Great Lakes Forecast
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FZUS63 KMQT 170125
GLFLS

Open Lake Forecast for Lake Superior
National Weather Service Marquette MI
925 PM EDT Tue Apr 16 2024

For waters beyond 5 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...High pressure centered over Hudson Bay at 30.5 inches
this evening, is extending a 30.1 inch ridge over the eastern
section of Lake Superior. Meanwhile, a 29.3 inch low pressure
over central Iowa tonight tracks northeast, reaching Wisconsin
Wednesday morning while filling to 29.5 inches. The low weakens
further to 29.7 inches as it lifts east across the Lower Peninsula
of Michigan on Wednesday night before phasing with another 29.7
inch low pressure over northern Ontario. This low moves into
eastern James Bay Friday night into Saturday, deepening to 29.3
inches. Meanwhile, a 30.4 inch high pressure ridge builds
southeast into the Northern Plains extending weak 30.0 inch
ridging across western Lake Superior. Ridging over the lake builds
to 30.1 inches on Saturday and weakens to 30.0 inches Sunday.

LSZ162-170930-
Lake Superior west of a line from Saxon Harbor WI to Grand
Portage MN beyond 5NM-
925 PM EDT Tue Apr 16 2024 /825 PM CDT Tue Apr 16 2024/

...GALE WARNING IN EFFECT THROUGH WEDNESDAY AFTERNOON...

.REST OF TONIGHT...East gales to 40 knots. Rain showers by late
evening, then a chance of rain showers after midnight. Waves
11 to 15 feet occasionally to 19 feet subsiding to 9 to 12 feet
occasionally to 15 feet.
.WEDNESDAY...East gales to 35 knots backing northeast in the
afternoon, then diminishing to 20 to 30 knots late. Rain showers.
Waves subsiding to 6 to 9 feet occasionally to 11 feet.
.WEDNESDAY NIGHT...North winds 10 to 20 knots backing west after
midnight. A chance of rain showers through midnight. Waves
subsiding to 2 to 4 feet.
.THURSDAY...Southwest winds 15 to 25 knots. A slight chance of
rain showers by mid afternoon. Waves building to 3 to 6 feet
occasionally to 8 feet.
.THURSDAY NIGHT...West winds 15 to 25 knots. Waves to 3 to 5 feet
occasionally to 7 feet.
.FRIDAY...West winds 20 to 30 knots increasing to gales to
35 knots by mid afternoon. A chance of rain showers, possibly
mixed with snow. Waves building to 4 to 8 feet occasionally to
10 feet.
.FRIDAY NIGHT...West gales to 35 knots becoming northwest 20 to
30 knots after midnight. Waves subsiding to 2 to 4 feet.
.SATURDAY...West winds 15 to 25 knots diminishing to 10 to
20 knots. Waves subsiding to calm to 2 feet.
.SUNDAY...Southwest winds 15 to 25 knots. Waves building to 2 to
4 feet, then subsiding to 1 to 3 feet.

$$

LSZ263-170930-
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-
925 PM EDT Tue Apr 16 2024

...GALE WARNING IN EFFECT THROUGH WEDNESDAY AFTERNOON...

.REST OF TONIGHT...East gales to 40 knots. A chance of rain
showers by late evening, then rain showers after midnight. Waves
8 to 11 feet occasionally to 14 feet subsiding to 7 to 10 feet
occasionally to 13 feet, then building to 11 to 15 feet
occasionally to 19 feet.
.WEDNESDAY...East gales to 35 knots diminishing to 20 to 30 knots
late. A chance of rain showers through early afternoon, then rain
showers by mid afternoon. Waves building to 12 to 17 feet
occasionally to 21 feet, then subsiding to 9 to 12 feet
occasionally to 15 feet.
.WEDNESDAY NIGHT...North winds 15 to 25 knots becoming west 10 to
20 knots after midnight. A chance of rain showers. Waves
subsiding to 2 to 4 feet.
.THURSDAY...West winds 15 to 25 knots. A slight chance of rain
showers by mid afternoon. Waves building to 3 to 6 feet
occasionally to 8 feet.
.THURSDAY NIGHT...West winds 10 to 20 knots increasing to 15 to
25 knots after midnight. Waves subsiding to 2 to 4 feet, then
building to 3 to 5 feet occasionally to 7 feet.
.FRIDAY...West gales to 35 knots. A chance of rain showers,
possibly mixed with snow. Waves building to 6 to 9 feet
occasionally to 11 feet.
.FRIDAY NIGHT...West winds 20 to 30 knots becoming northwest
15 to 25 knots after midnight. Waves subsiding to 3 to 5 feet
occasionally to 7 feet.
.SATURDAY...West winds 15 to 25 knots diminishing to 10 to
20 knots. Waves subsiding to 1 to 3 feet.
.SUNDAY...Southwest winds 15 to 25 knots diminishing to 10 to
20 knots. Waves building to 2 to 4 feet.

$$

LSZ264-170930-
Lake Superior from Upper Entrance to Portage Canal to Manitou
Island MI 5NM off shore to the US/Canadian Border-
925 PM EDT Tue Apr 16 2024

...GALE WARNING IN EFFECT THROUGH WEDNESDAY EVENING...

.REST OF TONIGHT...East gales to 40 knots. A slight chance of
rain showers by late evening, then rain showers after midnight.
Waves 5 to 8 feet occasionally to 10 feet building to 10 to
14 feet occasionally to 18 feet.
.WEDNESDAY...East gales to 40 knots. A chance of rain showers
through early afternoon, then rain showers by mid afternoon.
Waves building to 12 to 17 feet occasionally to 21 feet, then
subsiding to 9 to 12 feet occasionally to 15 feet.
.WEDNESDAY NIGHT...East winds 15 to 25 knots becoming west 10 to
20 knots after midnight, then increasing to 15 to 25 knots late.
Rain showers likely through midnight, then a chance of rain
showers after midnight. Waves subsiding to 3 to 5 feet
occasionally to 7 feet.
.THURSDAY...West winds 15 to 25 knots backing southwest by mid
afternoon. Waves subsiding to 2 to 4 feet, then building to 3 to
5 feet occasionally to 7 feet.
.THURSDAY NIGHT...West winds 10 to 20 knots increasing to 15 to
25 knots after midnight. Waves subsiding to 2 to 4 feet, then
building to 3 to 6 feet occasionally to 8 feet.
.FRIDAY...West gales to 35 knots. Waves building to 6 to 10 feet
occasionally to 13 feet.
.FRIDAY NIGHT...West gales to 35 knots becoming northwest 15 to
25 knots after midnight. Waves subsiding to 3 to 6 feet
occasionally to 8 feet.
.SATURDAY...Northwest winds 15 to 25 knots becoming west 10 to
20 knots. Waves subsiding to 1 to 3 feet.
.SUNDAY...West winds 15 to 25 knots. Waves building to 3 to
5 feet occasionally to 7 feet, then subsiding to 2 to 4 feet.

$$

LSZ265-170930-
Lake Superior West of Line from Manitou Island to Marquette MI
Beyond 5NM from shore-
925 PM EDT Tue Apr 16 2024

...GALE WARNING IN EFFECT THROUGH WEDNESDAY EVENING...

.REST OF TONIGHT...East winds 20 to 30 knots increasing to gales
to 35 knots after midnight. A chance of rain showers by late
evening, then rain showers after midnight. Waves 5 to 8 feet
occasionally to 10 feet building to 8 to 11 feet occasionally to
14 feet.
.WEDNESDAY...East gales to 35 knots diminishing to 20 to 30 knots
in the afternoon. A chance of rain showers through early
afternoon, then rain showers by mid afternoon. Waves building to
10 to 14 feet occasionally to 18 feet, then subsiding to 8 to
11 feet occasionally to 14 feet.
.WEDNESDAY NIGHT...Southeast winds 10 to 20 knots veering west
after midnight, then increasing to 15 to 25 knots late. A chance
of rain showers. Waves subsiding to 2 to 4 feet.
.THURSDAY...West winds 10 to 20 knots. A slight chance of rain
showers by mid afternoon. Waves subsiding to calm to 2 feet.
.THURSDAY NIGHT...West winds 5 to 15 knots increasing to 10 to
20 knots after midnight. Waves building to 1 to 3 feet.
.FRIDAY...West winds 20 to 30 knots increasing to gales to
35 knots by mid afternoon. A chance of rain showers. Waves
building to 3 to 6 feet occasionally to 8 feet.
.FRIDAY NIGHT...West gales to 35 knots diminishing to 20 to
30 knots after midnight. A chance of rain showers through
midnight. A chance of snow showers. Waves 3 to 5 feet
occasionally to 7 feet.
.SATURDAY...Northwest winds 20 to 30 knots becoming west 15 to
25 knots. Waves subsiding to calm to 2 feet.
.SUNDAY...West winds 15 to 25 knots. Waves calm to 2 feet.

$$

LSZ266-170930-
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-
925 PM EDT Tue Apr 16 2024

...GALE WARNING IN EFFECT THROUGH WEDNESDAY EVENING...

.REST OF TONIGHT...East gales to 40 knots. A slight chance of
rain showers by late evening, then rain showers after midnight.
Waves 3 to 6 feet occasionally to 8 feet building to 10 to
14 feet occasionally to 18 feet.
.WEDNESDAY...East gales to 40 knots. A chance of rain showers
through early afternoon, then rain showers by mid afternoon.
Waves building to 11 to 15 feet occasionally to 19 feet, then
subsiding to 9 to 12 feet occasionally to 15 feet.
.WEDNESDAY NIGHT...Southeast gales to 35 knots diminishing to
10 to 20 knots after midnight, then becoming west 15 to 25 knots
late. Rain showers likely through midnight, then a chance of rain
showers after midnight. Waves subsiding to 3 to 5 feet
occasionally to 7 feet.
.THURSDAY...West winds 15 to 25 knots. A slight chance of rain
showers by mid afternoon. Waves subsiding to 2 to 4 feet.
.THURSDAY NIGHT...Southwest winds 10 to 20 knots veering west
after midnight. A chance of rain showers. Waves building to 3 to
5 feet occasionally to 7 feet.
.FRIDAY...West winds 20 to 30 knots increasing to gales to
35 knots by mid afternoon. A chance of rain showers. Waves
building to 6 to 9 feet occasionally to 11 feet.
.FRIDAY NIGHT...West gales to 35 knots veering northwest after
midnight. A chance of rain showers through midnight. A chance of
snow showers. Waves subsiding to 4 to 8 feet occasionally to
10 feet.
.SATURDAY...Northwest winds 20 to 30 knots becoming west 15 to
25 knots. Waves subsiding to 2 to 4 feet.
.SUNDAY...West winds 15 to 25 knots. Waves building to 3 to
5 feet occasionally to 7 feet, then subsiding to 2 to 4 feet.

$$

LSZ267-170930-
Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off
shore to the US/Canadian border-
925 PM EDT Tue Apr 16 2024

...GALE WARNING IN EFFECT FROM 2 AM EDT WEDNESDAY THROUGH
WEDNESDAY EVENING...

.REST OF TONIGHT...East winds 20 to 30 knots increasing to gales
to 35 knots after midnight, then becoming southeast gales to
40 knots late. Rain showers after midnight. Waves 2 to 4 feet
building to 7 to 10 feet occasionally to 13 feet.
.WEDNESDAY...Southeast gales to 45 knots. Rain showers. Waves
building to 9 to 12 feet occasionally to 15 feet, then subsiding
to 7 to 10 feet occasionally to 13 feet.
.WEDNESDAY NIGHT...Southeast gales to 35 knots diminishing to
10 to 20 knots after midnight, then becoming west 15 to 25 knots
late. Rain showers likely through midnight, then a chance of rain
showers after midnight. Waves subsiding to 1 to 3 feet, then
building to 2 to 4 feet.
.THURSDAY...West winds 15 to 25 knots diminishing to 10 to
20 knots by mid afternoon. A slight chance of rain showers. Waves
building to 3 to 5 feet occasionally to 7 feet, then subsiding to
1 to 3 feet.
.THURSDAY NIGHT...South winds 10 to 20 knots veering west after
midnight. A chance of rain showers. Waves subsiding to calm to
2 feet, then building to 1 to 3 feet.
.FRIDAY...West winds 15 to 25 knots increasing to gales to
35 knots by mid afternoon. A chance of rain showers. Waves
building to 5 to 8 feet occasionally to 10 feet.
.FRIDAY NIGHT...West winds 20 to 30 knots. A chance of rain
showers through midnight. A chance of snow showers. Waves
subsiding to 4 to 8 feet occasionally to 10 feet.
.SATURDAY...Northwest gales to 35 knots becoming west 15 to
25 knots. Waves subsiding to 2 to 4 feet.
.SUNDAY...West winds 15 to 25 knots backing southwest. Waves
subsiding to 1 to 3 feet, then building to 2 to 4 feet.

$$
LSZ261-170930-
MAFOR 1703/
Superior West...GALE WARNING IN EFFECT...12256 12250 12156 11146
11820. Waves 9 to 13 feet overnight. Waves 8 to 12 feet
Wednesday. Waves 6 to 9 feet subsiding to 4 to 7 feet Wednesday
evening.

Superior North Central...GALE WARNING IN EFFECT...11250 11256
11266 11260 11250 12256 11246. Waves 5 to 8 feet building to 10
to 13 feet overnight. Waves 11 to 15 feet Wednesday. Waves 10 to
13 feet subsiding to 7 to 10 feet Wednesday evening.

Superior South Central...GALE WARNING IN EFFECT...11240 11356
11256 11350 11250 12246 11320. Waves 6 to 11 feet overnight
building to 9 to 12 feet Wednesday. Waves 8 to 11 feet subsiding
to 5 to 8 feet Wednesday evening.

Superior East...GALE WARNING IN EFFECT...12250 11356 13366 12356.
Waves 5 to 9 feet overnight building to 8 to 12 feet Wednesday.
Waves 8 to 11 feet subsiding to 6 to 9 feet Wednesday evening.

$$

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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