Great Lakes Forecast
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000
FZUS63 KLOT 211350
GLFLM

OPEN LAKE FORECAST for Lake Michigan
National Weather Service Chicago/Romeoville IL
850 AM CDT Mon Aug 21 2017

FOR WATERS BEYOND FIVE NAUTICAL MILES OF SHORE ON Lake Michigan.

Waves are provided as a range of significant wave heights, which
is the average of the highest 1/3 of the wave, along with the
average height of the highest 10% of the waves which will
occasionally be encountered.

.SYNOPSIS...A weak trough of low pressure of 30.0 inches extends
across the upper Great Lakes with an associated frontal boundary
within this trough extending southwest to low pressure of 29.7
inches over the western plains. The front will remain nearly
stationary through Tuesday evening. High pressure of 30.1 inches
building out of central Canada will begin to force the front south
down Lake Michigan Monday night. Low pressure of 29.7 inches is
expected to develop along the front and track across northern Lake
Michigan Late Monday night. As the low moves off to the east and
high pressure spreads across the northern plains and Upper
Mississippi Valley, the cold front will accelerate down the lake
early Tuesday, and push south of the lake by Tuesday afternoon.
Winds will turn northerly and strengthen following the frontal
passage. High pressure of 30.0 inches will park over the upper
Midwest through midweek as the exiting low deepens to 29.2 inches
as it movies into northern Quebec Wednesday afternoon. The high
will spread slowly wast across the Great Lakes late this week and
into the weekend.

LMZ261-362-364-366-563-565-567-868-212130-
Lake Michigan from Seul Choix Point to Rock Island Passage 5 NM
offshore to Mid Lake-
Lake Michigan South of a line from Seul Choix Point to the
Mackinac Bridge and north of a line from Charlevoix MI to South
Fox Island 5 NM offshore-
Lake Michigan from Charlevoix to Point Betsie MI 5 NM offshore to
Mid Lake-
Lake Michigan from Point Betsie to Manistee MI 5 NM offshore to
Mid Lake-
Lake Michigan from Rock Island Passage to Sturgeon Bay WI-
Lake Michigan from Sturgeon Bay to Two Rivers WI 5 NM offshore to
Mid Lake-
Lake Michigan from Two Rivers to Sheboygan WI 5 NM offshore to
Mid Lake-
Lake Michigan from Pentwater to Manistee MI 5 NM offshore to Mid
Lake-
850 AM CDT Mon Aug 21 2017

SHEBOYGAN WI TO PENTWATER MI NORTH...

.REST OF TODAY...Southwest winds 5 to 10 kt becoming south 10 to
15 kt. Slight chance of showers this afternoon. Waves 1 to 3 ft.
.TONIGHT...South winds 10 to 20 kt becoming west 15 to 25 kt.
Showers and thunderstorms likely in the evening...then showers
with thunderstorms likely overnight. Waves 1 to 3 ft building to
3 to 5 ft.
.TUESDAY...Northwest winds to 30 kt diminishing to 10 to 20 kt.
Chance of showers in the morning. Waves 4 to 7 ft occasionally to
9 ft subsiding to 3 to 5 ft.
.TUESDAY NIGHT...Northwest winds 15 to 25 kt. Waves 4 to 6 ft
occasionally to 8 ft.
.WEDNESDAY...Northwest winds 15 to 25 kt becoming north 10 to
20 kt. Waves 3 to 5 ft.
.WEDNESDAY NIGHT...North winds 10 to 20 kt. Waves 2 to 4 ft.
.THURSDAY...North winds 10 to 15 kt increasing to 10 to 20 kt.
Waves 1 to 3 ft.
.FRIDAY...Northeast winds 5 to 10 kt. Waves 1 to 2 ft.

$$

LMZ080-669-671-673-675-777-779-870-872-874-876-878-212130-
Lake Michigan from Michigan City IN to St. Joseph MI 5 NM
offshore to Mid Lake-
Lake Michigan from Sheboygan to Port Washington WI 5 NM offshore
to Mid Lake-
Lake Michigan from Port Washington to North Point Light WI 5 NM
offshore to Mid Lake-
Lake Michigan from North Point Light to Wind Point WI 5 NM
offshore to Mid Lake-
Lake Michigan from Wind Point WI to Winthrop Harbor IL 5 NM
offshore to Mid Lake-
Lake Michigan from Winthrop Harbor to Wilmette Harbor IL 5 NM
offshore to Mid Lake-
Lake Michigan from Wilmette Harbor IL to Michigan City IN 5 NM
offshore to Mid Lake-
Lake Michigan from Whitehall to Pentwater MI 5 NM offshore to Mid
Lake-
Lake Michigan from Grand Haven to Whitehall MI 5 NM offshore to
Mid Lake-
Lake Michigan from Holland to Grand Haven MI 5 NM offshore to Mid
Lake-
Lake Michigan from South Haven to Holland MI 5 NM offshore to Mid
Lake-
Lake Michigan from St. Joseph to South Haven MI 5 NM offshore to
Mid Lake-
850 AM CDT Mon Aug 21 2017

SHEBOYGAN WI TO PENTWATER MI SOUTH...

.REST OF TODAY...Southwest winds 10 to 15 kt becoming south.
Slight chance of showers and thunderstorms this afternoon. Waves 1
to 3 ft.
.TONIGHT...South winds 10 to 20 kt becoming southwest 15 to
25 kt. Chance of showers and thunderstorms in the evening... then
showers and thunderstorms likely overnight. Waves 1 to 3 ft
building to 4 to 6 ft occasionally to 8 ft.
.TUESDAY...West winds to 30 kt becoming northwest late in the
morning...then becoming northwest to 30 kt early in the afternoon
diminishing to 10 to 20 kt late. Chance of showers and
thunderstorms in the morning...then chance of showers in the
afternoon. Waves 5 to 8 ft occasionally to 10 ft.
.TUESDAY NIGHT...Northwest winds 15 to 25 kt diminishing to 10 to
20 kt. Waves 4 to 6 ft occasionally to 8 ft.
.WEDNESDAY...Northwest winds 10 to 20 kt becoming north. Waves
4 to 6 ft occasionally to 8 ft.
.WEDNESDAY NIGHT...North winds 10 to 20 kt becoming northeast.
Waves 3 to 5 ft.
.THURSDAY...Northeast winds 10 to 20 kt. Waves 1 to 3 ft.
.FRIDAY...East winds 10 to 15 kt becoming northeast. Waves 1 to
2 ft.

$$
LMZ761-212130-
MAFOR 2115/
MICHIGAN NORTH 11500 11510 11410 11420 11439 11539 11636 11740.
Chance of showers and thunderstorms late tonight. Chance of
showers Tuesday morning. Waves 1 to 3 feet today. Waves 1 to 3
feet building to 3 to 5 feet tonight. Waves 4 to 7 feet
occasionally to 9 feet Tuesday morning.

MICHIGAN SOUTH 11510 12410 11420 11520 12539 11646. Chance of
showers and thunderstorms this afternoon and tonight. Chance of
thunderstorms Tuesday morning. Waves 1 to 3 feet today building
to 4 to 6 feet occasionally to 8 feet tonight. Waves 4 to 7 feet
occasionally to 9 feet building to 5 to 8 feet occasionally to 10
feet Tuesday morning.

$$

MDB

Experimental modernized open lake forecast is available online at
weather.gov/lot/glftable

Graphical marine forecasts are available online at:
weather.gov/greatlakes



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