Marine Weather and Tide Forecast for Big Bay, MI

DISCUSSION
Issued at 352 PM EST Tue Jan 13 2026

Afternoon GOES-East water vapor imagery shows a clearing trend over the UP in the wake of the first cold front that brought a mess of precipitation types to the UP this morning. RAP analysis shows longwave troughing over Ontario with a number of embedded shortwaves within, the leading trough moving just off of eastern Lake Superior being the parent trough of a surface low of around 987mb over northeastern Ontario. The second of these embedded shortwaves will move over the UP this evening, helping bring a mix of rain and snow showers (mercifully, no FZRA expected) to the UP. The shortwave behind that one is the headliner though as it deepens and descends across the UP between 00Z and 06Z tonight.

With temperatures above freezing this afternoon, strong cold advection in the wake of the front will drop air temperatures sharply below freezing around 00Z tonight. This will make any water on the roads that melted this afternoon freeze on untreated surfaces, which will make travel locally hazardous. Then, with cold air over a still wide-open Lake Superior (ice coverage pretty much only over Thunder Bay and adjacent Canadian bays), lake effect snow invigorates out of the north to northwest, with CAMs showing a consistent multiband setup blanketing most of the Lake Superior shores and penetrating as far inland as eastern Gogebic County, northern Iron County, and Delta County. While the snow accumulations only reach Winter Weather Advisory in the rural north half of Delta County, significant parameters exist in support of snow squalls, so travel along US-41 may become hazardous overnight tonight even in locations outside of the Advisory. Despite snow totals through Wednesday only exceeding Winter Storm Warning threshold in rural Baraga and Marquette Counties north of US-41, impacts will be significant across the UP as saturated DGZ depths overnight of up to 7 kft and inversion heights in excess of 5 kft will lead to snow falling at 0.5-1 inch per hour along with wind gusts in excess of 40 mph (especially along the low-friction shores of Lake Superior), driving visibility to below a half mile in over half of the HRRR suite over a wide expanse of the UP through Wednesday morning. The combination of blowing and drifting snow and the flash freeze will make for some challenging road conditions well into Wednesday morning.

While soundings do show dry air aloft and slightly descending inversion heights to 3-4 kft, lake effect snow will remain in the forecast in the north wind belts through Wednesday. Expecting an extra 1-2" of fluffy snow each 6 hour period especially fir the north-central UP counties through the PM hours of Wednesday into Wednesday night. Ridging finally dampens the lake effect potential by 12Z Thursday, though relief is brief as the next clipper low approaches Thursday evening. Euro ensembles highlight the highest potential for advisory-level snowfall (3+ inches) over the terrain of Gogebic and Ontonagon counties Friday and Saturday with the rest of the UP seeing generally less snowfall. By the time this low pushes out Saturday afternoon, the cool air in the wake of the low will keep Saturday's highs only in the teens (NBM lows as low as 12 in Ironwood). With another clipper low forecast to pass through the region later in the weekend, more light-to-moderate lake-enhanced and lake-effect snow will be followed by another shot of cold air, with NBM low temperatures widespread in the negatives Monday and Tuesday mornings. Given the gusty conditions that tend to follow in the wake of clipper lows, wind chills in the negative double digits are a possibility to end the weekend and kick off next week.

AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/
Issued at 615 PM EST Tue Jan 13 2026

General MVFR cigs early this evening deteriorate to IFR/LIFR conditions tonight across the terminals as lake effect snowfall impacts the north wind snow belts. This, in addition to the strong winds creating areas of blowing snow near Lake Superior and rapid temperature drops creating the potential for flash freezing this evening (flash freeze around 1-3z), is expected to drop vis down to 3SM or less across the terminals. Some of the terminals could gust up to 34 knots or greater, with the greatest chance of this occurring at CMX tonight. We may flirt with airport mins at CMX and potentially even SAW too if the SN and/or BLSN is heavy enough. IWD seems to get the lightest of both, with vis looking to not drop below 3SM (although it very much could given if stronger than anticipated winds and/or snowfall rates occur). As snowfall rates lighten up Wednesday as the lake effect becomes more scattered, expect conditions to improve across the terminals, with a return to MVFR cigs being seen by the mid to later afternoon hours.

MARINE
Issued at 352 PM EST Tue Jan 13 2026

A shortwave trough moving north to south over Lake Superior tonight will ramp winds up from westerlies around 20-30 kt this afternoon to north-northwesterly gales to 35-45 kt, highest north of the Keweenaw Peninsula. Chances of storm-force gusts are generally 10 percent or less, though local terrain effects off of the MN Arrowhead and around Isle Royale locally increase those chances to around 30 percent. Gusts fall below 40 kt over the east and below 30 kt in the west Wednesday morning and below gales lakewide in the afternoon.
Winds fall below 20 kt lakewide by Thursday morning. With this gale event, temperatures will sharply fall below freezing tonight, creating a heavy freezing spray threat. Waves tonight rapidly increase to 8-16 ft (highest around the tip of the Keweenaw and near Stannard Rock) before peaking at around 18 ft in east-central Lake Superior Wednesday morning. Waves then gradually fall throughout the day Wednesday before falling below 4 ft lakewide Thursday morning.

A pair of weak clipper lows is then forecast to move near or over the lake, first between late Thursday night and early Saturday morning and then again between Sunday afternoon and Monday morning.
Ahead of the first low, southwesterly wind gusts of 25-30 kt are expected Thursday evening with chances of gales 15-30 percent (highest around Isle Royale) and moderate freezing spray. Winds briefly fall near and below 20 kt Friday morning before the northwesterlies in the wake of the low ramp up to 30 kt (with a 30 percent chance of a few gale force gusts). Northwesterly gusts will have a better chance at gales around the Keweenaw Peninsula Sunday night at around 40 percent. Moderate to heavy freezing spray is expected Friday evening through the weekend.

MQT WATCHES/WARNINGS/ADVISORIES
Upper Michigan...
Winter Weather Advisory until 7 AM EST /6 AM CST/ Wednesday for MIZ001>003-009.

Winter Weather Advisory until 1 PM EST Wednesday for MIZ004>007-085.

Lake Superior...
Gale Warning from 10 PM EST /9 PM CST/ this evening to 1 PM EST /noon CST/ Wednesday for LSZ162-240-241.

Heavy Freezing Spray Warning from 10 PM EST /9 PM CST/ this evening to 1 PM EST /noon CST/ Wednesday for LSZ162- 240>242-263.

Gale Warning until 1 PM EST Wednesday for LSZ242>244-263-264.

Heavy Freezing Spray Warning from 10 PM this evening to 1 AM EST Thursday for LSZ243>248-264-265.

Gale Warning until 7 PM EST Wednesday for LSZ245>249-265-266.

Heavy Freezing Spray Warning from 1 AM Wednesday to 1 AM EST Thursday for LSZ249-250-266.

Gale Warning from 10 PM this evening to 7 PM EST Wednesday for LSZ250-251-267.

Heavy Freezing Spray Warning from 4 AM Wednesday to 1 AM EST Thursday for LSZ251-267.

Lake Michigan...
Gale Warning from 4 AM to 10 PM EST Wednesday for LMZ221-250.