638
FZUS63 KMQT 040803
GLFLS

Open Lake Forecast for Lake Superior
National Weather Service Marquette MI
402 AM EDT Mon Aug 4 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...

30.1 inch high pressure holds over the Great Lakes through today.
Meanwhile, a 30.2 inch high over far northern Ontario builds to 30.3
inches. This high pressure will slowly reinvigorate ridging over the
Great Lakes through Tuesday morning as it builds to 30.4 inches over
Quebec. At the same time, 29.8 inch troughing sets up over the High
Plains. These features remain largely stationary on Wednesday. On
Thursday, a low of 29.7 inches emerges over Manitoba while the high
weakens to 30.3 inches off the New England coast. This low brings a
29.9 inch trough over the lake on Friday, followed by deeper 29.8
inch troughing into Saturday as 29.6inch low pressure moves through
Manitoba.


LSZ162-042000-
Lake Superior west of a line from Saxon Harbor WI to Grand
Portage MN beyond 5NM-
402 AM EDT Mon Aug 4 2025 /302 AM CDT Mon Aug 4 2025/

.EARLY THIS MORNING...South winds 5 to 15 knots. Waves calm to
2 feet.
.TODAY...East winds 5 to 15 knots becoming northeast 10 to
20 knots late. A slight chance of showers by mid afternoon. Waves
calm to 2 feet.
.TONIGHT...Northeast winds 10 to 20 knots diminishing to 5 to
15 knots after midnight. A slight chance of showers through
midnight. Haze after midnight. Waves calm to 2 feet.
.TUESDAY...East winds 5 to 15 knots becoming northeast 10 to
20 knots late. Haze. Waves calm to 2 feet.
.TUESDAY NIGHT...East winds 5 to 15 knots. Waves calm to 2 feet.
.WEDNESDAY...Southeast winds 10 to 20 knots backing east by mid
afternoon. Waves calm to 2 feet.
.WEDNESDAY NIGHT...Southeast winds 10 to 20 knots veering south
after midnight. A chance of showers and thunderstorms. Waves calm
to 2 feet.
.THURSDAY...South winds 5 to 15 knots. Waves calm to 2 feet.
.FRIDAY...South winds 5 to 15 knots becoming east 10 to 20 knots.
A chance of showers and thunderstorms. Waves calm to 2 feet.

$$

LSZ263-042000-
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-
402 AM EDT Mon Aug 4 2025

.EARLY THIS MORNING...South winds less than 10 knots. Haze. Waves
calm to 2 feet.
.TODAY...South winds less than 10 knots becoming east 5 to
15 knots in the afternoon, then backing northeast late. Waves
calm to 2 feet.
.TONIGHT...East winds 5 to 15 knots. Haze. Waves calm to 2 feet.
.TUESDAY...East winds 5 to 15 knots. Areas of smoke through early
afternoon. Haze. A slight chance of showers by mid afternoon.
Waves calm to 2 feet.
.TUESDAY NIGHT...East winds 5 to 15 knots veering southeast after
midnight. Waves calm to 2 feet.
.WEDNESDAY...Southeast winds 5 to 15 knots backing east by mid
afternoon. Waves calm to 2 feet.
.WEDNESDAY NIGHT...South winds 5 to 15 knots. A chance of showers
and thunderstorms. Waves building to 1 to 3 feet, then subsiding
to calm to 2 feet.
.THURSDAY...South winds 5 to 15 knots. A chance of showers. Waves
calm to 2 feet.
.FRIDAY...South winds 5 to 15 knots. A chance of showers. Waves
calm to 2 feet.

$$

LSZ264-042000-
Lake Superior from Upper Entrance to Portage Canal to Manitou
Island MI 5NM off shore to the US/Canadian Border-
402 AM EDT Mon Aug 4 2025

.EARLY THIS MORNING...South winds less than 10 knots. Waves calm
to 2 feet.
.TODAY...Southeast winds less than 10 knots becoming east 5 to
15 knots in the afternoon. Waves calm to 2 feet.
.TONIGHT...East winds 5 to 15 knots. Haze. Waves calm to 2 feet.
.TUESDAY...East winds 5 to 15 knots. Haze. Waves calm to 2 feet.
.TUESDAY NIGHT...Southeast winds 5 to 15 knots. Waves calm to
2 feet.
.WEDNESDAY...Southeast winds 5 to 15 knots. Waves calm to 2 feet.
.WEDNESDAY NIGHT...Southeast winds 5 to 15 knots veering south
after midnight. A chance of showers. Waves building to 1 to
3 feet.
.THURSDAY...South winds 5 to 15 knots. A chance of showers. Waves
subsiding to calm to 2 feet.
.FRIDAY...South winds 5 to 15 knots. A chance of showers. Waves
calm to 2 feet.

$$

LSZ265-042000-
Lake Superior West of Line from Manitou Island to Marquette MI
Beyond 5NM from shore-
402 AM EDT Mon Aug 4 2025

.EARLY THIS MORNING...Southeast winds 5 to 15 knots. Waves calm
to 2 feet.
.TODAY...Southeast winds 5 to 15 knots backing east in the
afternoon, then increasing to 10 to 20 knots late. Haze by mid
afternoon. Waves calm to 2 feet.
.TONIGHT...East winds 5 to 15 knots veering southeast late. Haze.
Areas of smoke after midnight. Waves calm to 2 feet.
.TUESDAY...Southeast winds 5 to 15 knots backing east in the
afternoon, then increasing to 10 to 20 knots late. Haze. Waves
calm to 2 feet.
.TUESDAY NIGHT...Southeast winds 5 to 15 knots. Waves calm to
2 feet.
.WEDNESDAY...Southeast winds 10 to 20 knots increasing to 15 to
25 knots by mid afternoon. Waves calm to 2 feet.
.WEDNESDAY NIGHT...South winds 10 to 20 knots. A chance of
showers after midnight. Waves calm to 2 feet.
.THURSDAY...South winds 10 to 20 knots. A chance of showers.
Waves calm to 2 feet.
.FRIDAY...South winds 10 to 20 knots. A chance of showers. Waves
calm to 2 feet.

$$

LSZ266-042000-
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-
402 AM EDT Mon Aug 4 2025

.EARLY THIS MORNING...Southeast winds 5 to 15 knots. Waves calm
to 2 feet.
.TODAY...East winds 5 to 15 knots. Haze by mid afternoon. Waves
calm to 2 feet.
.TONIGHT...East winds 5 to 15 knots. Haze. Waves calm to 2 feet.
.TUESDAY...Southeast winds 5 to 15 knots backing east in the
afternoon, then increasing to 10 to 20 knots late. Haze. Waves
calm to 2 feet.
.TUESDAY NIGHT...Southeast winds 5 to 15 knots. Waves calm to
2 feet.
.WEDNESDAY...Southeast winds 10 to 20 knots. Waves calm to
2 feet.
.WEDNESDAY NIGHT...South winds 10 to 20 knots. Waves building to
1 to 3 feet, then subsiding to calm to 2 feet.
.THURSDAY...South winds 10 to 20 knots. A chance of showers.
Waves calm to 2 feet.
.FRIDAY...South winds 10 to 20 knots. A chance of showers. Waves
calm to 2 feet.

$$

LSZ267-042000-
Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off
shore to the US/Canadian border-
402 AM EDT Mon Aug 4 2025

.EARLY THIS MORNING...East winds 5 to 15 knots. Waves calm to
2 feet.
.TODAY...East winds 5 to 15 knots backing northeast late. Haze by
mid afternoon. Waves calm to 2 feet.
.TONIGHT...East winds 5 to 15 knots veering southeast late. Haze.
Waves calm to 2 feet.
.TUESDAY...Southeast winds 10 to 20 knots becoming east 5 to
15 knots in the afternoon. Haze. Waves calm to 2 feet.
.TUESDAY NIGHT...East winds 10 to 20 knots veering southeast
after midnight. Waves calm to 2 feet.
.WEDNESDAY...Southeast winds 10 to 20 knots. Waves calm to
2 feet.
.WEDNESDAY NIGHT...Southeast winds 10 to 20 knots. Waves calm to
2 feet.
.THURSDAY...South winds 10 to 20 knots. A chance of showers and
thunderstorms. Waves calm to 2 feet.
.FRIDAY...South winds 10 to 20 knots. A chance of showers and
thunderstorms. Waves calm to 2 feet.

$$

LSZ261-041400-
MAFOR 0409/
Superior West 12400 11300 11200 11110 13210. Waves 2 feet or
less.

Superior North Central 13300 14200 11200. Waves 1 foot or less.

Superior South Central 12300 11200 12210 12200 11300. Waves 1
foot or less.

Superior East 14200 11100 13200. 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