931
FZUS63 KMQT 212001
GLFLS

Open Lake Forecast for Lake Superior
National Weather Service Marquette MI
401 PM EDT Tue Jul 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...

Heights continue to rise over the lake this evening into tonight as
29.3 inch low pressure east of James Bay continues to track through
northern Quebec and ridging over the Northern Plains expands
eastward. The ridge over Lake Superior becomes maximized at 30.1
inches over the western lake on Wednesday before the high flattens
and moves east towards New England Thursday into Friday morning.
While ridging of around 30.0 inches looks to remain over Lake
Superior on Thursday, a weak 29.9 to 30.0 inch low could move over
the northwestern half of the lake by Thursday night into Friday
morning. As a low around 29.3 inches lifts from far northern Ontario
into Hudson Bay Friday night into Saturday morning, expect troughing
of around 29.8 inches to move into Lake Superior in response by
Saturday morning. Troughing of at least 29.8 inches looks to remain
over the lake for the rest of the day.



LSZ162-220800-
Lake Superior west of a line from Saxon Harbor WI to Grand
Portage MN beyond 5NM-
401 PM EDT Tue Jul 21 2026 /301 PM CDT Tue Jul 21 2026/

.LATE THIS AFTERNOON...North winds 10 to 20 knots. Waves calm to
2 feet.
.TONIGHT...Northwest winds 10 to 20 knots. Waves calm to 2 feet.
.WEDNESDAY...West winds 5 to 15 knots backing southwest in the
afternoon, then increasing to 10 to 20 knots late. Waves building
to 1 to 3 feet.
.WEDNESDAY NIGHT...Southwest winds 5 to 15 knots. Waves subsiding
to calm to 2 feet.
.THURSDAY...Southwest winds 10 to 20 knots. Waves building to
1 to 3 feet.
.THURSDAY NIGHT...Southwest winds 10 to 20 knots. Waves subsiding
to calm to 2 feet.
.FRIDAY...Southwest winds 15 to 25 knots increasing to 20 to
30 knots by mid afternoon. Waves building to 2 to 4 feet, then
subsiding to 1 to 3 feet.
.FRIDAY NIGHT...Southwest winds 20 to 30 knots increasing to
gales to 35 knots after midnight. A chance of showers. Waves
subsiding to calm to 2 feet, then building to 2 to 4 feet.
.SATURDAY...Southwest winds 20 to 30 knots becoming north 5 to
15 knots. A chance of showers. Waves subsiding to calm to 2 feet.
.SUNDAY...East winds 5 to 15 knots backing northeast. Waves calm
to 2 feet.

$$

LSZ263-220800-
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 Tue Jul 21 2026

.LATE THIS AFTERNOON...North winds 10 to 20 knots. Waves 2 to
4 feet.
.TONIGHT...Northwest winds 10 to 20 knots diminishing to 5 to
15 knots after midnight. Waves subsiding to calm to 2 feet.
.WEDNESDAY...Northwest winds 5 to 15 knots backing west in the
afternoon, then becoming southwest 10 to 20 knots late. Waves
building to 1 to 3 feet.
.WEDNESDAY NIGHT...Southwest winds 10 to 20 knots becoming west
5 to 15 knots after midnight, then increasing to 10 to 20 knots
late. Waves subsiding to calm to 2 feet, then building to 1 to
3 feet.
.THURSDAY...Southwest winds 15 to 25 knots. Waves building to
2 to 4 feet.
.THURSDAY NIGHT...Southwest winds 10 to 20 knots increasing to
15 to 25 knots after midnight. Waves subsiding to 1 to 3 feet.
.FRIDAY...Southwest winds 20 to 30 knots. Waves building to 2 to
4 feet, then subsiding to 1 to 3 feet.
.FRIDAY NIGHT...Southwest winds 20 to 30 knots increasing to
gales to 35 knots after midnight. A chance of showers after
midnight. Waves building to 2 to 4 feet.
.SATURDAY...Southwest gales to 35 knots becoming north 5 to
15 knots. A chance of showers. Waves subsiding to calm to 2 feet.
.SUNDAY...East winds 5 to 15 knots. A chance of showers. Waves
calm to 2 feet.

$$

LSZ264-220800-
Lake Superior from Upper Entrance to Portage Canal to Manitou
Island MI 5NM off shore to the US/Canadian Border-
401 PM EDT Tue Jul 21 2026

.LATE THIS AFTERNOON...Northwest winds 20 to 30 knots. Waves 4 to
7 feet occasionally to 9 feet subsiding to 3 to 6 feet
occasionally to 8 feet.
.TONIGHT...Northwest winds 15 to 25 knots diminishing to 10 to
20 knots after midnight. Waves subsiding to 1 to 3 feet.
.WEDNESDAY...Northwest winds 5 to 15 knots backing west in the
afternoon, then increasing to 10 to 20 knots late. Waves
subsiding to calm to 2 feet.
.WEDNESDAY NIGHT...West winds 10 to 20 knots diminishing to 5 to
15 knots after midnight. Waves building to 1 to 3 feet.
.THURSDAY...Southwest winds 10 to 20 knots. Waves building to
2 to 4 feet.
.THURSDAY NIGHT...Southwest winds 10 to 20 knots increasing to
15 to 25 knots after midnight. A chance of showers. Waves
subsiding to 1 to 3 feet.
.FRIDAY...Southwest winds 15 to 25 knots. Waves building to 2 to
4 feet, then subsiding to 1 to 3 feet.
.FRIDAY NIGHT...South winds 20 to 30 knots veering southwest
after midnight. A chance of showers. Waves subsiding to calm to
2 feet, then building to 2 to 4 feet.
.SATURDAY...Southwest winds 20 to 30 knots becoming north 5 to
15 knots. A chance of showers. Waves subsiding to calm to 2 feet.
.SUNDAY...Southeast winds 5 to 15 knots backing east. Waves calm
to 2 feet.

$$

LSZ265-220800-
Lake Superior West of Line from Manitou Island to Marquette MI
Beyond 5NM from shore-
401 PM EDT Tue Jul 21 2026

...GALE WARNING IN EFFECT UNTIL 8 PM EDT THIS EVENING...

.LATE THIS AFTERNOON...Northwest gales to 40 knots. Waves 6 to
9 feet occasionally to 11 feet.
.TONIGHT...Northwest winds 20 to 30 knots diminishing to 15 to
25 knots late. Waves subsiding to 2 to 4 feet.
.WEDNESDAY...Northwest winds 15 to 25 knots becoming west 10 to
20 knots late. Waves subsiding to calm to 2 feet.
.WEDNESDAY NIGHT...West winds 10 to 20 knots increasing to 15 to
25 knots late. Waves calm to 2 feet.
.THURSDAY...West winds 10 to 20 knots backing southwest by mid
afternoon. Waves building to 1 to 3 feet, then subsiding to calm
to 2 feet.
.THURSDAY NIGHT...South winds 10 to 20 knots becoming southwest
15 to 25 knots after midnight. Waves building to 1 to 3 feet.
.FRIDAY...Southwest winds 10 to 20 knots backing south by mid
afternoon. Waves subsiding to calm to 2 feet.
.FRIDAY NIGHT...South winds 15 to 25 knots becoming southwest
20 to 30 knots after midnight. A chance of showers after
midnight. Waves calm to 2 feet.
.SATURDAY...Southwest winds 15 to 25 knots becoming south 10 to
20 knots. A chance of showers. Waves calm to 2 feet.
.SUNDAY...East winds 10 to 20 knots. A chance of showers. Waves
building to 1 to 3 feet, then subsiding to calm to 2 feet.

$$

LSZ266-220800-
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 Tue Jul 21 2026

...GALE WARNING IN EFFECT UNTIL 8 PM EDT THIS EVENING...

.LATE THIS AFTERNOON...Northwest gales to 35 knots. Waves 7 to
10 feet occasionally to 13 feet.
.TONIGHT...Northwest winds 20 to 30 knots. Waves subsiding to
3 to 5 feet occasionally to 7 feet.
.WEDNESDAY...Northwest winds 15 to 25 knots backing west late.
Waves subsiding to 2 to 4 feet.
.WEDNESDAY NIGHT...West winds 10 to 20 knots. Waves subsiding to
1 to 3 feet.
.THURSDAY...West winds 10 to 20 knots backing southwest by mid
afternoon. Waves 1 to 3 feet.
.THURSDAY NIGHT...South winds 10 to 20 knots becoming southwest
15 to 25 knots after midnight. A chance of showers. Waves
subsiding to calm to 2 feet, then building to 1 to 3 feet.
.FRIDAY...Southwest winds 10 to 20 knots backing south by mid
afternoon. Waves subsiding to calm to 2 feet.
.FRIDAY NIGHT...South winds 20 to 30 knots. A chance of showers
after midnight. Waves building to 2 to 4 feet.
.SATURDAY...South winds 15 to 25 knots becoming southwest 5 to
15 knots. Showers likely. A chance of thunderstorms. A chance of
showers. Waves subsiding to calm to 2 feet.
.SUNDAY...North winds 5 to 15 knots veering southeast. Waves
building to 1 to 3 feet, then subsiding to calm to 2 feet.

$$

LSZ267-220800-
Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off
shore to the US/Canadian border-
401 PM EDT Tue Jul 21 2026

...GALE WARNING IN EFFECT UNTIL 8 PM EDT THIS EVENING...

.LATE THIS AFTERNOON...Northwest gales to 35 knots. Waves 7 to
10 feet occasionally to 13 feet.
.TONIGHT...Northwest gales to 35 knots diminishing to 20 to
30 knots after midnight. Waves subsiding to 3 to 6 feet
occasionally to 8 feet.
.WEDNESDAY...Northwest winds 20 to 30 knots becoming west 15 to
25 knots late. Waves subsiding to 3 to 5 feet occasionally to
7 feet.
.WEDNESDAY NIGHT...West winds 10 to 20 knots diminishing to 5 to
15 knots after midnight. Waves subsiding to 1 to 3 feet.
.THURSDAY...Southwest winds 5 to 15 knots. Waves subsiding to
calm to 2 feet.
.THURSDAY NIGHT...South winds 10 to 20 knots increasing to 15 to
25 knots after midnight. Waves building to 1 to 3 feet.
.FRIDAY...Southwest winds 5 to 15 knots backing south by mid
afternoon. Waves subsiding to calm to 2 feet.
.FRIDAY NIGHT...South winds 15 to 25 knots increasing to 20 to
30 knots after midnight. Waves building to 2 to 4 feet.
.SATURDAY...South winds 15 to 25 knots becoming southwest 10 to
20 knots. A chance of showers. Waves subsiding to calm to 2 feet.
.SUNDAY...Northwest winds 10 to 20 knots becoming southeast 5 to
15 knots. Waves building to 1 to 3 feet, then subsiding to calm
to 2 feet.

$$

LSZ261-220200-
MAFOR 2121/
Superior West 11820 14710 11710 11610 11520. Waves 1 to 3 feet
subsiding to 1 foot or less tonight. Waves 2 feet or less
Wednesday.

Superior North Central 11740 11730 14720 11720 11620. Waves 4 to
7 feet subsiding to 2 to 4 feet tonight. Waves 1 to 3 feet
Wednesday.

Superior South Central...GALE WARNING IN EFFECT...12750 14730
12720. Waves 6 to 9 feet subsiding to 3 to 5 feet tonight. Waves
2 to 4 feet subsiding to 1 to 3 feet Wednesday.

Superior East...GALE WARNING IN EFFECT...12740 15730. Waves 5 to
9 feet subsiding to 3 to 6 feet tonight. Waves 3 to 5 feet
Wednesday.

$$

WFO MQT

Experimental modernized open lake forecast is available online at
weather.gov/mqt/glftable

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weather.gov/greatlakes