813
FZUS63 KMQT 042001
GLFLS

Open Lake Forecast for Lake Superior
National Weather Service Marquette MI
401 PM EDT Thu Sep 4 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 29.3 inch low over northern Ontario will remain mostly stationary
through tonight while a 29.5 inch Alberta Clipper low deepens to
29.3 inches as it reaches northern Wisconsin tonight. Throughout
Friday, these lows merge into a single low of 29.2 inches south of
James Bay. The consolidated low then shifts northeast through far
northern Quebec on Saturday as 30.1 inch high pressure moves into
the Midwest for the weekend, strengthening to 30.3 inches over the
Upper Mississippi Valley on Sunday. This high brings 30.3 inch
ridging over Lake Superior Sunday and Sunday night. Ridging begins
to dissipate over the Upper Great Lakes on Monday as the high
continues east towards New England.


LSZ162-050800-
Lake Superior west of a line from Saxon Harbor WI to Grand
Portage MN beyond 5NM-
401 PM EDT Thu Sep 4 2025 /301 PM CDT Thu Sep 4 2025/

.LATE THIS AFTERNOON...Southwest winds 15 to 25 knots. A slight
chance of showers. Waves 3 to 5 feet occasionally to 7 feet.
.TONIGHT...West winds 10 to 20 knots veering northwest after
midnight, then increasing to 15 to 25 knots late. A slight chance
of thunderstorms through midnight. A chance of showers. Waves
subsiding to calm to 2 feet, then building to 3 to 5 feet
occasionally to 7 feet.
.FRIDAY...West winds 20 to 30 knots increasing to 30 knots with a
few gale force gusts to 35 knots possible in the afternoon. A
slight chance of showers. Waves building to 5 to 8 feet
occasionally to 10 feet.
.FRIDAY NIGHT...Northwest winds 20 to 30 knots diminishing to
15 to 25 knots after midnight. Waves subsiding to 2 to 4 feet.
.SATURDAY...Northwest winds 10 to 20 knots backing west by mid
afternoon. Waves subsiding to calm to 2 feet.
.SATURDAY NIGHT...Northwest winds 10 to 20 knots veering north
after midnight. Waves calm to 2 feet.
.SUNDAY...Northwest winds 10 to 20 knots backing west by mid
afternoon. Waves calm to 2 feet.
.SUNDAY NIGHT...West winds 5 to 15 knots. Waves calm to 2 feet.
.MONDAY...Southwest winds 10 to 20 knots backing south. A chance
of showers. Waves calm to 2 feet.
.TUESDAY...South winds 10 to 20 knots becoming northeast 5 to
15 knots. A chance of showers. Waves calm to 2 feet.

$$

LSZ263-050800-
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-
401 PM EDT Thu Sep 4 2025

...GALE WARNING IN EFFECT FROM FRIDAY MORNING THROUGH FRIDAY
EVENING...

.LATE THIS AFTERNOON...West winds 15 to 25 knots. Waves 4 to
8 feet occasionally to 10 feet.
.TONIGHT...West winds 15 to 25 knots diminishing to 5 to 15 knots
after midnight, then becoming northwest 15 to 25 knots late. A
chance of showers and a slight chance of thunderstorms. Waves
subsiding to 2 to 4 feet, then building to 3 to 6 feet
occasionally to 8 feet.
.FRIDAY...Northwest winds 20 to 30 knots becoming west gales to
35 knots in the afternoon. A chance of showers. Waves building to
8 to 11 feet occasionally to 14 feet.
.FRIDAY NIGHT...Northwest gales to 35 knots diminishing to 15 to
25 knots. A slight chance of showers through midnight. Waves
subsiding to 3 to 6 feet occasionally to 8 feet.
.SATURDAY...Northwest winds 10 to 20 knots backing west by mid
afternoon. Waves subsiding to 1 to 3 feet.
.SATURDAY NIGHT...North winds 10 to 20 knots. Waves 1 to 3 feet.
.SUNDAY...North winds 10 to 20 knots backing west by mid
afternoon. Waves subsiding to calm to 2 feet.
.SUNDAY NIGHT...West winds 10 to 20 knots diminishing to 5 to
15 knots after midnight. Waves calm to 2 feet.
.MONDAY...Southwest winds 10 to 20 knots backing south. Waves
building to 1 to 3 feet, then subsiding to calm to 2 feet.
.TUESDAY...South winds 10 to 20 knots becoming northeast 5 to
15 knots. A chance of showers. Waves subsiding to calm to 2 feet.

$$

LSZ264-050800-
Lake Superior from Upper Entrance to Portage Canal to Manitou
Island MI 5NM off shore to the US/Canadian Border-
401 PM EDT Thu Sep 4 2025

...GALE WARNING IN EFFECT FROM FRIDAY MORNING THROUGH FRIDAY
EVENING...

.LATE THIS AFTERNOON...West winds 15 to 25 knots. A slight chance
of showers. Waves 5 to 8 feet occasionally to 10 feet.
.TONIGHT...West winds 15 to 25 knots diminishing to 5 to 15 knots
after midnight, then becoming northwest 10 to 20 knots late. A
slight chance of thunderstorms through midnight. A chance of
showers. Waves subsiding to 2 to 4 feet.
.FRIDAY...Northwest winds 20 to 30 knots backing west in the
afternoon, then increasing to gales to 35 knots late. A chance of
showers. Waves building to 7 to 10 feet occasionally to 13 feet.
.FRIDAY NIGHT...West gales to 35 knots becoming northwest 20 to
30 knots after midnight, then diminishing to 15 to 25 knots late.
A slight chance of showers through midnight. Waves subsiding to
4 to 7 feet occasionally to 9 feet.
.SATURDAY...Northwest winds 15 to 25 knots diminishing to 10 to
20 knots by mid afternoon. Waves subsiding to 1 to 3 feet.
.SATURDAY NIGHT...North winds 5 to 15 knots increasing to 10 to
20 knots after midnight. Waves 1 to 3 feet.
.SUNDAY...Northwest winds 10 to 20 knots. Waves building to 2 to
4 feet, then subsiding to calm to 2 feet.
.SUNDAY NIGHT...West winds 10 to 20 knots diminishing to 5 to
15 knots after midnight. Waves calm to 2 feet.
.MONDAY...Southwest winds 10 to 20 knots backing south. Waves
building to 1 to 3 feet, then subsiding to calm to 2 feet.
.TUESDAY...South winds 10 to 20 knots becoming north 5 to
15 knots. A chance of showers. Waves subsiding to calm to 2 feet.

$$

LSZ265-050800-
Lake Superior West of Line from Manitou Island to Marquette MI
Beyond 5NM from shore-
401 PM EDT Thu Sep 4 2025

...GALE WARNING IN EFFECT FROM FRIDAY MORNING THROUGH FRIDAY
EVENING...

.LATE THIS AFTERNOON...West winds 15 to 25 knots. Waves 3 to
6 feet occasionally to 8 feet.
.TONIGHT...West winds 15 to 25 knots becoming southwest 10 to
20 knots after midnight, then becoming northwest 15 to 25 knots
late. A slight chance of showers through midnight. A slight
chance of thunderstorms. Showers likely after midnight. Waves
subsiding to calm to 2 feet, then building to 1 to 3 feet.
.FRIDAY...Northwest gales to 35 knots backing west in the
afternoon. A slight chance of waterspouts through early
afternoon. Showers likely through early afternoon, then a chance
of showers by mid afternoon. Waves building to 4 to 7 feet
occasionally to 9 feet.
.FRIDAY NIGHT...West gales to 35 knots becoming northwest 20 to
30 knots late. A chance of showers. Waves subsiding to 2 to
4 feet.
.SATURDAY...Northwest winds 15 to 25 knots. A slight chance of
showers through early afternoon. Waves subsiding to calm to
2 feet.
.SATURDAY NIGHT...Northwest winds 10 to 20 knots. A chance of
showers. Waves calm to 2 feet.
.SUNDAY...Northwest winds 15 to 25 knots. Waves calm to 2 feet.
.SUNDAY NIGHT...West winds 10 to 20 knots. Waves calm to 2 feet.
.MONDAY...West winds 10 to 20 knots backing south. Waves calm to
2 feet.
.TUESDAY...South winds 10 to 20 knots veering southwest. A chance
of showers. Waves calm to 2 feet.

$$

LSZ266-050800-
Lake Superior East of a line from Manitou Island to Marquette MI
and West of a line from Grand Marais MI to the US/Canadian Border
Beyond 5NM from shore-
401 PM EDT Thu Sep 4 2025

...GALE WARNING IN EFFECT FROM FRIDAY MORNING THROUGH FRIDAY
EVENING...

.LATE THIS AFTERNOON...West winds 15 to 25 knots. A slight chance
of showers. Waves 5 to 9 feet occasionally to 11 feet.
.TONIGHT...West winds 15 to 25 knots becoming southwest 10 to
20 knots after midnight, then becoming northwest 15 to 25 knots
late. A slight chance of showers through midnight. A slight
chance of thunderstorms. Showers after midnight. Waves subsiding
to 2 to 4 feet.
.FRIDAY...Northwest winds 20 to 30 knots becoming west gales to
35 knots in the afternoon. Showers and a slight chance of
thunderstorms through early afternoon, then a chance of showers
by mid afternoon. Waves building to 8 to 11 feet occasionally to
14 feet.
.FRIDAY NIGHT...West gales to 35 knots diminishing to 20 to
30 knots after midnight, then veering northwest late. A chance of
showers. Waves building to 9 to 12 feet occasionally to 15 feet,
then subsiding to 6 to 9 feet occasionally to 11 feet.
.SATURDAY...Northwest winds 15 to 25 knots. A slight chance of
showers. Waves subsiding to 2 to 4 feet.
.SATURDAY NIGHT...Northwest winds 10 to 20 knots. A chance of
showers. Waves subsiding to 1 to 3 feet.
.SUNDAY...Northwest winds 15 to 25 knots diminishing to 10 to
20 knots by mid afternoon. A chance of showers through early
afternoon. Waves building to 2 to 4 feet.
.SUNDAY NIGHT...Northwest winds 10 to 20 knots backing west after
midnight. Waves subsiding to calm to 2 feet.
.MONDAY...West winds 10 to 20 knots backing south. Waves building
to 1 to 3 feet.
.TUESDAY...South winds 10 to 20 knots veering southwest. A chance
of showers. Waves subsiding to calm to 2 feet.

$$

LSZ267-050800-
Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off
shore to the US/Canadian border-
401 PM EDT Thu Sep 4 2025

...GALE WARNING IN EFFECT FROM FRIDAY MORNING THROUGH FRIDAY
EVENING...

.LATE THIS AFTERNOON...Southwest winds 20 to 30 knots. A chance
of showers. Waves 5 to 9 feet occasionally to 11 feet.
.TONIGHT...Southwest winds 15 to 25 knots becoming south 20 to
30 knots late. A slight chance of showers through midnight, then
showers and a slight chance of thunderstorms after midnight.
Waves subsiding to 2 to 4 feet, then building to 3 to 5 feet
occasionally to 7 feet.
.FRIDAY...Northwest winds 20 to 30 knots becoming west gales to
40 knots in the afternoon. A slight chance of thunderstorms
through early afternoon. Showers. Waves building to 9 to 12 feet
occasionally to 15 feet.
.FRIDAY NIGHT...West gales to 35 knots diminishing to 20 to
30 knots late. Showers likely through midnight, then a chance of
showers after midnight. Waves subsiding to 6 to 9 feet
occasionally to 11 feet.
.SATURDAY...West winds 15 to 25 knots becoming northwest 10 to
20 knots by mid afternoon. A chance of showers. Waves subsiding
to 3 to 5 feet occasionally to 7 feet.
.SATURDAY NIGHT...Northwest winds 10 to 20 knots. A chance of
showers. Waves subsiding to 1 to 3 feet.
.SUNDAY...North winds 10 to 20 knots becoming northwest 15 to
25 knots by mid afternoon. A chance of showers through early
afternoon. Waves building to 2 to 4 feet.
.SUNDAY NIGHT...Northwest winds 15 to 25 knots becoming west
10 to 20 knots after midnight. Waves subsiding to 1 to 3 feet.
.MONDAY...West winds 10 to 20 knots backing south. Waves
subsiding to calm to 2 feet, then building to 1 to 3 feet.
.TUESDAY...South winds 15 to 25 knots diminishing to 10 to
20 knots. A chance of showers. Waves subsiding to calm to 2 feet.

$$

LSZ261-050200-
MAFOR 0421/
Superior West...GALE WARNING IN EFFECT...11530 11630 11620 11720
11730 11740 12640. A chance of showers tonight and Friday
morning. Waves 3 to 6 feet subsiding to 2 to 4 feet tonight.
Waves 3 to 6 feet building to 5 to 9 feet Friday.

Superior North Central...GALE WARNING IN EFFECT...11640 11630
11620 11610 11730 12740 11650. A chance of showers overnight and
Friday. Waves 5 to 8 feet subsiding to 3 to 6 feet tonight. Waves
3 to 5 feet building to 6 to 9 feet Friday.

Superior South Central...GALE WARNING IN EFFECT...11630 11620
11520 11526 11736 12746 11650. Waves 4 to 7 feet subsiding to 1
to 3 feet tonight. Waves 2 to 4 feet building to 6 to 9 feet
Friday.

Superior East...GALE WARNING IN EFFECT...11640 11530 11520 11526
11436 12746 11646. Waves 5 to 9 feet subsiding to 3 to 6 feet
tonight. Waves 3 to 5 feet building to 7 to 11 feet Friday.

$$

WFO MQT

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weather.gov/greatlakes