textproduct: Marquette

KEY MESSAGES

- Windy conditions are expected tonight, especially in the Keweenaw where there is a 70% chance for wind gusts exceeding 45 mph. See the latest Wind Advisory for additional details.

- Multiple gale events could be seen across Lake Superior this week into this weekend, with the current one going until Wednesday morning. A Storm Force Wind and Heavy Freezing Spray event could be seen Thursday.

- The strong winds across the Great Lakes this week could create times of minor lakeshore flooding and beach erosion. See any pertinent Lakeshore Flood Advisories for more info.

- A strong Clipper low could bring high winds, a flash freeze, and/or several inches of snowfall across the area Thursday into Thursday night. Continue to monitor the forecast as impacts could change depending on subtle shifts in the strength and track of the low.

DISCUSSION

Issued at 345 PM EST Tue Dec 16 2025

Multiple clipper lows will impact the Upper Great Lakes through the upcoming weekend. Southerly winds today brought warmer temperatures to the U.P, especially in the west where temperatures had climbed into the 30s to lower 40s. Over the central and east temperatures were struggling to warm above freezing with model soundings showing a strong inversion in place along with cloud cover that was limiting heating. Winds were breezy from the south with gusts of 20 to 30 mph with stronger gusts at the immediate lakeshores. It was mainly dry across the U.P today, with a few freezing rain showers skirting the WI/MI border earlier this morning.

Tonight the first clipper low quickly moves from northern Ontario to east of Hudson Bay. This will drag a cold front through the U.P late this evening. Ahead of the front expecting temperatures will likely rise above freezing over most of the U.P but will quickly fall into the low 20s behind the front. Gusty northwest winds will accompany the front with strong pressure rises (8mb/6hr) and cross isallobaric flow. Gusts to 45 mph are expected in the Keweenaw where a Wind Advisory is in effect late this afternoon through tonight. Elsewhere expect gusts up to 30 mph and locally 40 mph along the immediate lakeshore.

Thermodynamic profiles will support light lake effect snow showers in the northwest wind snowbelts late tonight into the morning hours with a brief period of rain or freezing rain at the onset possible. Limited moisture will keep snow accumulations under an inch before diminishing in the afternoon as winds begin to shift southerly again, ahead of the next clipper. Temperatures will stay below freezing across the U.P on Wednesday with the cold air starting to retreat again Wednesday night.

A stronger clipper will move through the area Wednesday night into Thursday night bringing a variety of weather to the area including almost the whole kitchen sink as far as possible precipitation types, more strong winds and potential for accumulating snow.

Freezing rain potential...The first wave of precipitation will move into the U.P late Wednesday night into Thursday morning ahead of an approaching cold front. Thermal profiles show a warm layer above the boundary layer with temperatures of 1-3C. This will provide a sufficient melting layer to bring a freezing rain threat to the western and central U.P, at least during the onset of the precipitation. Model still diverge on the magnitude and rate of surface warming but the best chance to see a light glaze of ice will be over the higher terrain of the western and central U.P with temperatures warming above freezing rather quickly in the lower elevations.

Snowfall potential...The best chance for snow will be on the backside of the low pressure Thursday evening into Friday morning. NBM probabilities for 3"+ around 50-75% over the nnw wind snowbelts of western and central U.P. Most models keep stronger fgen well north of the area, over Lake Superior with a notable dry slot at 700mb and subsidence in the DGZ. The GFS and GEFS seem to be the outlier scenario with solutions that generally favor a more southerly track as the clipper low weakens around western Lake Superior and merges with a developing surface low over southern WI as it moves into the eastern U.P. This solution would result in more impactful snow amounts (8"+) across the northern and western U.P. The more likely scenario would be 3-6" in the Keweenaw and 2-4" if the north to northwest wind snowbelts Thursday night into Friday morning.

Wind potential...Another round of strong winds is expected behind the cold front Thursday night which could result in significant blowing and drifting of any snow that does fall, mainly over the Keweenaw and Lake Superior shoreline of the central and eastern U.P. NBM probabilities for 40+ mph gusts is 50-70% over the Keweenaw and 50% along the aforementioned lakeshores. Did not have enough confidence to go with winter headlines at this time but those with outdoor or travel plans, especially in the Keweenaw should monitor the forecast closely.

Flash freeze potential...Rapidly falling temperatures on Thursday afternoon and evening behind the cold front could result in a flash freeze where roads are still wet.

The clipper train will roll on into the weekend with another fast moving clipper possible Friday night into Saturday bringing the chance for accumulating snow and lake effect snow showers lingering into Sunday.

AVIATION /06Z TAFS THROUGH 06Z THURSDAY/

Issued at 1228 AM EST Wed Dec 17 2025

VFR conditions at all sites tonight, however, significant low level wind shear is present as SSW winds around 10-20 kt at the surface are contrasted with WSW winds up to 60 kt at 2kft. Gusty surface winds continue while veering westerly, though the wind shear will drop out as surface winds line up more with the winds aloft.

Chances of precipitation tonight remain around 15-30 percent, though a period of freezing drizzle to light freezing rain is expected initially before a brief transition to light lake effect snow. With confidence in fzra/fzdr low, have only opted to include a prob30 group for -rasn at CMX tonight. Regardless of the occurrence of precipitation, ceilings will be over 75 percent likely to fall to MVFR and 10-20 percent likely to fall to IFR tonight. Some recovery is expected tomorrow at IWD and SAW to VFR with SCT and lifting cloud bases, though CMX will retain 75+ percent chances to remain in MVFR.

MARINE

Issued at 345 PM EST Tue Dec 16 2025

A clipper low moving through northern Ontario will continue to bring gales to the lake through tonight. Southwest gales to 40kt will become northwest behind a cold front late tonight. Strong pressure rises and mixing behind the front will bring gales up to 45kt over the eastern half of the lake. Winds diminish quickly on Wednesday morning and remain lighter, less than 20 kts into the early afternoon hours. The next clipper approaches Wednesday evening bringing yet another round of potential gales as southerly winds develop. The best chance for gales (70% chance) will be over the eastern part of the lake Wednesday night with winds up to 30 kts over the western part of the lake. After a period of sub-gale winds Thursday early afternoon the next cold front will push across the lake bringing gales (60-80% chance) to much of the lake with potentially storm force gusts (30% chance) over the central part of the lake. Heavy freezing spray is expected to accompany the winds on Thursday night across the lake as temperatures fall into the single digits and teens.

Ridging will bring lighter winds to Lake Superior for Friday afternoon (below 20 knots). Thereafter the active pattern continues with the next low approaching and with potential gales Friday night (40% chance for gales, highest over the eastern half). As the low heads towards the St. Lawrence Seaway Saturday, expect the winds to veer to the west behind the low on Saturday as winds of 30 knots to gales up to 40 knots become possible late in the day into Saturday evening (40% chance for gales, highest over east). Freezing spray is possible Friday night and again late Saturday with each of the gale events.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... Wind Advisory until 4 AM EST early this morning for MIZ001-003.

Lakeshore Flood Advisory until 4 AM EST early this morning for MIZ001.

Lakeshore Flood Advisory until 10 AM EST this morning for MIZ006-007.

Lake Superior... Gale Warning until 1 AM EST /midnight CST/ early this morning for LSZ162.

Gale Watch from Thursday afternoon through late Thursday night for LSZ162.

Gale Warning until 4 AM EST /3 AM CST/ early this morning for LSZ241-242-263.

Gale Watch from Thursday afternoon through Friday morning for LSZ242>246-263-264.

Gale Warning until 7 AM EST this morning for LSZ243>248-250- 251-264>267.

Gale Watch from this evening through Friday morning for LSZ247>251-265>267.

Gale Warning until 7 AM EST this morning for LSZ249.

Lake Michigan... Gale Watch from this evening through Thursday morning for LMZ221-248-250.