009
FZUS63 KMQT 171401
GLFLS

Open Lake Forecast for Lake Superior
National Weather Service Marquette MI
1001 AM EDT Fri Oct 17 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...

A 29.4 inch low will lift through Manitoba today while deepening to
29.2 inches. It will continue onto Hudson Bay through Saturday
afternoon, deepening further to 29.1 inches. As a result, a 29.5
inch trough will be pulled over Lake Superior this afternoon and
tonight, followed by a second 29.6 inch through Saturday. A
secondary low develops over the Mid Mississippi Valley at the base
of this secondary trough late in the day Saturday, then deepens to
at least 29.2 inches on Sunday as it crosses Lower Michigan. This
low reaches James Bay Sunday night while a weak 29.8 inch ridge
briefly extends over Lake Superior. Another low pressure at 29.5
inches develops upstream over the Northern Plains, tracking east
over the region Monday night before coalescing into a compact 29.4
inch low over the Upper Great Lakes Tuesday morning.


LSZ162-172000-
Lake Superior west of a line from Saxon Harbor WI to Grand
Portage MN beyond 5NM-
1001 AM EDT Fri Oct 17 2025 /901 AM CDT Fri Oct 17 2025/

.REST OF TODAY...South winds 10 to 20 knots becoming southwest
15 to 25 knots late. A chance of showers. Waves 1 to 3 feet.
.TONIGHT...Southwest winds 15 to 25 knots diminishing to 10 to
20 knots late. Waves building to 2 to 4 feet, then subsiding to
1 to 3 feet.
.SATURDAY...West winds 10 to 20 knots. Waves subsiding to calm to
2 feet.
.SATURDAY NIGHT...Northwest winds 10 to 20 knots increasing to
15 to 25 knots after midnight. A slight chance of showers. Waves
building to 1 to 3 feet.
.SUNDAY...Northwest winds 15 to 25 knots backing west by mid
afternoon. A slight chance of showers through early afternoon.
Waves subsiding to calm to 2 feet.
.SUNDAY NIGHT...West winds 10 to 20 knots backing southwest after
midnight. Waves calm to 2 feet.
.MONDAY...South winds 10 to 20 knots becoming west 15 to
25 knots. A chance of showers. Waves building to 2 to 4 feet,
then subsiding to 1 to 3 feet.
.TUESDAY...Northwest winds 20 to 30 knots diminishing to 15 to
25 knots. A chance of rain showers. Waves building to 3 to 6 feet
occasionally to 8 feet, then subsiding to 1 to 3 feet.

$$

LSZ263-172000-
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 Fri Oct 17 2025

.REST OF TODAY...South winds 10 to 20 knots veering southwest
late. A chance of showers. Waves 1 to 3 feet.
.TONIGHT...Southwest winds 15 to 25 knots diminishing to 10 to
20 knots late. A slight chance of showers through midnight. Waves
building to 3 to 5 feet occasionally to 7 feet, then subsiding to
2 to 4 feet.
.SATURDAY...West winds 10 to 20 knots. Waves subsiding to 1 to
3 feet.
.SATURDAY NIGHT...Northwest winds 10 to 20 knots increasing to
15 to 25 knots after midnight. A slight chance of showers. Waves
subsiding to calm to 2 feet, then building to 3 to 5 feet
occasionally to 7 feet.
.SUNDAY...Northwest winds 20 to 30 knots backing west by mid
afternoon. A slight chance of showers through early afternoon.
Waves building to 3 to 6 feet occasionally to 8 feet.
.SUNDAY NIGHT...West winds 10 to 20 knots backing southwest after
midnight. Waves subsiding to 1 to 3 feet.
.MONDAY...South winds 15 to 25 knots becoming west 20 to
30 knots. A chance of showers. Waves building to 4 to 7 feet
occasionally to 9 feet.
.TUESDAY...Northwest gales to 40 knots. A chance of rain showers.
Waves building to 7 to 10 feet occasionally to 13 feet, then
subsiding to 3 to 6 feet occasionally to 8 feet.

$$

LSZ264-172000-
Lake Superior from Upper Entrance to Portage Canal to Manitou
Island MI 5NM off shore to the US/Canadian Border-
1001 AM EDT Fri Oct 17 2025

.REST OF TODAY...South winds 10 to 20 knots. A chance of showers.
Waves 3 to 5 feet occasionally to 7 feet subsiding to 2 to
4 feet.
.TONIGHT...Southwest winds 15 to 25 knots diminishing to 10 to
20 knots late. A chance of showers through midnight. Waves
building to 3 to 5 feet occasionally to 7 feet, then subsiding to
2 to 4 feet.
.SATURDAY...West winds 10 to 20 knots. Waves subsiding to 1 to
3 feet.
.SATURDAY NIGHT...Northwest winds 10 to 20 knots becoming north
15 to 25 knots after midnight. A slight chance of showers. Waves
subsiding to calm to 2 feet, then building to 3 to 5 feet
occasionally to 7 feet.
.SUNDAY...Northwest winds 20 to 30 knots. A slight chance of
showers through early afternoon. Waves building to 4 to 7 feet
occasionally to 9 feet, then subsiding to 3 to 5 feet
occasionally to 7 feet.
.SUNDAY NIGHT...Northwest winds 15 to 25 knots becoming west
10 to 20 knots after midnight. Waves subsiding to 1 to 3 feet.
.MONDAY...South winds 15 to 25 knots increasing to 20 to
30 knots. A chance of showers. Waves building to 4 to 7 feet
occasionally to 9 feet.
.TUESDAY...Northwest gales to 40 knots. A chance of rain showers.
Waves building to 5 to 9 feet occasionally to 11 feet.

$$

LSZ265-172000-
Lake Superior West of Line from Manitou Island to Marquette MI
Beyond 5NM from shore-
1001 AM EDT Fri Oct 17 2025

.REST OF TODAY...South winds 15 to 25 knots. A chance of showers.
Waves 2 to 4 feet.
.TONIGHT...South winds 15 to 25 knots becoming southwest 10 to
20 knots after midnight. A chance of showers and a slight chance
of thunderstorms through midnight. Waves subsiding to calm to
2 feet.
.SATURDAY...West winds 10 to 20 knots veering northwest late.
Waves calm to 2 feet.
.SATURDAY NIGHT...Northwest winds 10 to 20 knots increasing to
15 to 25 knots after midnight. A chance of showers. Waves
building to 1 to 3 feet.
.SUNDAY...Northwest winds 20 to 30 knots. A chance of showers.
Waves building to 3 to 6 feet occasionally to 8 feet.
.SUNDAY NIGHT...Northwest winds 15 to 25 knots becoming west
10 to 20 knots after midnight. Waves subsiding to calm to 2 feet.
.MONDAY...South winds 15 to 25 knots increasing to 20 to
30 knots. A chance of showers. Waves building to 2 to 4 feet.
.TUESDAY...Northwest gales to 35 knots. Showers likely. Waves
building to 4 to 7 feet occasionally to 9 feet, then subsiding to
3 to 6 feet occasionally to 8 feet.

$$

LSZ266-172000-
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 Fri Oct 17 2025

.REST OF TODAY...South winds 20 to 30 knots. A chance of showers.
Waves 3 to 6 feet occasionally to 8 feet.
.TONIGHT...South winds 20 to 30 knots becoming southwest 15 to
25 knots after midnight, then diminishing to 10 to 20 knots late.
A chance of showers and a slight chance of thunderstorms. Waves
building to 4 to 7 feet occasionally to 9 feet, then subsiding to
2 to 4 feet.
.SATURDAY...Southwest winds 10 to 20 knots veering west in the
afternoon, then veering north late. A slight chance of showers.
Waves subsiding to 1 to 3 feet.
.SATURDAY NIGHT...North winds 10 to 20 knots increasing to 15 to
25 knots after midnight. A chance of showers. Waves subsiding to
calm to 2 feet, then building to 2 to 4 feet.
.SUNDAY...North winds 20 to 30 knots backing northwest by mid
afternoon. A chance of showers. Waves building to 6 to 9 feet
occasionally to 11 feet.
.SUNDAY NIGHT...Northwest winds 20 to 30 knots becoming west
10 to 20 knots after midnight. A chance of showers. Waves
subsiding to 2 to 4 feet.
.MONDAY...South winds 15 to 25 knots increasing to 20 to
30 knots. A chance of showers. Waves subsiding to 1 to 3 feet,
then building to 4 to 7 feet occasionally to 9 feet.
.TUESDAY...Northwest gales to 40 knots. Showers likely, then a
chance of showers. Waves building to 9 to 12 feet occasionally to
15 feet, then subsiding to 7 to 10 feet occasionally to 13 feet.

$$

LSZ267-172000-
Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off
shore to the US/Canadian border-
1001 AM EDT Fri Oct 17 2025

.REST OF TODAY...South winds 15 to 25 knots increasing to 20 to
30 knots in the afternoon. A slight chance of showers. Waves 2 to
4 feet building to 3 to 5 feet occasionally to 7 feet.
.TONIGHT...South winds 20 to 30 knots becoming southwest 15 to
25 knots late. Showers likely through midnight. A slight chance
of thunderstorms. A slight chance of showers after midnight.
Waves building to 3 to 6 feet occasionally to 8 feet, then
subsiding to 1 to 3 feet.
.SATURDAY...Southwest winds 10 to 20 knots veering west late. A
chance of showers. Waves subsiding to calm to 2 feet.
.SATURDAY NIGHT...East winds 10 to 20 knots backing north after
midnight. A chance of showers through midnight, then showers
likely and a slight chance of thunderstorms after midnight. Waves
building to 1 to 3 feet.
.SUNDAY...North winds 15 to 25 knots becoming northwest gales to
35 knots by mid afternoon. Showers likely through early
afternoon, then a chance of showers by mid afternoon. Waves
building to 6 to 10 feet occasionally to 13 feet.
.SUNDAY NIGHT...Northwest winds 20 to 30 knots diminishing to
15 to 25 knots after midnight. A chance of showers. Waves
subsiding to 2 to 4 feet.
.MONDAY...South winds 15 to 25 knots increasing to 20 to
30 knots. A chance of showers. Waves building to 3 to 6 feet
occasionally to 8 feet.
.TUESDAY...Northwest winds 20 to 30 knots increasing to gales to
35 knots. Showers. Waves building to 9 to 12 feet occasionally to
15 feet, then subsiding to 7 to 10 feet occasionally to 13 feet.

$$

LSZ261-172000-
MAFOR 1715/
Superior West 12420 11520 13530 12520. A chance of showers this
afternoon. Waves 1 to 3 feet this afternoon. Waves 2 to 4 feet
tonight. Waves 1 to 3 feet Saturday morning.

Superior North Central 13420 11430 12530 11520 11620. A chance of
showers this afternoon and evening. Waves 2 to 4 feet this
afternoon. Waves 2 to 4 feet building to 3 to 5 feet tonight.
Waves 3 to 5 feet Saturday morning.

Superior South Central 14430 11530 11520 12510. A chance of
showers this evening. Waves 3 to 5 feet this afternoon. Waves 2
to 4 feet subsiding to 1 to 3 feet tonight. Waves 1 to 2 feet
Saturday morning.

Superior East 12430 11440 12446 11530 12520. Waves 3 to 6 feet
this afternoon and tonight. Waves 2 to 3 feet Saturday morning.

$$

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