590
FZUS63 KMQT 211401
GLFLS

Open Lake Forecast for Lake Superior
National Weather Service Marquette MI
1001 AM 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...

As a 29.2 inch low over far northern Ontario this morning moves into
northern Quebec later today, troughing from the low over Lake
Superior is replaced by ridging descending from a 30.1 inch high
moving in from the Canadian Prairies into the Midwest today into
Wednesday. The ridging 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.



LSZ162-212000-
Lake Superior west of a line from Saxon Harbor WI to Grand
Portage MN beyond 5NM-
1001 AM EDT Tue Jul 21 2026 /901 AM CDT Tue Jul 21 2026/

.REST OF TODAY...Northwest winds 20 to 30 knots diminishing to
15 to 25 knots in the afternoon, then veering north late. Waves
1 to 3 feet subsiding to calm to 2 feet.
.TONIGHT...North winds 10 to 20 knots backing northwest after
midnight. Waves calm to 2 feet.
.WEDNESDAY...Northwest 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 10 to 20 knots becoming west
5 to 15 knots after midnight. 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. A chance of
showers. Waves subsiding to calm to 2 feet.
.FRIDAY...Southwest winds 10 to 20 knots increasing to 20 to
30 knots. A chance of showers. Waves building to 1 to 3 feet,
then subsiding to calm to 2 feet.
.SATURDAY...Southwest winds 20 to 30 knots becoming north 10 to
20 knots. A chance of showers. Waves subsiding to 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-
1001 AM EDT Tue Jul 21 2026

.REST OF TODAY...Northwest winds 15 to 25 knots veering north in
the afternoon. Waves 3 to 5 feet occasionally to 7 feet subsiding
to 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 2 to 4 feet.
.WEDNESDAY NIGHT...Southwest winds 10 to 20 knots. 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. A chance of
showers. Waves subsiding to 1 to 3 feet.
.FRIDAY...Southwest winds 15 to 25 knots increasing to 20 to
30 knots. A chance of showers. Waves building to 2 to 4 feet,
then subsiding to calm to 2 feet.
.SATURDAY...Southwest winds 20 to 30 knots becoming north 10 to
20 knots. A chance of showers. Waves subsiding to 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-
1001 AM EDT Tue Jul 21 2026

.REST OF TODAY...North winds to 30 knots with a few gale force
gusts to 35 knots possible becoming northwest 20 to 30 knots
late. Waves 4 to 8 feet occasionally to 10 feet, then 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, then building to 1 to 3 feet.
.WEDNESDAY NIGHT...West winds 10 to 20 knots. Waves 1 to 3 feet.
.THURSDAY...Southwest winds 10 to 20 knots. Waves building to
2 to 4 feet.
.THURSDAY NIGHT...Southwest winds 5 to 15 knots increasing to
10 to 20 knots after midnight. A chance of showers. Waves
subsiding to 1 to 3 feet.
.FRIDAY...Southwest winds 10 to 20 knots increasing to 20 to
30 knots. A chance of showers. Waves building to 2 to 4 feet,
then subsiding to calm to 2 feet.
.SATURDAY...Southwest winds 20 to 30 knots becoming north 10 to
20 knots. A chance of showers. Waves subsiding to calm to 2 feet.

$$

LSZ265-212000-
Lake Superior West of Line from Manitou Island to Marquette MI
Beyond 5NM from shore-
1001 AM EDT Tue Jul 21 2026

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

.REST OF TODAY...Northwest gales to 40 knots. Waves 4 to 7 feet
occasionally to 9 feet building to 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 after midnight. Waves calm to 2 feet.
.THURSDAY...West winds 10 to 20 knots diminishing to 5 to
15 knots 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 increasing to 15 to
25 knots. A chance of showers. Waves subsiding to calm to 2 feet.
.SATURDAY...Southwest winds 15 to 25 knots veering northwest. A
chance of showers. Waves calm to 2 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-
1001 AM EDT Tue Jul 21 2026

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

.REST OF TODAY...Northwest gales to 40 knots. A slight chance of
showers by late morning. Waves 4 to 7 feet occasionally to 9 feet
building to 7 to 10 feet occasionally to 13 feet.
.TONIGHT...Northwest winds 20 to 30 knots. A slight chance of
showers through midnight. 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 increasing to 15 to
25 knots after midnight. 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. Waves subsiding to calm to 2 feet,
then building to 1 to 3 feet.
.FRIDAY...South winds 10 to 20 knots increasing to 15 to
25 knots. Waves subsiding to calm to 2 feet, then building to
2 to 4 feet.
.SATURDAY...South winds 15 to 25 knots diminishing to 10 to
20 knots. A chance of showers. Waves subsiding to calm to 2 feet.

$$

LSZ267-212000-
Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off
shore to the US/Canadian border-
1001 AM EDT Tue Jul 21 2026

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

.REST OF TODAY...Northwest winds 20 to 30 knots increasing to
gales to 35 knots in the afternoon. A slight chance of showers by
late morning. Waves 3 to 6 feet occasionally to 8 feet building
to 7 to 10 feet occasionally to 13 feet, then subsiding to 6 to
9 feet occasionally to 11 feet.
.TONIGHT...Northwest winds 20 to 30 knots. A slight chance of
showers through midnight. Waves subsiding to 3 to 6 feet
occasionally to 8 feet.
.WEDNESDAY...Northwest winds 15 to 25 knots backing west late.
Waves subsiding to 3 to 6 feet occasionally to 8 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 becoming southwest
15 to 25 knots after midnight. Waves building to 1 to 3 feet.
.FRIDAY...Southwest winds 5 to 15 knots becoming south 15 to
25 knots. Waves subsiding to calm to 2 feet, then building to
2 to 4 feet.
.SATURDAY...South winds 10 to 20 knots. A chance of showers.
Showers likely. Waves subsiding to calm to 2 feet.

$$

LSZ261-212000-
MAFOR 2115/
Superior West 12730 11820 14710 11710. Waves 2 to 4 feet
subsiding to 1 to 3 feet this afternoon. Waves 1 to 3 feet
tonight. Waves 2 feet or less Wednesday morning.

Superior North Central 12750 11740 11730 14720. Waves 5 to 7 feet
this afternoon. Waves 3 to 6 feet subsiding to 2 to 4 feet
tonight. Waves 2 to 3 feet Wednesday morning.

Superior South Central...GALE WARNING IN EFFECT...14750 14730.
Waves 5 to 9 feet this afternoon. Waves 6 to 9 feet subsiding to
3 to 6 feet tonight. Waves 2 to 4 feet Wednesday morning.

Superior East...GALE WARNING IN EFFECT...11740 11750 12740 14730.
Waves 5 to 9 feet this afternoon. Waves 5 to 8 feet subsiding to
3 to 5 feet tonight. Waves 3 to 5 feet Wednesday morning.

$$

WFO MQT

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

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weather.gov/greatlakes