Great Lakes Forecast
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FZUS63 KMQT 211947
GLFLS

Open Lake Forecast for Lake Superior
National Weather Service Marquette MI
347 PM EDT Mon May 21 2018

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...A high pressure ridge of 30.2 inches extending across
the Upper Great Lakes will linger through Tuesday as it weakens.
A weak low pressure trough of 30.0 inches will then drop south
across Lake Superior late Tuesday night and Wednesday morning. In
its wake, high pressure of 30.2 inches will build over northern
Ontario Wednesday. The high will then shift over the Great Lakes
region through Thursday as one low pressure trough of 29.7 inches
drops south into northern Ontario and a second trough of 29.7
inches moves over the western Plains. This troughing will stall
and weaken just west of Lake Superior on Friday night and
Saturday.

LSZ162-220400-
Lake Superior west of a line from Saxon Harbor WI to Grand
Portage MN beyond 5NM-
347 PM EDT Mon May 21 2018 /247 PM CDT Mon May 21 2018/

.LATE THIS AFTERNOON...Northeast winds 5 to 15 knots. Waves calm
to 2 feet.
.TONIGHT...Northeast winds 5 to 15 knots becoming west less than
10 knots after midnight. Waves calm to 2 feet.
.TUESDAY...Southwest winds 5 to 15 knots. Waves calm to 2 feet.
.TUESDAY NIGHT...Southwest winds 5 to 15 knots becoming west less
than 10 knots late. Waves calm to 2 feet.
.WEDNESDAY...Southwest winds less than 10 knots backing east by
mid afternoon. Waves calm to 2 feet.
.WEDNESDAY NIGHT...East winds less than 10 knots. Waves calm to
2 feet.
.THURSDAY...East winds less than 10 knots. Waves calm to 2 feet.
.THURSDAY NIGHT...South winds 5 to 15 knots veering southwest
after midnight. A chance of showers and thunderstorms. Waves calm
to 2 feet.
.FRIDAY...Southwest winds 5 to 15 knots veering west. Waves calm
to 2 feet.
.SATURDAY...Northeast winds 5 to 15 knots. Waves building to 2 to
4 feet, then subsiding to 1 to 3 feet.

$$

LSZ263-220400-
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-
347 PM EDT Mon May 21 2018

.LATE THIS AFTERNOON...Northeast winds 5 to 15 knots. Waves calm
to 2 feet.
.TONIGHT...East winds 5 to 15 knots veering south after midnight,
then becoming southwest less than 10 knots late. Waves calm to
2 feet.
.TUESDAY...Southwest winds 5 to 15 knots. Waves calm to 2 feet.
.TUESDAY NIGHT...Southwest winds 5 to 15 knots. Waves calm to
2 feet.
.WEDNESDAY...West winds less than 10 knots backing east by mid
afternoon. Waves calm to 2 feet.
.WEDNESDAY NIGHT...East winds less than 10 knots veering south
after midnight. Waves calm to 2 feet.
.THURSDAY...South winds less than 10 knots The western Plains trough
will reach the Upper Mississippi Valley late Friday.
becoming east 5 to 15 knots by mid afternoon. Waves calm to 2
feet.
.THURSDAY NIGHT...South winds 5 to 15 knots veering southwest
after midnight. A chance of showers and thunderstorms. Waves calm
to 2 feet.
.FRIDAY...Southwest winds 5 to 15 knots backing northeast. A
chance of showers and thunderstorms. Waves calm to 2 feet.
.SATURDAY...Northeast winds 5 to 15 knots veering east. A chance
of showers and thunderstorms. Waves building to 2 to 4 feet, then
subsiding to 1 to 3 feet.

$$

LSZ264-220400-
Lake Superior from Upper Entrance to Portage Canal to Manitou
Island MI 5NM off shore to the US/Canadian Border-
347 PM EDT Mon May 21 2018

.LATE THIS AFTERNOON...Southeast winds 10 to 20 knots. Waves calm
to 2 feet.
.TONIGHT...Southeast winds 5 to 15 knots veering south after
midnight. Waves calm to 2 feet.
.TUESDAY...Southwest winds 5 to 15 knots. Waves calm to 2 feet.
.TUESDAY NIGHT...Southwest winds 5 to 15 knots increasing to
10 to 20 knots after midnight, then diminishing to 5 to 15 knots
late. Waves calm to 2 feet.
.WEDNESDAY...Northeast winds 5 to 15 knots veering east 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 backing southeast by mid
afternoon. Waves calm to 2 feet.
.THURSDAY NIGHT...South winds 5 to 15 knots increasing to 10 to
20 knots after midnight. Showers and thunderstorms likely after
midnight. Waves calm to 2 feet.
.FRIDAY...Southwest winds 5 to 15 knots becoming east 10 to
20 knots. A chance of showers and thunderstorms. Waves building
to 1 to 3 feet.
.SATURDAY...East winds 10 to 20 knots. A chance of showers and
thunderstorms. Waves building to 2 to 4 feet, then subsiding to
calm to 2 feet.

$$

LSZ265-220400-
Lake Superior West of Line from Manitou Island to Marquette MI
Beyond 5NM from shore-
347 PM EDT Mon May 21 2018

.LATE THIS AFTERNOON...Southeast winds 10 to 20 knots. Waves calm
to 2 feet building to 1 to 3 feet.
.TONIGHT...Southeast winds 5 to 15 knots veering south after
midnight. Waves subsiding to calm to 2 feet.
.TUESDAY...South winds 5 to 15 knots backing east late. Waves
calm to 2 feet.
.TUESDAY NIGHT...South winds 5 to 15 knots veering southwest
after midnight. Waves calm to 2 feet.
.WEDNESDAY...East winds 5 to 15 knots. 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 backing southeast by mid
afternoon. Waves calm to 2 feet.
.THURSDAY NIGHT...South winds 5 to 15 knots veering southwest
after midnight. A chance of showers and thunderstorms. Waves calm
to 2 feet.
.FRIDAY...Southeast winds 5 to 15 knots. A chance of showers and
thunderstorms. Waves calm to 2 feet.
.SATURDAY...East winds 10 to 20 knots. Waves building to 1 to
3 feet, then subsiding to calm to 2 feet.

$$

LSZ266-220400-
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-
347 PM EDT Mon May 21 2018

.LATE THIS AFTERNOON...East winds 5 to 15 knots. Waves calm to
2 feet.
.TONIGHT...Southeast winds 5 to 15 knots veering south after
midnight. Waves calm to 2 feet.
.TUESDAY...South winds 5 to 15 knots backing east late. Waves
calm to 2 feet.
.TUESDAY NIGHT...South winds 5 to 15 knots veering southwest
after midnight. Waves calm to 2 feet.
.WEDNESDAY...South winds 5 to 15 knots backing northeast 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 backing southeast by mid
afternoon. Waves calm to 2 feet.
.THURSDAY NIGHT...South winds 10 to 20 knots. Showers and
thunderstorms likely after midnight. Waves building to 1 to
3 feet.
.FRIDAY...South winds 5 to 15 knots backing east. A chance of
showers and thunderstorms. Waves subsiding to calm to 2 feet,
then building to 1 to 3 feet.
.SATURDAY...East winds 10 to 20 knots. A chance of showers and
thunderstorms. Waves building to 2 to 4 feet, then subsiding to
calm to 2 feet.

$$

LSZ267-220400-
Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off
shore to the US/Canadian border-
347 PM EDT Mon May 21 2018

.LATE THIS AFTERNOON...East winds 5 to 15 knots. Waves calm to
2 feet.
.TONIGHT...Southeast winds 5 to 15 knots veering south after
midnight. Waves calm to 2 feet.
.TUESDAY...Southeast winds 5 to 15 knots backing northeast late.
Waves calm to 2 feet.
.TUESDAY NIGHT...Northwest winds 5 to 15 knots backing southwest
late. Waves calm to 2 feet.
.WEDNESDAY...East winds 5 to 15 knots backing northwest by mid
afternoon. Waves calm to 2 feet.
.WEDNESDAY NIGHT...South winds 5 to 15 knots. Waves calm to
2 feet.
.THURSDAY...South winds 5 to 15 knots backing southeast by mid
afternoon. Waves calm to 2 feet.
.THURSDAY NIGHT...South winds 10 to 20 knots. A chance of showers
and thunderstorms. Waves building to 1 to 3 feet.
.FRIDAY...South winds 5 to 15 knots backing southeast. A chance
of showers and thunderstorms. Waves subsiding to calm to 2 feet.
.SATURDAY...East winds 10 to 20 knots. A chance of showers and
thunderstorms. Waves building to 1 to 3 feet, then subsiding to
calm to 2 feet.

$$

LSZ261-220400-
MAFOR 2121/
Superior West 12100 11800 12600 11500 12510. Waves 2 feet or
less.

Superior North Central 13310 11410 14500. Waves 2 feet or less.

Superior South Central 12320 11410 14400 11300. Waves 1 to 3 feet
tonight. Waves 1 foot or less Tuesday.

Superior East 11200 12300 13400 12300. Waves 1 foot or less.

$$

KCW

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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