FZUS63 KMQT 181415
GLFLS
Experimental Tabular Open Lake Forecast for Lake Superior
National Weather Service Negaunee MI
1015 AM EDT Mon Aug 18 2025
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 30.3 inch high is south of James Bay this morning while broad 29.9
inch troughing extends through the Great Plains. Throughout today
into tonight, the trough will weaken slightly while the high shifts
fully into Quebec. As weak low pressure near 30.0 inches skirts
south of the lake, 30.1 inch high presssure builds over northern
Minnesota/northern Ontario/southern Manitoba Tuesday. This high
builds further to 30.2 inches over the lake Wednesday afternoon. By
late Thursday, a 29.7 inch low over northern Manitoba and far-
northern Ontario will erode the high pressure over the Upper Great
Lakes to 30.0 inches. For Friday and into the weekend, the low will
pass along the shores of Hudson Bay at around 29.6 inches, passing a
29.8 inch trough over Lake Superior.
LSZ162-182000-
Lake Superior west of a line from Saxon Harbor WI to Grand
Portage MN beyond 5NM-
1001 AM EDT Mon Aug 18 2025 /901 AM CDT Mon Aug 18 2025/
.REST OF TODAY, Southeast winds 10 to 20 knots becoming east
5 to 15 knots in the afternoon, then backing northeast late.
Showers likely by late morning. A chance of thunderstorms. A
chance of showers by mid afternoon. Waves 1 to 3 feet subsiding
to calm to 2 feet.
.TONIGHT, Northeast winds 5 to 15 knots backing north late. A
slight chance of showers through midnight. Waves calm to 2 feet.
.TUESDAY, North winds 10 to 20 knots diminishing to 5 to
15 knots in the afternoon, then veering east late. Waves calm to
2 feet.
.TUESDAY NIGHT, East winds 5 to 15 knots backing north after
midnight. Waves calm to 2 feet.
.WEDNESDAY, North winds 5 to 15 knots veering south by mid
afternoon. Waves calm to 2 feet.
.WEDNESDAY NIGHT, Southeast winds 5 to 15 knots veering south
after midnight. Waves calm to 2 feet.
.THURSDAY, South winds 5 to 15 knots becoming southwest 10 to
20 knots. A chance of showers. Waves calm to 2 feet.
.FRIDAY, West winds 10 to 20 knots. Waves building to 1 to
3 feet.
LSZ162-182000-
Lake Superior west of a line from Saxon Harbor WI to Grand
Portage MN beyond 5NM-
1015 AM EDT Mon Aug 18 2025 /915 AM CDT Mon Aug 18 2025/
.This Afternoon...
Weather.............Showers likely and slight chance of
thunderstorms, then cloudy with chance of
showers and slight chance of thunderstorms in
the afternoon.
Sfc winds...........East 10 to 15 knots.
100-ft winds........East 15 to 20 knots.
Sig waves...........3 to 5 feet.
Ocnl waves..........Around 5 feet.
.TONIGHT...
Weather.............Mostly cloudy with chance of showers and
thunderstorms, then mostly cloudy with a slight
chance of showers after midnight.
Sfc winds...........Northeast 10 to 15 knots.
100-ft winds........Northeast 15 to 20 knots.
Sig waves...........2 to 4 feet.
.TUESDAY...
Weather.............Partly sunny.
Sfc winds...........Northwest 5 to 10 knots.
100-ft winds........Northwest 10 to 15 knots.
Sig waves...........2 to 4 feet.
.TUESDAY NIGHT...
Weather.............Partly cloudy.
Sfc winds...........Light and variable winds.
100-ft winds........Light and variable winds.
Sig waves...........2 feet or less.
.FORECAST DAYS 3 THROUGH 5...
.WEDNESDAY...North winds 5 to 10 knots. Waves 4 to 6 feet.
.THURSDAY...North winds 5 to 10 knots. Waves 2 to 4 feet.
.FRIDAY...South winds 10 to 15 knots. Waves 2 to 4 feet.
$$
LSZ263-182000-
Lake Superior from Saxon Harbor WI to Upper Entrance to Portage
Canal MI 5NM off shore to the US/Canadian border including Isle
Royale National Park-
1015 AM EDT Mon Aug 18 2025
.This Afternoon...
Weather.............Showers likely and slight chance of
thunderstorms.
Sfc winds...........Southeast 10 to 15 knots.
100-ft winds........Southeast 15 to 20 knots.
Sig waves...........3 to 5 feet.
Ocnl waves..........Around 6 feet.
.TONIGHT...
Weather.............Cloudy with chance of showers and slight chance
of thunderstorms, then mostly cloudy with a
slight chance of showers after midnight.
Sfc winds...........East 10 to 15 knots.
100-ft winds........East 15 to 20 knots.
Sig waves...........3 to 5 feet.
Ocnl waves..........Around 6 feet.
.TUESDAY...
Weather.............Partly sunny.
Sfc winds...........North 10 to 15 knots.
100-ft winds........North 15 to 20 knots.
Sig waves...........2 to 4 feet.
.TUESDAY NIGHT...
Weather.............Partly cloudy.
Sfc winds...........North 5 to 10 knots.
100-ft winds........North 10 to 15 knots.
Sig waves...........2 to 4 feet.
.FORECAST DAYS 3 THROUGH 5...
.WEDNESDAY...North winds 5 to 10 knots. Waves 4 to 6 feet.
.THURSDAY...North winds 5 to 10 knots. Waves 2 to 4 feet.
.FRIDAY...South winds 10 to 15 knots. Waves 2 to 4 feet.
$$
LSZ264-182000-
Lake Superior from Upper Entrance to Portage Canal to Manitou
Island MI 5NM off shore to the US/Canadian Border-
1015 AM EDT Mon Aug 18 2025
.This Afternoon...
Weather.............Mostly cloudy with chance of showers, then
cloudy with showers likely in the afternoon.
Sfc winds...........Southeast 15 to 20 knots.
100-ft winds........Southeast 20 to 25 knots.
Sig waves...........4 to 6 feet.
Ocnl waves..........Around 7 feet.
.TONIGHT...
Weather.............Cloudy with chance of showers.
Sfc winds...........Southeast 15 to 20 knots.
100-ft winds........Southeast 20 to 25 knots.
Sig waves...........4 to 6 feet.
Ocnl waves..........Around 7 feet.
.TUESDAY...
Weather.............Partly sunny.
Sfc winds...........North 10 to 15 knots.
100-ft winds........North 15 to 20 knots.
Sig waves...........2 to 4 feet.
Ocnl waves..........Around 5 feet.
.TUESDAY NIGHT...
Weather.............Partly cloudy.
Sfc winds...........North 5 to 10 knots.
100-ft winds........North 10 to 15 knots.
Sig waves...........2 to 4 feet.
.FORECAST DAYS 3 THROUGH 5...
.WEDNESDAY...North winds 5 to 10 knots. Waves 4 to 6 feet.
.THURSDAY...North winds 5 to 10 knots. Waves 2 to 4 feet.
.FRIDAY...South winds 10 to 15 knots. Waves 2 to 4 feet.
$$
LSZ265-182000-
Lake Superior West of Line from Manitou Island to Marquette MI
Beyond 5NM from shore-
1015 AM EDT Mon Aug 18 2025
.This Afternoon...
Weather.............Mostly cloudy with chance of showers, then
cloudy with showers likely and slight chance of
thunderstorms in the afternoon.
Sfc winds...........Southeast 15 to 20 knots.
100-ft winds........Southeast 20 to 25 knots.
Sig waves...........4 to 6 feet.
Ocnl waves..........Around 7 feet.
.TONIGHT...
Weather.............Cloudy with chance of showers and slight chance
of thunderstorms, then cloudy with chance of
showers after midnight.
Sfc winds...........Southeast 15 to 20 knots.
100-ft winds........Southeast 20 to 25 knots.
Sig waves...........3 to 5 feet.
Ocnl waves..........Around 6 feet.
.TUESDAY...
Weather.............Mostly cloudy.
Sfc winds...........Southeast 5 to 10 knots becoming northwest 10
to 15 knots in the afternoon.
100-ft winds........Southeast 10 to 15 knots becoming northwest 15
to 20 knots in the afternoon.
Sig waves...........2 to 4 feet.
.TUESDAY NIGHT...
Weather.............Mostly cloudy.
Sfc winds...........North 5 to 10 knots.
100-ft winds........North 10 to 15 knots.
Sig waves...........2 to 4 feet.
.FORECAST DAYS 3 THROUGH 5...
.WEDNESDAY...North winds 5 to 10 knots. Waves 4 to 6 feet.
.THURSDAY...North winds 5 to 10 knots. Waves 2 to 4 feet.
.FRIDAY...South winds 10 to 15 knots. Waves 2 to 4 feet.
$$
LSZ266-182000-
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-
1015 AM EDT Mon Aug 18 2025
.This Afternoon...
Weather.............Partly sunny with a slight chance of showers,
then mostly cloudy with chance of showers in
the afternoon.
Sfc winds...........Southeast 15 to 20 knots.
100-ft winds........Southeast 20 to 25 knots.
Sig waves...........4 to 6 feet.
Ocnl waves..........Around 8 feet.
.TONIGHT...
Weather.............Cloudy with showers likely and slight chance of
thunderstorms, then cloudy with chance of
showers after midnight.
Sfc winds...........Southeast 15 to 20 knots.
100-ft winds........Southeast 20 to 25 knots.
Sig waves...........4 to 6 feet.
Ocnl waves..........Around 7 feet.
.TUESDAY...
Weather.............Mostly cloudy.
Sfc winds...........Southeast 10 to 15 knots.
100-ft winds........Southeast 15 to 20 knots becoming north in the
afternoon.
Sig waves...........2 to 4 feet.
Ocnl waves..........Around 5 feet.
.TUESDAY NIGHT...
Weather.............Mostly cloudy.
Sfc winds...........North 10 to 15 knots.
100-ft winds........North 15 to 20 knots.
Sig waves...........2 to 4 feet.
Ocnl waves..........Around 5 feet in the evening.
.FORECAST DAYS 3 THROUGH 5...
.WEDNESDAY...North winds 5 to 10 knots. Waves 4 to 6 feet.
.THURSDAY...North winds 5 to 10 knots. Waves 2 to 4 feet.
.FRIDAY...South winds 10 to 15 knots. Waves 2 to 4 feet.
$$
LSZ267-182000-
Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off
shore to the US/Canadian border-
1015 AM EDT Mon Aug 18 2025
.This Afternoon...
Weather.............Mostly sunny, then chance of showers in the
afternoon.
Sfc winds...........Southeast 15 to 20 knots.
100-ft winds........Southeast 20 to 25 knots.
Sig waves...........4 to 6 feet.
Ocnl waves..........Around 7 feet.
.TONIGHT...
Weather.............Mostly cloudy with chance of showers, then
cloudy with chance of showers and slight chance
of thunderstorms after midnight.
Sfc winds...........Southeast 15 to 20 knots.
100-ft winds........Southeast 20 to 25 knots.
Sig waves...........3 to 5 feet.
Ocnl waves..........Around 6 feet.
.TUESDAY...
Weather.............Mostly cloudy with chance of showers, then
mostly cloudy in the afternoon.
Sfc winds...........Southeast 10 to 15 knots.
100-ft winds........Southeast 15 to 20 knots.
Sig waves...........2 to 4 feet.
Ocnl waves..........Around 5 feet in the morning.
.TUESDAY NIGHT...
Weather.............Mostly cloudy.
Sfc winds...........North 10 to 15 knots.
100-ft winds........North 15 to 20 knots.
Sig waves...........2 to 4 feet.
.FORECAST DAYS 3 THROUGH 5...
.WEDNESDAY...North winds 5 to 10 knots. Waves 4 to 6 feet.
.THURSDAY...North winds 5 to 10 knots. Waves 2 to 4 feet.
.FRIDAY...South winds 10 to 15 knots. Waves 2 to 4 feet.
$$
LSZ261-182000-
MAFOR 1815/
Superior West 11316 11310 13210 12800 11810. A chance of
thunderstorms this afternoon and evening. Waves 1 to 3 feet this
afternoon. Waves 2 feet or less tonight and Tuesday morning.
Superior North Central 11330 12336 11330 11430 11420 11400 11120.
Waves 2 to 4 feet building to 3 to 5 feet this afternoon. Waves 3
to 5 feet subsiding to 1 to 3 feet tonight. Waves 1 to 3 feet
Tuesday morning.
Superior South Central 11330 11336 11436 12420 11310 11300 11620.
Waves 2 to 4 feet this afternoon. Waves 2 to 4 feet subsiding to
1 to 3 feet tonight. Waves 1 to 2 feet Tuesday morning.
Superior East 11330 12320 11336 12330 11320 11310. Waves 2 to 4
feet building to 3 to 5 feet this afternoon. Waves 2 to 4 feet
tonight and Tuesday morning.
$$
Occasional waves will only be displayed when values meet or exceed 5 feet.
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