Great Lakes Forecast
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FZUS63 KMQT 171359
GLFLS

Open Lake Forecast for Lake Superior
National Weather Service Marquette MI
959 AM EDT Thu Aug 17 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 western Wisconsin
will track across the Upper Great Lakes today and reach southwest
Quebec Friday night. In its wake, high pressure of 30.0 inches
will shift east to the western Great Lakes late Friday and then
expand over the Great Lakes region Saturday into Sunday.

LSZ162-172200-
Lake Superior west of a line from Saxon Harbor WI to Grand
Portage MN beyond 5NM-
959 AM EDT Thu Aug 17 2017 /859 AM CDT Thu Aug 17 2017/

.REST OF TODAY...Northeast winds 20 to 30 knots diminishing to
15 to 25 knots in the afternoon, then backing north late. Patchy
fog. Showers likely through early afternoon, then a chance of
showers. A chance of thunderstorms. Waves 5 to 8 feet
occasionally to 10 feet subsiding to 3 to 6 feet occasionally to 8
feet.
.TONIGHT...North winds 20 to 30 knots diminishing to 15 to
25 knots after midnight, then backing northwest late. Patchy fog.
A chance of showers. Waves subsiding to 2 to 4 feet.
.FRIDAY...Northwest winds 10 to 20 knots backing west in the
afternoon, then diminishing to 5 to 15 knots late. Waves
subsiding to calm to 2 feet.
.FRIDAY NIGHT...West winds 5 to 15 knots. Waves calm to 2 feet.
.SATURDAY...West winds 5 to 15 knots becoming southwest 10 to
20 knots by mid 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 diminishing to 5 to
15 knots. A chance of showers. Waves calm to 2 feet.
.MONDAY...Southwest winds 5 to 15 knots veering northwest. A
chance of showers and thunderstorms. Waves calm to 2 feet.

$$

LSZ263-172200-
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-
959 AM EDT Thu Aug 17 2017

.REST OF TODAY...East winds 15 to 25 knots backing northeast
late. Patchy fog. Showers likely through early afternoon, then a
chance of showers. A chance of thunderstorms. Waves 3 to 6 feet
occasionally to 8 feet building to 5 to 8 feet occasionally to 10
feet.
.TONIGHT...Northeast winds 15 to 25 knots backing north after
midnight. Patchy fog. A slight chance of thunderstorms through
midnight. A chance of showers. Waves building to 6 to 9 feet
occasionally to 11 feet, then subsiding to 3 to 6 feet
occasionally to 8 feet.
.FRIDAY...Northwest winds 10 to 20 knots backing west in the
afternoon, then diminishing to 5 to 15 knots late. A slight
chance of showers through early afternoon. Waves subsiding to
calm to 2 feet.
.FRIDAY NIGHT...West winds 5 to 15 knots. Waves calm to 2 feet.
.SATURDAY...West winds 5 to 15 knots backing southwest by mid
afternoon. Waves calm to 2 feet.
.SATURDAY NIGHT...Southwest winds 5 to 15 knots. Waves calm to
2 feet.
.SUNDAY...Southwest winds 5 to 15 knots. A chance of showers and
thunderstorms. Waves calm to 2 feet.
.MONDAY...Southwest winds 5 to 15 knots veering west. A chance of
showers. Waves calm to 2 feet.

$$

LSZ264-172200-
Lake Superior from Upper Entrance to Portage Canal to Manitou
Island MI 5NM off shore to the US/Canadian Border-
959 AM EDT Thu Aug 17 2017

.REST OF TODAY...East winds 20 to 30 knots. Patchy fog. Showers
likely and a chance of thunderstorms. Waves 3 to 5 feet
occasionally to 7 feet building to 6 to 9 feet occasionally to
11 feet.
.TONIGHT...East winds 15 to 25 knots becoming northeast 10 to
20 knots after midnight, then backing north late. Patchy fog.
Showers likely and a slight chance of thunderstorms through
midnight. A chance of showers after midnight. Waves subsiding to
3 to 6 feet occasionally to 8 feet.
.FRIDAY...North winds 10 to 20 knots backing northwest in the
afternoon. A chance of showers through early afternoon. Waves
subsiding to 2 to 4 feet.
.FRIDAY NIGHT...West winds 5 to 15 knots. Waves subsiding to calm
to 2 feet.
.SATURDAY...West winds 5 to 15 knots. Waves calm to 2 feet.
.SATURDAY NIGHT...Southwest winds 5 to 15 knots. Waves calm to
2 feet.
.SUNDAY...Southwest winds 5 to 15 knots. Waves building to 1 to
3 feet, then subsiding to calm to 2 feet.
.MONDAY...Southwest winds 5 to 15 knots. A chance of showers.
Waves calm to 2 feet.

$$

LSZ265-172200-
Lake Superior West of Line from Manitou Island to Marquette MI
Beyond 5NM from shore-
959 AM EDT Thu Aug 17 2017

.REST OF TODAY...East winds 20 to 30 knots diminishing to 10 to
20 knots. Patchy fog. Showers likely and a chance of
thunderstorms. Waves 5 to 8 feet occasionally to 10 feet.
.TONIGHT...East winds 5 to 15 knots becoming north 10 to 20 knots
after midnight, then increasing to 15 to 25 knots late. Patchy
fog. A slight chance of thunderstorms through midnight. Showers
likely. Waves subsiding to 3 to 5 feet occasionally to 7 feet.
.FRIDAY...Northwest winds 20 to 30 knots diminishing to 15 to
25 knots late. A chance of showers through early afternoon. Waves
building to 3 to 6 feet occasionally to 8 feet, then subsiding to
2 to 4 feet.
.FRIDAY NIGHT...West winds 10 to 20 knots. Waves subsiding to
calm to 2 feet.
.SATURDAY...West winds 10 to 20 knots diminishing to 5 to
15 knots by mid afternoon. Waves calm to 2 feet.
.SATURDAY NIGHT...Southwest winds 5 to 15 knots increasing to
10 to 20 knots after midnight. Waves calm to 2 feet.
.SUNDAY...South winds 10 to 20 knots veering southwest. A chance
of showers. Waves calm to 2 feet.
.MONDAY...Southwest winds 10 to 20 knots. A chance of showers and
thunderstorms. Waves calm to 2 feet.

$$

LSZ266-172200-
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-
959 AM EDT Thu Aug 17 2017

.REST OF TODAY...East winds 20 to 30 knots veering southeast in
the afternoon. Patchy fog. Showers likely and a chance of
thunderstorms. Waves to 6 to 9 feet occasionally to 11 feet,
then subsiding to 5 to 8 feet occasionally to 10 feet.
.TONIGHT...East winds 15 to 25 knots diminishing to 10 to
20 knots after midnight, then backing north late. Patchy fog. A
slight chance of thunderstorms through midnight. Showers likely.
Waves subsiding to 3 to 5 feet occasionally to 7 feet.
.FRIDAY...Northwest winds 15 to 25 knots increasing to 20 to
30 knots in the afternoon, then diminishing to 15 to 25 knots
late. A chance of showers through early afternoon. Waves building
to 4 to 7 feet occasionally to 9 feet, then subsiding to 3 to
6 feet occasionally to 8 feet.
.FRIDAY NIGHT...Northwest winds 10 to 20 knots backing west after
midnight. Waves subsiding to 1 to 3 feet.
.SATURDAY...West winds 10 to 20 knots diminishing to 5 to
15 knots by mid afternoon. Waves subsiding to calm to 2 feet.
.SATURDAY NIGHT...Southwest winds 5 to 15 knots increasing to
10 to 20 knots after midnight. Waves calm to 2 feet.
.SUNDAY...South winds 10 to 20 knots veering southwest. A chance
of showers. Waves building to 1 to 3 feet, then subsiding to calm
to 2 feet.
.MONDAY...Southwest winds 10 to 20 knots. A chance of showers and
thunderstorms. Waves calm to 2 feet.

$$

LSZ267-172200-
Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off
shore to the US/Canadian border-
959 AM EDT Thu Aug 17 2017

.REST OF TODAY...Southeast winds 20 to 30 knots. Patchy fog.
Showers and a slight chance of thunderstorms. Waves 4 to 7 feet
occasionally to 9 feet.
.TONIGHT...Southeast winds 15 to 25 knots becoming east 10 to
20 knots after midnight, then diminishing to 5 to 15 knots late.
Patchy fog. Showers likely and a slight chance of thunderstorms.
Waves subsiding to 1 to 3 feet.
.FRIDAY...Northwest winds 10 to 20 knots increasing to 20 to
30 knots. A chance of showers. Waves building to 3 to 6 feet
occasionally to 8 feet.
.FRIDAY NIGHT...Northwest winds 15 to 25 knots diminishing to
10 to 20 knots after midnight. A slight chance of showers through
midnight. Waves subsiding to 1 to 3 feet.
.SATURDAY...West winds 10 to 20 knots. Waves subsiding to calm to
2 feet.
.SATURDAY NIGHT...Southwest winds 5 to 15 knots. Waves calm to
2 feet.
.SUNDAY...South winds 5 to 15 knots becoming southwest 10 to
20 knots. A chance of showers. Waves building to 1 to 3 feet,
then subsiding to calm to 2 feet.
.MONDAY...Southwest winds 10 to 20 knots. A chance of showers and
thunderstorms. Waves calm to 2 feet.

$$
LSZ261-172200-
MAFOR 1715/
Superior West 11146 12130 13830 12720. Patchy fog. Chance of
thunderstorms early this afternoon. Chance of showers late this
afternoon through the early overnight. Waves 4 to 7 feet this
afternoon and tonight. Waves 3 to 5 feet Friday morning.

Superior North Central 13246 11236 11126 11120 11820 11730.
Patchy fog. Chance of thunderstorms late this afternoon. Chance
of thunderstorms tonight through Friday morning. Waves 5 to 8
feet this afternoon. Waves 5 to 9 feet tonight. Waves 4 to 6 feet
Friday morning.

Superior South Central 11246 11230 11226 12216 11826 11836 11730.
Patchy fog. Chance of showers and thunderstorms this afternoon.
Chance of thunderstorms through early evening. Chance of showers
tonight through Friday morning. Waves 3 to 6 feet building to 4
to 7 feet this afternoon. Waves 4 to 7 feet subsiding to 3 to 6
feet tonight. Waves 3 to 6 feet Friday morning.

Superior East 11346 11356 11346 11236 11226 11216 11116 11720.
Patchy fog. Chance of thunderstorms late this afternoon. Chance
of showers late Friday morning. Waves 5 to 8 feet this afternoon.
Waves 5 to 8 feet subsiding to 3 to 5 feet tonight. Waves 2 to 4
feet Friday 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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