715
FZUS63 KMQT 231401
GLFLS

Open Lake Forecast for Lake Superior
National Weather Service Marquette MI
1001 AM EDT Sat Aug 23 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...

29.7 inch low pressure near James Bay deepens to 29.5 inches today,
which maintains troughing of around 29.8 inches over Lake Superior
the rest of today. The parent low then slowly weakens to 29.6 inches
Sunday and Monday as it spins near James and 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 Monday and
Tuesday. High pressure of 30.2 inches remains over the Lower Midwest
Wednesday, though a 29.9 inch trough is projected to pass over Lake
Superior in association with a 29.7 inch shortwave racing through
far northern Ontario. Behind the trough and shortwave, a 30.3 inch
high drops down over northern Ontario Thursday and arrives over the
Upper Great Lakes by Friday.


LSZ162-232000-
Lake Superior west of a line from Saxon Harbor WI to Grand
Portage MN beyond 5NM-
1001 AM EDT Sat Aug 23 2025 /901 AM CDT Sat Aug 23 2025/

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

$$

LSZ263-232000-
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 Sat Aug 23 2025

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

$$

LSZ264-232000-
Lake Superior from Upper Entrance to Portage Canal to Manitou
Island MI 5NM off shore to the US/Canadian Border-
1001 AM EDT Sat Aug 23 2025

.REST OF TODAY...Northwest winds 15 to 25 knots becoming west
20 to 30 knots late. Waves 3 to 6 feet occasionally to 8 feet.
.TONIGHT...West winds 15 to 25 knots veering northwest after
midnight. Waves subsiding to 3 to 5 feet occasionally to 7 feet.
.SUNDAY...Northwest winds 15 to 25 knots. A slight chance of
showers. Waves subsiding to 2 to 4 feet, then building to 3 to
5 feet occasionally to 7 feet.
.SUNDAY NIGHT...Northwest winds 15 to 25 knots. Waves subsiding
to 2 to 4 feet, then building to 3 to 5 feet occasionally to
7 feet.
.MONDAY...Northwest winds 15 to 25 knots. Waves subsiding to 1 to
3 feet.
.MONDAY NIGHT...Northwest winds 5 to 15 knots. Waves subsiding to
calm to 2 feet.
.TUESDAY...West winds 10 to 20 knots. Waves building to 1 to
3 feet.
.WEDNESDAY...West winds 15 to 25 knots diminishing to 10 to
20 knots. Waves building to 3 to 5 feet occasionally to 7 feet,
then subsiding to 1 to 3 feet.

$$

LSZ265-232000-
Lake Superior West of Line from Manitou Island to Marquette MI
Beyond 5NM from shore-
1001 AM EDT Sat Aug 23 2025

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

$$

LSZ266-232000-
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 Sat Aug 23 2025

.REST OF TODAY...Northwest winds 20 to 30 knots backing west
late. A slight chance of showers by late morning. Waves 3 to
6 feet occasionally to 8 feet.
.TONIGHT...West winds 15 to 25 knots. A slight chance of showers
after midnight. Waves subsiding to 2 to 4 feet.
.SUNDAY...Northwest winds 15 to 25 knots increasing to 20 to
30 knots late. A chance of showers and a slight chance of
thunderstorms. Waves building to 3 to 5 feet occasionally to
7 feet.
.SUNDAY NIGHT...Northwest winds 15 to 25 knots. A slight chance
of showers. Waves building to 3 to 6 feet occasionally to 8 feet.
.MONDAY...Northwest winds 20 to 30 knots. Waves 3 to 6 feet
occasionally to 8 feet.
.MONDAY NIGHT...Northwest winds 10 to 20 knots. Waves subsiding
to 1 to 3 feet.
.TUESDAY...Northwest winds 10 to 20 knots backing west. Waves
subsiding to calm to 2 feet, then building to 1 to 3 feet.
.WEDNESDAY...West winds 10 to 20 knots. Waves building to 2 to
4 feet, then subsiding to 1 to 3 feet.

$$

LSZ267-232000-
Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off
shore to the US/Canadian border-
1001 AM EDT Sat Aug 23 2025

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

$$

LSZ261-232000-
MAFOR 2315/
Superior West 11730 11630 11640 14730 11730. Waves 3 to 5 feet
this afternoon. Waves 2 to 4 feet tonight. Waves 3 to 5 feet
Sunday morning.

Superior North Central 11740 11630 11640 11630 11730 11720 12730.
Waves 3 to 5 feet.

Superior South Central 12740 11640 14630 11720. A chance of
showers Sunday morning. Waves 3 to 5 feet this afternoon. Waves 3
to 5 feet subsiding to 2 to 4 feet tonight. Waves 2 to 3 feet
Sunday morning.

Superior East 14630 13620 11720. Waves 3 to 6 feet this afternoon
and tonight. Waves 3 to 5 feet subsiding to 2 to 4 feet Sunday
morning.

$$

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