Great Lakes Forecast
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565
FZUS63 KMQT 202055
GLFLS

Open Lake Forecast for Lake Superior
National Weather Service Marquette MI
355 PM EST Mon Nov 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 29.9 inch ridge of high pressure over the Lower
Great Lakes this evening will shift over New England tonight.
Meanwhile, a 29.2 inch low pressure over northwestern Ontario this
evening will deepen to 29.1 inches as it moves north of Lake
Superior tonight and reaches James Bay on Tuesday afternoon. A
30.4 inch high over the Northern Plains Tuesday evening will drift
south into the Central Plains Wednesday morning and weaken to
30.3 inches over the Ohio Valley on Wednesday night. On Thursday
morning, a 29.8 inch trough will settle south across the Upper
Great Lakes. A 30.0 inch ridge will move over the Upper Great
Lakes Thursday night and into the Lower Great Lakes on Friday
morning. A 29.0 inch low will move to Lake Winnipeg Friday morning
and track east across northern Ontario Friday evening. This low
will drag a 29.2 inch trough across Lake Superior on late Friday
night. A 30.0 inch ridge then builds into the Upper Great Lakes on
Saturday.

LSZ162-210500-
Lake Superior west of a line from Saxon Harbor WI to Grand
Portage MN beyond 5NM-
355 PM EST Mon Nov 20 2017 /255 PM CST Mon Nov 20 2017/

...GALE WARNING IN EFFECT FROM 10 PM EST /9 PM CST/ THIS EVENING
THROUGH TUESDAY AFTERNOON...

.LATE THIS AFTERNOON...Southwest winds 15 to 25 knots. Waves calm
to 2 feet.
.TONIGHT...Southwest winds 15 to 25 knots turning west and increasing
to gales to 40 knots by midnight. Isolated snow showers after
midnight. Waves building to 7 to 10 feet occasionally to 13 feet.
.TUESDAY...Northwest gales to 40 knots diminishing to 20 to
30 knots by mid afternoon. Scattered snow showers. Waves
subsiding to 4 to 7 feet occasionally to 9 feet.
.TUESDAY NIGHT...Northwest winds 20 to 30 knots diminishing to
15 to 25 knots by midnight, then backing west late. A slight
chance of snow showers in the evening. Waves subsiding to 1 to
3 feet.
.WEDNESDAY...West winds 10 to 20 knots backing southwest in the
afternoon. Waves building to 2 to 4 feet.
.WEDNESDAY NIGHT...Southwest winds 15 to 25 knots becoming west
10 to 20 knots after midnight. Waves building to 3 to 5 feet
occasionally to 7 feet, then subsiding to 2 to 4 feet.
.THURSDAY...West winds 10 to 20 knots diminishing to 5 to
15 knots in the afternoon. Waves subsiding to calm to 2 feet.
.THURSDAY NIGHT...West winds 5 to 15 knots becoming south 15 to
25 knots after midnight. Waves building to 1 to 3 feet.
.FRIDAY...Southwest winds 20 to 30 knots with a few gale force
gusts to 35 knots turning west late. A chance of rain showers,
possibly mixed with snow. Waves building to 3 to 6 feet
occasionally to 8 feet.
.SATURDAY...Northwest winds 20 to 30 knots diminishing to 15 to
25 knots. A chance of snow showers. Waves subsiding to 1 to
3 feet.

$$

LSZ263-210500-
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-
355 PM EST Mon Nov 20 2017

...GALE WARNING IN EFFECT FROM 10 PM EST THIS EVENING THROUGH
TUESDAY AFTERNOON...

.LATE THIS AFTERNOON...South winds 15 to 25 knots. Waves 1 to
3 feet.
.TONIGHT...South winds 15 to 25 knots veering west and increasing
to gales to 40 knots by midnight. Isolated rain and snow showers
after midnight. Waves building to 10 to 14 feet occasionally to 18
feet.
.TUESDAY...Northwest gales to 40 knots. Scattered snow showers.
Waves subsiding to 5 to 8 feet occasionally to 10 feet.
.TUESDAY NIGHT...Northwest winds 20 to 30 knots diminishing to
10 to 20 knots. A slight chance of snow showers. Waves subsiding
to 3 to 5 feet occasionally to 7 feet.
.WEDNESDAY...West winds 10 to 20 knots. Waves subsiding to 2 to
4 feet, then building to 3 to 5 feet occasionally to 7 feet.
.WEDNESDAY NIGHT...West winds 15 to 25 knots. Waves building to
3 to 6 feet occasionally to 8 feet.
.THURSDAY...West winds 10 to 20 knots veering northwest in the
afternoon. Waves subsiding to 1 to 3 feet.
.THURSDAY NIGHT...Southwest winds 5 to 15 knots becoming south
15 to 25 knots after midnight. Waves subsiding to calm to 2 feet,
then building to 1 to 3 feet.
.FRIDAY...Southwest winds 20 to 30 knots with a few gale force
gusts to 35 knots becoming west late. A chance of rain showers,
possibly mixed with snow. Waves building to 4 to 8 feet
occasionally to 10 feet.
.SATURDAY...North winds 20 to 30 knots becoming northwest 15 to
25 knots. A chance of snow showers. Waves subsiding to 1 to
3 feet.

$$

LSZ264-210500-
Lake Superior from Upper Entrance to Portage Canal to Manitou
Island MI 5NM off shore to the US/Canadian Border-
355 PM EST Mon Nov 20 2017

...GALE WARNING IN EFFECT FROM 10 PM EST THIS EVENING THROUGH
TUESDAY EVENING...

.LATE THIS AFTERNOON...South winds 15 to 25 knots. Waves 3 to
5 feet occasionally to 7 feet.
.TONIGHT...South winds 15 to 25 knots becoming west gales to 40
knots by midnight. Scattered snow showers, possibly mixed with
rain after midnight. Waves building to 10 to 14 feet occasionally
to 18 feet.
.TUESDAY...Northwest gales to 45 knots diminishing to gales to 40
knots by mid afternoon. Scattered snow showers. Waves 10 to 14
feet occasionally to 18 feet.
.TUESDAY NIGHT...Northwest gales to 35 knots diminishing to 15 to
25 knots by midnight. A chance of snow showers. Waves subsiding
to 3 to 6 feet occasionally to 8 feet.
.WEDNESDAY...West winds 15 to 25 knots. A slight chance of snow
showers in the morning. Waves subsiding to 2 to 4 feet, then
building to 3 to 5 feet occasionally to 7 feet.
.WEDNESDAY NIGHT...West winds 15 to 25 knots. A chance of
freezing rain after midnight. Waves building to 4 to 7 feet
occasionally to 9 feet.
.THURSDAY...Northwest winds 15 to 25 knots. Waves subsiding to
2 to 4 feet.
.THURSDAY NIGHT...Northwest winds 5 to 15 knots becoming south
20 to 30 knots after midnight. Snow showers likely after
midnight. Waves subsiding to calm to 2 feet, then building to
1 to 3 feet.
.FRIDAY...Southwest winds 20 to 30 knots with a few gale force
gusts to 35 knots becoming west late. A chance of rain showers,
possibly mixed with snow. Waves building to 7 to 10 feet
occasionally to 13 feet.
.SATURDAY...North gales to 35 knots becoming northwest 20 to
30 knots. A chance of snow showers. Waves subsiding to 3 to
5 feet occasionally to 7 feet.

$$

LSZ265-210500-
Lake Superior West of Line from Manitou Island to Marquette MI
Beyond 5NM from shore-
355 PM EST Mon Nov 20 2017

...GALE WARNING IN EFFECT FROM LATE TONIGHT THROUGH TUESDAY
EVENING...

.LATE THIS AFTERNOON...South winds 15 to 25 knots. Waves 2 to
4 feet building to 3 to 5 feet occasionally to 7 feet.
.TONIGHT...South winds 20 to 30 knots becoming west gales to 40
knots after midnight. Scattered snow showers, possibly mixed with
rain after midnight. Waves building to 3 to 6 feet occasionally
to 8 feet.
.TUESDAY...West gales to 40 knots veering northwest. Snow
showers. Waves building to 10 to 14 feet occasionally to 18 feet,
then subsiding to 8 to 11 feet occasionally to 14 feet.
.TUESDAY NIGHT...Northwest gales to 35 knots diminishing to 20 to
30 knots by midnight. A chance of snow showers. Waves subsiding
to 3 to 5 feet occasionally to 7 feet.
.WEDNESDAY...West winds 15 to 25 knots diminishing to 10 to
20 knots in the afternoon. A slight chance of snow showers in the
morning. Waves subsiding to 1 to 3 feet.
.WEDNESDAY NIGHT...West winds 15 to 25 knots increasing to 20 to
30 knots after midnight. Waves building to 2 to 4 feet.
.THURSDAY...West winds 20 to 30 knots becoming northwest 15 to
25 knots in the afternoon. Waves building to 3 to 5 feet
occasionally to 7 feet, then subsiding to 2 to 4 feet.
.THURSDAY NIGHT...Northwest winds 10 to 20 knots becoming south
15 to 25 knots after midnight. A chance of snow showers. Waves
subsiding to calm to 2 feet, then building to 1 to 3 feet.
.FRIDAY...Southwest winds 20 to 30 knots with a few gale force
gusts to 35 knots becoming west late. A chance of rain showers,
possibly mixed with snow. Waves building to 3 to 5 feet
occasionally to 7 feet, then subsiding to 2 to 4 feet.
.SATURDAY...Northwest gales to 35 knots diminishing to 20 to
30 knots. Snow showers likely. Waves building to 7 to 10 feet
occasionally to 13 feet, then subsiding to 3 to 6 feet
occasionally to 8 feet.

$$

LSZ266-210500-
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-
355 PM EST Mon Nov 20 2017

...GALE WARNING IN EFFECT FROM LATE TONIGHT THROUGH TUESDAY
EVENING...

.LATE THIS AFTERNOON...South winds 20 to 30 knots. Waves 3 to 6
feet occasionally to 8 feet.
.TONIGHT...South winds 20 to 30 knots increasing to gales to 40
knots veering west late. Scattered rain showers, possibly mixed
with snow after midnight. Waves building to 4 to 8 feet
occasionally to 10 feet.
.TUESDAY...West gales to 40 knots becoming northwest gales to
45 knots. Numerous snow showers. Waves building to 12 to 17 feet
occasionally to 21 feet, then subsiding to 11 to 15 feet
occasionally to 19 feet.
.TUESDAY NIGHT...Northwest gales to 40 knots diminishing to 20 to
30 knots late. A chance of snow showers. Waves subsiding to 5 to
8 feet occasionally to 10 feet.
.WEDNESDAY...West winds 15 to 25 knots diminishing to 10 to
20 knots in the afternoon. A slight chance of snow showers. Waves
subsiding to 3 to 5 feet occasionally to 7 feet.
.WEDNESDAY NIGHT...Southwest winds 15 to 25 knots veering west
after midnight. A chance of rain and snow showers. Waves building
to 4 to 7 feet occasionally to 9 feet.
.THURSDAY...West winds 20 to 30 knots becoming northwest 15 to
25 knots in the afternoon. A chance of rain showers and freezing
rain in the morning. A chance of snow showers. Waves subsiding to
3 to 6 feet occasionally to 8 feet.
.THURSDAY NIGHT...Northwest winds 10 to 20 knots becoming south
20 to 30 knots after midnight. A chance of snow showers. Waves
subsiding to 1 to 3 feet, then building to 2 to 4 feet.
.FRIDAY...South winds 20 to 30 knots with a few gale force gusts
to 25 knots turning west late. A chance of rain showers, possibly
mixed with snow. Waves building to 8 to 11 feet occasionally to
14 feet.
.SATURDAY...North gales to 35 knots diminishing to 20 to 30
knots. Snow showers likely. Waves building to 9 to 12 feet
occasionally to 15 feet, then subsiding to 4 to 7 feet
occasionally to 9 feet.

$$

LSZ267-210500-
Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off
shore to the US/Canadian border-
355 PM EST Mon Nov 20 2017

...GALE WARNING IN EFFECT FROM TUESDAY MORNING THROUGH TUESDAY
EVENING...

.LATE THIS AFTERNOON...South winds 20 to 30 knots. Waves 2 to
4 feet.
.TONIGHT...South winds 20 to 30 knots veering southwest by
midnight. Scattered rain showers after midnight. Waves building to
6 to 9 feet occasionally to 11 feet.
.TUESDAY...West gales to 40 knots veering northwest late.
Numerous rain and snow showers. Waves building to 12 to 17 feet
occasionally to 21 feet, then subsiding to 11 to 15 feet
occasionally to 19 feet.
.TUESDAY NIGHT...Northwest gales to 35 knots diminishing to 20 to
30 knots by midnight. A chance of snow showers. Waves subsiding
to 5 to 8 feet occasionally to 10 feet.
.WEDNESDAY...West winds 15 to 25 knots. A chance of snow showers.
Waves subsiding to 3 to 5 feet occasionally to 7 feet.
.WEDNESDAY NIGHT...Southwest winds 15 to 25 knots veering west
after midnight. A chance of snow showers. Waves building to 3 to
6 feet occasionally to 8 feet.
.THURSDAY...West winds 20 to 30 knots veering northwest in the
afternoon. A chance of freezing rain, rain, and snow. Waves
building to 4 to 7 feet occasionally to 9 feet, then subsiding to
3 to 6 feet occasionally to 8 feet.
.THURSDAY NIGHT...Northwest winds 10 to 20 knots becoming west
15 to 25 knots after midnight. A chance of snow showers. Waves
subsiding to 1 to 3 feet.
.FRIDAY...South winds 20 to 30 knots with a few gale force gusts
to 35 knots turning west late. Rain and snow showers. Waves
building to 9 to 12 feet occasionally to 15 feet.
.SATURDAY...North gales to 35 knots diminishing to 20 to 30
knots. Snow showers likely. Waves subsiding to 4 to 7 feet
occasionally to 9 feet.

$$

LSZ261-210500-
MAFOR 2022/
Superior West...Gale Warning in effect...11540 11550 11650 12650
13750. Scattered snow showers Tuesday morning. Waves 1 to 2 feet
building to 8 to 11 feet tonight, and then subsiding to 5 to 9
feet Tuesday.

Superior North Central...Gale Warning in effect...11440 12550
11650 11657 11757 11760 11750. Scattered rain and snow showers.
Waves 2 to 4 feet building to 9 to 13 feet tonight.

Superior South Central...Gale Warning in effect...11440 11540
11550 12650 11757 12767. Scattered snow showers. Waves 2 to 4
feet building to 8 to 12 feet tonight, and then building to 11 to
15 feet Tuesday.

Superior East...Gale Warning in effect...11440 11450 12550 11650
11657 12757. Scattered rain showers. Waves 3 to 6 feet building
to 9 to 12 feet tonight, and then building to 11 to 15 feet
Tuesday.

$$

Borchardt

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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