Great Lakes Forecast
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941
FZUS63 KMQT 240902
GLFLS

Open Lake Forecast for Lake Superior
National Weather Service Marquette MI
402 AM EST Sat Feb 24 2018

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 of 30.2 inches will build over the
Great Lakes today. The high will move into Quebec tonight as low
pressure of 29.5 inches tracks northeast from the Central Plains
into the Great Lakes while deepening to 29.3 inches. Expect the
low to deepen to 29.0 inches by late Sunday over James Bay while
high pressure of 30.2 inches crosses the central Mississippi river
valley. Expect the ridge to build across the Upper Great Lakes on
Monday as a 29.4 inch low moves across southern Manitoba. On
Tuesday morning, a 29.8 inch low will move across northern Ontario
while a 30.3 inch high pressure moves over the Lower Great Lakes.
A 30.1 inch ridge will arrive over the Upper Great Lakes on
Wednesday.

LSZ162-241715-
Lake Superior west of a line from Saxon Harbor WI to Grand
Portage MN beyond 5NM-
402 AM EST Sat Feb 24 2018 /302 AM CST Sat Feb 24 2018/

...GALE WARNING IN EFFECT FROM SUNDAY MORNING THROUGH LATE SUNDAY
NIGHT...

.EARLY THIS MORNING...West winds less than 10 knots.
.TODAY...Southwest winds less than 10 knots backing south by late
morning, then becoming northeast 5 to 15 knots by mid afternoon.
A slight chance of snow in the afternoon.
.TONIGHT...Northeast winds 15 to 25 knots increasing to 20 to
30 knots by midnight, then veering east late. Snow.
.SUNDAY...West gales to 40 knots. A chance of snow.
.SUNDAY NIGHT...Southwest gales to 35 knots diminishing to 15 to
25 knots after midnight. A slight chance of snow showers in the
evening.
.MONDAY...Southwest winds 5 to 15 knots.
.MONDAY NIGHT...Southwest winds 10 to 20 knots.
.TUESDAY...Southwest winds 5 to 15 knots becoming northeast less
than 10 knots.
.WEDNESDAY...East winds 5 to 15 knots.

Note, waves omitted for mostly ice covered areas.

$$

LSZ263-241715-
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-
402 AM EST Sat Feb 24 2018

...GALE WARNING IN EFFECT FROM SUNDAY MORNING THROUGH LATE SUNDAY
NIGHT...

.EARLY THIS MORNING...West winds 5 to 15 knots.
.TODAY...Southwest winds less than 10 knots backing south by late
morning, then becoming northeast 5 to 15 knots by mid afternoon.
.TONIGHT...East winds 10 to 20 knots increasing to 20 to 30 knots
by midnight, then diminishing to 15 to 25 knots late. A slight
chance of snow in the evening, then snow after midnight.
.SUNDAY...West gales to 45 knots. A chance of snow. A slight
chance of drizzle in the afternoon.
.SUNDAY NIGHT...West gales to 40 knots diminishing to 20 to
30 knots after midnight. A slight chance of snow showers.
.MONDAY...Southwest winds 5 to 15 knots.
.MONDAY NIGHT...Southwest winds 10 to 20 knots.
.TUESDAY...Southwest winds 5 to 15 knots becoming northeast less
than 10 knots.
.WEDNESDAY...East winds 5 to 15 knots.

Note, waves omitted for mostly ice covered areas.

$$

LSZ264-241715-
Lake Superior from Upper Entrance to Portage Canal to Manitou
Island MI 5NM off shore to the US/Canadian Border-
402 AM EST Sat Feb 24 2018

...GALE WARNING IN EFFECT FROM SUNDAY MORNING THROUGH LATE SUNDAY
NIGHT...

.EARLY THIS MORNING...West winds 5 to 15 knots.
.TODAY...West winds 5 to 15 knots backing southwest by late
morning, then backing southeast by mid afternoon.
.TONIGHT...East winds 10 to 20 knots increasing to 20 to 30 knots
by midnight. A chance of snow in the evening, then snow after
midnight.
.SUNDAY...East gales to 40 knots becoming west gales to 45 knots.
A chance of snow. A chance of drizzle in the afternoon.
.SUNDAY NIGHT...West gales to 40 knots diminishing to 20 to
30 knots after midnight. A slight chance of snow showers.
.MONDAY...Southwest winds 10 to 20 knots.
.MONDAY NIGHT...Southwest winds 15 to 25 knots veering west after
midnight.
.TUESDAY...West winds 10 to 20 knots becoming southwest 5 to
15 knots.
.WEDNESDAY...East winds 5 to 15 knots increasing to 15 to
25 knots.

Note, waves omitted for mostly ice covered areas.

$$

LSZ265-241715-
Lake Superior West of Line from Manitou Island to Marquette MI
Beyond 5NM from shore-
402 AM EST Sat Feb 24 2018

...GALE WARNING IN EFFECT FROM SUNDAY MORNING THROUGH LATE SUNDAY
NIGHT...

.EARLY THIS MORNING...West winds 5 to 15 knots.
.TODAY...Southwest winds 5 to 15 knots backing south by late
morning, then becoming southeast 10 to 20 knots by mid afternoon.
.TONIGHT...East winds 10 to 20 knots increasing to 20 to 30 knots
by midnight, then becoming southeast 15 to 25 knots late. A
chance of snow in the evening, then snow, possibly mixed with
rain after midnight.
.SUNDAY...West gales to 45 knots. A chance of snow and a slight
chance of drizzle.
.SUNDAY NIGHT...West gales to 35 knots diminishing to 20 to
30 knots after midnight. A slight chance of snow showers.
.MONDAY...Southwest winds 10 to 20 knots backing south in the
afternoon.
.MONDAY NIGHT...Southwest winds 15 to 25 knots becoming west
10 to 20 knots after midnight.
.TUESDAY...West winds 5 to 15 knots backing southwest.
.WEDNESDAY...East winds 5 to 15 knots increasing to 10 to
20 knots.

Note, waves omitted for mostly ice covered areas.

$$

LSZ266-241715-
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-
402 AM EST Sat Feb 24 2018

...GALE WARNING IN EFFECT FROM LATE TONIGHT THROUGH LATE SUNDAY
NIGHT...

.EARLY THIS MORNING...West winds 5 to 15 knots. Waves calm to
2 feet.
.TODAY...West winds 5 to 15 knots backing southwest by late
morning, then backing southeast by mid afternoon. Waves calm to
2 feet.
.TONIGHT...East winds 15 to 25 knots increasing to gales to
35 knots by midnight, then becoming southeast gales to 40 knots
late. A chance of snow in the evening, then snow, possibly mixed
with rain after midnight. Waves building to 7 to 11 feet
occasionally to 14 feet.
.SUNDAY...South gales to 45 knots veering west. A chance of rain
in the morning. A chance of snow and drizzle. Waves subsiding to
3 to 6 feet occasionally to 8 feet, then building to 7 to 10 feet
occasionally to 13 feet.
.SUNDAY NIGHT...West gales to 40 knots. A chance of snow showers.
Waves subsiding to 3 to 5 feet occasionally to 7 feet.
.MONDAY...Southwest winds 10 to 20 knots backing south in the
afternoon. Waves subsiding to calm to 2 feet.
.MONDAY NIGHT...Southwest winds 15 to 25 knots diminishing to
10 to 20 knots after midnight. Waves building to 2 to 4 feet.
.TUESDAY...West winds 10 to 20 knots becoming southwest 5 to
15 knots. Waves subsiding to calm to 2 feet.
.WEDNESDAY...East winds 10 to 20 knots increasing to 15 to
25 knots. Waves building to 3 to 5 feet occasionally to 7 feet.

Note, wave height forecasts are for ice free areas.

$$

LSZ267-241715-
Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off
shore to the US/Canadian border-
402 AM EST Sat Feb 24 2018

...GALE WARNING IN EFFECT FROM LATE TONIGHT THROUGH LATE SUNDAY
NIGHT...

.EARLY THIS MORNING...West winds 5 to 15 knots. Waves calm to
2 feet.
.TODAY...West winds 5 to 15 knots backing southwest by late
morning, then backing southeast by mid afternoon. Waves calm to
2 feet.
.TONIGHT...East winds 15 to 25 knots increasing to gales to
35 knots by midnight, then becoming southeast gales to 45 knots
late. Snow, possibly mixed with rain after midnight. Waves
building to 5 to 9 feet occasionally to 11 feet.
.SUNDAY...Southwest gales to 45 knots veering west. A chance of
rain in the morning. A chance of snow. A chance of drizzle in the
afternoon. Waves subsiding to 3 to 5 feet occasionally to 7 feet,
then building to 7 to 10 feet occasionally to 13 feet.
.SUNDAY NIGHT...West gales to 40 knots diminishing to 20 to
30 knots after midnight. A chance of snow showers. Waves
subsiding to 3 to 5 feet occasionally to 7 feet.
.MONDAY...Southwest winds 15 to 25 knots becoming south 10 to
20 knots in the afternoon. Waves subsiding to calm to 2 feet.
.MONDAY NIGHT...South winds 15 to 25 knots becoming southwest
10 to 20 knots after midnight. Waves building to 2 to 4 feet.
.TUESDAY...West winds 10 to 20 knots becoming east 5 to 15 knots.
Waves subsiding to calm to 2 feet.
.WEDNESDAY...East winds 10 to 20 knots. Waves building to 2 to
4 feet.

Note, wave height forecasts are for ice free areas.

$$

LSZ261-241715-
MAFOR 2410/
Superior West 11600 11500 11400 11200 11120 11130 12147. Chance
of snow late this evening. Waves omitted for mostly ice covered
areas.

Superior North Central 11600 12500 11400 11310 11220 11240 11247.
Chance of snow after midnight tonight. Waves omitted for mostly
ice covered areas.

Superior South Central...Gale Warning in effect...12500 11400
12310 11230 11240 11347. Chance of snow late this evening. Waves
omitted for mostly ice covered areas.

Superior East...Gale Warning in effect...12610 11500 11400 11320
11330 11250 11357. Chance of snow after midnight tonight. Waves 2
feet or less today. Waves 1 to 3 feet building to 6 to 10 feet
tonight.

$$

JLA

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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