109
FZUS63 KMKX 181950
GLFLM

OPEN LAKE FORECAST for Lake Michigan
National Weather Service Milwaukee/Sullivan WI
250 PM CDT Fri Jul 18 2025

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 around 30.2 inches over the Great Lakes region will
slowly exit to the east tonight as low pressure around 29.7
inches develops in the lee of the Colorado Rockies. A warm front
will develop across northern Wisconsin and the Upper Peninsula
overnight, bringing thunderstorms to the northern half of the lake
into the late overnight hours. Additional thunderstorm development
is expected across the southern half into Saturday morning. Winds
become southwesterly as these storms end midday Saturday, then
become northerly behind a cold front Saturday afternoon. Isolated
thunderstorms are possible along this front. High pressure around
30.0 inches will settle back into the region on Sunday, slowly
departing into Monday and shifting winds to easterly. A low
pressure trough of 29.8 inches will cross the Upper Midwest on
Tuesday, bringing southeasterly winds.


LMZ261-362-364-366-563-565-567-868-190315-
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-
250 PM CDT Fri Jul 18 2025

SHEBOYGAN WI TO PENTWATER MI NORTH...

.TONIGHT...Southwest winds 5 to 10 kt becoming south. Slight
chance of showers overnight. Waves 1 ft or less.
.SATURDAY...South winds 10 to 15 kt increasing to 10 to 20 kt,
then veering to northwest 10 to 15 kt late. Chance of showers and
thunderstorms in the morning, then chance of showers and slight
chance of thunderstorms in the afternoon. Waves 1 to 2 ft.
.SATURDAY NIGHT...North winds 10 to 15 kt. Waves 1 to 3 ft.
.SUNDAY...North winds 10 to 15 kt increasing to 10 to 20 kt.
Waves 1 to 3 ft.
.SUNDAY NIGHT...Northeast winds 10 to 20 kt diminishing to 10 to
15 kt. Waves 1 to 2 ft.
.MONDAY...East winds 10 to 15 kt. Waves 1 to 3 ft.
.MONDAY NIGHT...East winds 10 to 15 kt becoming southeast 10 to
20 kt. Waves 1 to 3 ft.
.TUESDAY...South winds 10 to 20 kt. Waves 2 to 4 ft.
.WEDNESDAY...Southwest winds 10 to 20 kt. Chance of showers and
thunderstorms. Waves 1 to 3 ft.

$$

LMZ080-669-671-673-675-777-779-870-872-874-876-878-190315-
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-
250 PM CDT Fri Jul 18 2025

SHEBOYGAN WI TO PENTWATER MI SOUTH...

.TONIGHT...East winds 5 to 10 kt becoming south. Waves 1 to 2 ft.
.SATURDAY...South winds 10 to 15 kt becoming southwest 10 to
20 kt. Chance of showers and slight chance of thunderstorms in
the morning, then chance of showers and thunderstorms in the
afternoon. Waves 1 to 3 ft.
.SATURDAY NIGHT...Northwest winds 10 to 15 kt becoming north.
Chance of showers and thunderstorms in the evening. Waves 1 to
3 ft.
.SUNDAY...Northeast winds 10 to 20 kt becoming north. Waves 2 to
4 ft.
.SUNDAY NIGHT...Northeast winds 10 to 20 kt becoming east 10 to
15 kt. Waves 1 to 3 ft.
.MONDAY...East winds 10 to 20 kt diminishing to 10 to 15 kt.
Waves 2 to 4 ft.
.MONDAY NIGHT...East winds 10 to 15 kt becoming southeast 10 to
20 kt. Waves 1 to 3 ft.
.TUESDAY...Southeast winds 10 to 20 kt becoming south. Waves 2 to
4 ft.
.WEDNESDAY...South winds 10 to 20 kt becoming southwest. Waves
2 to 4 ft.

$$

LMZ761-190315-
MAFOR 1822/
MICHIGAN NORTH 11500 13400 11410 11416 11410 11710. A chance of
thunderstorms Saturday morning. Waves 2 feet or less.

MICHIGAN SOUTH 11200 12300 11400 12410 11526 11520. A chance of
thunderstorms Saturday afternoon. Waves 2 feet or less.

$$


MH

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

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