textproduct: Detroit/Pontiac

KEY MESSAGES

- Light snow chances return this afternoon and evening. Snow accumulations to range between a half-inch to 2 inches by late tonight. Some isolated snow squalls are possible which may bring brief heavy snow rates and reduced visibilities.

- Windchills are expected to range in the single digits below zero late tonight and Thursday morning.

- Seasonally cold weather will persist into the weekend. Windchills are expected to fluctuate between the single digits and teens above zero.

Flurries or light snow chances are possible both Saturday and Sunday nights.

DISCUSSION

Wave of isentropic lift and midlevel moisture advection will track across Southeast Michigan this afternoon and tonight. Deep column saturation is anticipated, leading to widespread light to moderate snow across all of Southeast Michigan in the 19-02z time window. Respectable large scale dynamics for lift with an already strong potential vorticity anomaly digging at an almost due equatorward trajectory. Conservation of vorticity and the influence of increasing cyclonic curvature is forecasted to result in sharpening 925-850mb and 850-700mb frontogenesis particularly over the southern half of the cwa after 21z. Steepened lapse rates between 1.5-4.0 kft agl on the north side of the cold front, and supersaturation with respect to ice will lead to the potential for some brief snow squalls. UVVs through the DGZ and surface temperatures in the 20s supports high LSRs and a powdery snow at better than 16:1. EPS data for once shows a very tightly clustered solution space with regards to snow amounts with the control, mean, and interquartile range around 1.0 to 1.5 inches at Detroit, Pontiac, Flint and Bad Axe. A short duration of forcing is expected to be the limiting factor in this event. Snow covered and slippery roadways are certainly possible and any communication of impacts will be better handled by short fused products.

Cold advection will drop temperatures into the single digits late tonight and daybreak Thursday. Mixed northwesterly flow of 10 to 20 mph is expected to result in windchills in the single digits below zero. Cold troughing will then be in place and largely remain the influence over the region going into the weekend. The control run of the ECMWF has been bullish with some very light QPF spreading into Lower Michigan Thursday evening/night. Decent enough phased upper level jet forcing which should be good for seeding, but forecast soundings show very little frontal structure aloft. With 850mb temperatures around -15C, would not be surprised if there are virga returns on radar with some flurries. Added flurries to the forecast but given the lack of any good QPF signal in the models and to maintain collaboration will not increase PoPs.

Differential geopotential height rises with confluence aloft will largely support ridging at the surface Friday and this wekeend. With that stated, fast northwest flow is projected to direct some weak shortwave energy into the region at times. One shortwave will be Saturday night, but the wave should undergo significant dampening as it becomes increasingly detached away from the exit region forcing. Light snow shower chances Saturday night mainly north of the area. The next potential shortwave that is advertised over the region early Monday will have a potential for more synoptic scale lift support. Quick look at plan view progs show a much better setup for warm air advection in addition to upper level jet forcing. Highs Monday and Tuesday look to be at or slightly above normal.

MARINE

Weak clipper system currently dropping through lower MI at time of discussion drags an arctic cold front through the central/southern Great Lakes this evening-early tonight. Winds flip to the northwest post-front with a 2-3hr uptick in wind gusts towards 30-35kts in the immediate wake before slightly diminishing back towards 25-30kts for the night. Given the marginal nature in duration of gusts reaching 35kt gales, have continued to hold off on any headline for Lake Huron. Arctic air filtering south however supports areas of heavy freezing spray, particularly across the northern half of Lake Huron, warranting the issuance of a Heavy Freezing Spray Warning for these waters. Troughing influence holds across the Great Lakes Thursday into Friday resulting in persistent moderate (20-30kts) WNW winds. In combination with an arctic airmass lingering overhead, freezing spray lingers through the end of the week. Additional weak clippers round the trough into the region this weekend bringing light snow chances however a still fairly diffuse gradient keeps winds sub 25kts.

PREV DISCUSSION

Issued at 234 PM EST Wed Dec 31 2025

DTX WATCHES/WARNINGS/ADVISORIES

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

Small Craft Advisory until 10 AM EST Thursday for LHZ442-443.

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