880
FZUS63 KMQT 171948
GLFLS

Open Lake Forecast for Lake Superior
National Weather Service Marquette MI
Issued by National Weather Service Green Bay WI
348 PM EDT Thu Apr 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...Ridging of 30.0 inches over Lake Superior will
continue to give way to a weakening low pressure of 29.4 inches
over southern MN this evening, becoming 29.5 inches as it moves
over the lake tonight. Additionally, another low pressure of 29.4
inches will develop and move across the Central Plains tonight,
but weaken to 29.5 inches as it arrives over the lake Friday
morning and continue to weaken to 29.7 inches by Friday evening.
High pressure around 30.0 inches builds back over the Upper Great
Lakes Saturday, building to 30.4 inches by 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.

LSZ162-180400-
Lake Superior west of a line from Saxon Harbor WI to Grand
Portage MN beyond 5NM-
348 PM EDT Thu Apr 17 2025 /248 PM CDT Thu Apr 17 2025/

.LATE THIS AFTERNOON...Northeast winds 10 to 20 knots. Rain
showers and a slight chance of thunderstorms. Waves 2 to 4 feet.
.TONIGHT...Northeast winds 5 to 15 knots backing northwest late.
Patchy fog. Rain showers through midnight. A slight chance of
rain showers after midnight. Waves subsiding to calm to 2 feet.
.FRIDAY...Northwest winds 10 to 20 knots becoming north 5 to
15 knots in the afternoon. A chance of rain showers. Waves calm
to 2 feet.
.FRIDAY NIGHT...Northwest winds 5 to 15 knots increasing to 10 to
20 knots after midnight. A chance of rain showers through
midnight. Waves calm to 2 feet.
.SATURDAY...Northwest winds 5 to 15 knots backing west by mid
afternoon. Waves calm to 2 feet.
.SATURDAY NIGHT...South winds 5 to 15 knots backing east after
midnight. Waves calm to 2 feet.
.SUNDAY...East winds 5 to 15 knots. Waves building to 1 to
3 feet.
.SUNDAY NIGHT...East winds 10 to 20 knots backing northeast after
midnight. A chance of rain showers. Waves 1 to 3 feet.
.MONDAY...Northeast winds 10 to 20 knots becoming northwest 5 to
15 knots. A chance of rain showers. Waves subsiding to calm to
2 feet.
.TUESDAY...East winds 5 to 15 knots increasing to 10 to 20 knots.
A chance of rain showers. Waves calm to 2 feet.

$$

LSZ263-180400-
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-
348 PM EDT Thu Apr 17 2025

.LATE THIS AFTERNOON...Southeast winds 10 to 20 knots. Rain
showers likely and a slight chance of thunderstorms. Waves 3 to
6 feet occasionally to 8 feet.
.TONIGHT...Southeast winds 5 to 15 knots backing east after
midnight, then backing north late. Patchy fog. A slight chance of
thunderstorms through midnight. Rain showers. Waves subsiding to
1 to 3 feet.
.FRIDAY...North winds 5 to 15 knots backing northwest late. A
chance of rain showers. Waves subsiding to calm to 2 feet, then
building to 1 to 3 feet.
.FRIDAY NIGHT...North winds 5 to 15 knots increasing to 10 to
20 knots after midnight. A chance of rain showers, possibly mixed
with snow through midnight. Waves building to 2 to 4 feet.
.SATURDAY...Northwest winds 10 to 20 knots becoming west 5 to
15 knots by mid afternoon. Waves subsiding to calm to 2 feet.
.SATURDAY NIGHT...Southwest winds 5 to 15 knots backing south
after midnight. 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 10 to 20 knots. A chance of rain
showers. Waves building to 1 to 3 feet.
.MONDAY...Northeast winds 10 to 20 knots backing northwest. Rain
showers likely. Waves building to 2 to 4 feet, then subsiding to
calm to 2 feet.
.TUESDAY...East winds 5 to 15 knots increasing to 10 to 20 knots.
A chance of rain showers. Waves building to 1 to 3 feet.

$$

LSZ264-180400-
Lake Superior from Upper Entrance to Portage Canal to Manitou
Island MI 5NM off shore to the US/Canadian Border-
348 PM EDT Thu Apr 17 2025

.LATE THIS AFTERNOON...Southeast winds 20 to 30 knots. A chance
of rain showers and a slight chance of thunderstorms. Waves 6 to
9 feet occasionally to 11 feet.
.TONIGHT...Southeast winds 20 to 30 knots diminishing to 10 to
20 knots after midnight, then backing north late. Patchy fog. A
slight chance of thunderstorms through midnight. Rain showers.
Waves subsiding to 2 to 4 feet.
.FRIDAY...North winds 10 to 20 knots. A chance of rain showers.
Waves subsiding to 1 to 3 feet.
.FRIDAY NIGHT...North winds 10 to 20 knots increasing to 15 to
25 knots after midnight, then diminishing to 10 to 20 knots late.
A chance of rain showers, possibly mixed with snow through
midnight. Waves building to 3 to 5 feet occasionally to 7 feet.
.SATURDAY...North winds 10 to 20 knots backing northwest by mid
afternoon. Waves subsiding to calm to 2 feet.
.SATURDAY NIGHT...West winds 5 to 15 knots. Waves calm to 2 feet.
.SUNDAY...South winds 5 to 15 knots becoming southeast 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 showers. Waves building to 1 to
3 feet.
.MONDAY...Northeast winds 15 to 25 knots becoming north 10 to
20 knots. Rain showers likely, then a chance of rain showers.
Waves building to 2 to 4 feet, then subsiding to 1 to 3 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 1 to 3 feet.

$$

LSZ265-180400-
Lake Superior West of Line from Manitou Island to Marquette MI
Beyond 5NM from shore-
348 PM EDT Thu Apr 17 2025

.LATE THIS AFTERNOON...Southeast winds 20 to 30 knots. A slight
chance of showers and thunderstorms. Waves 3 to 6 feet
occasionally to 8 feet.
.TONIGHT...Southeast winds 15 to 25 knots diminishing to 10 to
20 knots after midnight, then becoming south 5 to 15 knots late.
Patchy fog. A slight chance of thunderstorms through midnight.
Rain showers. Waves subsiding to 1 to 3 feet.
.FRIDAY...West winds 10 to 20 knots veering northwest in the
afternoon. A chance of rain showers. Waves subsiding to calm to
2 feet, then building to 1 to 3 feet.
.FRIDAY NIGHT...Northwest winds 10 to 20 knots veering north
after midnight, then backing northwest late. A chance of rain
showers through midnight. Waves building to 3 to 5 feet
occasionally to 7 feet.
.SATURDAY...Northwest winds 10 to 20 knots. Waves subsiding to
1 to 3 feet.
.SATURDAY NIGHT...West winds 5 to 15 knots. 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...East winds 10 to 20 knots. A chance of rain
showers. Waves calm to 2 feet.
.MONDAY...East winds 15 to 25 knots becoming northwest 10 to
20 knots. Rain showers likely, then a chance of rain showers.
Waves building to 2 to 4 feet, then subsiding to calm to 2 feet.
.TUESDAY...Northwest winds 5 to 15 knots backing southeast. A
chance of rain showers. Waves calm to 2 feet.

$$

LSZ266-180400-
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-
348 PM EDT Thu Apr 17 2025

.LATE THIS AFTERNOON...Southeast winds 20 to 30 knots. A slight
chance of rain showers. Waves 5 to 9 feet occasionally to
11 feet.
.TONIGHT...Southeast winds 20 to 30 knots becoming south 15 to
25 knots after midnight. Patchy fog. A slight chance of
thunderstorms through midnight. Rain showers. Waves subsiding to
3 to 5 feet occasionally to 7 feet.
.FRIDAY...Southwest winds 10 to 20 knots veering northwest in the
afternoon. A chance of rain showers. Waves subsiding to 1 to
3 feet, then building to 2 to 4 feet.
.FRIDAY NIGHT...North winds 15 to 25 knots. A chance of rain
showers. A slight chance of snow showers after midnight. Waves
building to 3 to 6 feet occasionally to 8 feet.
.SATURDAY...Northwest winds 10 to 20 knots. Waves subsiding to
2 to 4 feet.
.SATURDAY NIGHT...Northwest winds 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...East winds 10 to 20 knots. A chance of rain
showers. Waves building to 2 to 4 feet.
.MONDAY...East winds 10 to 20 knots becoming northwest 15 to
25 knots. Rain showers likely, then a chance of rain showers.
Waves 2 to 4 feet.
.TUESDAY...Northwest winds 10 to 20 knots becoming east 5 to
15 knots. A chance of rain showers. Waves subsiding to calm to
2 feet.

$$

LSZ267-180400-
Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off
shore to the US/Canadian border-
348 PM EDT Thu Apr 17 2025

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

$$

LSZ261-180400-
MAFOR 1721/
Superior West 12216 11116 11816 11810 13700. Waves 1 to 3 feet.

Superior North Central 11340 11346 11336 11326 12820 12720. Waves
6 to 9 feet subsiding to 3 to 6 feet tonight. Waves 3 to 5 feet
subsiding to 2 to 4 feet Friday.

Superior South Central 11340 12336 11436 11420 11610 11710 11720.
Waves 3 to 6 feet tonight. Waves 1 to 3 feet Friday.

Superior East 12340 11336 12436 11420 11510 11610. Waves 3 to 5
feet building to 5 to 8 feet, then subsiding to 3 to 6 feet
tonight. Waves 3 to 5 feet subsiding to 1 to 3 feet Friday.

$$

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