textproduct: Marquette

KEY MESSAGES

- Light lake effect snow continues downwind of Lake Superior through Tuesday, diminishing in the west by morning and in the evening in the east.

- Widespread light to moderate snow is expected Thursday night. Stronger winds are then expected as lake effect develops, resulting in potential for hazardous conditions from blowing snow.

DISCUSSION

Issued at 147 PM EST Mon Feb 2 2026

Latest GOES water vapor imagery and RAP analysis highlight a closed low over northern Ontario caught in northwest flow downstream of broad longwave ridging stretching across western Canada. At the surface, this morning's front is observed pushing into Ontario with upstream high pressure building south through Manitoba. Lake effect snow showers have been the name of the game behind the front today, although webcams highlight only light snowfall, which aligns with expectations. Under mostly cloudy skies, temperatures have warmed into the 20s for most of the region.

Guidance continues to suggest the pattern across Canada and CONUS for this forecast period will include large scale ridging building up the west coast and Rocky Mountains, with broad troughing fluctuating across eastern CONUS. This pattern favors average northwest flow aloft into the Great Lakes, providing surface troughs and clippers a road to drive through the region. After high pressure gradually diminishes lake effect Tuesday from west to east, a weak shortwave may dive south into the Upper Great Lakes Wednesday. Guidance is a little mixed on how much moisture will be available with the wave, but should it produce anything, high end values are still light in the Keweenaw and eastern Upper Michigan, with mostly dry conditions elsewhere.

Thursday night into Friday, a more organized surface low will track eastward through northern Ontario while a preceding shortwave dives south into the Upper Great Lakes and Upper Midwest before the cold air arrives Friday. Since guidance has latched on to this basic idea, they've been very much in line with each other, suggesting limited moisture available with the front and only suggesting about 30% chance of exceeding 3 inches in 24 hours. Strong cold air advection after frontal passage, on the order of 10C in 6 hours at 850mb, while pressure rises of 10 to 13mb per 6 hours occur beginning late Thursday night into Friday morning, will support a quick increase in northwesterly to northerly winds. This continues to be favorable for widespread gusts of 25 to 35 mph with 40+ most likely isolated to the Lake Superior lakeshore and Keweenaw. Latest NBM has trended probabilities of 40+ mph upwards, now near 45%. The same guidance suggests higher speeds near Copper Harbor cannot be ruled out (15% for 50 mph gusts). The same cold airmass will promote the transition from all synoptic snow to lake effect as the system pulls away. 850mb temps look to fall to near 20C Friday morning, allowing the DGZ to begin near or at the surface. Given the combination of light snow, increasing cold air, and the stronger winds, blowing and drifting snow may result in hazardous travel Friday. Uncertain when lake effect will end afterwards and there's indications another shortwave could drop into the region Saturday night into Sunday.

Seasonable temperatures are largely expected through Thursday, with highs either in the teens or 20s, and overnight lows in the single digits above and below. Thursday though, southwesterly flow will kick off a warm air advection spell. Latest GEFS, GEPS, and EC ensemble all bring probabilities of 850mb temps >=0C up into northern Wisconsin and their deterministic counterparts warm to ~-3 to -5C by Thursday evening. This translates to potential of warming above freezing Thursday, potentially lingering into the overnight hours Thursday. Raw EC deterministic output even holds near or above freezing temps until the cold air arrives Friday morning.

AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/

Issued at 1233 AM EST Tue Feb 3 2026

Generally MVFR conditions continue across the TAF sites for most of the forecast period as lake effect snowfall continues across the terminals. We could see the cloud deck rise enough over SAW to get into VFR conditions over the next couple of hours, but there is still uncertainty on whether this happens (same can be said for the MVFR conditions on Tuesday too). It is not out of the question for heavier snow bands to graze SAW into the daytime hours, dropping visiblity down to IFR, but confidence is too low to include in the TAF. Otherwise, expect a slow improvement to VFR Tuesday afternoon at IWD and SAW, while MVFR ceilings linger at CMX.

MARINE

Issued at 147 PM EST Mon Feb 2 2026

Northwest flow of near 15 kts across the west and 25 kts across the east will continue into Tuesday, before lighten to below 20kts lake wide by afternoon. Light winds continue through at least Wednesday evening, when northwest may increase to near 25kts in the east.. Then, winds pick up Thursday ahead of the next system. Confidence in gale force winds, especially by Friday morning, is high as increasing cold air and a strong pressure gradient pour into the area. This will also create heavy freezing spray into Saturday morning when winds fall back to near 20kts lake-wide. These conditions look to prevail through the weekend.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... Winter Weather Advisory until 7 AM EST this morning for MIZ006.

Lake Superior... Heavy Freezing Spray Warning until 7 AM EST this morning for LSZ243-244-251-264-267.

Heavy Freezing Spray Warning until 1 PM EST this afternoon for LSZ245>250-265-266.

Lake Michigan... None.