735
FZUS63 KMKX 130820
GLFLM

OPEN LAKE FORECAST for Lake Michigan
National Weather Service Milwaukee/Sullivan WI
320 AM CDT Thu Aug 13 2026

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 stalled frontal boundary just to the south of Lake Michigan will
remain in place until midday today, before retreating south
toward the Ohio River Valley. Periodic rain, storms and areas of
fog will be possible across the southern half of the lake until
this front moves south. Light and variable winds are expected
across the Lake today into tonight.

High pressure around 30.3 inches is expected to build down from
Ontario into the eastern Great Lakes tonight into Friday.
Northeast to east winds will increase across the lake becoming
breezy as the high pressure builds in and a low pressure system
develops across the Central Plains. As the low pressure around
29.9 inches moves northeast toward the Great Lakes Region, the
high pressure will be slowly moving northeast toward the New
England States. Winds will turn to southeasterly and remain breezy
Saturday ahead of the approaching low. This low is expected to
track across the Lake late Saturday into Sunday. Rain and
thunderstorms will be possible across the Lake Saturday into
Saturday night. As the low exits to the northeast Sunday, high
pressure around 30.2 inches is expected to move in from the
northern plains for early next week.

LMZ261-362-364-366-563-565-567-868-131530-
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-
320 AM CDT Thu Aug 13 2026

SHEBOYGAN WI TO PENTWATER MI NORTH...

.TODAY...Northeast winds less than 10 kt becoming northwest late
this morning, then becoming southwest early this afternoon
becoming south late. Waves 1 ft or less.
.TONIGHT...Northeast winds 5 to 10 kt increasing to 10 to 15 kt.
Waves 1 to 2 ft.
.FRIDAY...Northeast winds 10 to 15 kt increasing to 15 to 25 kt.
Waves 2 to 4 ft.
.FRIDAY NIGHT...Northeast winds 10 to 20 kt becoming southeast.
Waves 2 to 4 ft.
.SATURDAY...Southeast winds 15 to 25 kt. Chance of showers. Waves
4 to 6 ft occasionally to 8 ft.
.SATURDAY NIGHT...South winds 10 to 20 kt becoming southwest
10 to 15 kt. Showers likely with a chance of thunderstorms. Waves
3 to 5 ft subsiding to 2 to 4 ft.
.SUNDAY...Northwest winds 10 to 20 kt becoming north 15 to 25 kt.
Waves 1 to 3 ft.
.MONDAY...North winds 10 to 20 kt backing to west. Waves 1 to
3 ft.

$$

LMZ080-669-671-673-675-777-779-870-872-874-876-878-131530-
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-
320 AM CDT Thu Aug 13 2026

SHEBOYGAN WI TO PENTWATER MI SOUTH...

.TODAY...East winds 5 to 10 kt. Patchy fog this morning. Chance
of showers this afternoon. Waves 1 ft or less.
.TONIGHT...East winds 10 to 15 kt. Chance of showers. Waves 1 to
2 ft.
.FRIDAY...East winds 10 to 15 kt becoming northeast 10 to 20 kt
early in the afternoon, then increasing to 15 to 25 kt late.
Chance of showers in the morning. Waves 2 to 4 ft.
.FRIDAY NIGHT...Northeast winds 10 to 20 kt becoming southeast.
Chance of showers overnight. Waves 3 to 5 ft.
.SATURDAY...Southeast winds 15 to 25 kt. Showers likely. Waves
4 to 6 ft occasionally to 8 ft.
.SATURDAY NIGHT...South winds 10 to 20 kt becoming southwest.
Showers likely with a chance of thunderstorms. Waves 3 to 5 ft
subsiding to 2 to 4 ft.
.SUNDAY...West winds 10 to 20 kt becoming northwest. Waves 2 to
4 ft.
.MONDAY...North winds 10 to 20 kt. Waves 2 to 4 ft.

$$

LMZ761-131530-
MAFOR 1310/
MICHIGAN NORTH 11100 11800 12510 11110 12100 11110. Waves 1 foot
or less.

MICHIGAN SOUTH 12200 12300 11210 11110 12210. A chance of showers
this afternoon and tonight. Waves 2 feet or less.

$$


CMiller

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

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