textproduct: Marquette

KEY MESSAGES

- Gusty northerly to northwesterly winds expected in the wake of the low pressure. 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 UP.

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

DISCUSSION

Issued at 220 AM EST Sun Nov 30 2025

Early this morning water vapor imagery and model height analysis showed an upper level trough moving through the Great Lakes with the 500mb trough axis along he MN/WI border. A surface low pressure of 1010mb was over northern Illinois tracking east-northeastwards. Radar imagery showed widespread light snow across the U.P with surface visiblity observations generally in the 1 to 3 mile range. Heavier snow showers were continuing to organize over eastern Lake Superior and continuing to move onshore into northern Marquette and Baraga counties under easterly flow. Another band was over the western lake which was starting to shift east towards the U.P's western shoreline. Temperatures were mainly in the low 20s inland to mid 20s near the lakeshores.

Through this morning the low pressure will quickly move from IL to lower Michigan. Widespread light snow should quickly taper off from west to east, however, LES snow showers will increase in coverage and intensity as winds become northeasterly and then northerly, resulting in strong convergence. Model reflectivity from the CAMs shows well organized bands with embedded mesolow features coming into the western U.P and Keweenaw through the early morning hours and into the central U.P, mainly Marquette, Baraga and Alger counties through mid morning. LES then shifts east into the northwest wind belts by this afternoon. HREF probabilities show 1 in/hr snow rates are possible with these bands (50-70% chance) through 8am EST with intensity quickly dropping off thereafter. Wind will also become gusty (up to 35 mph), especially near the Lake Superior lakeshore. The combination of moderate to heavy snow and wind/blowing snow could result in a period of low visiblity (down to 1/4 mile) between 6am and 8am in Marquette and Alger counties along with snow covered roads, making travel difficult. Conditions should improve by mid morning as the intensity of the snow showers decrease. By afternoon light snow showers will set up in the northwest wind snowbelts but moisture and thermal profiles will limit intensity.

Light snow showers will continue for the northwest wind snowbelts this evening before winds turn westerly. This will end the lake effect for all but the Keweenaw where a west-east orientated snow band may lift north through morning

LES will continue to some extent on Monday, as thermodynamic support for LES will be abundant considering 50-90% chances within the LREF ensemble of 850mb temperatures being at least -10 C or colder over around 5 C temperature Lake Superior all week. This will allow for the potential for some rare SW-wind LES over the Keweenaw Peninsula Monday, though accumulations exceeding 1 inch by Tuesday morning are only above 50% north of Laurium. Otherwise, the next system threatening to bring widespread snowfall to the UP will come with a weak Alberta Clipper low passing through northern Ontario late Tuesday into Wednesday. While snow totals look unimpressive with the trailing cold front, chances of multiple inches of accumulating NW wind LES climbs to 30-60 percent for Wednesday. Additionally, the cool NW winds behind the front will allow for Thursday morning low temperatures to fall to the single digits for much of the UP, with 20-40% chances of sub-zero lows along the MI/WI state line. Uncertainty then grows in the forecast as a high pressure takes place over much of the Midwest Thursday and ensembles have a wide range of solutions on when a low pressure might pass through the region to break up the high pressure. The CPC outlooks through at least the month of December prefer higher than normal precipitation and cooler than normal temperatures, so hopes for a White Christmas for the UP remain high.

AVIATION /18Z TAFS THROUGH 18Z MONDAY/

Issued at 1257 PM EST Sun Nov 30 2025

Primarily MVFR restrictions are expected into this evening under a northwest lake effect regime. SAW initially starts off at IFR as the last push of heavier snow moves through. Winds between 10-15 kts with gusts to around 25 kts at CMX/SAW are expected this afternoon. Winds become west tonight ~5 kts and southwest by Monday morning at ~10 kts. This wind shift lifts lingering LES showers and MVFR cigs out of IWD and SAW, but keeps MVFR restrictions at CMX into Monday morning where showers persist. Upgraded PROB30 groups to TEMPO groups at CMX to capture those expected impacts. The timing in which CMX returns VFR on Monday will ultimately depend on how fast the winds shift southwest, and as a result, how long it takes the LES showers to lift north. 12Z may be too optimistic, but this improvement should occur by the end of the 18Z TAF period. Otherwise gusts to ~25 kts return on Monday at CMX.

MARINE

Issued at 220 AM EST Sun Nov 30 2025

Northerly gales to 35 kt are expected today for the eastern part of the lake, east of the Keweenaw, as a fast moving low pressure tracks through Lower Michigan to Quebec. Over the rest of the lake winds to 30 kt are expected. As high pressure builds into the lower Great Lakes tonight winds will fall below 20 kt. Monday, chances of a brief southwesterly gale are around 20-30 percent over the west half of the lake as the pressure gradient tightens ahead of an approaching Clipper Low. In the wake of that low, northwesterly wind gusts ramp up to 30 kt with chances of gales around 40-60% on Wednesday. Winds fall back down to 25-30 kt for Thursday with the resumption of high pressure near the Great Lakes, though uncertainty increases late in the week into the weekend as models differ on when the arrival of the next system will be and how strong that system might be.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... Winter Weather Advisory until 1 PM EST /noon CST/ this afternoon for MIZ001>007-009-014-084-085.

Lake Superior... Gale Warning until 7 PM EST this evening for LSZ245>248-265.

Gale Warning until 9 PM EST this evening for LSZ249-250-266.

Gale Warning until 7 PM EST this evening for LSZ251-267.

Lake Michigan... None.