textproduct: Marquette

KEY MESSAGES

- Gusty northerly to northwesterly winds expected into this evening. Gale Warnings in effect for the east half of Lake Superior, with wind gusts of 25 to 35 mph expected over the land.

- Light to moderate lake effect snowfall expected to continue through next week as a cooler than normal airmass resides over the region.

- The next chance of widespread snowfall comes with a fast- hitting Clipper Low Tuesday night into Wednesday.

DISCUSSION

Issued at 402 PM EST Sun Nov 30 2025

Afternoon GOES water vapor imagery and RAP analysis show a mid level trough present over the Great Lakes with the main driving shortwave southeast of the UP. Beneath it, a 1008 mb low pressure is moving over southern Ontario and high pressure is building over the Northern Plains in its wake. The radar mosaic is reflective of trailing north becoming northwest LES showers as a result of the cold 850 mb temps between -14C and -16C descending across Lake Superior per the latest SPC mesoanalysis.

In the wake of the low: deep moisture is now gone, low levels continue to dry out, and inversion heights settle to around 5-7 kft. With QPF between 0.05-0.10", additional snow accumulations broadly will be trace to 2" over the northwest wind snow belts through tonight. That said, a few CAMs highlight stronger convergent bands setting up over Alger and Luce Counties for a few hours this evening/tonight, yielding higher amounts up to 3-4" (10-30% chance). Winds taper off through tonight as the pressure gradient relaxes, but gusts in the east and near Lake Superior hold in the 20-35 mph range into this evening. Temps continue in the 20s the rest of today.

Tonight will be much colder in the single digits in the interior to teens by the lakeshores, coldest interior west where a few spots may dip below 0 (25% chance). Although light winds are anticipated, wind chills are expected in the single digits above/below 0 into Monday morning. High pressure shifting east from the Plains to the Great Lakes by Monday morning means light LES showers shift from the northwest to west-southwest wind snow belts for Monday. Similar thermodynamic profiles to this afternoon suggest low impacts are expected where LES showers are present during this period. Rolling and drifting snow is anticipated in the Keweenaw tomorrow where southwest wind gusts will frequent the 20-30 mph range. Otherwise temps warm into the upper teens to upper 20s on Monday.

A shortwave and weak surface trough drop southeast over the CWA Monday night. The better forcing remains outside the UP and unimpressive thermodynamic profiles persist, but a uptick in snow shower coverage is anticipated over the Keweenaw and near Lake Michigan thanks to more than supportive delta-Ts. Similar lows in the single digits to teens are expected Monday night, but wind chills will be a bit warmer.

There is pretty decent model agreement in an Alberta Clipper Tuesday night into Wednesday bringing the next round of widespread snow. That said, amounts will not be impressive. NBM 24 HR probabilities of just 2" struggle to reach 20% in the south-central and are only 30-60% over the western spine and north-central. Wednesday night into Thursday presents 850 mb temps into the -20C to -24C range as a mid level trough progresses over Ontario, meaning additional LES showers and cold temps across the UP. Lows Wednesday night will be in the single digits with highs on Thursday in the teens. Wind chills will hold in the single digits above/below 0 during this period. Beyond this midweek system, model guidance diverges on track and timing of the next clipper system Friday/Saturday, but an active and cooler pattern looks to continue into December.

AVIATION /06Z TAFS THROUGH 06Z TUESDAY/

Issued at 1233 AM EST Mon Dec 1 2025

Winds backing to the W and eventually SW the rest of tonight will allow lake effect clouds and snow showers to lift over Superior. Already, conditions have improved to VFR at SAW, but MVFR restrictions linger at least into the morning hours at CMX and IWD with the combination of lake effect clouds and a large area of low clouds (2kft-3kft) over northern MN, Northern WI and the western U.P. Models are not handling the cloud deck will, however, based on moisture profiles expecting that the clouds will begin to break in IWD during the mid-morning hours. For CMX the return to VFR will ultimately depend on how fast the winds shift southwest, and as a result, how long it takes snow showers to shift north of the terminal, so a 09-12Z timing may be too optimistic. VFR at all terminals during the daytime hours gives way to MVFR ceilings at IWD and CMX into the evening as another trough moves through the region. Otherwise, gusts to ~25 kts return on Monday at CMX.

MARINE

Issued at 402 PM EST Sun Nov 30 2025

Northwest winds of 20-30 kts with gales to ~35 kts over the east continue into this evening. Significant wave heights are at their peak this afternoon between 4-9 ft, highest over the southeastern waters. Winds settle from west to east to ~20 kts or less by late tonight, gradually backing west by Monday morning as high pressure moves in over the Great Lakes. Waves briefly settle around or below 4 ft late tonight/early Monday. Maintained Gale Warnings as is.

High pressure gives way to the east and a low pressure trough descends southeast over the lake on Monday, increasing southwest winds to 20-30 kts with a 30% chance for gale force gusts to 35 kts. Strongest winds will reside over the central waters, particularly between Isle Royale and the Keweenaw. This increases significant waves to 4-9 ft again, this time highest waves will be over the northern waters. Westerly winds fall below 20 kts by Tuesday morning with waves settling below 4 ft by a similar time.

The pressure gradient tightens with a Clipper Low Tuesday night into Wednesday. Southwest winds increase once again to 20-30 kts Tuesday night, veering northwest on Wednesday behind the cold front and maintaining between 20-30 kts overnight into Thursday. This system brings the best shot at gales to 35 kts during the forecast period (40-60% Wednesday into Wednesday night) as a cold airmass descends overhead accompanied by strong pressure rises. Significant wave heights build to 6-12 ft, highest southeast. The elevated winds/waves and cold airmass support light to moderate freezing spray across the lake, and likely some heavy freezing spray over the north central waters (60% chance).

Winds fall back down to 20-30 kt for Thursday into Friday with the resumption of high pressure near the Great Lakes, though uncertainty increases late this week into the weekend as models differ on the arrival and strength of the next system.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... None. Lake Superior... None. Lake Michigan... None.