595
FZUS63 KMQT 181939
GLFLS

Open Lake Forecast for Lake Superior
National Weather Service Marquette MI
339 PM EDT Fri Apr 18 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... Low pressure of 29.6 inches moves through Lower
Michigan through this evening, heading to souteastern Ontario by
Saturday morning. High pressure of 30.2 inches over the northern
Plains Saturday morning will strengthen to 30.5 inches over the
Upper Great Lakes Sunday morning. This high pressure will give
way to another low pressure lifting into the Upper Great Lakes at
around 29.6 inches by Monday morning. Behind the low, weak ridging
of around 30.0 inches moves back over Lake Superior on Tuesday
into Wednesday.

LSZ162-190345-
Lake Superior west of a line from Saxon Harbor WI to Grand
Portage MN beyond 5NM-
339 PM EDT Fri Apr 18 2025 /239 PM CDT Fri Apr 18 2025/

.LATE THIS AFTERNOON...Northwest winds 10 to 20 knots. Waves calm
to 2 feet.
.TONIGHT...Northwest winds 10 to 20 knots. Waves calm to 2 feet.
.SATURDAY...Northwest winds 10 to 20 knots becoming west 5 to
15 knots in the afternoon, then backing southwest late. Waves
calm to 2 feet.
.SATURDAY NIGHT...Southwest winds 5 to 15 knots becoming south
less than 10 knots after midnight, then becoming southeast 5 to
15 knots late. Waves calm to 2 feet.
.SUNDAY...Southeast winds 5 to 15 knots becoming east 10 to
20 knots by mid afternoon. Waves calm to 2 feet.
.SUNDAY NIGHT...East winds 10 to 20 knots backing northeast after
midnight. A chance of rain. Waves building to 1 to 3 feet.
.MONDAY...Northeast winds 15 to 25 knots backing north by mid
afternoon. Rain likely through early afternoon, then a chance of
rain by mid afternoon. Waves building to 3 to 5 feet occasionally
to 7 feet, then subsiding to 2 to 4 feet.
.MONDAY NIGHT...Northwest winds 10 to 20 knots. Waves subsiding
to calm to 2 feet.
.TUESDAY...East winds 10 to 20 knots. A chance of rain showers.
Waves building to 1 to 3 feet.
.WEDNESDAY...Southwest winds 10 to 20 knots veering west. Waves
subsiding to calm to 2 feet.

$$

LSZ263-190345-
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-
339 PM EDT Fri Apr 18 2025

.LATE THIS AFTERNOON...Northwest winds 5 to 15 knots. Patchy fog.
Isolated rain showers. Waves calm to 2 feet.
.TONIGHT...North winds 5 to 15 knots. Patchy fog through
midnight. Isolated rain showers through midnight. Waves calm to
2 feet.
.SATURDAY...Northwest winds 5 to 15 knots backing southwest late.
Waves calm to 2 feet.
.SATURDAY NIGHT...Southwest winds 5 to 15 knots diminishing to
less than 10 knots after midnight, then backing south late. Waves
calm to 2 feet.
.SUNDAY...South winds 5 to 15 knots backing east by mid
afternoon. Waves calm to 2 feet.
.SUNDAY NIGHT...East winds 5 to 15 knots increasing to 10 to
20 knots after midnight. A chance of rain. Waves building to 1 to
3 feet.
.MONDAY...Northeast winds 15 to 25 knots backing north by mid
afternoon. Snow likely through early afternoon. Rain likely.
Waves building to 3 to 6 feet occasionally to 8 feet.
.MONDAY NIGHT...Northwest winds 10 to 20 knots veering north
after midnight. Waves subsiding to 1 to 3 feet.
.TUESDAY...East winds 5 to 15 knots becoming southeast 10 to
20 knots. A chance of rain showers. Waves subsiding to calm to
2 feet, then building to 1 to 3 feet.
.WEDNESDAY...Southwest winds 10 to 20 knots becoming west 5 to
15 knots. Waves building to 2 to 4 feet, then subsiding to calm
to 2 feet.

$$

LSZ264-190345-
Lake Superior from Upper Entrance to Portage Canal to Manitou
Island MI 5NM off shore to the US/Canadian Border-
339 PM EDT Fri Apr 18 2025

.LATE THIS AFTERNOON...Northwest winds 5 to 15 knots. Patchy fog.
Waves 1 to 3 feet.
.TONIGHT...North winds 5 to 15 knots increasing to 10 to 20 knots
late. Patchy fog through midnight. Waves building to 2 to 4 feet.
.SATURDAY...North winds 10 to 20 knots becoming northwest 5 to
15 knots in the afternoon, then backing west late. Waves
subsiding to calm to 2 feet.
.SATURDAY NIGHT...West winds 5 to 15 knots becoming southwest
less than 10 knots after midnight, then backing south late. Waves
calm to 2 feet.
.SUNDAY...South winds 5 to 15 knots backing southeast by mid
afternoon. Waves calm to 2 feet.
.SUNDAY NIGHT...Southeast winds 5 to 15 knots becoming east 10 to
20 knots after midnight. A chance of rain after midnight. Waves
building to 2 to 4 feet.
.MONDAY...Northeast winds 15 to 25 knots backing north by mid
afternoon. Snow likely through early afternoon. Rain likely.
Waves building to 3 to 6 feet occasionally to 8 feet.
.MONDAY NIGHT...North winds 15 to 25 knots diminishing to 10 to
20 knots after midnight. A chance of rain showers. Waves
subsiding to 2 to 4 feet.
.TUESDAY...North winds 5 to 15 knots veering southeast. A chance
of rain showers. Waves subsiding to calm to 2 feet, then building
to 2 to 4 feet.
.WEDNESDAY...South winds 10 to 20 knots becoming west 5 to
15 knots. Waves subsiding to calm to 2 feet.

$$

LSZ265-190345-
Lake Superior West of Line from Manitou Island to Marquette MI
Beyond 5NM from shore-
339 PM EDT Fri Apr 18 2025

.LATE THIS AFTERNOON...Northwest winds 10 to 20 knots. Patchy
fog. Isolated rain showers. Waves calm to 2 feet.
.TONIGHT...Northwest winds 10 to 20 knots. A slight chance of
thunderstorms and isolated rain showers through midnight. Patchy
fog. Waves building to 2 to 4 feet.
.SATURDAY...Northwest winds 15 to 25 knots diminishing to 10 to
20 knots late. Waves subsiding to 1 to 3 feet.
.SATURDAY NIGHT...Northwest winds 5 to 15 knots backing southwest
after midnight, then backing south late. Waves subsiding to calm
to 2 feet.
.SUNDAY...Southeast winds 5 to 15 knots becoming east 10 to
20 knots by mid afternoon. Waves calm to 2 feet.
.SUNDAY NIGHT...Southeast winds 10 to 20 knots backing east after
midnight. A chance of rain. Waves building to 1 to 3 feet.
.MONDAY...East winds 15 to 25 knots backing north by mid
afternoon. Rain. Waves building to 3 to 6 feet occasionally to
8 feet.
.MONDAY NIGHT...North winds 20 to 30 knots becoming northwest
15 to 25 knots after midnight. A chance of rain showers through
midnight. Waves subsiding to 2 to 4 feet.
.TUESDAY...North winds 10 to 20 knots veering southeast. A chance
of rain showers. Waves subsiding to calm to 2 feet.
.WEDNESDAY...South winds 15 to 25 knots becoming west 10 to
20 knots. Waves calm to 2 feet.

$$

LSZ266-190345-
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-
339 PM EDT Fri Apr 18 2025

.LATE THIS AFTERNOON...Northwest winds 10 to 20 knots. Patchy
fog. A slight chance of thunderstorms and isolated rain showers.
Waves 1 to 3 feet building to 2 to 4 feet.
.TONIGHT...Northwest winds 15 to 25 knots veering north after
midnight, then backing northwest late. Patchy fog through
midnight. A slight chance of thunderstorms and isolated rain
showers through midnight. Waves building to 3 to 5 feet
occasionally to 7 feet.
.SATURDAY...Northwest winds 15 to 25 knots diminishing to 10 to
20 knots late. Waves subsiding to 2 to 4 feet.
.SATURDAY NIGHT...Northwest winds 10 to 20 knots becoming west
5 to 15 knots after midnight, then backing southwest late. Waves
subsiding to calm to 2 feet.
.SUNDAY...South winds 5 to 15 knots becoming east 10 to 20 knots
by mid afternoon. Waves calm to 2 feet.
.SUNDAY NIGHT...Southeast winds 10 to 20 knots backing east after
midnight. A chance of rain. Waves building to 2 to 4 feet.
.MONDAY...East winds 15 to 25 knots becoming northeast 20 to
30 knots by mid afternoon. Rain. Waves building to 3 to 6 feet
occasionally to 8 feet.
.MONDAY NIGHT...North winds 20 to 30 knots diminishing to 15 to
25 knots after midnight. A chance of rain showers. Waves 3 to
6 feet occasionally to 8 feet.
.TUESDAY...North winds 10 to 20 knots veering southeast. A chance
of rain showers. Waves subsiding to calm to 2 feet, then building
to 1 to 3 feet.
.WEDNESDAY...South winds 10 to 20 knots veering west. Waves
subsiding to calm to 2 feet.

$$

LSZ267-190345-
Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off
shore to the US/Canadian border-
339 PM EDT Fri Apr 18 2025

.LATE THIS AFTERNOON...West winds 10 to 20 knots. Patchy fog. A
slight chance of thunderstorms and isolated rain showers. Waves
calm to 2 feet building to 1 to 3 feet.
.TONIGHT...Northwest winds 10 to 20 knots increasing to 15 to
25 knots late. Patchy fog. A slight chance of thunderstorms
through midnight. Scattered rain showers. Waves building to 3 to
5 feet occasionally to 7 feet.
.SATURDAY...Northwest winds 15 to 25 knots. Waves 3 to 5 feet
occasionally to 7 feet.
.SATURDAY NIGHT...Northwest winds 15 to 25 knots diminishing to
5 to 15 knots. Waves subsiding to calm to 2 feet.
.SUNDAY...South winds 5 to 15 knots backing east by mid
afternoon. Waves calm to 2 feet.
.SUNDAY NIGHT...Southeast winds 10 to 20 knots becoming east
15 to 25 knots after midnight. A chance of rain after midnight.
Waves building to 2 to 4 feet.
.MONDAY...East winds 15 to 25 knots backing northeast by mid
afternoon. Rain. Waves building to 3 to 6 feet occasionally to
8 feet.
.MONDAY NIGHT...North winds 20 to 30 knots becoming northwest
15 to 25 knots after midnight. Rain showers likely through
midnight, then a chance of rain showers after midnight. Waves
3 to 6 feet occasionally to 8 feet.
.TUESDAY...Northwest winds 10 to 20 knots backing southeast. A
chance of rain showers. Waves subsiding to calm to 2 feet.
.WEDNESDAY...Southeast winds 10 to 20 knots veering west. A
chance of rain showers. Waves building to 1 to 3 feet, then
subsiding to calm to 2 feet.

$$

LSZ261-190345-
MAFOR 1821/
Superior West 15710 12610. Waves 1 to 2 feet.

Superior North Central 11720 14820 11820 12720. Waves 2 to 3 feet
tonight. Waves 2 to 4 feet subsiding to 1 to 3 feet Saturday.

Superior South Central 12710 15720. Waves 1 to 3 feet building to
2 to 4 feet tonight. Waves 2 to 4 feet Saturday.

Superior East 11710 11720 11720 19726 14720 11720. Waves 2 to 4
feet building to 3 to 5 feet tonight. Waves 3 to 5 feet Saturday.

$$

BW

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

Graphical marine forecasts are available online at:
weather.gov/greatlakes