fzus63 kmqt 210813 cca
glfls 
expires:202607212000;;338674

open lake forecast for lake superior...corrected
national weather service marquette mi
413 am edt tue jul 21 2026

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... 

as a 29.2 inch low over far northern ontario this morning moves into 
northern quebec later today, troughing from the low over lake 
superior is replaced by ridging descending from a 30.1 inch high 
moving in from the canadian prairies into the midwest today into 
wednesday. the ridging over lake superior becomes maximized at 30.1 
inches over the western lake on wednesday before the high flattens 
and moves east towards new england thursday into friday morning. 
while ridging of around 30.0 inches looks to remain over lake 
superior on thursday, a weak 29.9 to 30.0 inch low could move over 
the northwestern half of the lake by thursday night into friday 
morning. as a low around 29.3 inches lifts from far northern ontario 
into hudson bay friday night into saturday morning, expect troughing 
of around 29.8 inches to move into lake superior in response by 
saturday morning. troughing of at least 29.8 inches looks to remain 
over the lake for the rest of the day. 




lsz162-212000-
lake superior west of a line from saxon harbor wi to grand
portage mn beyond 5nm-
413 am edt tue jul 21 2026 /313 am cdt tue jul 21 2026/

.early this morning...northwest winds 20 to 30 knots. a slight
chance of showers. waves 1 to 3 feet. 
.today...northwest winds 20 to 30 knots diminishing to 15 to
25 knots in the afternoon, then veering north late. waves
subsiding to calm to 2 feet. 
.tonight...north winds 10 to 20 knots backing northwest after
midnight. waves calm to 2 feet. 
.wednesday...northwest winds 5 to 15 knots backing southwest in
the afternoon, then increasing to 10 to 20 knots late. waves
building to 1 to 3 feet. 
.wednesday night...southwest winds 10 to 20 knots becoming west
5 to 15 knots after midnight. waves subsiding to calm to 2 feet. 
.thursday...southwest winds 10 to 20 knots. waves building to
1 to 3 feet. 
.thursday night...southwest winds 10 to 20 knots. a chance of
showers. waves subsiding to calm to 2 feet. 
.friday...southwest winds 10 to 20 knots increasing to 20 to
30 knots. a chance of showers. waves building to 1 to 3 feet,
then subsiding to calm to 2 feet. 
.saturday...southwest winds 20 to 30 knots becoming north 10 to
20 knots. a chance of showers. waves subsiding to calm to 2 feet.

$$

fzus63 kmqt 210813 cca
glfls 
expires:202607212000;;338675

open lake forecast for lake superior...corrected
national weather service marquette mi
413 am edt tue jul 21 2026

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... 

as a 29.2 inch low over far northern ontario this morning moves into 
northern quebec later today, troughing from the low over lake 
superior is replaced by ridging descending from a 30.1 inch high 
moving in from the canadian prairies into the midwest today into 
wednesday. the ridging over lake superior becomes maximized at 30.1 
inches over the western lake on wednesday before the high flattens 
and moves east towards new england thursday into friday morning. 
while ridging of around 30.0 inches looks to remain over lake 
superior on thursday, a weak 29.9 to 30.0 inch low could move over 
the northwestern half of the lake by thursday night into friday 
morning. as a low around 29.3 inches lifts from far northern ontario 
into hudson bay friday night into saturday morning, expect troughing 
of around 29.8 inches to move into lake superior in response by 
saturday morning. troughing of at least 29.8 inches looks to remain 
over the lake for the rest of the day. 




lsz263-212000-
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-
413 am edt tue jul 21 2026

.early this morning...northwest winds 15 to 25 knots. a slight
chance of showers and thunderstorms. waves 3 to 5 feet
occasionally to 7 feet. 
.today...northwest winds 15 to 25 knots veering north in the
afternoon. waves subsiding to 2 to 4 feet. 
.tonight...northwest winds 10 to 20 knots diminishing to 5 to
15 knots after midnight. waves subsiding to calm to 2 feet. 
.wednesday...northwest winds 5 to 15 knots backing west in the
afternoon, then becoming southwest 10 to 20 knots late. waves
building to 1 to 3 feet. 
.wednesday night...southwest winds 10 to 20 knots. waves
subsiding to calm to 2 feet, then building to 1 to 3 feet. 
.thursday...southwest winds 15 to 25 knots. waves building to
2 to 4 feet. 
.thursday night...southwest winds 10 to 20 knots. a chance of
showers. waves subsiding to 1 to 3 feet. 
.friday...southwest winds 15 to 25 knots increasing to 20 to
30 knots. a chance of showers. waves building to 2 to 4 feet,
then subsiding to 1 to 3 feet. 
.saturday...southwest winds 20 to 30 knots becoming north 10 to
20 knots. a chance of showers. waves building to 4 to 7 feet
occasionally to 9 feet, then subsiding to calm to 2 feet. 

$$