Great Lakes Forecast
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FZUS63 KMQT 202003
GLFLS

Open Lake Forecast for Lake Superior
National Weather Service Marquette MI
403 PM EDT Wed Sep 20 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...A 29.6 inch trough extending from western Lake
Superior to Iowa will weaken to 29.8 inches as it sweeps eastward,
passing across Lake Superior this evening. High pressure of 30.0
inch will shift in across the Upper Mississippi Valley tonight and
linger across the Upper Great Lakes through Thursday. Lake Superior
will then remain situated between a 30.1 inch ridge across the Lower
Great Lakes and a 29.7 inch trough over the Upper Mississippi Valley
Friday through Sunday. On Monday the trough axis shifts eastward
over the Upper Great Lakes.

LSZ162-210415-
Lake Superior west of a line from Saxon Harbor WI to Grand
Portage MN beyond 5NM-
403 PM EDT Wed Sep 20 2017 /303 PM CDT Wed Sep 20 2017/

.LATE THIS AFTERNOON...West winds 10 to 20 knots. Waves 2 to
4 feet.
.TONIGHT...West winds 5 to 15 knots becoming southwest less than
10 knots late. Waves subsiding to calm to 2 feet.
.THURSDAY...East winds 5 to 15 knots increasing to 10 to 20 knots
late. Isolated showers by mid afternoon. Waves building to 2 to
4 feet.
.THURSDAY NIGHT...East winds 10 to 20 knots. A chance of showers
and thunderstorms. Waves subsiding to calm to 2 feet.
.FRIDAY...East winds 5 to 15 knots becoming southeast 10 to
20 knots by mid afternoon. A chance of showers and thunderstorms.
Waves calm to 2 feet.
.FRIDAY NIGHT...South winds 10 to 20 knots veering southwest
after midnight. Waves building to 1 to 3 feet.
.SATURDAY...Southwest winds 10 to 20 knots becoming west 5 to
15 knots by mid afternoon. A chance of showers and thunderstorms.
Waves subsiding to calm to 2 feet.
.SATURDAY NIGHT...North winds 5 to 15 knots veering south after
midnight. A chance of showers and thunderstorms. Waves calm to
2 feet.
.SUNDAY...Southwest winds 10 to 20 knots backing northeast. A
chance of showers and thunderstorms. Waves calm to 2 feet.
.MONDAY...Northeast winds 10 to 20 knots veering east. A chance
of showers and thunderstorms. Waves building to 1 to 3 feet.

$$

LSZ263-210415-
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-
403 PM EDT Wed Sep 20 2017

.LATE THIS AFTERNOON...Southwest winds 10 to 20 knots. Scattered
showers and isolated thunderstorms. Waves 3 to 6 feet
occasionally to 8 feet.
.TONIGHT...West winds 10 to 20 knots diminishing to 5 to 15 knots
after midnight, then becoming north less than 10 knots late.
Patchy fog. Waves subsiding to calm to 2 feet.
.THURSDAY...East winds less than 10 knots increasing to 10 to
20 knots. Waves building to 1 to 3 feet.
.THURSDAY NIGHT...East winds 10 to 20 knots becoming southeast
5 to 15 knots after midnight, then veering south late. A chance
of showers and thunderstorms. Waves subsiding to calm to 2 feet.
.FRIDAY...South winds 5 to 15 knots backing southeast by mid
afternoon. A chance of showers and thunderstorms. Waves calm to
2 feet.
.FRIDAY NIGHT...South winds 5 to 15 knots veering southwest after
midnight. Waves building to 1 to 3 feet.
.SATURDAY...Southwest winds 5 to 15 knots. A chance of showers
and thunderstorms. Waves subsiding to calm to 2 feet.
.SATURDAY NIGHT...West winds 5 to 15 knots backing south after
midnight. A chance of showers and thunderstorms. Waves calm to
2 feet.
.SUNDAY...Southwest winds 5 to 15 knots backing south. A chance
of showers and thunderstorms. Waves calm to 2 feet.
.MONDAY...Northeast winds 5 to 15 knots veering east. A chance of
showers and thunderstorms. Waves building to 1 to 3 feet.

$$

LSZ264-210415-
Lake Superior from Upper Entrance to Portage Canal to Manitou
Island MI 5NM off shore to the US/Canadian Border-
403 PM EDT Wed Sep 20 2017

.LATE THIS AFTERNOON...South winds 15 to 25 knots. Scattered
showers and thunderstorms. Waves 4 to 8 feet occasionally to
10 feet.
.TONIGHT...West winds 5 to 15 knots veering northwest after
midnight, then becoming north less than 10 knots late. Isolated
showers through midnight. Patchy fog. Waves subsiding to 1 to
3 feet.
.THURSDAY...East winds less than 10 knots increasing to 5 to
15 knots in the afternoon. Patchy fog through early afternoon.
Waves subsiding to calm to 2 feet.
.THURSDAY NIGHT...Southeast winds 5 to 15 knots. A chance of
showers. A chance of thunderstorms after midnight. Waves calm to
2 feet.
.FRIDAY...South winds 5 to 15 knots. A chance of showers and
thunderstorms. Waves building to 1 to 3 feet.
.FRIDAY NIGHT...South winds 5 to 15 knots. A chance of showers
and thunderstorms. Waves 1 to 3 feet.
.SATURDAY...Southwest winds 5 to 15 knots. A chance of showers
and thunderstorms. Waves subsiding to calm to 2 feet.
.SATURDAY NIGHT...Southwest winds 5 to 15 knots backing south
after midnight. A chance of showers and thunderstorms. Waves calm
to 2 feet.
.SUNDAY...South winds 5 to 15 knots. A chance of showers and
thunderstorms. Waves calm to 2 feet.
.MONDAY...North winds 5 to 15 knots veering northeast. A chance
of showers and thunderstorms. Waves building to 1 to 3 feet.

$$

LSZ265-210415-
Lake Superior West of Line from Manitou Island to Marquette MI
Beyond 5NM from shore-
403 PM EDT Wed Sep 20 2017

.LATE THIS AFTERNOON...South winds 10 to 20 knots. Scattered
showers and thunderstorms. Waves 3 to 6 feet occasionally to
8 feet.
.TONIGHT...West winds 10 to 20 knots becoming northwest 5 to
15 knots after midnight, then veering north late. Scattered
showers and isolated thunderstorms through midnight. Patchy fog.
Waves subsiding to calm to 2 feet.
.THURSDAY...North winds 5 to 15 knots veering east in the
afternoon. Patchy fog through early afternoon. Waves calm to
2 feet.
.THURSDAY NIGHT...Southeast winds 10 to 20 knots veering south
late. A chance of showers and thunderstorms after midnight. Waves
calm to 2 feet.
.FRIDAY...South winds 10 to 20 knots. A slight chance of showers
and thunderstorms through early afternoon. Waves building to 1 to
3 feet.
.FRIDAY NIGHT...South winds 10 to 20 knots. A chance of showers
and thunderstorms after midnight. Waves 1 to 3 feet.
.SATURDAY...South winds 10 to 20 knots diminishing to 5 to
15 knots by mid afternoon. Waves subsiding to calm to 2 feet.
.SATURDAY NIGHT...South winds 10 to 20 knots. Waves calm to
2 feet.
.SUNDAY...Southwest winds 10 to 20 knots. Waves calm to 2 feet.
.MONDAY...East winds 10 to 20 knots. A chance of showers and
thunderstorms. Waves calm to 2 feet.

$$

LSZ266-210415-
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-
403 PM EDT Wed Sep 20 2017

.LATE THIS AFTERNOON...South winds 15 to 25 knots. Scattered
showers and thunderstorms. Waves 4 to 8 feet occasionally to
10 feet.
.TONIGHT...South winds 10 to 20 knots veering northwest after
midnight, then becoming north 5 to 15 knots late. Scattered
showers and thunderstorms through midnight. Patchy fog. Waves
subsiding to 1 to 3 feet.
.THURSDAY...North winds 5 to 15 knots veering east late. Patchy
fog through early afternoon. Waves subsiding to calm to 2 feet.
.THURSDAY NIGHT...Southeast winds 10 to 20 knots veering south
late. A chance of showers and thunderstorms after midnight. Waves
calm to 2 feet.
.FRIDAY...South winds 10 to 20 knots. A chance of showers and
thunderstorms. Waves building to 1 to 3 feet.
.FRIDAY NIGHT...South winds 15 to 25 knots diminishing to 10 to
20 knots after midnight. A chance of showers and thunderstorms.
Waves building to 2 to 4 feet.
.SATURDAY...South winds 10 to 20 knots diminishing to 5 to
15 knots by mid afternoon. Waves subsiding to calm to 2 feet.
.SATURDAY NIGHT...South winds 10 to 20 knots. Waves calm to
2 feet.
.SUNDAY...South winds 10 to 20 knots. Waves building to 1 to
3 feet, then subsiding to calm to 2 feet.
.MONDAY...South winds 10 to 20 knots backing east. A chance of
showers and thunderstorms. Waves building to 1 to 3 feet.

$$

LSZ267-210415-
Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off
shore to the US/Canadian border-
403 PM EDT Wed Sep 20 2017

.LATE THIS AFTERNOON...Southeast winds 15 to 25 knots. Waves 3 to
6 feet occasionally to 8 feet.
.TONIGHT...Southeast winds 10 to 20 knots veering south after
midnight, then becoming northwest 5 to 15 knots late. Patchy fog.
Numerous showers through midnight. Scattered thunderstorms.
Isolated showers after midnight. Waves subsiding to calm to
2 feet.
.THURSDAY...North winds 5 to 15 knots becoming northeast less
than 10 knots in the afternoon, then veering east late. Patchy
fog through early afternoon. Waves calm to 2 feet.
.THURSDAY NIGHT...East winds 10 to 20 knots veering south late. A
chance of showers and thunderstorms after midnight. Waves calm to
2 feet.
.FRIDAY...South winds 10 to 20 knots. A chance of showers and
thunderstorms. Waves building to 1 to 3 feet.
.FRIDAY NIGHT...South winds 15 to 25 knots diminishing to 10 to
20 knots after midnight. A chance of showers and thunderstorms.
Waves 1 to 3 feet.
.SATURDAY...South winds 10 to 20 knots. Waves subsiding to calm
to 2 feet.
.SATURDAY NIGHT...South winds 10 to 20 knots veering southwest
after midnight. Waves calm to 2 feet.
.SUNDAY...South winds 10 to 20 knots. Waves calm to 2 feet.
.MONDAY...South winds 5 to 15 knots becoming southeast 10 to
20 knots. Waves calm to 2 feet.

$$

LSZ261-210415-
MAFOR 2021/
Superior West 11520 11620 11610 11600 11400 12200 11210. Waves 2
to 4 feet subsiding to 1 to 3 feet tonight and Thursday.

Superior North Central 11440 11520 11710 11700 11800 11100 12200.
Patchy fog late this evening through Thursday morning. Scattered
showers and thunderstorms this evening. Waves 5 to 8 feet
subsiding to 1 to 3 feet tonight and Thursday.

Superior South Central 11430 11520 11610 11710 12800 11100 11200.
Patchy fog late this evening through Thursday morning. Scattered
showers and thunderstorms through late this evening. Waves 3 to 5
feet subsiding to 1 to 3 feet tonight. Waves 1 foot or less
Thursday.

Superior East 11420 11426 11526 11710 12810 12100. Patchy fog
from late this evening through Thursday morning. Scattered
showers and thunderstorms through late tonight. Waves 3 to 6
feet subsiding to 1 to 3 feet tonight and Thursday.

$$

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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