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Latest Great Lakes Marine Forecast by KMQT
Issued 9/18/2026 10:02 PM America/New_York.
Valid through 9/19/2026 4:00 AM America/New_York.
fzus63 kmqt 190202
glfls
expires:202609190800;;685127
open lake forecast for lake superior
national weather service marquette mi
1001 pm edt fri sep 18 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...
30.4 inch high weakens to 30.2 inches as it moves into western
quebec saturday morning. meanwhile, 29.9 inch low pressure develops
over the central plains, reaching western iowa by saturday morning
as another 29.8 inch low tracks across hudson bay. saturday into
sunday, a 30.2 inch high over the canadian prairie builds to 30.4
inches as it moves into northwestern ontario, creating a 30.2 inch
ridging pattern over lake superior. this high pressure center slowly
builds to 30.5 inches as it shifts into quebec by midday tuesday,
trailing a 30.4 inch ridge over lake superior. the high builds
further to 30.6 inches wednesday as it progresses eastward.
lsz162-190800-
lake superior west of a line from saxon harbor wi to grand
portage mn beyond 5nm-
1001 pm edt fri sep 18 2026 /901 pm cdt fri sep 18 2026/
.rest of tonight...east winds 10 to 20 knots diminishing to 5 to
15 knots after midnight. a slight chance of rain by midnight.
waves 1 to 3 feet subsiding to calm to 2 feet.
.saturday...east winds 5 to 15 knots becoming northeast 10 to
20 knots in the afternoon, then becoming east 5 to 15 knots late.
waves calm to 2 feet.
.saturday night...northeast winds 5 to 15 knots backing north
after midnight, then becoming northeast 15 to 25 knots late.
waves building to 2 to 4 feet.
.sunday...northeast winds 20 to 30 knots veering east by mid
afternoon. waves building to 4 to 7 feet occasionally to 9 feet,
then subsiding to 3 to 6 feet occasionally to 8 feet.
.sunday night...east winds 15 to 25 knots diminishing to 10 to
20 knots after midnight. waves subsiding to calm to 2 feet.
.monday...east winds 15 to 25 knots increasing to 20 to 30 knots
by mid afternoon. waves building to 2 to 4 feet.
.monday night...east winds 15 to 25 knots diminishing to 5 to
15 knots after midnight. waves subsiding to calm to 2 feet.
.tuesday...east winds 15 to 25 knots diminishing to 10 to
20 knots. waves calm to 2 feet.
.wednesday...east winds 10 to 20 knots diminishing to 5 to
15 knots. waves calm to 2 feet.
$$
(2/2)
Latest Great Lakes Marine Forecast by KMQT
Issued 9/18/2026 10:02 PM America/New_York.
Valid through 9/19/2026 4:00 AM America/New_York.
fzus63 kmqt 190202
glfls
expires:202609190800;;685128
open lake forecast for lake superior
national weather service marquette mi
1001 pm edt fri sep 18 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...
30.4 inch high weakens to 30.2 inches as it moves into western
quebec saturday morning. meanwhile, 29.9 inch low pressure develops
over the central plains, reaching western iowa by saturday morning
as another 29.8 inch low tracks across hudson bay. saturday into
sunday, a 30.2 inch high over the canadian prairie builds to 30.4
inches as it moves into northwestern ontario, creating a 30.2 inch
ridging pattern over lake superior. this high pressure center slowly
builds to 30.5 inches as it shifts into quebec by midday tuesday,
trailing a 30.4 inch ridge over lake superior. the high builds
further to 30.6 inches wednesday as it progresses eastward.
lsz263-190800-
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-
1001 pm edt fri sep 18 2026
.rest of tonight...east winds 10 to 20 knots veering southeast
after midnight, then diminishing to 5 to 15 knots late. waves
1 to 3 feet subsiding to calm to 2 feet.
.saturday...southeast winds 5 to 15 knots backing northeast in
the afternoon. waves calm to 2 feet.
.saturday night...northeast winds 5 to 15 knots becoming north
10 to 20 knots after midnight, then becoming northeast 15 to
25 knots late. waves building to 2 to 4 feet.
.sunday...northeast winds 20 to 30 knots. waves building to 4 to
7 feet occasionally to 9 feet, then subsiding to 3 to 6 feet
occasionally to 8 feet.
.sunday night...east winds 15 to 25 knots diminishing to 10 to
20 knots after midnight. waves subsiding to 1 to 3 feet.
.monday...east winds 5 to 15 knots increasing to 15 to 25 knots
by mid afternoon. waves building to 2 to 4 feet.
.monday night...east winds 15 to 25 knots diminishing to 5 to
15 knots after midnight. waves subsiding to calm to 2 feet.
.tuesday...east winds 10 to 20 knots veering southeast. waves
calm to 2 feet.
.wednesday...southeast winds 5 to 15 knots veering south. waves
calm to 2 feet.
$$
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