545
FZUS63 KMQT 200801
GLFLS

Open Lake Forecast for Lake Superior
National Weather Service Marquette MI
401 AM EDT Wed Aug 20 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 high pressure of 30.1 to 30.2 inches will move over the lake from
the west today, loitering over the lake until at least Thursday
afternoon. By Friday morning, the high will shift to the southern
portions of the Great Lakes basin, eroded to 30.0 inches by a 29.7
inch low over Manitoba to the northwest and by Hurricane Erin at
28.3 inches over the open waters of the Atlantic east of New Jersey.
As Erin shifts north and east through the day Friday, the high is
allowed to shift over the East Coast while the Manitoba 29.7 inch
low slides over northern Ontario Friday evening. This low deepens to
29.6 inches over James Bay Saturday. Sunday and Monday, Lake
Superior will be between a 29.7 inch low over Quebec and a 30.2 inch
high over the Great Plains.


LSZ162-202000-
Lake Superior west of a line from Saxon Harbor WI to Grand
Portage MN beyond 5NM-
401 AM EDT Wed Aug 20 2025 /301 AM CDT Wed Aug 20 2025/

.EARLY THIS MORNING...Northeast winds 5 to 15 knots. Waves calm
to 2 feet.
.TODAY...Northeast winds 5 to 15 knots veering south in the
afternoon. Patchy dense fog through early afternoon. Waves calm
to 2 feet.
.TONIGHT...West winds 5 to 15 knots backing east after midnight,
then becoming southeast less than 10 knots late. Patchy fog.
Waves calm to 2 feet.
.THURSDAY...South winds less than 10 knots increasing to 5 to
15 knots in the afternoon, then backing southeast late. Waves
calm to 2 feet.
.THURSDAY NIGHT...South winds 5 to 15 knots veering southwest
after midnight. A chance of showers and a slight chance of
thunderstorms after midnight. Waves calm to 2 feet.
.FRIDAY...Southwest winds 10 to 20 knots increasing to 15 to
25 knots by mid afternoon. A chance of showers. Waves building to
1 to 3 feet.
.FRIDAY NIGHT...West winds 15 to 25 knots. Waves subsiding to
calm to 2 feet, then building to 2 to 4 feet.
.SATURDAY...West winds 15 to 25 knots becoming northwest 20 to
30 knots. Waves building to 3 to 5 feet occasionally to 7 feet,
then subsiding to 2 to 4 feet.
.SUNDAY...Northwest winds 20 to 30 knots diminishing to 15 to
25 knots. Waves subsiding to 1 to 3 feet, then building to 2 to
4 feet.

$$

LSZ263-202000-
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 Wed Aug 20 2025

.EARLY THIS MORNING...Northeast winds less than 10 knots. Waves
calm to 2 feet.
.TODAY...North winds less than 10 knots becoming southwest 5 to
15 knots late. Waves calm to 2 feet.
.TONIGHT...West winds less than 10 knots backing south late.
Waves calm to 2 feet.
.THURSDAY...South winds 5 to 15 knots. Waves calm to 2 feet.
.THURSDAY NIGHT...South winds 5 to 15 knots becoming southwest
10 to 20 knots after midnight. A slight chance of showers and
thunderstorms after midnight. Waves calm to 2 feet.
.FRIDAY...Southwest winds 10 to 20 knots. A chance of showers.
Waves building to 2 to 4 feet.
.FRIDAY NIGHT...West winds 10 to 20 knots increasing to 15 to
25 knots after midnight. Waves subsiding to 1 to 3 feet, then
building to 3 to 5 feet occasionally to 7 feet.
.SATURDAY...West winds 20 to 30 knots veering northwest. Waves
building to 4 to 7 feet occasionally to 9 feet, then subsiding to
3 to 6 feet occasionally to 8 feet.
.SUNDAY...Northwest winds 15 to 25 knots veering north. A chance
of showers. Waves subsiding to 3 to 5 feet occasionally to
7 feet.

$$

LSZ264-202000-
Lake Superior from Upper Entrance to Portage Canal to Manitou
Island MI 5NM off shore to the US/Canadian Border-
401 AM EDT Wed Aug 20 2025

.EARLY THIS MORNING...North winds less than 10 knots. Waves calm
to 2 feet.
.TODAY...North winds less than 10 knots backing southwest late.
Waves calm to 2 feet.
.TONIGHT...West winds less than 10 knots backing southwest late.
Waves calm to 2 feet.
.THURSDAY...South winds less than 10 knots increasing to 5 to
15 knots in the afternoon. Waves calm to 2 feet.
.THURSDAY NIGHT...South winds 5 to 15 knots becoming southwest
10 to 20 knots after midnight. A slight chance of showers and
thunderstorms after midnight. Waves calm to 2 feet.
.FRIDAY...Southwest winds 10 to 20 knots. A chance of showers.
Waves building to 1 to 3 feet.
.FRIDAY NIGHT...West winds 10 to 20 knots increasing to 15 to
25 knots after midnight. Waves building to 3 to 5 feet
occasionally to 7 feet.
.SATURDAY...West winds 20 to 30 knots becoming northwest 15 to
25 knots. Waves building to 4 to 7 feet occasionally to 9 feet,
then subsiding to 3 to 6 feet occasionally to 8 feet.
.SUNDAY...Northwest winds 15 to 25 knots veering north. Waves
subsiding to 2 to 4 feet, then building to 3 to 5 feet
occasionally to 7 feet.

$$

LSZ265-202000-
Lake Superior West of Line from Manitou Island to Marquette MI
Beyond 5NM from shore-
401 AM EDT Wed Aug 20 2025

.EARLY THIS MORNING...North winds 5 to 15 knots. Waves calm to
2 feet.
.TODAY...North winds 5 to 15 knots. Waves calm to 2 feet.
.TONIGHT...North winds 5 to 15 knots becoming south less than
10 knots after midnight, then veering southwest late. Patchy fog.
Waves calm to 2 feet.
.THURSDAY...South winds less than 10 knots becoming southeast
5 to 15 knots in the afternoon, then increasing to 10 to 20 knots
late. Waves calm to 2 feet.
.THURSDAY NIGHT...Southeast winds 10 to 20 knots veering
southwest after midnight. Waves calm to 2 feet.
.FRIDAY...Southwest winds 10 to 20 knots. A chance of showers.
Waves calm to 2 feet.
.FRIDAY NIGHT...West winds 10 to 20 knots. Waves calm to 2 feet.
.SATURDAY...West winds 20 to 30 knots. Waves building to 1 to
3 feet, then subsiding to calm to 2 feet.
.SUNDAY...Northwest winds 20 to 30 knots diminishing to 15 to
25 knots. A chance of showers. Waves 1 to 3 feet.

$$

LSZ266-202000-
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 Wed Aug 20 2025

.EARLY THIS MORNING...North winds 5 to 15 knots. Waves calm to
2 feet.
.TODAY...North winds 5 to 15 knots backing northwest late. Waves
calm to 2 feet.
.TONIGHT...North winds 5 to 15 knots. Patchy fog after midnight.
Waves calm to 2 feet.
.THURSDAY...Southwest winds less than 10 knots becoming south
5 to 15 knots in the afternoon, then backing southeast late.
Waves calm to 2 feet.
.THURSDAY NIGHT...Southeast winds 5 to 15 knots becoming south
10 to 20 knots after midnight. Waves calm to 2 feet.
.FRIDAY...Southwest winds 10 to 20 knots. Waves building to 1 to
3 feet.
.FRIDAY NIGHT...Southwest winds 10 to 20 knots veering west after
midnight. A chance of showers. Waves 1 to 3 feet.
.SATURDAY...West winds 15 to 25 knots. Waves building to 3 to
6 feet occasionally to 8 feet, then subsiding to 2 to 4 feet.
.SUNDAY...Northwest winds 15 to 25 knots veering north. A chance
of showers. Waves 3 to 5 feet occasionally to 7 feet.

$$

LSZ267-202000-
Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off
shore to the US/Canadian border-
401 AM EDT Wed Aug 20 2025

.EARLY THIS MORNING...North winds 5 to 15 knots. Waves calm to
2 feet.
.TODAY...North winds 5 to 15 knots increasing to 10 to 20 knots
in the afternoon, then backing northwest late. Waves calm to
2 feet.
.TONIGHT...Northwest winds 5 to 15 knots veering north late.
Waves calm to 2 feet.
.THURSDAY...North winds 5 to 15 knots backing northwest in the
afternoon, then veering north late. Waves calm to 2 feet.
.THURSDAY NIGHT...South winds 5 to 15 knots increasing to 10 to
20 knots after midnight. Waves calm to 2 feet.
.FRIDAY...South winds 10 to 20 knots veering southwest by mid
afternoon. Waves calm to 2 feet.
.FRIDAY NIGHT...Southwest winds 10 to 20 knots veering west after
midnight. A chance of showers. Waves calm to 2 feet.
.SATURDAY...West winds 10 to 20 knots increasing to 15 to
25 knots. Waves building to 3 to 5 feet occasionally to 7 feet.
.SUNDAY...Northwest winds 15 to 25 knots. A chance of showers.
Waves building to 3 to 6 feet occasionally to 8 feet.

$$

LSZ261-201400-
MAFOR 2009/
Superior West 13100 11300 11400 11500 11800 11300. Waves 1 foot
or less.

Superior North Central 13800 11700 13600 11500 19504. Waves 1
foot or less.

Superior South Central 15800 11800 11700. Waves 1 foot or less.

Superior East 13800 14700 11800. Waves 1 foot or less.

$$

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