Great Lakes Forecast
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FZUS63 KMQT 180802
GLFLS

Open Lake Forecast for Lake Superior
National Weather Service Marquette MI
402 AM EDT Mon Sep 18 2017

For waters beyond five 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...High pressure of 30.2 inches will dominate the Upper
Great Lakes today. As the high shifts to southern Quebec on
Tuesday, a 29.5 inch trough will move across the Northern Plains.
This trough will weaken to 29.8 inches as it sweeps eastward,
passing across Lake Superior Wednesday afternoon and Wednesday
night. Another low pressure trough of 29.6 inches will emerge over
the Plains states on Thursday. This trough will then remain over
the Plains on Friday while high pressure of 30.1 inches builds
over the Lower Great Lakes region.

LSZ162-181615-
Lake Superior west of a line from Saxon Harbor WI to Grand
Portage MN beyond 5NM-
402 AM EDT Mon Sep 18 2017 /302 AM CDT Mon Sep 18 2017/

.EARLY THIS MORNING...West winds 5 to 15 knots. Waves calm to
2 feet.
.TODAY...South winds 5 to 15 knots backing southeast in the
afternoon, then becoming east 10 to 20 knots late. A slight
chance of showers by mid afternoon. Waves calm to 2 feet.
.TONIGHT...South winds 5 to 15 knots backing southeast late. A
slight chance of showers through midnight. Waves calm to 2 feet.
.TUESDAY...Southeast winds 5 to 15 knots becoming east 10 to
20 knots in the afternoon. Waves calm to 2 feet.
.TUESDAY NIGHT...East winds 10 to 20 knots becoming southeast
15 to 25 knots after midnight. A slight chance of showers through
midnight, then showers likely and a slight chance of
thunderstorms after midnight. Waves building to 1 to 3 feet.
.WEDNESDAY...South winds 10 to 20 knots veering west by mid
afternoon. A chance of showers and thunderstorms. Waves building
to 2 to 4 feet, then subsiding to calm to 2 feet.
.WEDNESDAY NIGHT...West winds 5 to 15 knots veering north after
midnight. Waves calm to 2 feet.
.THURSDAY...East winds 5 to 15 knots becoming southeast 10 to
20 knots. A chance of showers. Waves calm to 2 feet.
.FRIDAY...Southeast winds 10 to 20 knots veering south. A chance
of showers. Waves building to 1 to 3 feet.

$$

LSZ263-181615-
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-
402 AM EDT Mon Sep 18 2017

.EARLY THIS MORNING...West winds 5 to 15 knots. Waves 1 to
3 feet.
.TODAY...South winds 5 to 15 knots backing east late. A slight
chance of showers by mid afternoon. Waves subsiding to calm to
2 feet.
.TONIGHT...Southeast winds 5 to 15 knots veering south after
midnight, then backing southeast late. A slight chance of showers
through midnight. Waves calm to 2 feet.
.TUESDAY...Southeast winds 5 to 15 knots backing east in the
afternoon. Waves building to 1 to 3 feet.
.TUESDAY NIGHT...Southeast winds 10 to 20 knots. A chance of
showers and a slight chance of thunderstorms after midnight.
Waves building to 2 to 4 feet.
.WEDNESDAY...South winds 15 to 25 knots becoming southwest 10 to
20 knots by mid afternoon. A chance of showers and thunderstorms.
Waves building to 3 to 5 feet occasionally to 7 feet, then
subsiding to 2 to 4 feet.
.WEDNESDAY NIGHT...West winds 5 to 15 knots becoming northwest
less than 10 knots after midnight. Waves subsiding to calm to
2 feet.
.THURSDAY...Southeast winds 5 to 15 knots. A chance of showers.
Waves calm to 2 feet.
.FRIDAY...South winds 5 to 15 knots increasing to 10 to 20 knots.
Waves building to 1 to 3 feet.

$$

LSZ264-181615-
Lake Superior from Upper Entrance to Portage Canal to Manitou
Island MI 5NM off shore to the US/Canadian Border-
402 AM EDT Mon Sep 18 2017

.EARLY THIS MORNING...Northwest winds 5 to 15 knots. Waves 2 to
4 feet subsiding to 1 to 3 feet.
.TODAY...West winds 5 to 15 knots backing south in the afternoon,
then backing southeast late. A slight chance of showers by mid
afternoon. Waves subsiding to calm to 2 feet.
.TONIGHT...Southeast winds 5 to 15 knots veering south after
midnight. A slight chance of showers through midnight. Waves
building to 1 to 3 feet, then subsiding to calm to 2 feet.
.TUESDAY...Southeast winds 5 to 15 knots. Waves building to 1 to
3 feet.
.TUESDAY NIGHT...Southeast winds 10 to 20 knots increasing to
15 to 25 knots after midnight. A slight chance of showers and
thunderstorms after midnight. Waves building to 3 to 5 feet
occasionally to 7 feet.
.WEDNESDAY...Southeast winds 15 to 25 knots veering south by mid
afternoon. A chance of showers and thunderstorms. Waves building
to 4 to 8 feet occasionally to 10 feet.
.WEDNESDAY NIGHT...Southwest winds 5 to 15 knots veering
northwest after midnight. A chance of showers through midnight.
Waves subsiding to calm to 2 feet.
.THURSDAY...Southeast winds 5 to 15 knots. A chance of showers.
Waves calm to 2 feet.
.FRIDAY...Southeast winds 5 to 15 knots becoming south 10 to
20 knots. A chance of showers. Waves building to 1 to 3 feet,
then subsiding to calm to 2 feet.

$$

LSZ265-181615-
Lake Superior West of Line from Manitou Island to Marquette MI
Beyond 5NM from shore-
402 AM EDT Mon Sep 18 2017

.EARLY THIS MORNING...North winds 5 to 15 knots. Waves 1 to
3 feet subsiding to calm to 2 feet.
.TODAY...South winds 5 to 15 knots backing southeast in the
afternoon, then increasing to 10 to 20 knots late. A slight
chance of showers by mid afternoon. Waves building to 1 to
3 feet.
.TONIGHT...Southeast winds 10 to 20 knots. A chance of showers.
Waves subsiding to calm to 2 feet.
.TUESDAY...Southeast winds 10 to 20 knots backing east late.
Waves building to 1 to 3 feet.
.TUESDAY NIGHT...Southeast winds 15 to 25 knots. A slight chance
of showers after midnight. Waves building to 3 to 5 feet
occasionally to 7 feet.
.WEDNESDAY...Southeast winds 20 to 30 knots becoming south 15 to
25 knots by mid afternoon. A chance of showers and thunderstorms.
Waves 3 to 6 feet occasionally to 8 feet.
.WEDNESDAY NIGHT...Southwest winds 10 to 20 knots becoming
northwest 5 to 15 knots after midnight. A chance of showers.
Waves subsiding to calm to 2 feet.
.THURSDAY...East winds 10 to 20 knots veering southeast. Waves
calm to 2 feet.
.FRIDAY...Southeast winds 10 to 20 knots veering south. A chance
of showers. Waves building to 1 to 3 feet.

$$

LSZ266-181615-
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-
402 AM EDT Mon Sep 18 2017

.EARLY THIS MORNING...North winds 10 to 20 knots. Waves 3 to
5 feet occasionally to 7 feet.
.TODAY...North winds 5 to 15 knots veering southeast in the
afternoon. A slight chance of showers by mid afternoon. Waves
subsiding to calm to 2 feet.
.TONIGHT...Southeast winds 10 to 20 knots. A chance of showers.
Waves building to 1 to 3 feet, then subsiding to calm to 2 feet.
.TUESDAY...Southeast winds 10 to 20 knots backing east late.
Waves building to 1 to 3 feet.
.TUESDAY NIGHT...Southeast winds 15 to 25 knots. Waves building
to 3 to 5 feet occasionally to 7 feet.
.WEDNESDAY...Southeast winds 20 to 30 knots veering south by mid
afternoon. A chance of showers and thunderstorms. Waves building
to 4 to 8 feet occasionally to 10 feet.
.WEDNESDAY NIGHT...South winds 10 to 20 knots becoming northwest
5 to 15 knots after midnight. Showers likely through midnight. A
chance of showers after midnight. Waves subsiding to calm to
2 feet.
.THURSDAY...North winds 5 to 15 knots becoming southeast 10 to
20 knots. Waves calm to 2 feet.
.FRIDAY...South winds 10 to 20 knots increasing to 15 to
25 knots. Waves building to 2 to 4 feet.

$$

LSZ267-181615-
Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off
shore to the US/Canadian border-
402 AM EDT Mon Sep 18 2017

.EARLY THIS MORNING...North winds 10 to 20 knots. Waves 3 to
5 feet occasionally to 7 feet.
.TODAY...North winds 5 to 15 knots. Waves subsiding to calm to
2 feet.
.TONIGHT...East winds 5 to 15 knots. A slight chance of showers
through midnight. Waves calm to 2 feet.
.TUESDAY...Southeast winds 10 to 20 knots backing east late.
Waves calm to 2 feet.
.TUESDAY NIGHT...Southeast winds 10 to 20 knots increasing to
15 to 25 knots after midnight. Waves building to 2 to 4 feet.
.WEDNESDAY...Southeast winds 20 to 30 knots. Waves building to
3 to 5 feet occasionally to 7 feet.
.WEDNESDAY NIGHT...South winds 15 to 25 knots diminishing to
10 to 20 knots after midnight. A chance of showers through
midnight. Showers likely after midnight. Waves subsiding to calm
to 2 feet.
.THURSDAY...South winds 10 to 20 knots backing southeast. Waves
calm to 2 feet.
.FRIDAY...South winds 10 to 20 knots. Waves calm to 2 feet.

$$

LSZ261-181615-
MAFOR 1809/
Superior West 11600 12410 11310 11210 11310 11410 11300. Waves 2
feet or less.

Superior North Central 11710 11600 12410 13310 11410. Waves 1 to
4 feet.

Superior South Central 11810 11100 11300 12320 13310. Chance of
showers this evening. Waves 1 to 3 feet.

Superior East 11810 11800 11100 12300 12310 11300. Waves 3 to 5
feet subsiding to 1 to 3 feet today. Waves 2 feet or less
tonight.

$$

Rolfson

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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