Great Lakes Forecast
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FZUS63 KMQT 200805
GLFLS

Open Lake Forecast for Lake Superior
National Weather Service Marquette MI
405 AM 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 29.4 inch trough over the northern High Plains will
weaken to 29.8 inches as it sweeps eastward, passing across Lake
Superior this afternoon and evening. High pressure of 30.0 inch
will slide in across the Upper Mississippi Valley tonight and
linger across the Upper Great Lakes through Thursday. Then, 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.

LSZ162-201615-
Lake Superior west of a line from Saxon Harbor WI to Grand
Portage MN beyond 5NM-
405 AM EDT Wed Sep 20 2017 /305 AM CDT Wed Sep 20 2017/

.EARLY THIS MORNING...Southeast winds 15 to 25 knots. Numerous
showers and scattered thunderstorms. Waves 2 to 4 feet.
.TODAY...Southeast winds 15 to 25 knots veering south in the
afternoon, then becoming southwest 10 to 20 knots late. Showers
and thunderstorms this afternoon. Waves building to 3 to 5 feet
occasionally to 7 feet, then subsiding to 2 to 4 feet.
.TONIGHT...West winds 5 to 15 knots backing southwest late. Waves
subsiding to calm to 2 feet.
.THURSDAY...Southeast winds 5 to 15 knots becoming east 10 to
20 knots in the afternoon. Areas of fog. Waves building to 1 to
3 feet.
.THURSDAY NIGHT...East winds 10 to 20 knots diminishing to 5 to
15 knots after midnight. Patchy fog through midnight. A chance of
showers and thunderstorms. Waves subsiding to calm to 2 feet.
.FRIDAY...Southeast winds 5 to 15 knots. A chance of showers and
thunderstorms. Waves calm to 2 feet.
.FRIDAY NIGHT...South winds 10 to 20 knots. A chance of showers
and thunderstorms. Waves calm to 2 feet.
.SATURDAY...Southwest winds 10 to 20 knots backing southeast. A
chance of showers and thunderstorms. Waves calm to 2 feet.
.SUNDAY...South winds 10 to 20 knots backing east. A chance of
showers and thunderstorms. Waves calm to 2 feet.

$$

LSZ263-201615-
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-
405 AM EDT Wed Sep 20 2017

.EARLY THIS MORNING...Southeast winds 15 to 25 knots. Scattered
showers and thunderstorms. Waves 2 to 4 feet.
.TODAY...Southeast winds 15 to 25 knots becoming south 20 to
30 knots in the afternoon, then becoming southwest 15 to 25 knots
late. Scattered showers and thunderstorms. Waves building to 5 to
8 feet occasionally to 10 feet, then subsiding to 3 to 5 feet
occasionally to 7 feet.
.TONIGHT...West winds 10 to 20 knots diminishing to 5 to 15 knots
after midnight, then becoming south less than 10 knots late.
Patchy fog. Waves subsiding to calm to 2 feet.
.THURSDAY...Southeast winds less than 10 knots becoming east 5 to
15 knots in the afternoon, then increasing to 10 to 20 knots
late. Areas of fog. Waves building to 1 to 3 feet.
.THURSDAY NIGHT...East winds 10 to 20 knots becoming southeast
5 to 15 knots after midnight. Areas of fog through midnight. A
chance of showers and thunderstorms. Waves subsiding to calm to
2 feet.
.FRIDAY...South winds 5 to 15 knots. A chance of showers and
thunderstorms. Waves calm to 2 feet.
.FRIDAY NIGHT...South winds 5 to 15 knots. A chance of showers
and thunderstorms. Waves calm to 2 feet.
.SATURDAY...Southwest winds 5 to 15 knots backing southeast. A
chance of showers and thunderstorms. Waves calm to 2 feet.
.SUNDAY...Southwest winds 5 to 15 knots backing east. A chance of
showers and thunderstorms. Waves calm to 2 feet.

$$

LSZ264-201615-
Lake Superior from Upper Entrance to Portage Canal to Manitou
Island MI 5NM off shore to the US/Canadian Border-
405 AM EDT Wed Sep 20 2017

.EARLY THIS MORNING...Southeast winds 15 to 25 knots. Isolated
showers. Waves 2 to 4 feet building to 3 to 5 feet occasionally
to 7 feet.
.TODAY...Southeast winds 20 to 30 knots veering south late.
Scattered showers and thunderstorms. Waves building to 6 to
9 feet occasionally to 11 feet, then subsiding to 4 to 7 feet
occasionally to 9 feet.
.TONIGHT...West winds 10 to 20 knots diminishing to 5 to 15 knots
after midnight, then becoming southwest less than 10 knots late.
Isolated showers and thunderstorms through midnight. Areas of
fog. Waves subsiding to calm to 2 feet.
.THURSDAY...Southeast winds less than 10 knots becoming east 5 to
15 knots in the afternoon. Areas of fog. Waves calm to 2 feet.
.THURSDAY NIGHT...Southeast winds 5 to 15 knots. Areas of fog. A
chance of showers. A chance of thunderstorms after midnight.
Waves building to 1 to 3 feet.
.FRIDAY...South winds 5 to 15 knots. A chance of showers and
thunderstorms through early afternoon. Waves subsiding to calm to
2 feet, then building to 1 to 3 feet.
.FRIDAY NIGHT...South winds 5 to 15 knots. A chance of showers
and thunderstorms. Waves building to 1 to 3 feet.
.SATURDAY...South winds 5 to 15 knots. A chance of showers and
thunderstorms. Waves subsiding to calm to 2 feet.
.SUNDAY...Southwest winds 5 to 15 knots backing northeast. A
chance of showers and thunderstorms. Waves calm to 2 feet.

$$

LSZ265-201615-
Lake Superior West of Line from Manitou Island to Marquette MI
Beyond 5NM from shore-
405 AM EDT Wed Sep 20 2017

.EARLY THIS MORNING...Southeast winds 15 to 25 knots. Waves 2 to
4 feet.
.TODAY...Southeast winds 20 to 30 knots veering south late.
Scattered showers and thunderstorms. Waves building to 3 to
6 feet occasionally to 8 feet.
.TONIGHT...West winds 5 to 15 knots veering north late. Scattered
showers and thunderstorms through midnight. Patchy fog. Waves
subsiding to calm to 2 feet.
.THURSDAY...East winds 5 to 15 knots increasing to 10 to 20 knots
late. Areas of fog. Waves calm to 2 feet.
.THURSDAY NIGHT...Southeast winds 10 to 20 knots. Areas of fog
through midnight. A chance of showers. A chance of thunderstorms
after midnight. Waves calm to 2 feet.
.FRIDAY...South winds 10 to 20 knots. Waves calm to 2 feet.
.FRIDAY NIGHT...South winds 10 to 20 knots. Waves calm to 2 feet.
.SATURDAY...South winds 10 to 20 knots. Waves calm to 2 feet.
.SUNDAY...South winds 10 to 20 knots. Waves calm to 2 feet.

$$

LSZ266-201615-
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-
405 AM EDT Wed Sep 20 2017

.EARLY THIS MORNING...Southeast winds 15 to 25 knots. Waves 2 to
4 feet.
.TODAY...Southeast winds 15 to 25 knots increasing to 20 to
30 knots in the afternoon, then veering south late. Scattered
showers and thunderstorms. Waves building to 4 to 8 feet
occasionally to 10 feet.
.TONIGHT...South winds 10 to 20 knots becoming northwest 5 to
15 knots after midnight, then veering north late. Scattered
showers and thunderstorms through midnight. Areas of fog. Waves
subsiding to calm to 2 feet.
.THURSDAY...North winds 5 to 15 knots veering east late. Areas of
fog. Waves calm to 2 feet.
.THURSDAY NIGHT...Southeast winds 10 to 20 knots veering south
after midnight. Patchy fog through midnight. A chance of showers.
A chance of thunderstorms after midnight. Waves calm to 2 feet.
.FRIDAY...South winds 10 to 20 knots. Waves building to 1 to
3 feet, then subsiding to calm to 2 feet.
.FRIDAY NIGHT...South winds 15 to 25 knots diminishing to 10 to
20 knots after midnight. Waves 1 to 3 feet.
.SATURDAY...South winds 10 to 20 knots. Waves subsiding to calm
to 2 feet, then building to 1 to 3 feet.
.SUNDAY...South winds 10 to 20 knots. Waves subsiding to calm to
2 feet.

$$

LSZ267-201615-
Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off
shore to the US/Canadian border-
405 AM EDT Wed Sep 20 2017

.EARLY THIS MORNING...Southeast winds 15 to 25 knots. Patchy fog.
Waves calm to 2 feet building to 1 to 3 feet.
.TODAY...Southeast winds 15 to 25 knots increasing to 20 to
30 knots in the afternoon, then diminishing to 15 to 25 knots
late. Scattered showers and isolated thunderstorms by mid
afternoon. Waves building to 3 to 5 feet occasionally to 7 feet.
.TONIGHT...South winds 15 to 25 knots becoming southwest 10 to
20 knots after midnight, then becoming north 5 to 15 knots late.
Areas of 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 veering northeast late.
Areas of fog. Waves calm to 2 feet.
.THURSDAY NIGHT...Southeast winds 10 to 20 knots. Patchy fog
through midnight. A chance of showers. A chance of thunderstorms
after midnight. Waves calm to 2 feet.
.FRIDAY...South winds 10 to 20 knots. Waves calm to 2 feet.
.FRIDAY NIGHT...South winds 10 to 20 knots. Waves building to
1 to 3 feet.
.SATURDAY...South winds 10 to 20 knots. Waves subsiding to calm
to 2 feet, then building to 1 to 3 feet.
.SUNDAY...South winds 10 to 20 knots. Waves subsiding to calm to
2 feet.

$$

LSZ261-201615-
MAFOR 2009/

Superior West 12336 11430 12520 11620 12600. Thunderstorms this
morning...then scattered showers and thunderstorms this
afternoon. Patchy fog late tonight. Waves 1 to 4 feet.

Superior North Central 14340 11440 11523 11613 11703. Scattered
showers late this morning...then scattered showers and
thunderstorms this afternoon through early evening. Waves 2 to 4
feet building to 5 to 9 feet today. Waves 5 to 8 feet subsiding to
2 to 4 feet tonight.

Superior South Central 11330 13340 11430 11520 11610 11700.
Scattered showers and thunderstorms late today and this evening.
Patchy fog late tonight. Waves 1 to 5 feet.

Superior East 14330 11330 11426 11526 11603. Patchy fog this
morning. Scattered showers and thunderstorms this evening and
tonight. Patchy fog late. Waves 2 to 5 feet.

$$

Ritzman

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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