581 FXUS63 KDTX 300804 AFDDTX Area Forecast Discussion National Weather Service Detroit/Pontiac MI 304 AM EST Tue Dec 30 2025 .KEY MESSAGES... - Two periods of light snow, each of which are forecast to produce an inch or two of accumulation, will affect the area. The first will be this evening and the second during the day Wednesday. - Seasonally cold weather will persist into the weekend. The coldest temperatures will be New Years Eve evening into News Years Day with wind chills mainly in the single digits. && .DISCUSSION... Low level wind fields will remain on a gradual diminishing trend during the morning with the continued departure of yesterday's storm system. Lingering lake aggregate troughing will however sustain a west-northwesterly gradient across Se Mi through the day, with a solid 20 knots residing in the mixed layer. This will maintain brisk conditions as daytime temperatures hold in the 20s with wind chills in the single digits and teens. Early day deep layer subsidence from 850mb up through 500 mb will lower inversion heights, allowing a decrease in remnant lake effect. Supersaturation wrt ice within remnant strato cu will support a few flurries. The region of deep layer moisture noted on upstream satellite imagery over North Dakota is tied to a weak mid level short wave along the nose of an upper jet streak. This wave will traverse srn Lower Mi late this afternoon into the early portion of the overnight. Large scale isentropic ascent will remain weak and quite elevated (aob 700mb) within a relatively stable mid level profile. Despite the Canadian origin of this system, it does have relatively decent deep layer moisture; specific humidities of 1.5 to 2 g/kg are projected up through 700mb. The approach of this wave will force a more westerly low level flow which will add some enhancement off Lake Mi. Latest hi res guidance suggests this will be focused between the I-94 and I-69 corridors. Thermodynamic profiles suggest the potential for some good dendrites. The weak nature of the ascent argues for total snow accumulations (between 21Z today and 06Z Wed morning) for an inch or less. Localized accums up toward 2 inches are possible within any persistent lake enhanced bands. This first round of light snow will be followed by a brief interval of subsidence early Wednesday morning before the next round of light snow arrives mid-late Wed morning. A more amplified mid level wave rotating around the deep upper low over Hudson Bay will track across Lake Superior into eastern Ontario. This will drive an arctic cold front across Se Mi late in the day Wednesday. Better mid level height falls and frontogenetical forcing will contribute to a broad region of light snow. There is the potential for a little bit of lake enhancement in advance of the associated arctic front. Probabilistic guidance is highly supportive of accumulations in the 1 to 2 inch range. Given the convective component due to steepening low level lapse rates, some isolated three inch amounts can not be ruled out. Within the increased mixed layer on Wednesday, model soundings suggest a fairly good core of 30 knot winds. While not advisory worthy, this will still make for brisk conditions with some blowing snow. The cold front will push south of the area around/shortly after 00Z with a fairly good push of arctic air arriving within north-northwest winds during the evening hours of New Years Eve, persisting into the start of the New Year. The near persistence of the upper low over eastern Canada will maintain seasonally cold conditions into the weekend. && .MARINE... Gales continue for a few more hours this morning as Monday's strong low pressure system exits toward the Atlantic coast. The system leaves behind diminished NW flow that is still able to maintain arctic air across the Great Lakes as the next much weaker low pressure system moves into Lake Superior tonight. This system brings a round of light snow tonight and Wednesday until moving eastward Wednesday night. The trailing cold front reinforces arctic air with an uptick in NW wind that is projected to remain below gales through Thursday. Sub gales, occasional snow showers, and freezing spray then persist over the central Great Lakes into next weekend. && .PREV DISCUSSION... Issued at 1203 AM EST Tue Dec 30 2025 AVIATION... Broken bands of lake effect snow showers decreased coverage and intensity during the evening but remaining activity lingers nearby to the west of the terminal corridor leading up to midnight. A stray IFR snow shower is most likely from PTK southward through the late night. The Lake Superior to Lake Michigan connection also remains intact and could produce bands strong enough to survive the downhill trip toward MBS. Broken coverage of VFR stratocu occurs in between for a wide range of aviation conditions that last through the morning. Wind gusts settle below 30 knots and direction backs slightly more W-NW to keep clusters of stratocu streaming in from Lake Michigan in the afternoon. Accumulating IFR snow tied to the next much weaker low pressure system arrives first at MBS toward sunset and spreads south/east Tuesday night. For DTW... Wind gusts settle below 30 knots while direction holds from about 300 deg. This allows lingering lake effect snow showers to graze the terminal area during the late night. DTW THRESHOLD PROBABILITIES... * Moderate for ceiling below 5000 feet late tonight. High Tuesday afternoon and night. * Moderate for crosswind threshold exceedence late tonight. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...None. Lake Huron...Gale Warning until 11 AM EST this morning for LHZ361>363-421-422- 441>443-462>464. Heavy Freezing Spray Warning until 11 AM EST this morning for LHZ361>363. Lake St Clair...Gale Warning until 7 AM EST this morning for LCZ460. Michigan waters of Lake Erie...Gale Warning until 7 AM EST this morning for LEZ444. && $$ DISCUSSION...SC MARINE.......BT AVIATION.....BT You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit.