141
FZUS63 KMQT 092002
GLFLS

Open Lake Forecast for Lake Superior
National Weather Service Marquette MI
401 PM EDT Sat Aug 9 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...

High pressure at 30.2 inches remains centered along the Eastern
Seaboard through the remainder of the weekend. Meanwhile, a 29.6
inch low over the Canadian Prairie lifts to Hudson Bay, leaving Lake
Superior sandwiched between the two features. The high erodes away
on Monday as the low continues over Quebec, sending a 29.9 inch
trough over the lake. A secondary trough around 29.8 inches then
rotates across the lake Tuesday into Wednesday. High pressure
quickly passes over the Great Lakes late in the day Wednesday into
Thursday.


LSZ162-100800-
Lake Superior west of a line from Saxon Harbor WI to Grand
Portage MN beyond 5NM-
401 PM EDT Sat Aug 9 2025 /301 PM CDT Sat Aug 9 2025/

.LATE THIS AFTERNOON...Southwest winds 10 to 20 knots. Waves calm
to 2 feet.
.TONIGHT...Southwest winds 5 to 15 knots. Waves calm to 2 feet.
.SUNDAY...Southwest winds 5 to 15 knots increasing to 10 to
20 knots in the afternoon. Waves calm to 2 feet.
.SUNDAY NIGHT...West winds 10 to 20 knots diminishing to 5 to
15 knots late. Waves calm to 2 feet.
.MONDAY...Southwest winds 5 to 15 knots increasing to 10 to
20 knots by mid afternoon. Waves calm to 2 feet.
.MONDAY NIGHT...Southwest winds 10 to 20 knots increasing to
15 to 25 knots after midnight. Waves calm to 2 feet.
.TUESDAY...West winds 10 to 20 knots. Waves building to 1 to
3 feet, then subsiding to calm to 2 feet.
.TUESDAY NIGHT...West winds 10 to 20 knots becoming northwest
5 to 15 knots after midnight. Waves calm to 2 feet.
.WEDNESDAY...Southeast winds 5 to 15 knots becoming east 10 to
20 knots. Waves calm to 2 feet.
.THURSDAY...East winds 10 to 20 knots veering south. A chance of
showers. Waves calm to 2 feet.

$$

LSZ263-100800-
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 PM EDT Sat Aug 9 2025

.LATE THIS AFTERNOON...Southwest winds 5 to 15 knots. A slight
chance of showers and thunderstorms. Waves calm to 2 feet.
.TONIGHT...Southwest winds 5 to 15 knots increasing to 10 to
20 knots after midnight, then diminishing to 5 to 15 knots late.
Waves calm to 2 feet.
.SUNDAY...Southwest winds 5 to 15 knots increasing to 10 to
20 knots late. Waves building to 1 to 3 feet, then subsiding to
calm to 2 feet.
.SUNDAY NIGHT...Southwest winds 10 to 20 knots becoming west 5 to
15 knots after midnight. Waves subsiding to calm to 2 feet.
.MONDAY...West winds 5 to 15 knots becoming southwest 10 to
20 knots by mid afternoon. Waves building to 1 to 3 feet.
.MONDAY NIGHT...Southwest winds 5 to 15 knots increasing to 10 to
20 knots after midnight. Waves subsiding to calm to 2 feet, then
building to 1 to 3 feet.
.TUESDAY...Southwest winds 10 to 20 knots veering west by mid
afternoon. Waves building to 2 to 4 feet, then subsiding to 1 to
3 feet.
.TUESDAY NIGHT...West winds 10 to 20 knots becoming northwest
5 to 15 knots after midnight. Waves subsiding to calm to 2 feet.
.WEDNESDAY...North winds 5 to 15 knots veering east. Waves calm
to 2 feet.
.THURSDAY...Southeast winds 5 to 15 knots veering south. Waves
calm to 2 feet.

$$

LSZ264-100800-
Lake Superior from Upper Entrance to Portage Canal to Manitou
Island MI 5NM off shore to the US/Canadian Border-
401 PM EDT Sat Aug 9 2025

.LATE THIS AFTERNOON...South winds 5 to 15 knots. A chance of
showers and a slight chance of thunderstorms. Waves calm to
2 feet.
.TONIGHT...South winds 5 to 15 knots veering southwest after
midnight. A slight chance of showers through midnight. Waves calm
to 2 feet.
.SUNDAY...Southwest winds 5 to 15 knots backing south late. Waves
calm to 2 feet.
.SUNDAY NIGHT...South winds 5 to 15 knots veering west late.
Waves calm to 2 feet.
.MONDAY...West winds 5 to 15 knots backing southwest by mid
afternoon. Waves calm to 2 feet.
.MONDAY NIGHT...South winds 5 to 15 knots becoming southwest
10 to 20 knots after midnight. Waves building to 1 to 3 feet.
.TUESDAY...Southwest winds 10 to 20 knots veering west by mid
afternoon. Waves building to 2 to 4 feet, then subsiding to 1 to
3 feet.
.TUESDAY NIGHT...West winds 10 to 20 knots becoming northwest
5 to 15 knots after midnight. Waves subsiding to calm to 2 feet.
.WEDNESDAY...North winds 5 to 15 knots veering east. Waves calm
to 2 feet.
.THURSDAY...Southeast winds 5 to 15 knots veering south. Waves
calm to 2 feet.

$$

LSZ265-100800-
Lake Superior West of Line from Manitou Island to Marquette MI
Beyond 5NM from shore-
401 PM EDT Sat Aug 9 2025

.LATE THIS AFTERNOON...South winds 10 to 20 knots. A chance of
showers and a slight chance of thunderstorms. Waves calm to
2 feet.
.TONIGHT...South winds 10 to 20 knots veering southwest after
midnight. A chance of showers through midnight. Waves calm to
2 feet.
.SUNDAY...South winds 10 to 20 knots. A slight chance of showers.
Waves calm to 2 feet.
.SUNDAY NIGHT...South winds 5 to 15 knots veering southwest after
midnight. A slight chance of showers after midnight. Waves calm
to 2 feet.
.MONDAY...West winds 5 to 15 knots. Waves calm to 2 feet.
.MONDAY NIGHT...South winds 5 to 15 knots becoming southwest
10 to 20 knots after midnight. Waves calm to 2 feet.
.TUESDAY...Southwest winds 10 to 20 knots veering west by mid
afternoon. Waves calm to 2 feet.
.TUESDAY NIGHT...West winds 10 to 20 knots veering northwest
after midnight. Waves calm to 2 feet.
.WEDNESDAY...Northwest winds 10 to 20 knots becoming southeast
5 to 15 knots. Waves calm to 2 feet.
.THURSDAY...Southeast winds 10 to 20 knots veering south. Waves
calm to 2 feet.

$$

LSZ266-100800-
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 PM EDT Sat Aug 9 2025

.LATE THIS AFTERNOON...South winds 10 to 20 knots. Showers likely
and a chance of thunderstorms. Waves 1 to 3 feet.
.TONIGHT...South winds 10 to 20 knots. A slight chance of
thunderstorms through midnight. A chance of showers. Waves
subsiding to calm to 2 feet.
.SUNDAY...South winds 10 to 20 knots. A slight chance of showers.
Waves calm to 2 feet.
.SUNDAY NIGHT...South winds 10 to 20 knots becoming southwest
5 to 15 knots after midnight. A slight chance of showers. Waves
calm to 2 feet.
.MONDAY...Southwest winds 5 to 15 knots veering west by mid
afternoon. A slight chance of showers. Waves calm to 2 feet.
.MONDAY NIGHT...South winds 5 to 15 knots. Waves calm to 2 feet.
.TUESDAY...Southwest winds 10 to 20 knots veering west by mid
afternoon. A chance of showers. Waves building to 1 to 3 feet.
.TUESDAY NIGHT...West winds 10 to 20 knots veering northwest
after midnight. Waves subsiding to calm to 2 feet.
.WEDNESDAY...Northwest winds 10 to 20 knots becoming east 5 to
15 knots. Waves calm to 2 feet.
.THURSDAY...Southeast winds 5 to 15 knots becoming south 10 to
20 knots. Waves calm to 2 feet.

$$

LSZ267-100800-
Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off
shore to the US/Canadian border-
401 PM EDT Sat Aug 9 2025

.LATE THIS AFTERNOON...South winds 10 to 20 knots. A chance of
showers and thunderstorms. Waves 1 to 3 feet subsiding to calm to
2 feet.
.TONIGHT...South winds 10 to 20 knots. A chance of showers and
thunderstorms. Waves calm to 2 feet.
.SUNDAY...South winds 10 to 20 knots. A chance of showers and a
slight chance of thunderstorms. Waves calm to 2 feet.
.SUNDAY NIGHT...South winds 10 to 20 knots. A chance of showers
and a slight chance of thunderstorms. Waves calm to 2 feet.
.MONDAY...Southwest winds 5 to 15 knots veering west by mid
afternoon. A chance of showers. Waves calm to 2 feet.
.MONDAY NIGHT...South winds 5 to 15 knots increasing to 10 to
20 knots after midnight. Waves calm to 2 feet.
.TUESDAY...South winds 10 to 20 knots veering southwest by mid
afternoon. A chance of showers. A chance of thunderstorms by mid
afternoon. Waves calm to 2 feet.
.TUESDAY NIGHT...West winds 10 to 20 knots veering northwest
after midnight. Waves calm to 2 feet.
.WEDNESDAY...Northwest winds 10 to 20 knots veering north. Waves
calm to 2 feet.
.THURSDAY...Southeast winds 10 to 20 knots. Waves calm to 2 feet.

$$

LSZ261-100200-
MAFOR 0921/
Superior West 11510 11410 12520 14510. Waves 1 to 2 feet.

Superior North Central 12410 15510. A chance of showers this
evening. Waves 1 to 3 feet.

Superior South Central 11416 12410 11510 14410. Waves 2 feet or
less.

Superior East 11416 11420 15410. A chance of thunderstorms this
evening. Waves 1 to 3 feet.

$$

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