339
FZUS63 KMQT 122001
GLFLS

Open Lake Forecast for Lake Superior
National Weather Service Marquette MI
401 PM EDT Wed Aug 12 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...

This afternoon, weak 29.8 inch ridging over Lake Superior separates
a 29.5 inch low pressure over the Gulf of St. Lawrence and a Plains
low of 29.7 inches. This pattern holds, leading to calm open lake
conditions, until Thursday morning, when a 30.2 inch high over the
Canadian Rockies begins to extend stronger ridging over Lake
Superior before eventually becoming centered over the lake at 30.2
inches Friday afternoon. A 29.9 inch trough then moves over the
western end of the lake Saturday afternoon as the 30.2 inch high
moves over the Lower Great Lakes. This trough consolidates to a 29.8
inch low as it passes over Lake Superior, reaching Ontario by Sunday
afternoon, with 30.1 inch ridging over Lake Superior to follow.



LSZ162-130800-
Lake Superior west of a line from Saxon Harbor WI to Grand
Portage MN beyond 5NM-
401 PM EDT Wed Aug 12 2026 /301 PM CDT Wed Aug 12 2026/

.LATE THIS AFTERNOON...South winds 5 to 15 knots. Waves calm to
2 feet.
.TONIGHT...North winds 5 to 15 knots. Patchy fog after midnight.
A slight chance of showers after midnight. Waves calm to 2 feet.
.THURSDAY...Northeast winds 5 to 15 knots veering east in the
afternoon. A slight chance of showers through early afternoon.
Waves calm to 2 feet.
.THURSDAY NIGHT...Northeast winds 5 to 15 knots. Waves calm to
2 feet.
.FRIDAY...Northeast winds 10 to 20 knots increasing to 15 to
25 knots by mid afternoon. Waves building to 1 to 3 feet.
.FRIDAY NIGHT...Northeast winds 15 to 25 knots diminishing to
5 to 15 knots after midnight. Waves subsiding to calm to 2 feet.
.SATURDAY...East winds 10 to 20 knots backing northeast by mid
afternoon. A chance of showers. Waves calm to 2 feet.
.SATURDAY NIGHT...North winds 5 to 15 knots backing northwest
after midnight. A chance of showers. Waves calm to 2 feet.
.SUNDAY...West winds 5 to 15 knots veering northwest. Waves calm
to 2 feet.
.MONDAY...Southwest winds 5 to 15 knots veering west. Waves calm
to 2 feet.

$$

LSZ263-130800-
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 Wed Aug 12 2026

.LATE THIS AFTERNOON...Southwest winds 5 to 15 knots. Waves calm
to 2 feet.
.TONIGHT...West winds less than 10 knots veering north after
midnight. Waves calm to 2 feet.
.THURSDAY...North winds less than 10 knots becoming northeast
5 to 15 knots in the afternoon, then veering east late. A slight
chance of showers through early afternoon. Waves calm to 2 feet.
.THURSDAY NIGHT...Northeast winds less than 10 knots increasing
to 5 to 15 knots late. Waves calm to 2 feet.
.FRIDAY...Northeast winds 5 to 15 knots increasing to 15 to
25 knots by mid afternoon. Waves calm to 2 feet.
.FRIDAY NIGHT...East winds 10 to 20 knots diminishing to 5 to
15 knots after midnight. Waves calm to 2 feet.
.SATURDAY...East winds 5 to 15 knots. Waves calm to 2 feet.
.SATURDAY NIGHT...Northeast winds 5 to 15 knots backing northwest
after midnight. A chance of showers. Waves calm to 2 feet.
.SUNDAY...West winds 5 to 15 knots. Waves calm to 2 feet.
.MONDAY...West winds 10 to 20 knots backing southwest. Waves calm
to 2 feet.

$$

LSZ264-130800-
Lake Superior from Upper Entrance to Portage Canal to Manitou
Island MI 5NM off shore to the US/Canadian Border-
401 PM EDT Wed Aug 12 2026

.LATE THIS AFTERNOON...Southwest winds less than 10 knots. Waves
calm to 2 feet.
.TONIGHT...West winds less than 10 knots veering northwest late.
Waves calm to 2 feet.
.THURSDAY...Northwest winds less than 10 knots backing southwest
late. Waves calm to 2 feet.
.THURSDAY NIGHT...Southwest winds less than 10 knots veering
north after midnight, then veering northeast late. Waves calm to
2 feet.
.FRIDAY...Northeast winds 5 to 15 knots veering east by mid
afternoon. Waves calm to 2 feet.
.FRIDAY NIGHT...East winds 5 to 15 knots veering southeast after
midnight. Waves calm to 2 feet.
.SATURDAY...Southeast winds 5 to 15 knots. Waves calm to 2 feet.
.SATURDAY NIGHT...Southeast winds 5 to 15 knots veering west
after midnight. A chance of showers. Waves calm to 2 feet.
.SUNDAY...Northwest winds 5 to 15 knots backing west. Waves calm
to 2 feet.
.MONDAY...West winds 5 to 15 knots backing southwest. Waves calm
to 2 feet.

$$

LSZ265-130800-
Lake Superior West of Line from Manitou Island to Marquette MI
Beyond 5NM from shore-
401 PM EDT Wed Aug 12 2026

.LATE THIS AFTERNOON...East winds 5 to 15 knots. Waves calm to
2 feet.
.TONIGHT...Southeast winds 5 to 15 knots veering southwest after
midnight, then veering west late. Waves calm to 2 feet.
.THURSDAY...Northwest winds 5 to 15 knots veering north in the
afternoon, then veering east late. Waves calm to 2 feet.
.THURSDAY NIGHT...Southeast winds 5 to 15 knots backing east
after midnight. Waves calm to 2 feet.
.FRIDAY...Northeast winds 5 to 15 knots becoming east 10 to
20 knots by mid afternoon. Waves calm to 2 feet.
.FRIDAY NIGHT...Southeast winds 5 to 15 knots. Waves calm to
2 feet.
.SATURDAY...Southeast winds 10 to 20 knots increasing to 15 to
25 knots by mid afternoon. Waves calm to 2 feet.
.SATURDAY NIGHT...South winds 15 to 25 knots becoming west 10 to
20 knots after midnight. A chance of showers and thunderstorms.
Waves calm to 2 feet.
.SUNDAY...Northwest winds 10 to 20 knots backing west. Waves
building to 1 to 3 feet, then subsiding to calm to 2 feet.
.MONDAY...West winds 10 to 20 knots backing southwest. Waves calm
to 2 feet.

$$

LSZ266-130800-
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 Wed Aug 12 2026

.LATE THIS AFTERNOON...Northwest winds 5 to 15 knots. Waves calm
to 2 feet.
.TONIGHT...Northwest winds 5 to 15 knots backing west after
midnight. Waves calm to 2 feet.
.THURSDAY...Northwest winds 5 to 15 knots. Waves calm to 2 feet.
.THURSDAY NIGHT...Northwest winds 5 to 15 knots veering north
late. Waves calm to 2 feet.
.FRIDAY...Northeast winds 5 to 15 knots. Waves calm to 2 feet.
.FRIDAY NIGHT...East winds 5 to 15 knots veering southeast after
midnight. Waves calm to 2 feet.
.SATURDAY...Southeast winds 10 to 20 knots. Waves calm to 2 feet.
.SATURDAY NIGHT...South winds 10 to 20 knots veering west after
midnight. A chance of showers. Waves calm to 2 feet.
.SUNDAY...Northwest winds 10 to 20 knots. Waves building to 1 to
3 feet, then subsiding to calm to 2 feet.
.MONDAY...West winds 5 to 15 knots backing southwest. Waves calm
to 2 feet.

$$

LSZ267-130800-
Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off
shore to the US/Canadian border-
401 PM EDT Wed Aug 12 2026

.LATE THIS AFTERNOON...Northwest winds 5 to 15 knots. Waves calm
to 2 feet.
.TONIGHT...Northwest winds 5 to 15 knots backing west late. Waves
calm to 2 feet.
.THURSDAY...Northwest winds 5 to 15 knots. Waves calm to 2 feet.
.THURSDAY NIGHT...Northwest winds 5 to 15 knots veering north
late. Waves calm to 2 feet.
.FRIDAY...North winds 5 to 15 knots. Waves calm to 2 feet.
.FRIDAY NIGHT...Northeast winds 5 to 15 knots veering southeast
after midnight. Waves calm to 2 feet.
.SATURDAY...Southeast winds 10 to 20 knots. Waves calm to 2 feet.
.SATURDAY NIGHT...South winds 10 to 20 knots. A chance of
showers. Waves calm to 2 feet.
.SUNDAY...Northwest winds 10 to 20 knots. Waves calm to 2 feet.
.MONDAY...West winds 5 to 15 knots backing southwest. Waves calm
to 2 feet.

$$

LSZ261-130200-
MAFOR 1221/
Superior West 12400 13800 12100 11200. Waves 1 foot or less.

Superior North Central 14600 13700 11600. Waves 1 foot or less.

Superior South Central 11100 13500 11600 12700 11800. Waves 1
foot or less.

Superior East 13700 12600 13700. Waves 1 foot or less.

$$

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