643
FZUS63 KMKX 130200
GLFLM

OPEN LAKE FORECAST for Lake Michigan
National Weather Service Milwaukee/Sullivan WI
900 PM CDT Wed Aug 12 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 into mid day Thursday 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
Thursday into Thursday night.

High pressure around 30.3 inches is expected to build down from
Ontario into the eastern Great Lakes Thursday night 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.

LMZ261-362-364-366-563-565-567-868-130915-
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-
900 PM CDT Wed Aug 12 2026

SHEBOYGAN WI TO PENTWATER MI NORTH...

.REST OF TONIGHT...North winds 5 to 10 kt becoming northeast.
Waves 1 ft or less.
.THURSDAY...Northeast winds 5 to 10 kt increasing to 10 to 15 kt.
Waves nearly calm.
.THURSDAY NIGHT...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 10 to 20 kt.
Waves 1 to 3 ft.
.FRIDAY NIGHT...Northeast winds 10 to 20 kt becoming east. Waves
2 to 4 ft.
.SATURDAY...Southeast winds 15 to 25 kt. Waves 3 to 5 ft.
.SATURDAY NIGHT...Southeast winds 10 to 20 kt becoming southwest.
Chance of showers and thunderstorms. Waves 1 to 3 ft.
.SUNDAY...Northwest winds 10 to 20 kt becoming north 15 to 25 kt.
Waves 1 to 3 ft.
.MONDAY...North winds 10 to 15 kt becoming west 10 to 20 kt.
Waves 1 to 2 ft.

$$

LMZ080-669-671-673-675-777-779-870-872-874-876-878-130915-
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-
900 PM CDT Wed Aug 12 2026

SHEBOYGAN WI TO PENTWATER MI SOUTH...

.REST OF TONIGHT...North winds 5 to 10 kt becoming northeast.
Areas of fog. Waves 1 ft or less.
.THURSDAY...East winds 5 to 10 kt becoming northeast. Areas of
fog in the morning. Chance of showers in the afternoon. Waves 1 ft
or less.
.THURSDAY NIGHT...Northeast winds 5 to 10 kt becoming east 10 to
15 kt. Chance of showers overnight. Waves 1 to 2 ft.
.FRIDAY...East winds 10 to 15 kt becoming northeast 10 to 20 kt.
Chance of showers in the morning. Waves 1 to 3 ft.
.FRIDAY NIGHT...Northeast winds 10 to 20 kt becoming east. Chance
of showers and thunderstorms in the evening, then chance of
showers overnight. Waves 2 to 4 ft building to 3 to 5 ft.
.SATURDAY...Southeast winds 15 to 25 kt. Chance of showers. Waves
3 to 5 ft.
.SATURDAY NIGHT...South winds 10 to 20 kt becoming southwest
10 to 15 kt. Chance of showers and thunderstorms. Waves 1 to
3 ft.
.SUNDAY...Northwest winds 10 to 20 kt becoming north. Chance of
showers and thunderstorms. Waves 1 to 3 ft.
.MONDAY...North winds 10 to 20 kt. Waves 2 to 4 ft.

$$

LMZ761-130915-
MAFOR 1304/
MICHIGAN NORTH 14100 12810 11110 11100. Waves 1 foot or less.

MICHIGAN SOUTH 12100 11200 11200 19204 11200 13100. A chance of
showers Thursday afternoon. Waves 1 foot or less.

$$


Sheppard

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

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