Great Lakes Forecast
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519
FZUS63 KMQT 220757
GLFLS

Open Lake Forecast for Lake Superior
National Weather Service Marquette MI
357 AM EDT Sun Oct 22 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 29.8 inch trough will sweep across Lake Superior
today and then dissipate as it continues eastward tonight. A new
low pressure trough of 29.8 inches moving across south central
Canada and the Northern Plains tonight will reach central Lake
Superior Monday afternoon. The trough will then give way to low
pressure of 29.5 inches organizing over the Ohio Valley on Monday.
This low will deepen to 29.1 inches as it lifts north to near
Drummond Island by Tuesday morning. As the low then weakens to
29.3 inches while tracking toward James Bay Tuesday night, a 29.5
inch trough will linger back across the Upper Great Lakes. The
trough will drop south on Wednesday as a high pressure ridge of
29.9 inches builds southeast into northern Ontario. A 29.7 inch
trough will then move out across the Plains States on Thursday.

LSZ162-221600-
Lake Superior west of a line from Saxon Harbor WI to Grand
Portage MN beyond 5NM-
357 AM EDT Sun Oct 22 2017 /257 AM CDT Sun Oct 22 2017/

.EARLY THIS MORNING...Southwest winds 15 to 25 knots. Isolated
showers. Waves 2 to 4 feet building to 3 to 5 feet occasionally
to 7 feet.
.TODAY...West winds 20 to 30 knots becoming southwest 15 to
25 knots late. Isolated showers through early afternoon. Waves
building to 3 to 6 feet occasionally to 8 feet.
.TONIGHT...Southwest winds 15 to 25 knots increasing to 20 to
30 knots after midnight. Isolated showers late. Waves subsiding
to 2 to 4 feet, then building to 3 to 5 feet occasionally to 7
feet.
.MONDAY...Southwest winds 15 to 25 knots veering west late. A
slight chance of showers. Waves subsiding to 2 to 4 feet.
.MONDAY NIGHT...Northwest winds 20 to 30 knots becoming north
gales to 35 knots after midnight. A chance of showers. Waves
building to 5 to 8 feet occasionally to 10 feet.
.TUESDAY...North gales to 35 knots diminishing to 20 to 30 knots
by mid afternoon. A chance of rain showers. Waves building to
6 to 9 feet occasionally to 11 feet, then subsiding to 4 to
7 feet occasionally to 9 feet.
.TUESDAY NIGHT...Northwest winds 20 to 30 knots diminishing to
10 to 20 knots after midnight. A chance of rain showers after
midnight. Waves subsiding to calm to 2 feet.
.WEDNESDAY...North winds 10 to 20 knots veering southeast. A
chance of rain showers. Waves building to 1 to 3 feet.
.THURSDAY...Southeast winds 15 to 25 knots becoming northwest
20 to 30 knots. A chance of rain showers. Waves building to 3 to
6 feet occasionally to 8 feet.

$$

LSZ263-221600-
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-
357 AM EDT Sun Oct 22 2017

.EARLY THIS MORNING...Southwest winds 15 to 25 knots. Scattered
showers. Waves 2 to 4 feet building to 3 to 5 feet occasionally
to 7 feet.
.TODAY...West winds 20 to 30 knots becoming southwest 15 to
25 knots late. Scattered showers. Waves building to 4 to 8 feet
occasionally to 10 feet.
.TONIGHT...Southwest winds 10 to 20 knots increasing to 15 to
25 knots after midnight. Waves subsiding to 3 to 5 feet
occasionally to 7 feet.
.MONDAY...Southwest winds 15 to 25 knots diminishing to 10 to
20 knots in the afternoon, then veering west late. A chance of
showers. Waves subsiding to 2 to 4 feet.
.MONDAY NIGHT...Northwest winds 15 to 25 knots becoming north
gales to 35 knots after midnight. A chance of showers. Waves
building to 5 to 8 feet occasionally to 10 feet.
.TUESDAY...North gales to 40 knots. A chance of rain showers.
Waves building to 7 to 11 feet occasionally to 14 feet.
.TUESDAY NIGHT...North winds 20 to 30 knots diminishing to 10 to
20 knots after midnight. Waves subsiding to 2 to 4 feet.
.WEDNESDAY...North winds 5 to 15 knots veering southeast. Waves
subsiding to calm to 2 feet.
.THURSDAY...Southeast winds 15 to 25 knots becoming north 20 to
30 knots. Rain showers. Waves building to 4 to 7 feet
occasionally to 9 feet.

$$

LSZ264-221600-
Lake Superior from Upper Entrance to Portage Canal to Manitou
Island MI 5NM off shore to the US/Canadian Border-
357 AM EDT Sun Oct 22 2017

.EARLY THIS MORNING...South winds 15 to 25 knots. Scattered
showers. Waves 3 to 6 feet occasionally to 8 feet.
.TODAY...Southwest winds 20 to 30 knots veering west in the
afternoon, then becoming southwest 15 to 25 knots late. Scattered
showers. Waves building to 4 to 8 feet occasionally to 10 feet.
.TONIGHT...Southwest winds 10 to 20 knots. Waves subsiding to
3 to 5 feet occasionally to 7 feet.
.MONDAY...South winds 10 to 20 knots veering southwest in the
afternoon. A chance of showers. Waves subsiding to 2 to 4 feet.
.MONDAY NIGHT...West winds 10 to 20 knots becoming north gales to
35 knots after midnight. A slight chance of showers through
midnight, then showers likely after midnight. Waves building to
4 to 7 feet occasionally to 9 feet.
.TUESDAY...North gales to 40 knots. Showers. Waves building to
10 to 14 feet occasionally to 18 feet.
.TUESDAY NIGHT...North gales to 35 knots diminishing to 15 to
25 knots after midnight. A chance of rain showers. Waves
subsiding to 3 to 5 feet occasionally to 7 feet.
.WEDNESDAY...North winds 10 to 20 knots veering east. Waves
subsiding to calm to 2 feet.
.THURSDAY...Southeast winds 15 to 25 knots backing east. A chance
of rain showers, then rain showers. Waves building to 4 to 7 feet
occasionally to 9 feet.

$$

LSZ265-221600-
Lake Superior West of Line from Manitou Island to Marquette MI
Beyond 5NM from shore-
357 AM EDT Sun Oct 22 2017

.EARLY THIS MORNING...South winds 15 to 25 knots. Scattered
showers. Waves 3 to 5 feet occasionally to 7 feet.
.TODAY...West winds 10 to 20 knots. Scattered showers. Waves
subsiding to 1 to 3 feet.
.TONIGHT...Southwest winds 10 to 20 knots. Waves 1 to 3 feet.
.MONDAY...South winds 15 to 25 knots diminishing to 10 to
20 knots in the afternoon, then veering west late. A slight
chance of showers by mid afternoon. Waves subsiding to calm to
2 feet.
.MONDAY NIGHT...West winds 10 to 20 knots becoming northwest
15 to 25 knots after midnight. A slight chance of showers through
midnight, then showers likely after midnight. Waves building to
2 to 4 feet.
.TUESDAY...North gales to 40 knots. Showers. Waves building to
11 to 15 feet occasionally to 19 feet.
.TUESDAY NIGHT...North gales to 40 knots diminishing to 15 to
25 knots after midnight. Rain showers likely through midnight,
then a chance of rain showers after midnight. Waves subsiding to
4 to 7 feet occasionally to 9 feet.
.WEDNESDAY...North winds 10 to 20 knots veering northeast. Waves
subsiding to calm to 2 feet.
.THURSDAY...Southeast winds 15 to 25 knots increasing to 20 to
30 knots. A chance of rain showers, then rain showers likely.
Waves building to 4 to 7 feet occasionally to 9 feet.

$$

LSZ266-221600-
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-
357 AM EDT Sun Oct 22 2017

.EARLY THIS MORNING...South winds 20 to 30 knots. Isolated
showers. Waves 3 to 6 feet occasionally to 8 feet.
.TODAY...South winds 15 to 25 knots veering west in the
afternoon. Scattered showers through early afternoon, then
numerous showers by mid afternoon. Waves building to 4 to 8 feet
occasionally to 10 feet.
.TONIGHT...Southwest winds 10 to 20 knots increasing to 15 to
25 knots late. Isolated showers through midnight. Waves subsiding
to 2 to 4 feet.
.MONDAY...South winds 15 to 25 knots becoming southwest 10 to
20 knots late. A slight chance of showers by mid afternoon. Waves
subsiding to 1 to 3 feet.
.MONDAY NIGHT...West winds 10 to 20 knots becoming north 15 to
25 knots after midnight. A chance of showers through midnight,
then showers after midnight. Waves building to 2 to 4 feet.
.TUESDAY...North gales to 40 knots. Showers. Waves building to
11 to 15 feet occasionally to 19 feet.
.TUESDAY NIGHT...North gales to 40 knots diminishing to 20 to
30 knots after midnight. Rain showers likely through midnight,
then a chance of rain showers after midnight. Waves subsiding to
4 to 7 feet occasionally to 9 feet.
.WEDNESDAY...North winds 15 to 25 knots becoming northeast 10 to
20 knots. Waves subsiding to calm to 2 feet.
.THURSDAY...Southeast winds 15 to 25 knots increasing to 20 to
30 knots. A chance of rain showers, then rain showers likely.
Waves building to 4 to 8 feet occasionally to 10 feet.

$$

LSZ267-221600-
Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off
shore to the US/Canadian border-
357 AM EDT Sun Oct 22 2017

.EARLY THIS MORNING...South winds 20 to 30 knots. Waves 2 to
4 feet building to 3 to 5 feet occasionally to 7 feet.
.TODAY...South winds 20 to 30 knots becoming west 15 to 25 knots
in the afternoon, then diminishing to 10 to 20 knots late.
Scattered showers through early afternoon, then showers by mid
afternoon. Waves subsiding to 1 to 3 feet.
.TONIGHT...Southwest winds 10 to 20 knots. Scattered showers
through midnight. Waves 1 to 3 feet.
.MONDAY...South winds 10 to 20 knots. A slight chance of showers
by mid afternoon. Waves 1 to 3 feet.
.MONDAY NIGHT...Southwest winds 10 to 20 knots veering north
after midnight. A chance of showers through midnight, then
showers after midnight. Waves subsiding to calm to 2 feet.
.TUESDAY...North winds 20 to 30 knots increasing to gales to
35 knots by mid afternoon. Showers. Waves building to 7 to
10 feet occasionally to 13 feet.
.TUESDAY NIGHT...North winds 20 to 30 knots. Rain showers through
midnight, then a chance of rain showers after midnight. Waves
building to 8 to 11 feet occasionally to 14 feet, then subsiding
to 3 to 6 feet occasionally to 8 feet.
.WEDNESDAY...North winds 15 to 25 knots diminishing to 10 to
20 knots. A chance of rain showers. Waves subsiding to calm to
2 feet.
.THURSDAY...Southeast winds 15 to 25 knots increasing to 20 to
30 knots. A chance of rain showers. Waves building to 4 to 7 feet
occasionally to 9 feet, then subsiding to 3 to 6 feet
occasionally to 8 feet.

$$

LSZ261-221600-
MAFOR 2209/
Superior West 11530 11540 11640 12530 11520 12530. Scattered
showers early this morning. Waves 3 to 7 feet.

Superior North Central 11430 11530 12640 12530 12520. Scattered
showers through early afternoon today. Waves 3 to 8 feet.

Superior South Central 11430 11530 12636 14520. Scattered showers
through mid morning and also late today. Waves 1 to 5 feet.

Superior East 12430 11536 12626 12520 11510. Scattered showers
late this morning. Waves 2 to 6 feet.

$$

Rolfson

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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