122
FZUS63 KMQT 190801
GLFLS

Open Lake Forecast for Lake Superior
National Weather Service Marquette MI
400 AM EDT Wed Aug 19 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...

Weak 29.9 inch ridging over Lake Superior early this morning builds
to 30.0 inches this afternoon as high pressure over the Canadian
Prairies and Northern Plains moves into the Upper Great Lakes. This
high then expands into the rest of the Great Lakes by tomorrow as it
strengthens to 30.1 inches. Friday into the weekend, a low pressure
of around 29.8 inches transits across northern Ontario, bringing
29.9 inch troughing over Lake Superior Friday into Saturday. This is
quickly 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 Canada.



LSZ162-192000-
Lake Superior west of a line from Saxon Harbor WI to Grand
Portage MN beyond 5NM-
400 AM EDT Wed Aug 19 2026 /300 AM CDT Wed Aug 19 2026/

.EARLY THIS MORNING...Northwest winds 5 to 15 knots. Waves calm
to 2 feet.
.TODAY...West winds 5 to 15 knots backing southwest in the
afternoon. Waves calm to 2 feet.
.TONIGHT...Southwest winds 5 to 15 knots backing northeast after
midnight. A slight chance of showers after midnight. Waves calm
to 2 feet.
.THURSDAY...East winds 5 to 15 knots. A chance of showers. A
slight chance of thunderstorms by mid afternoon. Waves calm to
2 feet.
.THURSDAY NIGHT...East winds 10 to 20 knots becoming northeast
5 to 15 knots after midnight. Showers likely and a slight chance
of thunderstorms through midnight, then a slight chance of
showers after midnight. Waves calm to 2 feet.
.FRIDAY...Northeast winds 5 to 15 knots veering southwest by mid
afternoon. Waves calm to 2 feet.
.FRIDAY NIGHT...West winds 5 to 15 knots veering northwest after
midnight. Waves calm to 2 feet.
.SATURDAY...Northwest winds 5 to 15 knots veering north. Waves
calm to 2 feet.
.SUNDAY...North winds 5 to 15 knots veering northeast. Waves calm
to 2 feet.

$$

LSZ263-192000-
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-
400 AM EDT Wed Aug 19 2026

.EARLY THIS MORNING...Northwest winds 5 to 15 knots. Waves calm
to 2 feet.
.TODAY...Northwest winds 5 to 15 knots backing southwest late.
Waves calm to 2 feet.
.TONIGHT...Southeast winds 5 to 15 knots becoming east less than
10 knots late. Waves calm to 2 feet.
.THURSDAY...East winds less than 10 knots becoming southeast 5 to
15 knots in the afternoon, then backing east late. A chance of
showers. A slight chance of thunderstorms by mid afternoon. Waves
calm to 2 feet.
.THURSDAY NIGHT...Southeast winds 5 to 15 knots backing east
after midnight. A slight chance of thunderstorms through
midnight. A chance of showers. Waves calm to 2 feet.
.FRIDAY...Northeast winds 5 to 15 knots backing north by mid
afternoon. Waves calm to 2 feet.
.FRIDAY NIGHT...West winds 5 to 15 knots. Waves calm to 2 feet.
.SATURDAY...Northwest winds 10 to 20 knots veering north. Waves
calm to 2 feet.
.SUNDAY...North winds 10 to 20 knots becoming southeast 5 to
15 knots. Waves calm to 2 feet.

$$

LSZ264-192000-
Lake Superior from Upper Entrance to Portage Canal to Manitou
Island MI 5NM off shore to the US/Canadian Border-
400 AM EDT Wed Aug 19 2026

.EARLY THIS MORNING...Northwest winds 5 to 15 knots. Waves calm
to 2 feet.
.TODAY...Northwest winds 5 to 15 knots backing southwest late.
Waves calm to 2 feet.
.TONIGHT...Southeast winds 5 to 15 knots diminishing to less than
10 knots after midnight. Waves calm to 2 feet.
.THURSDAY...Southeast winds less than 10 knots increasing to 5 to
15 knots late. A slight chance of showers. Waves calm to 2 feet.
.THURSDAY NIGHT...Southeast winds 5 to 15 knots. A slight chance
of showers. Waves calm to 2 feet.
.FRIDAY...East winds 5 to 15 knots. Waves calm to 2 feet.
.FRIDAY NIGHT...West winds 5 to 15 knots. Waves calm to 2 feet.
.SATURDAY...Northwest winds 10 to 20 knots veering north. Waves
calm to 2 feet.
.SUNDAY...North winds 10 to 20 knots becoming northwest 5 to
15 knots. Waves calm to 2 feet.

$$

LSZ265-192000-
Lake Superior West of Line from Manitou Island to Marquette MI
Beyond 5NM from shore-
400 AM EDT Wed Aug 19 2026

.EARLY THIS MORNING...Northwest winds 10 to 20 knots. Waves calm
to 2 feet.
.TODAY...Northwest winds 10 to 20 knots becoming northeast 5 to
15 knots late. Waves calm to 2 feet.
.TONIGHT...Southeast winds 5 to 15 knots increasing to 10 to
20 knots after midnight, then veering south late. Waves calm to
2 feet.
.THURSDAY...Southwest winds 5 to 15 knots backing southeast in
the afternoon, then increasing to 10 to 20 knots late. A chance
of showers. Waves calm to 2 feet.
.THURSDAY NIGHT...Southeast winds 10 to 20 knots. A chance of
showers through midnight, then showers likely after midnight.
Waves calm to 2 feet.
.FRIDAY...Southeast winds 10 to 20 knots backing northeast by mid
afternoon. A chance of showers. Waves calm to 2 feet.
.FRIDAY NIGHT...Northwest winds 5 to 15 knots increasing to 10 to
20 knots after midnight. Waves calm to 2 feet.
.SATURDAY...Northwest winds 15 to 25 knots increasing to 20 to
30 knots. Waves building to 3 to 5 feet occasionally to 7 feet,
then subsiding to 2 to 4 feet.
.SUNDAY...North gales to 35 knots becoming northwest 10 to
20 knots. Waves subsiding to calm to 2 feet.

$$

LSZ266-192000-
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-
400 AM EDT Wed Aug 19 2026

.EARLY THIS MORNING...Northwest winds 10 to 20 knots. Waves calm
to 2 feet.
.TODAY...Northwest winds 5 to 15 knots. Waves calm to 2 feet.
.TONIGHT...West winds 5 to 15 knots backing south after midnight.
Waves calm to 2 feet.
.THURSDAY...South winds 5 to 15 knots backing southeast in the
afternoon. A slight chance of showers. Waves calm to 2 feet.
.THURSDAY NIGHT...Southeast winds 5 to 15 knots increasing to
10 to 20 knots after midnight. A chance of showers through
midnight, then showers likely after midnight. Waves calm to
2 feet.
.FRIDAY...Southeast winds 10 to 20 knots becoming east 5 to
15 knots by mid afternoon. A chance of showers. Waves calm to
2 feet.
.FRIDAY NIGHT...Northwest winds 5 to 15 knots increasing to 10 to
20 knots after midnight. Waves calm to 2 feet.
.SATURDAY...Northwest winds 20 to 30 knots veering north. Waves
building to 3 to 6 feet occasionally to 8 feet, then subsiding to
2 to 4 feet.
.SUNDAY...Northwest gales to 35 knots diminishing to 10 to
20 knots. Waves subsiding to calm to 2 feet.

$$

LSZ267-192000-
Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off
shore to the US/Canadian border-
400 AM EDT Wed Aug 19 2026

.EARLY THIS MORNING...Northwest winds 10 to 20 knots. Waves calm
to 2 feet.
.TODAY...Northwest winds 10 to 20 knots diminishing to 5 to
15 knots late. Waves calm to 2 feet.
.TONIGHT...Northwest winds 5 to 15 knots backing west after
midnight. Waves calm to 2 feet.
.THURSDAY...South winds 5 to 15 knots backing east late. A slight
chance of showers by mid afternoon. Waves calm to 2 feet.
.THURSDAY NIGHT...Southeast winds 5 to 15 knots increasing to
10 to 20 knots after midnight. A slight chance of showers through
midnight, then showers likely after midnight. Waves calm to
2 feet.
.FRIDAY...Southeast winds 10 to 20 knots. Showers likely through
early afternoon. A chance of showers by mid afternoon. Waves calm
to 2 feet.
.FRIDAY NIGHT...Southeast winds 10 to 20 knots veering northwest
after midnight. A chance of showers. Waves calm to 2 feet.
.SATURDAY...Northwest winds 10 to 20 knots increasing to 15 to
25 knots. Waves building to 2 to 4 feet.
.SUNDAY...Northwest winds 20 to 30 knots diminishing to 15 to
25 knots. Waves subsiding to calm to 2 feet.

$$

LSZ261-191400-
MAFOR 1909/
Superior West 11710 12600 13510 11100 11200. Waves 1 foot or
less.

Superior North Central 11710 12700 11600 11500 11400 11300 11400.
Waves 2 feet or less.

Superior South Central 11720 12710 11810 11110 11200 12310. Waves
2 feet or less.

Superior East 11710 14700 11700 12600. Waves 2 feet 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