952
FZUS63 KMQT 200201
GLFLS

Open Lake Forecast for Lake Superior
National Weather Service Marquette MI
1001 PM EDT Tue Aug 19 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 30.1 inch high over southern Manitoba builds to 30.2 inches over
Lake Superior by Wednesday afternoon. By late Thursday, a 29.7 inch
low over northern Manitoba and far-northern Ontario will erode the
high pressure over the Upper Great Lakes to 30.0 inches. For Friday
and into the weekend, the low will pass along the shores of Hudson
Bay at around 29.6 inches, sending a 29.8 inch trough over Lake
Superior.


LSZ162-200800-
Lake Superior west of a line from Saxon Harbor WI to Grand
Portage MN beyond 5NM-
1001 PM EDT Tue Aug 19 2025 /901 PM CDT Tue Aug 19 2025/

.REST OF TONIGHT...Northeast winds 5 to 15 knots. Patchy fog.
Waves calm to 2 feet.
.WEDNESDAY...Northeast winds 5 to 15 knots veering southeast
late. Patchy fog through early afternoon. Waves calm to 2 feet.
.WEDNESDAY NIGHT...East winds less than 10 knots veering
southeast late. Waves calm to 2 feet.
.THURSDAY...South winds 5 to 15 knots backing southeast by mid
afternoon. Waves calm to 2 feet.
.THURSDAY NIGHT...South winds 5 to 15 knots becoming southwest
10 to 20 knots 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 becoming west 15 to
25 knots by mid afternoon. 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 veering northwest. Waves
building to 3 to 5 feet occasionally to 7 feet, then subsiding to
2 to 4 feet.
.SUNDAY...Northwest winds 15 to 25 knots diminishing to 10 to
20 knots. Waves subsiding to 1 to 3 feet.

$$

LSZ263-200800-
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 PM EDT Tue Aug 19 2025

...DENSE FOG ADVISORY IN EFFECT UNTIL 2 AM EDT WEDNESDAY...

.REST OF TONIGHT...Northeast winds less than 10 knots backing
north late. Patchy fog. Waves calm to 2 feet.
.WEDNESDAY...North winds less than 10 knots becoming northeast
5 to 15 knots in the afternoon, then veering southwest late.
Waves calm to 2 feet.
.WEDNESDAY NIGHT...Southwest 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 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
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. Waves subsiding to 2 to
4 feet.

$$

LSZ264-200800-
Lake Superior from Upper Entrance to Portage Canal to Manitou
Island MI 5NM off shore to the US/Canadian Border-
1001 PM EDT Tue Aug 19 2025

...DENSE FOG ADVISORY IN EFFECT UNTIL 2 AM EDT WEDNESDAY...

.REST OF TONIGHT...Northeast winds less than 10 knots backing
north after midnight. Patchy dense fog. Waves calm to 2 feet.
.WEDNESDAY...North winds less than 10 knots increasing to 5 to
15 knots in the afternoon, then becoming west less than 10 knots
late. Patchy fog through early afternoon. Waves calm to 2 feet.
.WEDNESDAY NIGHT...Southwest winds less than 10 knots. 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 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
2 to 4 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 5 feet occasionally to 7 feet.
.SUNDAY...Northwest winds 15 to 25 knots diminishing to 10 to
20 knots. Waves building to 3 to 6 feet occasionally to 8 feet,
then subsiding to 2 to 4 feet.

$$

LSZ265-200800-
Lake Superior West of Line from Manitou Island to Marquette MI
Beyond 5NM from shore-
1001 PM EDT Tue Aug 19 2025

.REST OF TONIGHT...Northeast winds 5 to 15 knots backing north
after midnight. Patchy fog. Waves calm to 2 feet.
.WEDNESDAY...North winds 5 to 15 knots increasing to 10 to
20 knots in the afternoon, then diminishing to 5 to 15 knots
late. Waves calm to 2 feet.
.WEDNESDAY NIGHT...Southeast winds less than 10 knots veering
southwest late. Waves calm to 2 feet.
.THURSDAY...South winds 5 to 15 knots becoming southeast 10 to
20 knots by mid afternoon. 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. Waves subsiding to calm to 2 feet, then building to
1 to 3 feet.

$$

LSZ266-200800-
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 PM EDT Tue Aug 19 2025

...DENSE FOG ADVISORY IN EFFECT UNTIL 2 AM EDT WEDNESDAY...

.REST OF TONIGHT...Northeast winds 5 to 15 knots backing north
late. Patchy fog. Waves calm to 2 feet.
.WEDNESDAY...North winds 5 to 15 knots. Waves calm to 2 feet.
.WEDNESDAY NIGHT...Northwest winds less than 10 knots veering
north late. Waves calm to 2 feet.
.THURSDAY...South winds 5 to 15 knots backing southeast by mid
afternoon. 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. A chance of showers.
Waves building to 1 to 3 feet.
.FRIDAY NIGHT...Southwest winds 10 to 20 knots veering west after
midnight. Waves building to 2 to 4 feet.
.SATURDAY...West winds 15 to 25 knots. Waves building to 3 to
6 feet occasionally to 8 feet.
.SUNDAY...Northwest winds 15 to 25 knots. Waves building to 3 to
6 feet occasionally to 8 feet.

$$

LSZ267-200800-
Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off
shore to the US/Canadian border-
1001 PM EDT Tue Aug 19 2025

.REST OF TONIGHT...Southeast winds 5 to 15 knots backing
northeast late. Patchy fog. Waves calm to 2 feet.
.WEDNESDAY...North winds 5 to 15 knots increasing to 10 to
20 knots in the afternoon, then backing northwest late. Waves
calm to 2 feet.
.WEDNESDAY NIGHT...Northwest winds 5 to 15 knots veering north
late. Waves calm to 2 feet.
.THURSDAY...Northwest winds 5 to 15 knots veering north by mid
afternoon. 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. A chance of showers 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 building to 1 to 3 feet.
.SATURDAY...West winds 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.

$$

LSZ261-200800-
MAFOR 2003/
Superior West 14100 11200 12300 11200. Waves 1 foot or less.

Superior North Central 11100 11804 11800 19804 12800 11700 12600.
Waves 1 foot or less.

Superior South Central 16800. Waves 1 foot or less.

Superior East 12200 11100 12800 13700. 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