Great Lakes Forecast
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FZUS63 KMQT 181358
GLFLS

Open Lake Forecast for Lake Superior
National Weather Service Marquette MI
958 AM EDT Tue May 18 2021

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 30.2 inch ridge over Lake Superior this morning
will weaken to 30.1 inches tonight. This ridge will remain over
Lake Superior through the rest of the week as a 30.4 inch high
remains in place over the East Coast. A 29.9 inch trough will
sweep across the Upper Great Lakes late Saturday into Sunday.

LSZ162-182200-
Lake Superior west of a line from Saxon Harbor WI to Grand
Portage MN beyond 5NM-
958 AM EDT Tue May 18 2021 /858 AM CDT Tue May 18 2021/

.REST OF TODAY...Southeast winds 5 to 15 knots backing northeast
in the afternoon, then increasing to 10 to 20 knots late. Waves
calm to 2 feet.
.TONIGHT...East winds 10 to 20 knots. A chance of rain showers.
Waves calm to 2 feet.
.WEDNESDAY...Southeast winds 5 to 15 knots veering south in the
afternoon, then backing east late. Patchy fog. A chance of rain
showers. Waves calm to 2 feet.
.WEDNESDAY NIGHT...East winds 5 to 15 knots veering south after
midnight. Patchy fog. A chance of showers through midnight. A
slight chance of thunderstorms. Showers likely after midnight.
Waves calm to 2 feet.
.THURSDAY...South winds 5 to 15 knots. Showers likely. Waves calm
to 2 feet.
.THURSDAY NIGHT...South winds 5 to 15 knots. Showers likely and a
chance of thunderstorms. Waves calm to 2 feet.
.FRIDAY...South winds 5 to 15 knots becoming east 10 to 20 knots.
A chance of showers. Waves calm to 2 feet.
.SATURDAY...East winds 10 to 20 knots backing northeast. A chance
of showers. Showers likely. Waves calm to 2 feet.

$$

LSZ263-182200-
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-
958 AM EDT Tue May 18 2021

.REST OF TODAY...South winds 5 to 15 knots backing northeast in
the afternoon, then increasing to 10 to 20 knots late. Waves calm
to 2 feet.
.TONIGHT...East winds 10 to 20 knots veering south after
midnight, then backing southeast late. A chance of rain showers.
Waves building to 1 to 3 feet.
.WEDNESDAY...Southeast winds 10 to 20 knots becoming south 5 to
15 knots in the afternoon. Patchy fog. A chance of rain showers.
Waves subsiding to calm to 2 feet.
.WEDNESDAY NIGHT...South winds 5 to 15 knots. Patchy fog. A
chance of showers and a slight chance of thunderstorms. Waves
calm to 2 feet.
.THURSDAY...South winds 5 to 15 knots. A chance of showers
through early afternoon. Showers likely by mid afternoon. Waves
calm to 2 feet.
.THURSDAY NIGHT...South winds 5 to 15 knots becoming southwest
10 to 20 knots after midnight. Showers likely. Waves calm to
2 feet.
.FRIDAY...Southwest winds 5 to 15 knots becoming southeast 10 to
20 knots. A chance of showers. Waves calm to 2 feet.
.SATURDAY...South winds 10 to 20 knots backing northeast. A
chance of showers, then showers likely. Waves calm to 2 feet.

$$

LSZ264-182200-
Lake Superior from Upper Entrance to Portage Canal to Manitou
Island MI 5NM off shore to the US/Canadian Border-
958 AM EDT Tue May 18 2021

.REST OF TODAY...Southwest winds 5 to 15 knots backing east in
the afternoon, then increasing to 10 to 20 knots late. Waves calm
to 2 feet building to 1 to 3 feet.
.TONIGHT...Southeast winds 15 to 25 knots veering south after
midnight, then becoming southeast 10 to 20 knots late. A chance
of rain showers after midnight. Waves building to 3 to 5 feet
occasionally to 7 feet, then subsiding to 2 to 4 feet.
.WEDNESDAY...Southeast winds 10 to 20 knots becoming south 5 to
15 knots late. Patchy fog. A chance of rain showers. Waves 2 to
4 feet.
.WEDNESDAY NIGHT...South winds 5 to 15 knots. Patchy fog. A
chance of showers. A slight chance of thunderstorms after
midnight. Waves subsiding to 1 to 3 feet.
.THURSDAY...South winds 5 to 15 knots. A chance of showers. Waves
1 to 3 feet.
.THURSDAY NIGHT...South winds 5 to 15 knots veering southwest
after midnight. A chance of showers through midnight, then
showers likely after midnight. Waves subsiding to calm to 2 feet.
.FRIDAY...Southwest winds 5 to 15 knots backing southeast. A
chance of showers. Waves calm to 2 feet.
.SATURDAY...South winds 5 to 15 knots backing north. A chance of
rain showers, then rain showers likely. Waves calm to 2 feet.

$$

LSZ265-182200-
Lake Superior West of Line from Manitou Island to Marquette MI
Beyond 5NM from shore-
958 AM EDT Tue May 18 2021

.REST OF TODAY...Southeast winds 10 to 20 knots backing east in
the afternoon, then becoming southeast 15 to 25 knots late. Waves
calm to 2 feet building to 2 to 4 feet.
.TONIGHT...South winds 10 to 20 knots backing southeast after
midnight. A chance of showers after midnight. Waves subsiding to
1 to 3 feet.
.WEDNESDAY...Southeast winds 10 to 20 knots veering south late.
Patchy fog. A chance of showers. Waves building to 2 to 4 feet,
then subsiding to 1 to 3 feet.
.WEDNESDAY NIGHT...South winds 5 to 15 knots increasing to 10 to
20 knots after midnight. A chance of showers and a slight chance
of thunderstorms. Waves subsiding to calm to 2 feet.
.THURSDAY...South winds 10 to 20 knots. A chance of showers.
Waves calm to 2 feet.
.THURSDAY NIGHT...South winds 10 to 20 knots. A chance of
showers. Waves calm to 2 feet.
.FRIDAY...Southwest winds 10 to 20 knots backing south. A chance
of showers. Waves calm to 2 feet.
.SATURDAY...Southeast winds 10 to 20 knots backing north. A
chance of showers, then showers likely. Waves calm to 2 feet.

$$

LSZ266-182200-
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-
958 AM EDT Tue May 18 2021

.REST OF TODAY...South winds 10 to 20 knots becoming southeast
5 to 15 knots in the afternoon, then increasing to 10 to 20 knots
late. Waves calm to 2 feet building to 2 to 4 feet.
.TONIGHT...South winds 15 to 25 knots diminishing to 10 to
20 knots late. A slight chance of rain showers after midnight.
Waves 2 to 4 feet.
.WEDNESDAY...Southeast winds 15 to 25 knots veering south in the
afternoon, then diminishing to 10 to 20 knots late. Patchy fog. A
chance of showers. Waves 2 to 4 feet.
.WEDNESDAY NIGHT...South winds 10 to 20 knots. Patchy fog. A
chance of showers and a slight chance of thunderstorms. Waves
subsiding to 1 to 3 feet.
.THURSDAY...South winds 10 to 20 knots. A chance of showers.
Waves 1 to 3 feet.
.THURSDAY NIGHT...South winds 10 to 20 knots. A chance of
showers. Waves 1 to 3 feet.
.FRIDAY...South winds 10 to 20 knots. A chance of showers. Waves
subsiding to calm to 2 feet.
.SATURDAY...South winds 10 to 20 knots backing north. A chance of
showers. Waves calm to 2 feet.

$$

LSZ267-182200-
Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off
shore to the US/Canadian border-
958 AM EDT Tue May 18 2021

.REST OF TODAY...South winds 10 to 20 knots becoming east 5 to
15 knots in the afternoon. Waves calm to 2 feet.
.TONIGHT...Southeast winds 10 to 20 knots veering south after
midnight, then backing southeast late. A slight chance of showers
after midnight. Waves calm to 2 feet.
.WEDNESDAY...Southeast winds 10 to 20 knots veering south late. A
chance of showers. Patchy fog by mid afternoon. Waves building to
1 to 3 feet.
.WEDNESDAY NIGHT...South winds 10 to 20 knots. Patchy fog. A
chance of showers. A slight chance of thunderstorms after
midnight. Waves 1 to 3 feet.
.THURSDAY...South winds 10 to 20 knots. A chance of showers.
Waves subsiding to calm to 2 feet.
.THURSDAY NIGHT...South winds 10 to 20 knots. A chance of
showers. Waves building to 1 to 3 feet.
.FRIDAY...South winds 10 to 20 knots. A chance of showers. Waves
subsiding to calm to 2 feet.
.SATURDAY...Southeast winds 5 to 15 knots becoming west 10 to
20 knots. A chance of showers. Waves calm to 2 feet.

$$
LSZ261-182200-
MAFOR 1815/
Superior West 11200 11110 12210 14310. A chance of rain showers
overnight and Wednesday morning. Waves 2 feet or less.

Superior North Central 11400 11220 11320 11330 12430 11330 11320.
A chance of showers overnight and Wednesday morning. Waves 2 feet
or less this afternoon. Waves 2 to 4 feet tonight and Wednesday
morning.

Superior South Central 11310 11320 11330 11320 11420 13320. A
chance of showers Wednesday morning. Waves 1 to 4 feet.

Superior East 11400 11200 11210 11310 11420 13320. A chance of
showers Wednesday morning. Waves 1 to 3 feet.

$$

RJC

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

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


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