657
FZUS63 KMQT 170801
GLFLS

Open Lake Forecast for Lake Superior
National Weather Service Marquette MI
401 AM EDT Fri Oct 17 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 29.4 inch low over northern North Dakota early this morning
continues lifting into Manitoba this morning, eventually deepening
to 29.2 inches this afternoon as it crosses northeast over Lake
Winnipeg before continuing northeast to Hudson Bay through Saturday
afternoon. As a result, a 29.6 inch trough is sent over Lake
Superior this afternoon through Saturday. A secondary low develops
over the Mid Mississippi Valley late in the day Saturday and deepens
to at least 29.2 inches on Sunday as it crosses Lower Michigan. This
low reaches northern Quebec/Hudson Bay by Monday morning while a
weak 29.8 inch ridge briefly extends over Lake Superior. Meanwhile,
another low pressure at 29.5 inches is developing upstream over the
Northern Plains, tracking east over the region Monday night before
coalescing into a compact 29.4 inch low over the Upper Great Lakes
Tuesday morning.


LSZ162-172000-
Lake Superior west of a line from Saxon Harbor WI to Grand
Portage MN beyond 5NM-
401 AM EDT Fri Oct 17 2025 /301 AM CDT Fri Oct 17 2025/

.EARLY THIS MORNING...South winds 10 to 20 knots. A slight chance
of showers. Waves calm to 2 feet.
.TODAY...South winds 10 to 20 knots becoming southwest 15 to
25 knots late. A chance of showers. Waves building to 1 to
3 feet.
.TONIGHT...Southwest winds 15 to 25 knots diminishing to 10 to
20 knots late. Waves building to 2 to 4 feet, then subsiding to
1 to 3 feet.
.SATURDAY...West winds 10 to 20 knots. Waves subsiding to calm to
2 feet.
.SATURDAY NIGHT...Northwest winds 10 to 20 knots increasing to
15 to 25 knots after midnight. A slight chance of showers. Waves
building to 1 to 3 feet.
.SUNDAY...Northwest winds 15 to 25 knots backing west by mid
afternoon. Waves subsiding to calm to 2 feet.
.SUNDAY NIGHT...West winds 10 to 20 knots backing southwest after
midnight. Waves calm to 2 feet.
.MONDAY...South winds 10 to 20 knots becoming west 15 to
25 knots. A chance of showers. Waves building to 2 to 4 feet,
then subsiding to 1 to 3 feet.
.TUESDAY...Northwest winds 20 to 30 knots diminishing to 15 to
25 knots. A chance of rain showers. Waves building to 3 to 6 feet
occasionally to 8 feet, then subsiding to 1 to 3 feet.

$$

LSZ263-172000-
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 AM EDT Fri Oct 17 2025

.EARLY THIS MORNING...South winds 10 to 20 knots. A chance of
showers. Waves 1 to 3 feet.
.TODAY...South winds 10 to 20 knots veering southwest late. A
chance of showers. Waves 1 to 3 feet.
.TONIGHT...Southwest winds 15 to 25 knots diminishing to 10 to
20 knots late. A slight chance of showers through midnight. Waves
building to 3 to 5 feet occasionally to 7 feet, then subsiding to
2 to 4 feet.
.SATURDAY...West winds 10 to 20 knots. Waves subsiding to 1 to
3 feet.
.SATURDAY NIGHT...Northwest winds 10 to 20 knots increasing to
15 to 25 knots after midnight. A slight chance of showers. Waves
subsiding to calm to 2 feet, then building to 3 to 5 feet
occasionally to 7 feet.
.SUNDAY...Northwest winds 20 to 30 knots backing west by mid
afternoon. Waves building to 3 to 6 feet occasionally to 8 feet.
.SUNDAY NIGHT...West winds 10 to 20 knots backing southwest after
midnight. Waves subsiding to 1 to 3 feet.
.MONDAY...South winds 15 to 25 knots becoming west 20 to
30 knots. A chance of showers. Waves building to 4 to 7 feet
occasionally to 9 feet.
.TUESDAY...Northwest gales to 40 knots. A chance of rain showers.
Waves building to 7 to 10 feet occasionally to 13 feet, then
subsiding to 3 to 6 feet occasionally to 8 feet.

$$

LSZ264-172000-
Lake Superior from Upper Entrance to Portage Canal to Manitou
Island MI 5NM off shore to the US/Canadian Border-
401 AM EDT Fri Oct 17 2025

.EARLY THIS MORNING...South winds 10 to 20 knots. A chance of
showers. Waves 3 to 5 feet occasionally to 7 feet.
.TODAY...South winds 10 to 20 knots. A chance of showers. Waves
subsiding to 2 to 4 feet.
.TONIGHT...Southwest winds 15 to 25 knots diminishing to 10 to
20 knots late. A chance of showers through midnight. Waves
building to 3 to 5 feet occasionally to 7 feet, then subsiding to
2 to 4 feet.
.SATURDAY...West winds 10 to 20 knots. Waves subsiding to 1 to
3 feet.
.SATURDAY NIGHT...Northwest winds 10 to 20 knots becoming north
15 to 25 knots after midnight. A slight chance of showers. Waves
subsiding to calm to 2 feet, then building to 3 to 5 feet
occasionally to 7 feet.
.SUNDAY...Northwest winds 20 to 30 knots. Waves building to 4 to
7 feet occasionally to 9 feet, then subsiding to 3 to 5 feet
occasionally to 7 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...South winds 15 to 25 knots increasing to 20 to
30 knots. A chance of showers. Waves building to 4 to 7 feet
occasionally to 9 feet.
.TUESDAY...Northwest gales to 40 knots. A chance of rain showers.
Waves building to 5 to 9 feet occasionally to 11 feet.

$$

LSZ265-172000-
Lake Superior West of Line from Manitou Island to Marquette MI
Beyond 5NM from shore-
401 AM EDT Fri Oct 17 2025

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

$$

LSZ266-172000-
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 AM EDT Fri Oct 17 2025

.EARLY THIS MORNING...South winds 15 to 25 knots. Showers likely.
Waves 3 to 6 feet occasionally to 8 feet.
.TODAY...South winds 20 to 30 knots. A chance of showers. Waves
3 to 6 feet occasionally to 8 feet.
.TONIGHT...South winds 20 to 30 knots becoming southwest 15 to
25 knots after midnight, then diminishing to 10 to 20 knots late.
A chance of showers and a slight chance of thunderstorms. Waves
building to 4 to 7 feet occasionally to 9 feet, then subsiding to
2 to 4 feet.
.SATURDAY...Southwest winds 10 to 20 knots veering west in the
afternoon, then veering north late. A slight chance of showers.
Waves subsiding to 1 to 3 feet.
.SATURDAY NIGHT...North winds 10 to 20 knots increasing to 15 to
25 knots after midnight. A chance of showers. Waves subsiding to
calm to 2 feet, then building to 2 to 4 feet.
.SUNDAY...North winds 20 to 30 knots backing northwest by mid
afternoon. A chance of showers. Waves building to 6 to 9 feet
occasionally to 11 feet.
.SUNDAY NIGHT...Northwest winds 20 to 30 knots becoming west
10 to 20 knots after midnight. A chance of showers. Waves
subsiding to 2 to 4 feet.
.MONDAY...South winds 15 to 25 knots increasing to 20 to
30 knots. A chance of showers. Waves subsiding to 1 to 3 feet,
then building to 4 to 7 feet occasionally to 9 feet.
.TUESDAY...Northwest gales to 40 knots. Showers likely, then a
chance of showers. Waves building to 9 to 12 feet occasionally to
15 feet, then subsiding to 7 to 10 feet occasionally to 13 feet.

$$

LSZ267-172000-
Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off
shore to the US/Canadian border-
401 AM EDT Fri Oct 17 2025

.EARLY THIS MORNING...South winds 15 to 25 knots. Showers. Waves
3 to 5 feet occasionally to 7 feet.
.TODAY...South winds 15 to 25 knots increasing to 20 to 30 knots
in the afternoon. Showers likely through early afternoon. A
slight chance of showers by mid afternoon. Waves subsiding to
2 to 4 feet, then building to 3 to 5 feet occasionally to 7 feet.
.TONIGHT...South winds 20 to 30 knots becoming southwest 15 to
25 knots late. Showers likely through midnight. A slight chance
of thunderstorms. A slight chance of showers after midnight.
Waves building to 3 to 6 feet occasionally to 8 feet, then
subsiding to 1 to 3 feet.
.SATURDAY...Southwest winds 10 to 20 knots veering west late. A
chance of showers. Waves subsiding to calm to 2 feet.
.SATURDAY NIGHT...East winds 10 to 20 knots backing north after
midnight. A chance of showers through midnight, then showers
likely and a slight chance of thunderstorms after midnight. Waves
building to 1 to 3 feet.
.SUNDAY...North winds 15 to 25 knots becoming northwest gales to
35 knots by mid afternoon. Showers likely through early
afternoon, then a chance of showers by mid afternoon. Waves
building to 6 to 10 feet occasionally to 13 feet.
.SUNDAY NIGHT...Northwest winds 20 to 30 knots diminishing to
15 to 25 knots after midnight. A chance of showers. Waves
subsiding to 2 to 4 feet.
.MONDAY...South winds 15 to 25 knots increasing to 20 to
30 knots. A chance of showers. Waves building to 3 to 6 feet
occasionally to 8 feet.
.TUESDAY...Northwest winds 20 to 30 knots increasing to gales to
35 knots. Showers. Waves building to 9 to 12 feet occasionally to
15 feet, then subsiding to 7 to 10 feet occasionally to 13 feet.

$$

LSZ261-171400-
MAFOR 1709/
Superior West 11410 13420 11520 13530. A chance of showers today.
Waves 1 to 3 feet today. Waves 2 to 4 feet tonight.

Superior North Central 14420 11420 11430 12530. A chance of
showers today and this evening. Waves 3 to 5 feet subsiding to 2
to 4 feet today. Waves 2 to 4 feet building to 3 to 5 feet
tonight.

Superior South Central 11420 14430 11430 11530 11520. A chance of
showers this morning and this evening. Waves 2 to 4 feet building
to 3 to 5 feet today. Waves 2 to 4 feet subsiding to 1 to 3 feet
tonight.

Superior East 12436 12430 11440 12446 11530. Waves 3 to 6 feet.

$$

WFO MQT

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weather.gov/mqt/glftable

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weather.gov/greatlakes