textproduct: Marquette

KEY MESSAGES

- Another round of light freezing rain is possible (<25%) Saturday night.

- Confidence in widespread impactful winter weather is increasing Sunday night through Monday. A Winter Storm Watch has been issued for much of the UP. Heavy snow and localized blizzard conditions are possible during this timeframe.

- Gale and Storm Watches are in effect Sunday night into Monday night, with a high probability (90-100%) chance of Gales to 35 kts and moderate probability of Storms to 50 kts (30-50%).

DISCUSSION

Issued at 329 PM EST Fri Dec 26 2025

Afternoon GOES satellite imagery and RAP analysis shows cloudy skies as low level moisture is trapped under a subsidence inversion behind this morning's mixed precipitation maker. Cannot rule out some light freezing drizzle and patchy dense fog tonight, especially for upslope areas of the interior west and central. A few weak waves moving through broad troughing being established across the west- central CONUS tomorrow through Sunday morning look to isentropically force light rain and potentially freezing rain/drizzle ahead of the main event (more on that below), but NBM probability for a glaze of ice remains capped at 10% or lower.

Our attention then turns to the Sunday night - Monday period where confidence in a high impact winter storm is increasing. The most recent 12z.26 global model suite continues to trend the upper level wave deeper than previously advertised, reflecting a strengthening low pressure system that lifts northeast from the lower MS River Valley through Lower Michigan. Their ensemble counterparts also continue the slight westward trend in surface low track, reaching the Straits of Mackinac/Lake Huron by Monday morning between 980-990 mb, the minimum of NAEFS climatology for this time of year. This forecast track through the lower Peninsula places the UP within the favored region for sufficient synoptic scale ascent coupled with lake enhancement off of Lake Superior. Additionally, the increasingly packed pressure gradient, strong pressure falls/rises, and a 45-55 kt LLJ will contribute to winds capable of producing localized blizzard conditions, power outages, and dangerous travel conditions. While there is still wiggle room for change and the ultimate track of the surface feature will play a large role in where the heaviest snowfall axis sets up, the latest NBM5.0 10th (low end) percentile still manages to output 6-12" of snow for the northern tier of the UP by Monday evening. From a probabilistic stand point, the same NBM suggests a 50-80% chance for at least 12" of snow through Monday from Ironwood to Whitefish Point, and a 30-50% chance for 18". Confidence is further increased by the trend in ECMWF EFI/SoT exceeding both 0.9 and 2, respectively, across much of Upper Michigan, pointing towards a potentially high impact nature of this event.

Those with post-Christmas weekend travel plans and other interested parties should continue to monitor the forecast this weekend for further developments and official snowfall accumulation forecasts.

Troughing expected to continue into the new year with colder than normal temperatures favored as well as continuing northwest flow lake effect snow.

AVIATION /00Z TAFS THROUGH 00Z SATURDAY/

Issued at 608 PM EST Fri Dec 26 2025

Flight categories will continue overnight and Saturday as abundant low level moisture and an inversion aloft persists. Ceilings will generally remain IFR at all sites through the period, although KIWD is expected to fall to LIFR tonight. Fog/mist is also expected tonight, which could support visibility reductions to IFR at KIWD/KCMX. Fog will lift Saturday morning, but ceilings will continue through the day as southerly winds.

MARINE

Issued at 329 PM EST Fri Dec 26 2025

High-impact marine weather is set to occur Sunday night into Monday night as low pressure quickly strengthens over the western Great Lakes and moves into Quebec. There is a high (90-100%) probability of gales and a moderate (30-50%) probability of storms out of the north to northwest. There is also risk for 15-20 foot waves over the eastern lake, heavy freezing spray, and limited visibility in heavy snow. Additional periods of gales and heavy freezing spray will be possible over the upcoming week as a cold airmass resides over the lake.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... Winter Storm Watch from Sunday afternoon through Monday evening for MIZ001>007-009>014-084-085.

Lake Superior... Gale Watch from Sunday evening through Monday evening for LSZ162-240>247-263-264.

Storm Watch from late Sunday night through Monday evening for LSZ248>251-265>267.

Lake Michigan... None.