141
FZUS63 KMQT 221401
GLFLS

Open Lake Forecast for Lake Superior
National Weather Service Marquette MI
1001 AM EDT Fri Aug 22 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...

This morning, high pressure of 30.1 inches shifts to the southern
portions of the Great Lakes basin thanks to a 29.7 inch low over
northern Manitoba to the northwest and Hurricane Erin at 28.3 inches
over the Gulf Stream east of New Jersey. As Erin shifts north and
east through the day today, the high is allowed to shift over the
East Coast while the 29.7 inch low from northern Manitoba slides
into northern Ontario. This low deepens to 29.5 inches and lifts
toward James Bay Saturday before slowly weakening to 29.6 inches
Sunday and Monday as it moves into northern Quebec. As this happens,
30.2 inch high pressure stretches over the Great Plains early next
week, eventually bringing ridging of at least 30.1 inches back over
the western portions of Lake Superior on Tuesday. High pressure of
30.2 inches remains over the Midwest Wednesday, though a trough may
pass over the lake associated with low pressure passing near Hudson
Bay.


LSZ162-222000-
Lake Superior west of a line from Saxon Harbor WI to Grand
Portage MN beyond 5NM-
1001 AM EDT Fri Aug 22 2025 /901 AM CDT Fri Aug 22 2025/

.REST OF TODAY...West winds 10 to 20 knots backing southwest in
the afternoon. A chance of showers and a slight chance of
thunderstorms. Waves calm to 2 feet.
.TONIGHT...Southwest winds 10 to 20 knots veering west after
midnight, then increasing to 15 to 25 knots late. A slight chance
of showers and thunderstorms through midnight. Waves building to
2 to 4 feet.
.SATURDAY...West winds 15 to 25 knots increasing to 20 to
30 knots in the afternoon. A slight chance of showers by mid
afternoon. Waves building to 3 to 5 feet occasionally to 7 feet,
then subsiding to 2 to 4 feet.
.SATURDAY NIGHT...West winds 20 to 30 knots diminishing to 15 to
25 knots after midnight. A slight chance of showers after
midnight. Waves 2 to 4 feet.
.SUNDAY...Northwest winds 20 to 30 knots. A slight chance of
showers. Waves 2 to 4 feet.
.SUNDAY NIGHT...Northwest winds 15 to 25 knots. Waves subsiding
to 1 to 3 feet, then building to 2 to 4 feet.
.MONDAY...Northwest winds 10 to 20 knots becoming north 5 to
15 knots. Waves subsiding to calm to 2 feet.
.TUESDAY...Southwest winds 5 to 15 knots veering west. Waves calm
to 2 feet.

$$

LSZ263-222000-
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 AM EDT Fri Aug 22 2025

.REST OF TODAY...West winds 10 to 20 knots diminishing to 5 to
15 knots in the afternoon, then backing southwest late. A chance
of showers and thunderstorms. Waves 1 to 3 feet subsiding to calm
to 2 feet.
.TONIGHT...Southwest winds 5 to 15 knots increasing to 10 to
20 knots after midnight, then becoming west 15 to 25 knots late.
A slight chance of thunderstorms through midnight. A slight
chance of showers. Waves building to 3 to 5 feet occasionally to
7 feet.
.SATURDAY...West winds 15 to 25 knots increasing to 20 to
30 knots in the afternoon. A slight chance of showers 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.
.SATURDAY NIGHT...West winds 20 to 30 knots diminishing to 15 to
25 knots after midnight. A slight chance of showers. Waves
subsiding to 3 to 6 feet occasionally to 8 feet.
.SUNDAY...Northwest winds 15 to 25 knots increasing to 20 to
30 knots by mid afternoon. A chance of showers. A slight chance
of thunderstorms by mid afternoon. Waves 3 to 6 feet occasionally
to 8 feet.
.SUNDAY NIGHT...Northwest winds 15 to 25 knots. Waves subsiding
to 3 to 6 feet occasionally to 8 feet.
.MONDAY...Northwest winds 15 to 25 knots becoming north 5 to
15 knots. A chance of showers. Waves subsiding to calm to 2 feet.
.TUESDAY...Northwest winds 5 to 15 knots backing west. Waves calm
to 2 feet.

$$

LSZ264-222000-
Lake Superior from Upper Entrance to Portage Canal to Manitou
Island MI 5NM off shore to the US/Canadian Border-
1001 AM EDT Fri Aug 22 2025

.REST OF TODAY...West winds 10 to 20 knots diminishing to 5 to
15 knots in the afternoon, then backing southwest late. A slight
chance of showers and thunderstorms by mid afternoon. Waves 1 to
3 feet subsiding to calm to 2 feet.
.TONIGHT...Southwest winds 5 to 15 knots becoming west 10 to
20 knots late. A slight chance of showers and thunderstorms.
Waves building to 2 to 4 feet.
.SATURDAY...West winds 15 to 25 knots increasing to 20 to
30 knots in the afternoon. Waves building to 4 to 7 feet
occasionally to 9 feet, then subsiding to 3 to 6 feet
occasionally to 8 feet.
.SATURDAY NIGHT...West winds 15 to 25 knots. A slight chance of
showers after midnight. Waves subsiding to 3 to 5 feet
occasionally to 7 feet.
.SUNDAY...Northwest winds 15 to 25 knots increasing to 20 to
30 knots by mid afternoon. A chance of showers. Waves building to
3 to 6 feet occasionally to 8 feet.
.SUNDAY NIGHT...Northwest winds 15 to 25 knots. A chance of
showers. Waves 3 to 5 feet occasionally to 7 feet.
.MONDAY...Northwest winds 15 to 25 knots becoming north 5 to
15 knots. A chance of showers. Waves subsiding to calm to 2 feet.
.TUESDAY...Northwest winds 5 to 15 knots backing west. Waves calm
to 2 feet.

$$

LSZ265-222000-
Lake Superior West of Line from Manitou Island to Marquette MI
Beyond 5NM from shore-
1001 AM EDT Fri Aug 22 2025

.REST OF TODAY...Southwest winds 10 to 20 knots becoming west
5 to 15 knots in the afternoon. A chance of showers and
thunderstorms by mid afternoon. Waves calm to 2 feet.
.TONIGHT...Southwest winds 5 to 15 knots becoming west 10 to
20 knots late. A chance of thunderstorms through midnight. A
slight chance of showers. Waves building to 1 to 3 feet.
.SATURDAY...West winds 15 to 25 knots increasing to 20 to
30 knots in the afternoon. Waves subsiding to calm to 2 feet,
then building to 1 to 3 feet.
.SATURDAY NIGHT...West winds 15 to 25 knots. A chance of showers
after midnight. Waves subsiding to calm to 2 feet.
.SUNDAY...West winds 15 to 25 knots becoming northwest 20 to
30 knots by mid afternoon. A chance of showers. A slight chance
of thunderstorms by mid afternoon. Waves building to 1 to 3 feet.
.SUNDAY NIGHT...Northwest winds 20 to 30 knots. A chance of
showers. Waves subsiding to calm to 2 feet, then building to 1 to
3 feet.
.MONDAY...Northwest winds 20 to 30 knots diminishing to 10 to
20 knots. A chance of showers. Waves building to 2 to 4 feet,
then subsiding to calm to 2 feet.
.TUESDAY...Northwest winds 10 to 20 knots backing west. Waves
calm to 2 feet.

$$

LSZ266-222000-
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-
1001 AM EDT Fri Aug 22 2025

.REST OF TODAY...Southwest winds 10 to 20 knots diminishing to
5 to 15 knots in the afternoon. A chance of showers and
thunderstorms by mid afternoon. Waves 1 to 3 feet subsiding to
calm to 2 feet.
.TONIGHT...Southwest winds 5 to 15 knots increasing to 10 to
20 knots after midnight. A chance of showers and thunderstorms.
Waves building to 1 to 3 feet.
.SATURDAY...West winds 15 to 25 knots. Waves building to 3 to
6 feet occasionally to 8 feet.
.SATURDAY NIGHT...West winds 15 to 25 knots. A chance of showers
and a slight chance of thunderstorms after midnight. Waves
subsiding to 2 to 4 feet.
.SUNDAY...West winds 15 to 25 knots becoming northwest 20 to
30 knots by mid afternoon. A chance of showers. A slight chance
of thunderstorms by mid afternoon. Waves building to 3 to 5 feet
occasionally to 7 feet.
.SUNDAY NIGHT...Northwest winds 15 to 25 knots. A chance of
showers. Waves building to 3 to 6 feet occasionally to 8 feet.
.MONDAY...Northwest winds 15 to 25 knots becoming north 10 to
20 knots. A chance of showers. Waves subsiding to 1 to 3 feet.
.TUESDAY...Northwest winds 10 to 20 knots backing west. Waves
subsiding to calm to 2 feet.

$$

LSZ267-222000-
Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off
shore to the US/Canadian border-
1001 AM EDT Fri Aug 22 2025

.REST OF TODAY...Southwest winds 10 to 20 knots diminishing to
5 to 15 knots in the afternoon. A chance of showers and
thunderstorms by mid afternoon. Waves calm to 2 feet.
.TONIGHT...Southwest winds 10 to 20 knots. Showers likely through
midnight. A chance of thunderstorms. A chance of showers after
midnight. Waves calm to 2 feet.
.SATURDAY...West winds 10 to 20 knots increasing to 15 to
25 knots in the afternoon. A slight chance of showers and
thunderstorms through early afternoon. Waves building to 2 to
4 feet.
.SATURDAY NIGHT...West winds 15 to 25 knots. A slight chance of
showers after midnight. Waves building to 3 to 5 feet
occasionally to 7 feet.
.SUNDAY...West winds 15 to 25 knots. A chance of showers. A
slight chance of thunderstorms by mid afternoon. Waves building
to 3 to 6 feet occasionally to 8 feet.
.SUNDAY NIGHT...Northwest winds 15 to 25 knots. A chance of
showers. Waves subsiding to 3 to 6 feet occasionally to 8 feet.
.MONDAY...Northwest winds 15 to 25 knots veering north. Waves
subsiding to 1 to 3 feet.
.TUESDAY...Northwest winds 10 to 20 knots backing west. Waves
subsiding to calm to 2 feet.

$$

LSZ261-222000-
MAFOR 2215/
Superior West 11610 13510 11520 12630 11640. A chance of showers
and thunderstorms this afternoon. Waves 1 to 3 feet this
afternoon. Waves 1 to 3 feet building to 2 to 4 feet tonight.
Waves 3 to 5 feet Saturday morning.

Superior North Central 11620 14510 11510 11620 11630. A chance of
showers this evening. Waves 1 to 3 feet this afternoon and
tonight. Waves 2 to 4 feet Saturday morning.

Superior South Central 12510 11616 11500 11510 11520 11620 11630.
A chance of thunderstorms this afternoon and evening. Waves 2
feet or less this afternoon and tonight. Waves 1 to 3 feet
Saturday morning.

Superior East 13510 11516 13510 11620. A chance of thunderstorms
this afternoon and tonight. Waves 1 to 3 feet.

$$

WFO MQT

Experimental modernized open lake forecast is available online at
weather.gov/mqt/glftable

Graphical marine forecasts are available online at:
weather.gov/greatlakes