fzus63 kmqt 181501
glfls 
expires:202512182100;;802593

open lake forecast for lake superior
national weather service marquette mi
1000 am est thu dec 18 2025

for waters beyond 5 nautical miles of shore on lake superior.

waves are the significant wave height - the average of the
highest 1/3 of the wave spectrum. occasional wave height is the
average of the highest 1/10 of the wave spectrum.

.synopsis...

a 29.0 inch clipper over northern minnesota this morning moves into 
lake superior this afternoon. this low lifts northeast away from the 
lake tonight before reaching northern quebec friday morning. a 29.9 
inch ridge then returns to the lake on friday via a 30.2 inch high 
over the lower mississippi valley and a weakening 29.9 inch high 
over northern ontario. another low pressure of around 29.3 inches 
tracks north of lake superior on saturday. this is then followed by 
a 30.3 inch high over the canadian prairies sliding southeast into 
the ohio river valley late this weekend, building to 30.7 inches by 
monday morning.



lsz162-182100-
lake superior west of a line from saxon harbor wi to grand
portage mn beyond 5nm-
1000 am est thu dec 18 2025 /900 am cst thu dec 18 2025/

...gale warning in effect from 4 pm est /3 pm cst/ this afternoon
through late tonight...
...heavy freezing spray warning in effect from 7 pm est /6 pm
cst/ this evening through friday morning...

.rest of today...south winds 15 to 25 knots becoming southwest
20 to 30 knots by late morning, then becoming north gales to
45 knots by mid afternoon. rain showers likely and a chance of
drizzle. snow showers in the afternoon. freezing spray in the
afternoon. waves 3 to 5 feet occasionally to 7 feet building to
6 to 9 feet occasionally to 11 feet. 
.tonight...north gales to 45 knots. heavy freezing spray. snow
showers in the evening. a slight chance of snow showers after
midnight. waves building to 9 to 12 feet occasionally to 15 feet,
then subsiding to 5 to 8 feet occasionally to 10 feet. 
.friday...north winds 15 to 25 knots diminishing to 5 to 15 knots
by late morning, then becoming south 10 to 20 knots by mid
afternoon. a chance of snow showers. waves subsiding to calm to
2 feet. 
.friday night...south winds 20 to 30 knots veering southwest
after midnight. snow showers likely in the evening, then a chance
of snow showers after midnight. waves building to 3 to 6 feet
occasionally to 8 feet. 
.saturday...west winds 20 to 30 knots increasing to gales to
35 knots in the afternoon. a slight chance of snow showers in the
morning. freezing spray in the afternoon. waves building to 5 to
8 feet occasionally to 10 feet. 
.saturday night...west winds 20 to 30 knots becoming northwest
15 to 25 knots after midnight. freezing spray in the evening.
waves subsiding to 2 to 4 feet. 
.sunday...west winds 10 to 20 knots backing southwest. waves
subsiding to calm to 2 feet. 
.monday...south winds 10 to 20 knots veering southwest. waves
building to 1 to 3 feet. 

note, wave height forecasts are for ice free areas.

$$

fzus63 kmqt 181501
glfls 
expires:202512182100;;802594

open lake forecast for lake superior
national weather service marquette mi
1000 am est thu dec 18 2025

for waters beyond 5 nautical miles of shore on lake superior.

waves are the significant wave height - the average of the
highest 1/3 of the wave spectrum. occasional wave height is the
average of the highest 1/10 of the wave spectrum.

.synopsis...

a 29.0 inch clipper over northern minnesota this morning moves into 
lake superior this afternoon. this low lifts northeast away from the 
lake tonight before reaching northern quebec friday morning. a 29.9 
inch ridge then returns to the lake on friday via a 30.2 inch high 
over the lower mississippi valley and a weakening 29.9 inch high 
over northern ontario. another low pressure of around 29.3 inches 
tracks north of lake superior on saturday. this is then followed by 
a 30.3 inch high over the canadian prairies sliding southeast into 
the ohio river valley late this weekend, building to 30.7 inches by 
monday morning.



lsz263-182100-
lake superior from saxon harbor wi to upper entrance to portage
canal mi 5nm off shore to the us/canadian border including isle
royale national park-
1000 am est thu dec 18 2025

...storm warning in effect from 4 pm est this afternoon through
friday morning...
...heavy freezing spray warning in effect from 7 pm est this
evening through friday morning...

.rest of today...south winds 10 to 20 knots becoming southwest
15 to 25 knots by late morning, then becoming north storm force
winds to 50 knots by mid afternoon. a chance of drizzle late in
the morning. rain showers. snow showers in the afternoon. waves
3 to 5 feet occasionally to 7 feet building to 7 to 10 feet
occasionally to 13 feet. 
.tonight...north storm force winds to 55 knots diminishing to
gales to 45 knots late. heavy freezing spray. snow showers in the
evening. a chance of snow showers after midnight. waves building
to 12 to 17 feet occasionally to 21 feet, then subsiding to 10 to
14 feet occasionally to 18 feet. 
.friday...north winds 20 to 30 knots diminishing to 10 to
20 knots by late morning, then becoming southeast 5 to 15 knots
by mid afternoon. heavy freezing spray in the morning. a slight
chance of snow showers. waves subsiding to 1 to 3 feet. 
.friday night...south winds 20 to 30 knots. a chance of snow
showers. waves building to 4 to 7 feet occasionally to 9 feet. 
.saturday...southwest gales to 35 knots becoming west gales to
40 knots in the afternoon. a chance of snow showers. freezing
spray in the afternoon. waves building to 10 to 14 feet
occasionally to 18 feet, then subsiding to 9 to 12 feet
occasionally to 15 feet. 
.saturday night...west gales to 40 knots becoming northwest 20 to
30 knots after midnight. freezing spray. waves subsiding to 4 to
7 feet occasionally to 9 feet. 
.sunday...northwest winds 15 to 25 knots becoming west 5 to
15 knots. waves subsiding to 1 to 3 feet. 
.monday...south winds 10 to 20 knots veering southwest. waves
subsiding to calm to 2 feet, then building to 2 to 4 feet. 

note, wave height forecasts are for ice free areas.

$$