Great Lakes Forecast
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FZUS63 KMQT 172009
GLFLS

Open Lake Forecast for Lake Superior
National Weather Service Marquette MI
409 PM 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 northwest Wisconsin
will cross the Upper Great Lakes tonight 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. On Sunday afternoon a
29.9 inch trough moves into western Lake Superior and then tracks
east through Sunday night. A 30.1 inch high pressure ridge
follows on Monday. A 29.8 inch low moves across the Upper Great
Lakes on Tuesday.

LSZ162-180415-
Lake Superior west of a line from Saxon Harbor WI to Grand
Portage MN beyond 5NM-
409 PM EDT Thu Aug 17 2017 /309 PM CDT Thu Aug 17 2017/

.LATE THIS AFTERNOON...North winds 15 to 25 knots. Patchy fog.
Scattered showers and isolated thunderstorms. Waves 3 to 5 feet
occasionally to 7 feet.
.TONIGHT...North winds 15 to 25 knots backing northwest after
midnight. Patchy fog through midnight. A slight chance of showers
through midnight. Waves building to 3 to 6 feet occasionally to
8 feet, then subsiding to 2 to 4 feet.
.FRIDAY...Northwest winds 10 to 20 knots backing west in the
afternoon. Waves subsiding to calm to 2 feet.
.FRIDAY NIGHT...West winds 5 to 15 knots. A chance of showers
through midnight. 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. Waves calm to 2 feet.
.SUNDAY NIGHT...West winds 5 to 15 knots. A chance of showers.
Waves calm to 2 feet.
.MONDAY...East winds 5 to 15 knots backing northwest. A chance of
showers. Waves calm to 2 feet.
.TUESDAY...West winds 5 to 15 knots becoming northwest 10 to
20 knots. Waves calm to 2 feet.

$$

LSZ263-180415-
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-
409 PM EDT Thu Aug 17 2017

.LATE THIS AFTERNOON...Northeast winds 15 to 25 knots. Patchy
fog. Scattered showers and thunderstorms. Waves 4 to 8 feet
occasionally to 10 feet.
.TONIGHT...North winds 15 to 25 knots backing northwest late.
Patchy fog. A slight chance of thunderstorms through midnight. A
chance of showers. Waves subsiding to 3 to 5 feet occasionally to
7 feet.
.FRIDAY...Northwest winds 15 to 25 knots becoming west 10 to
20 knots in the afternoon, then diminishing to 5 to 15 knots
late. Waves subsiding to 1 to 3 feet.
.FRIDAY NIGHT...West winds 5 to 15 knots. Waves subsiding to calm
to 2 feet.
.SATURDAY...West winds 5 to 15 knots backing southwest by mid
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 increasing to 10 to
20 knots by mid afternoon. Waves subsiding to calm to 2 feet.
.SUNDAY NIGHT...West winds 5 to 15 knots. A chance of
thunderstorms through midnight. A chance of showers. Waves calm
to 2 feet.
.MONDAY...West winds 5 to 15 knots. Waves calm to 2 feet.
.TUESDAY...West winds 5 to 15 knots veering northwest. Waves calm
to 2 feet.

$$

LSZ264-180415-
Lake Superior from Upper Entrance to Portage Canal to Manitou
Island MI 5NM off shore to the US/Canadian Border-
409 PM EDT Thu Aug 17 2017

.LATE THIS AFTERNOON...East winds 15 to 25 knots. Patchy fog.
Numerous showers and scattered thunderstorms. Waves 5 to 8 feet
occasionally to 10 feet.
.TONIGHT...Northeast winds 15 to 25 knots becoming north 10 to
20 knots after midnight, then increasing to 15 to 25 knots late.
Patchy fog. Showers likely and a slight chance of thunderstorms
through midnight. A chance of showers after midnight. Waves
subsiding to 3 to 5 feet occasionally to 7 feet.
.FRIDAY...Northwest winds 15 to 25 knots diminishing to 10 to
20 knots late. Patchy fog through early afternoon. A slight
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 backing southwest by mid
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. A chance of showers and
thunderstorms by mid afternoon. Waves 1 to 3 feet.
.SUNDAY NIGHT...Southwest winds 5 to 15 knots veering west after
midnight. A chance of thunderstorms through midnight. A chance of
showers. Waves subsiding to calm to 2 feet.
.MONDAY...Southwest winds 5 to 15 knots. Waves calm to 2 feet.
.TUESDAY...West winds 5 to 15 knots veering northwest. Waves
building to 1 to 3 feet.

$$

LSZ265-180415-
Lake Superior West of Line from Manitou Island to Marquette MI
Beyond 5NM from shore-
409 PM EDT Thu Aug 17 2017

.LATE THIS AFTERNOON...East winds 10 to 20 knots. Widespread fog.
Numerous showers and scattered thunderstorms. Waves 4 to 7 feet
occasionally to 9 feet subsiding to 3 to 6 feet occasionally to
8 feet.
.TONIGHT...East winds 5 to 15 knots becoming north 10 to 20 knots
after midnight, then becoming northwest 20 to 30 knots late.
Areas of fog. Showers likely and a slight chance of thunderstorms
through midnight. A chance of showers after midnight. Waves
subsiding to 2 to 4 feet, then building to 3 to 5 feet
occasionally to 7 feet.
.FRIDAY...Northwest winds 20 to 30 knots diminishing to 15 to
25 knots late. Patchy fog through early afternoon. A slight
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...Northwest winds 10 to 20 knots backing west after
midnight. Waves subsiding to calm to 2 feet.
.SATURDAY...West winds 10 to 20 knots. 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...Southwest winds 10 to 20 knots backing south by mid
afternoon. A chance of showers and thunderstorms by mid
afternoon. Waves calm to 2 feet.
.SUNDAY NIGHT...Southwest winds 10 to 20 knots veering west after
midnight. A chance of thunderstorms through midnight. A chance of
showers. Waves calm to 2 feet.
.MONDAY...Southwest winds 10 to 20 knots veering west. A chance
of showers and thunderstorms. Waves calm to 2 feet.
.TUESDAY...West winds 10 to 20 knots. Waves calm to 2 feet.

$$

LSZ266-180415-
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-
409 PM EDT Thu Aug 17 2017

.LATE THIS AFTERNOON...Southeast winds 15 to 25 knots. Patchy
fog. Scattered showers and thunderstorms. Waves 4 to 8 feet
occasionally to 10 feet.
.TONIGHT...East winds 10 to 20 knots becoming north 15 to
25 knots 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...Northwest winds 15 to 25 knots increasing to 20 to
30 knots in the afternoon, then diminishing to 15 to 25 knots
late. Patchy fog through early afternoon. A slight chance of
showers through early afternoon. Waves 3 to 6 feet occasionally
to 8 feet.
.FRIDAY NIGHT...Northwest winds 15 to 25 knots diminishing to
10 to 20 knots after midnight, then backing west late. 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. A chance of showers and thunderstorms by mid
afternoon. Waves subsiding to calm to 2 feet.
.SUNDAY NIGHT...Southwest winds 10 to 20 knots. A chance of
showers and thunderstorms. Waves calm to 2 feet.
.MONDAY...Southwest winds 10 to 20 knots veering west. A chance
of showers and thunderstorms. Waves calm to 2 feet.
.TUESDAY...West winds 10 to 20 knots veering northwest. A chance
of showers. Waves building to 1 to 3 feet, then subsiding to calm
to 2 feet.

$$

LSZ267-180415-
Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off
shore to the US/Canadian border-
409 PM EDT Thu Aug 17 2017

.LATE THIS AFTERNOON...Southeast winds 20 to 30 knots. Patchy
fog. Scattered showers and isolated thunderstorms. Waves 4 to
7 feet occasionally to 9 feet subsiding to 3 to 6 feet
occasionally to 8 feet.
.TONIGHT...Southeast winds 15 to 25 knots becoming east 10 to
20 knots after midnight, then becoming northeast 5 to 15 knots
late. Patchy fog. A chance of showers and a slight chance of
thunderstorms. Waves subsiding to calm to 2 feet.
.FRIDAY...Northwest winds 10 to 20 knots increasing to 20 to
30 knots. Patchy fog through early afternoon. 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 increasing to
10 to 20 knots after midnight. 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 veering southwest
after midnight. A chance of showers and thunderstorms. Waves
building to 1 to 3 feet, then subsiding to calm to 2 feet.
.MONDAY...Southwest winds 5 to 15 knots increasing to 10 to
20 knots. A chance of showers and thunderstorms. Waves calm to
2 feet.
.TUESDAY...West winds 10 to 20 knots veering northwest. A chance
of showers. Waves building to 1 to 3 feet, then subsiding to calm
to 2 feet.

$$

LSZ261-180415-
MAFOR 1721/
Superior West 12830 11730 13720 12620. Patchy fog this evening.
Scattered showers through this evening. Waves 1 to 5 feet.

Superior North Central 11236 12136 11820 11830 13730. Patchy fog
through late Friday morning. Scattered showers through late
tonight. Scattered thunderstorms through early this evening.
Waves 3 to 8 feet.

Superior South Central 11226 11216 11816 11723 11730 13740.
Patchy fog early this evening through mid Friday morning.
Scattered thunderstorms this evening. Chance of showers late
tonight through mid Friday morning. Waves 2 to 6 feet.

Superior East 11340 11330 11220 11213 11110 11830 12730. Patchy
fog this evening through Friday morning. Scattered showers through
Friday morning. Scattered thunderstorms through early this
evening. Waves 4 to 7 feet subsiding to 1 to 5 feet tonight and
Friday.

$$

JSS

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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