Great Lakes Forecast
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FZUS63 KMQT 181403
GLFLS

Open Lake Forecast for Lake Superior
National Weather Service Marquette MI
1003 AM EDT Fri Aug 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...Low pressure of 29.5 inches over Sault Saint Marie
will reach southwest Quebec tonight. High pressure of 29.9 inches
will reach the western Great Lakes and then expand southward over
the Ohio River Valley Saturday into Sunday. On Sunday afternoon a
29.8 inch trough moves into western Lake Superior and then tracks
east through Sunday night. This trough will stall out across the
Upper Great Lakes through Monday, followed by a 30.0 inch area of
high pressure dropping south across the Upper Mississippi Valley
on Tuesday.

LSZ162-182215-
Lake Superior west of a line from Saxon Harbor WI to Grand
Portage MN beyond 5NM-
1003 AM EDT Fri Aug 18 2017 /903 AM CDT Fri Aug 18 2017/

.REST OF TODAY...Northwest winds 5 to 15 knots backing west in
the afternoon. Waves 2 to 4 feet subsiding to calm to 2 feet.
.TONIGHT...West winds 5 to 15 knots. A slight chance of showers
and isolated thunderstorms through midnight. Waves calm to
2 feet.
.SATURDAY...West winds 10 to 20 knots backing southwest in the
afternoon. Waves calm to 2 feet.
.SATURDAY NIGHT...Southwest winds 10 to 20 knots. Waves calm to
2 feet.
.SUNDAY...Southwest winds 10 to 20 knots. Waves building to 1 to
3 feet, then subsiding to calm to 2 feet.
.SUNDAY NIGHT...West winds 5 to 15 knots veering northwest after
midnight. A chance of showers. Waves calm to 2 feet.
.MONDAY...Northeast winds 5 to 15 knots backing north. Waves calm
to 2 feet.
.TUESDAY...Northwest winds 10 to 20 knots. Waves calm to 2 feet.

$$

LSZ263-182215-
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-
1003 AM EDT Fri Aug 18 2017

.REST OF TODAY...Northwest winds 10 to 20 knots backing west in
the afternoon, then diminishing to 5 to 15 knots late. Waves 3 to
5 feet occasionally to 7 feet subsiding to 1 to 3 feet.
.TONIGHT...West winds 5 to 15 knots. A slight chance of showers
through midnight. Waves subsiding to calm to 2 feet.
.SATURDAY...West winds 5 to 15 knots backing southwest in the
afternoon. Waves building to 1 to 3 feet.
.SATURDAY NIGHT...Southwest winds 5 to 15 knots. Waves subsiding
to calm to 2 feet, then building to 1 to 3 feet.
.SUNDAY...Southwest winds 5 to 15 knots increasing to 10 to
20 knots by mid afternoon. Waves 1 to 3 feet.
.SUNDAY NIGHT...West winds 5 to 15 knots. A chance of showers.
Waves subsiding to calm to 2 feet.
.MONDAY...Northeast winds 5 to 15 knots backing northwest. Waves
calm to 2 feet.
.TUESDAY...Northwest winds 5 to 15 knots. Waves calm to 2 feet.

$$

LSZ264-182215-
Lake Superior from Upper Entrance to Portage Canal to Manitou
Island MI 5NM off shore to the US/Canadian Border-
1003 AM EDT Fri Aug 18 2017

.REST OF TODAY...Northwest winds 15 to 25 knots diminishing to
10 to 20 knots late. Patchy fog by late morning. Waves 3 to
6 feet occasionally to 8 feet subsiding to 2 to 4 feet.
.TONIGHT...West winds 10 to 20 knots diminishing to 5 to 15 knots
after midnight. A slight chance of showers through midnight.
Waves subsiding to calm to 2 feet.
.SATURDAY...West winds 5 to 15 knots backing southwest in the
afternoon. Waves building to 1 to 3 feet.
.SATURDAY NIGHT...Southwest winds 5 to 15 knots. Waves 1 to
3 feet.
.SUNDAY...Southwest winds 5 to 15 knots. Waves 1 to 3 feet.
.SUNDAY NIGHT...West winds 5 to 15 knots. Waves subsiding to calm
to 2 feet.
.MONDAY...Southwest winds 5 to 15 knots veering west. Waves calm
to 2 feet.
.TUESDAY...West winds 5 to 15 knots veering northwest. A chance
of showers. Waves calm to 2 feet.

$$

LSZ265-182215-
Lake Superior West of Line from Manitou Island to Marquette MI
Beyond 5NM from shore-
1003 AM EDT Fri Aug 18 2017

.REST OF TODAY...Northwest winds 20 to 30 knots diminishing to
15 to 25 knots late. Isolated showers by late morning. Patchy
fog. Waves 4 to 7 feet occasionally to 9 feet subsiding to 3 to
5 feet occasionally to 7 feet.
.TONIGHT...Northwest winds 10 to 20 knots backing west after
midnight. A slight chance of showers through midnight. Waves
subsiding to calm to 2 feet.
.SATURDAY...West winds 5 to 15 knots increasing to 10 to 20 knots
late. Waves calm to 2 feet.
.SATURDAY NIGHT...Southwest winds 10 to 20 knots. Waves calm to
2 feet.
.SUNDAY...Southwest winds 10 to 20 knots backing south by mid
afternoon. A chance of showers by mid afternoon. Waves calm to
2 feet.
.SUNDAY NIGHT...Southwest winds 10 to 20 knots becoming west 5 to
15 knots after midnight. A chance of showers. Waves calm to
2 feet.
.MONDAY...West winds 5 to 15 knots. Waves calm to 2 feet.
.TUESDAY...North winds 10 to 20 knots backing northwest. A chance
of showers. Waves calm to 2 feet.

$$

LSZ266-182215-
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-
1003 AM EDT Fri Aug 18 2017

.REST OF TODAY...Northwest winds 20 to 30 knots. A few gale force
gusts to 35 knots through early afternoon. Patchy fog. Scattered
showers. Waves 4 to 8 feet occasionally to 10 feet.
.TONIGHT...Northwest winds 10 to 20 knots backing west late. A
slight chance of showers through midnight. Waves subsiding to
1 to 3 feet.
.SATURDAY...West winds 5 to 15 knots. Waves subsiding to calm to
2 feet, then building to 1 to 3 feet.
.SATURDAY NIGHT...Southwest winds 5 to 15 knots increasing to
10 to 20 knots after midnight. Waves 1 to 3 feet.
.SUNDAY...Southwest winds 10 to 20 knots backing south by mid
afternoon. Waves 1 to 3 feet.
.SUNDAY NIGHT...Southwest winds 10 to 20 knots becoming west 5 to
15 knots after midnight. A chance of showers. Waves subsiding to
calm to 2 feet, then building to 1 to 3 feet.
.MONDAY...West winds 5 to 15 knots. A chance of showers. Waves
calm to 2 feet.
.TUESDAY...North winds 10 to 20 knots backing northwest. A chance
of showers. Waves building to 1 to 3 feet.

$$

LSZ267-182215-
Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off
shore to the US/Canadian border-
1003 AM EDT Fri Aug 18 2017

.REST OF TODAY...Northwest winds 20 to 30 knots. A few gale force
gusts to 35 knots through early afternoon. Patchy fog. Scattered
showers. Waves 3 to 6 feet occasionally to 8 feet building to 5 to
8 feet occasionally to 10 feet.
.TONIGHT...Northwest winds 20 to 30 knots diminishing to 10 to
20 knots. A slight chance of showers through midnight. Patchy fog
after midnight. Waves subsiding to 1 to 3 feet.
.SATURDAY...West winds 10 to 20 knots diminishing to 5 to
15 knots late. Patchy fog through early afternoon. Waves
subsiding to calm to 2 feet.
.SATURDAY NIGHT...Southwest winds 5 to 15 knots. Waves calm to
2 feet.
.SUNDAY...Southwest winds 5 to 15 knots becoming south 10 to
20 knots by mid afternoon. Waves calm to 2 feet.
.SUNDAY NIGHT...South winds 10 to 20 knots becoming southwest
5 to 15 knots after midnight. A chance of showers. Waves calm to
2 feet.
.MONDAY...Southwest winds 5 to 15 knots veering north. A chance
of showers. Waves calm to 2 feet.
.TUESDAY...North winds 10 to 20 knots backing northwest. A chance
of showers. Waves calm to 2 feet.

$$
LSZ261-182215-
MAFOR 1815/
Superior West 13620 14610 11610. Waves 1 to 4 feet.

Superior North Central 12730 12720 11610 12600 11610. Patchy fog
morning. Waves 1 to 6 feet.

Superior South Central 12740 11730 11720 11710 13610. Patchy fog
through late afternoon. Waves 4 to 7 feet this afternoon. Waves 3
to 6 feet subsiding to 1 to 3 feet tonight and Saturday morning.

Superior East 14740 11730 11720 11710 11600. Patchy fog through
tonight. Scattered showers late this morning. Waves 3 to 6 feet
building to 4 to 7 feet this afternoon. Waves 4 to 7 feet
subsiding to 1 to 4 feet tonight and Saturday morning.

$$

Petro

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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