510
FZUS63 KMQT 211401
GLFLS

Open Lake Forecast for Lake Superior
National Weather Service Marquette MI
1000 AM EDT Fri Aug 21 2026

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 29.9 inch low moves over Lake Superior today. With reinforcing
troughing from northern Ontario of around 29.9 inches dropping in
through Saturday morning, the low deepens to 29.8 inches over
eastern Lake Superior tonight. This is followed by 30.1 inch ridging
for the latter part of the weekend into early next week via a 30.2
inch parent high from the Canadian Prairies that drops down into the
Ohio River Valley by late Monday, weakening to 30.1 inches as it
does so. A 29.7 inch low over the Canadian Prairies Monday night
then drops southeast towards Lake Superior, arriving on Wednesday.



LSZ162-212000-
Lake Superior west of a line from Saxon Harbor WI to Grand
Portage MN beyond 5NM-
1000 AM EDT Fri Aug 21 2026 /900 AM CDT Fri Aug 21 2026/

.REST OF TODAY...North winds 5 to 15 knots backing west in the
afternoon, then backing southwest late. Waves calm to 2 feet.
.TONIGHT...Southwest winds 5 to 15 knots veering northwest after
midnight, then increasing to 10 to 20 knots late. Waves calm to
2 feet.
.SATURDAY...Northwest winds 10 to 20 knots diminishing to 5 to
15 knots late. Waves calm to 2 feet.
.SATURDAY NIGHT...North winds 10 to 20 knots diminishing to 5 to
15 knots after midnight. Waves calm to 2 feet.
.SUNDAY...North winds 5 to 15 knots veering south by mid
afternoon. Waves calm to 2 feet.
.SUNDAY NIGHT...Southeast winds 5 to 15 knots becoming northeast
less than 10 knots after midnight. Waves calm to 2 feet.
.MONDAY...East winds 5 to 15 knots. Waves calm to 2 feet.
.TUESDAY...South winds 5 to 15 knots veering west. A chance of
showers. Waves calm to 2 feet.

$$

LSZ263-212000-
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-
1000 AM EDT Fri Aug 21 2026

.REST OF TODAY...North winds 5 to 15 knots backing west late.
Waves calm to 2 feet.
.TONIGHT...Southwest winds 5 to 15 knots veering northwest late.
A slight chance of showers after midnight. Waves calm to 2 feet.
.SATURDAY...Northwest winds 10 to 20 knots diminishing to 5 to
15 knots in the afternoon, then backing west late. Waves calm to
2 feet.
.SATURDAY NIGHT...North winds 5 to 15 knots increasing to 10 to
20 knots after midnight. Waves calm to 2 feet.
.SUNDAY...North winds 10 to 20 knots becoming southwest 5 to
15 knots by mid afternoon. Waves calm to 2 feet.
.SUNDAY NIGHT...Southwest winds 5 to 15 knots veering west after
midnight. Waves calm to 2 feet.
.MONDAY...South winds 5 to 15 knots. Waves calm to 2 feet.
.TUESDAY...South winds 5 to 15 knots becoming west 10 to
20 knots. A chance of showers. Waves calm to 2 feet.

$$

LSZ264-212000-
Lake Superior from Upper Entrance to Portage Canal to Manitou
Island MI 5NM off shore to the US/Canadian Border-
1000 AM EDT Fri Aug 21 2026

.REST OF TODAY...South winds less than 10 knots becoming north
5 to 15 knots in the afternoon, then backing northwest late. A
slight chance of showers by mid afternoon. Waves 1 to 3 feet
subsiding to calm to 2 feet.
.TONIGHT...West winds 5 to 15 knots veering northwest late.
Patchy fog after midnight. Waves calm to 2 feet.
.SATURDAY...Northwest winds 5 to 15 knots increasing to 10 to
20 knots in the afternoon. Waves calm to 2 feet.
.SATURDAY NIGHT...North winds 10 to 20 knots. Waves building to
1 to 3 feet.
.SUNDAY...North winds 10 to 20 knots becoming northwest 5 to
15 knots by mid afternoon. Waves subsiding to calm to 2 feet.
.SUNDAY NIGHT...West winds 5 to 15 knots veering northwest after
midnight. Waves calm to 2 feet.
.MONDAY...West winds 5 to 15 knots backing south. Waves calm to
2 feet.
.TUESDAY...South winds 5 to 15 knots becoming southwest 10 to
20 knots. A chance of showers. Waves calm to 2 feet.

$$

LSZ265-212000-
Lake Superior West of Line from Manitou Island to Marquette MI
Beyond 5NM from shore-
1000 AM EDT Fri Aug 21 2026

.REST OF TODAY...South winds 10 to 20 knots veering northwest
late. A chance of showers. A slight chance of thunderstorms by
mid afternoon. Waves calm to 2 feet.
.TONIGHT...Northwest winds 10 to 20 knots backing west after
midnight, then increasing to 15 to 25 knots late. Waves calm to
2 feet.
.SATURDAY...Northwest winds 15 to 25 knots increasing to 20 to
30 knots in the afternoon. A slight chance of showers through
early afternoon. Waves building to 3 to 5 feet occasionally to
7 feet.
.SATURDAY NIGHT...Northwest winds 15 to 25 knots becoming north
20 to 30 knots after midnight. Waves subsiding to 2 to 4 feet,
then building to 3 to 5 feet occasionally to 7 feet.
.SUNDAY...North winds 15 to 25 knots. Waves building to 3 to
6 feet occasionally to 8 feet, then subsiding to 2 to 4 feet.
.SUNDAY NIGHT...Northwest winds 10 to 20 knots. Waves subsiding
to calm to 2 feet.
.MONDAY...Northwest winds 5 to 15 knots backing south. Waves calm
to 2 feet.
.TUESDAY...Southeast winds 10 to 20 knots becoming south 15 to
25 knots. A chance of showers. Waves building to 1 to 3 feet.

$$

LSZ266-212000-
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-
1000 AM EDT Fri Aug 21 2026

.REST OF TODAY...South winds 10 to 20 knots diminishing to 5 to
15 knots late. A chance of showers. A slight chance of
thunderstorms by mid afternoon. Waves 1 to 3 feet subsiding to
calm to 2 feet.
.TONIGHT...Northwest winds 5 to 15 knots increasing to 10 to
20 knots after midnight. A slight chance of showers through
midnight. Patchy fog after midnight. Waves calm to 2 feet.
.SATURDAY...Northwest winds 15 to 25 knots increasing to 20 to
30 knots in the afternoon. Patchy dense fog through early
afternoon. Waves building to 3 to 6 feet occasionally to 8 feet.
.SATURDAY NIGHT...North winds 20 to 30 knots diminishing to 15 to
25 knots after midnight. Waves subsiding to 3 to 6 feet
occasionally to 8 feet.
.SUNDAY...North winds 20 to 30 knots backing northwest by mid
afternoon. Waves subsiding to 3 to 5 feet occasionally to 7 feet.
.SUNDAY NIGHT...Northwest winds 10 to 20 knots. Waves subsiding
to calm to 2 feet.
.MONDAY...Northwest winds 5 to 15 knots backing southwest. Waves
calm to 2 feet.
.TUESDAY...South winds 10 to 20 knots increasing to 15 to
25 knots. A chance of showers. Waves building to 1 to 3 feet.

$$

LSZ267-212000-
Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off
shore to the US/Canadian border-
1000 AM EDT Fri Aug 21 2026

.REST OF TODAY...South winds 15 to 25 knots diminishing to 10 to
20 knots in the afternoon. A chance of showers by late morning. A
slight chance of thunderstorms. Showers likely by mid afternoon.
Waves 1 to 3 feet building to 2 to 4 feet, then subsiding to calm
to 2 feet.
.TONIGHT...South winds 5 to 15 knots becoming northwest 10 to
20 knots after midnight. A chance of showers and a slight chance
of thunderstorms through midnight. Patchy fog. Waves calm to
2 feet.
.SATURDAY...Northwest winds 10 to 20 knots increasing to 15 to
25 knots late. Patchy dense fog through early afternoon. Waves
building to 2 to 4 feet.
.SATURDAY NIGHT...North winds 20 to 30 knots. Waves building to
3 to 5 feet occasionally to 7 feet.
.SUNDAY...North winds 20 to 30 knots backing northwest by mid
afternoon. Waves building to 3 to 6 feet occasionally to 8 feet.
.SUNDAY NIGHT...Northwest winds 15 to 25 knots diminishing to
10 to 20 knots after midnight. Waves subsiding to 1 to 3 feet.
.MONDAY...Northwest winds 10 to 20 knots becoming west 5 to
15 knots. Waves subsiding to calm to 2 feet.
.TUESDAY...Southeast winds 5 to 15 knots becoming south 10 to
20 knots. A chance of showers. Waves building to 1 to 3 feet.

$$

LSZ261-212000-
MAFOR 2115/
Superior West 11800 11600 12500 11600 13710. Waves 1 foot or
less.

Superior North Central 11300 12700 12600 11610 12710. Waves 1 to
3 feet this afternoon. Waves 2 feet or less tonight and Saturday
morning.

Superior South Central 11420 11510 13710 12720 11730. A chance of
showers this afternoon and evening. Waves 1 to 3 feet.

Superior East 12420 11400 11500 11600 13710. A chance of showers
this afternoon and evening. Waves 2 to 4 feet this afternoon.
Waves 1 to 3 feet tonight and Saturday 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