textproduct: Marquette

KEY MESSAGES

- A mix of freezing rain, sleet and snow is expected to taper off from west to east through the morning hours. Winter Weather Advisories are in effect for all of Upper Michigan as untreated surfaces will be slippery.

- Another round of light freezing rain is possible (40% chance) Saturday night.

- A Gale Warning is in effect for eastern and central Lake Superior through this morning. More gales are likely (70-90% chance) Sunday night into Monday night, with a moderate probability of storm force winds.

- There is high confidence in temperatures becoming sharply colder Sunday night into Monday with accumulating lake effect snow. In addition, there is growing confidence in the potential for an impactful winter storm for much of the UP Sunday night into Monday, although details are uncertain at this time.

DISCUSSION

Issued at 359 AM EST Fri Dec 26 2025

Compact, strong shortwave continues eastward across the Upper Midwest early this morning. Good isentropic lift ahead of this feature is resulting in an area of wintry precipitation, with the lift augmented by a coupled jet structure. The warm nose aloft has made it further north and east than previously thought, which has allowed freezing rain to be the dominant p-type as far north/east as Houghton, Marquette, and perhaps further afield. This has resulted in untreated surfaces becoming very slick (including here at the WFO), so travel will certainly be impacted this morning. There is still potential for 1-4 inches of snow over the tip of the Keweenaw as well as east of a Munising to Manistique line, but a glaze of ice is even possible in those areas as well. It's still possible for dynamic cooling to result in p-type ending as snow where it is currently freezing rain, but the window on this is closing as midlevel dry air is quickly punching in from the west, with the back edge of the steadier precip just reaching near Ironwood as of 0830Z. Still may see some patchy freezing drizzle behind this, as is being observed in Duluth, through the morning hours. The only changes to the headlines are to group Delta and Menominee in with the remainder of the western/central UP to emphasize the dominance of freezing rain over snow, and to end these zones at 18Z. It's possible that some zones may be cancelled early, but prefer to have the day shift make this call due to the potential for lingering FZDZ and uncertainty with how fast temps rise above freezing today (if at all). NBM5.0 probs of high temps reaching/exceeding 0C are 80-90% for most of the UP except the eastern third, with western areas reaching freezing most likely by mid-morning, while the north- central most likely will take until the afternoon. The other possible hazard today will be fog, which is occurring upstream over MN and models suggest it will impact at least the western UP today.

For tonight, there is not much cold advection to speak of behind this system, so temps remain above normal, but likely fall a couple degrees below freezing, with the possible exception of the west where it is more of a 50/50 shot. Maintained a dry forecast but cannot totally rule out a few patches of freezing drizzle and fog, primarily in the central and east where RH > 85% in the 0-1km layer and models hint at a weak convergence zone as well as southeasterly flow being established off Lake Michigan. Will monitor trends through the day to see if this needs to be added to the forecast.

Midlevel ridging makes more inroads over the Midwest and Northeast Saturday in response to troughing diving into the northern Rockies. Forcing is pretty nebulous through the Saturday night with just fast SW midlevel flow, but can't rule out some drizzle and fog, especially in areas upslope to SE flow. Highs look to range through the 30s with most areas above freezing. We could see a few spots of freezing drizzle Saturday night as temps sink a degree or two below freezing, but only moderate confidence in the freezing drizzle scenario (~40%) at this time. Any freezing rain accumulation looks to be a light glaze at most.

Then, all eyes are on the aforementioned trough as it shifts its way through the Great Lakes Sunday night into Monday. Model trends over the last 24 hours have been quite interesting to say the least. The 500 mb pattern in the 00Z.26 suite has largely trended toward the low quickly cutting off in the vicinity of the upper Great Lakes from its earlier positive tilt open wave solutions. This has resulted in a stronger and westward shift in mean ensemble and deterministic surface low tracks. While we have been advertising a return to much colder temperatures and accumulating lake effect snow in the northwest belts for days now, if recent model trends hold, this opens the door for a potentially high-impact winter storm with heavy snow and strong winds over the most if not all of the UP (but especially the north half) Sunday night into Monday. Worth noting the latest NBM5.0 probabilities for > 8" of snow is as high as 60- 80% for the north half, with ECMWF EFI/SoT exceeding 0.9"/2 respectively, depicting both the increasing model agreement and possibility for a high impact event. Stay tuned.

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

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/

Issued at 1238 AM EST Fri Dec 26 2025

Ceilings and visibility restrictions are expected at all terminals tonight, as a system pushes abundant low level moisture and precipitation into the area. Expecting all sites to fall to IFR, with KCMX/KIWD most likely to fall to LIFR. Ptype will include a mix of snow, freezing rain, and sleet, with the greatest uncertainty being over KSAW. KCMX is likely to remain all snow, while KIWD is favored for freezing rain. Gusty winds near 20-25kts impact all terminals and low level wind shear at KIWD.

MARINE

Issued at 410 AM EST Fri Dec 26 2025

Southeasterly gales to 35-40 kt continue through mid-morning before quickly dissipating as low pressure moves over the area. After a calmer period through tonight, southeasterly winds increase to 30 kt late Saturday, with a 20% chance of brief gales. High-impact marine weather looks 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 (70-90%) probability of gales and a moderate (30-50%) probability of storms out of the north to northwest. Should current trends hold, 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 Weather Advisory until 1 PM EST /noon CST/ this afternoon for MIZ001>005-009>013-084.

Winter Weather Advisory until 4 PM EST this afternoon for MIZ006-014-085.

Winter Weather Advisory until 7 PM EST this evening for MIZ007.

Lake Superior... Gale Warning until 10 AM EST this morning for LSZ244-245-264- 266-267.

Lake Michigan... None.