wind daytime Saturday with only a fairly brief uptick in NW winds (still likely sub 25kts) in the immediate wake of the low Saturday night. Plains high then drifts east over the Great Lakes/Ohio Valley Sunday supporting light (<15kt) winds and dry weather to close out the weekend.

PREV DISCUSSION

Issued at 1157 PM EST Thu Jan 1 2026

AVIATION...

There remains potential for some periods of light snow showers or flurries through the remainder of the night, as weak mid level energy engages ongoing lake Michigan moisture flux. This will occur within a fluctuating cloud base between high MVFR and low VFR. A reduction in moisture depth Friday will favor mainly dry conditions with a lingering stratus deck carrying cigs within the 2500 to 3500 ft range. Gradual warming and drying of cloud layer with time will eventually support erosion of stratus late Friday and Friday night, while building high pressure ensures benign conditions during this time.

DTW THRESHOLD PROBABILITIES...

* High for ceiling aob 5000 feet through Friday afternoon. * High for snow precipitation type.

DTX WATCHES/WARNINGS/ADVISORIES

MI...None. Lake Huron...Small Craft Advisory until 10 PM EST this evening for LHZ421-441.

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