421
FZUS63 KMKX 250803
GLFLM

OPEN LAKE FORECAST for Lake Michigan
National Weather Service Milwaukee/Sullivan WI
303 AM CDT Tue Aug 25 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...

High pressure of 30.1 inches centered over southern Lake Michigan
will exit the region as low pressure system around 29.7 inches
approaches from the northern Plains. As the low crosses Lake
Superior east, an associated cold front will move across Lake
Michigan Wednesday. Showers and thunderstorms will accompany the
approaching/passing surface low and cold front tonight into
Wednesday. An isolated stronger storm with hail and gusty winds
will be possible but chances are low. Increasing southerly winds
today will shift to the northwest late Wednesday afternoon/evening.
Breezy northwest winds are expected through Wednesday night.

High pressure around 30.1 inches will gradually build in from the
Northern Plains behind this exiting low for Thursday and Friday.
Light north to northeast winds are expected.

LMZ261-362-364-366-563-565-567-868-251530-
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-
303 AM CDT Tue Aug 25 2026

SHEBOYGAN WI TO PENTWATER MI NORTH...

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

$$

LMZ080-669-671-673-675-777-779-870-872-874-876-878-251530-
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-
303 AM CDT Tue Aug 25 2026

SHEBOYGAN WI TO PENTWATER MI SOUTH...

.TODAY...South winds 5 to 10 kt increasing to 15 to 25 kt. Waves
1 ft or less building to 3 to 5 ft.
.TONIGHT...South winds 15 to 25 kt becoming southwest. Slight
chance of showers and thunderstorms overnight. Waves 3 to 5 ft
building to 4 to 6 ft occasionally to 8 ft.
.WEDNESDAY...Southwest winds 15 to 25 kt diminishing to 10 to
20 kt. Chance of showers. Waves 4 to 7 ft occasionally to 9 ft
subsiding to 3 to 5 ft.
.WEDNESDAY NIGHT...West winds 10 to 20 kt becoming northwest.
Waves 2 to 4 ft.
.THURSDAY...North winds 10 to 20 kt increasing to 15 to 25 kt.
Waves 2 to 4 ft.
.THURSDAY NIGHT...North winds 10 to 20 kt becoming northeast
10 to 15 kt. Waves 2 to 4 ft subsiding to 1 to 3 ft.
.FRIDAY...Northeast winds 5 to 10 kt increasing to 10 to 15 kt.
Waves 1 to 2 ft.
.SATURDAY...South winds 10 to 20 kt increasing to 30 kt. Waves
1 to 3 ft building to 3 to 5 ft.

$$

LMZ761-251530-
MAFOR 2510/
MICHIGAN NORTH 11500 11510 11520 14430 11430. A chance of showers
overnight. Waves 1 foot or less building to 2 to 4 feet today.
Waves 3 to 5 feet tonight.

MICHIGAN SOUTH 11400 11410 11420 12430 12420 11530. Waves 2 feet
or less building to 2 to 4 feet today. Waves 2 to 4 feet building
to 3 to 5 feet tonight.

$$


Cronce

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

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