


Nearshore Marine Forecast
Issued by NWS Chicago, IL
Issued by NWS Chicago, IL
758 FZUS53 KLOT 181502 NSHLOT Nearshore Marine Forecast National Weather Service Chicago/Romeoville IL 1002 AM CDT Mon Aug 18 2025 For waters within 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 waves, along with the average height of the highest 10 percent of the waves which will occasionally be encountered. LMZ740>742-182115- Winthrop Harbor to Wilmette Harbor IL- Wilmette Harbor to Northerly Island IL- Northerly Island to Calumet Harbor IL- 1002 AM CDT Mon Aug 18 2025 .REST OF TODAY...Southeast winds 15 to 20 kt diminishing to 10 to 15 kt. Scattered showers and thunderstorms. Waves 2 to 4 ft subsiding to 1 to 3 ft. .TONIGHT...Southeast winds around 10 kt becoming south overnight. Numerous showers and thunderstorms in the evening, then chance of showers and thunderstorms overnight. Waves 1 to 2 ft. .TUESDAY...Southwest winds around 10 kt becoming northeast in the afternoon. 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. .TUESDAY NIGHT...Northeast winds around 10 kt becoming north 15 to 20 kt. Mostly cloudy. Waves 1 to 2 ft building to 3 to 5 ft. $$ LMZ743>745-182115- Calumet Harbor IL to Gary IN-Gary to Burns Harbor IN- Burns Harbor to Michigan City IN- 1002 AM CDT Mon Aug 18 2025 .REST OF TODAY...Southeast winds 10 to 15 kt diminishing to 5 to 10 kt. Scattered showers and thunderstorms. Waves 1 to 2 ft. .TONIGHT...Southeast winds 5 to 10 kt becoming south 10 to 15 kt. Numerous showers and thunderstorms in the evening, then chance of showers and thunderstorms overnight. Waves around 1 ft. .TUESDAY...Southwest winds 10 to 15 kt becoming north in the afternoon. Chance of showers and thunderstorms in the morning, then slight chance of showers and thunderstorms in the afternoon. Waves around 1 ft. .TUESDAY NIGHT...North winds around 10 kt increasing to 15 to 20 kt late. Partly cloudy in the evening, then becoming mostly cloudy. Waves 1 to 2 ft building to 2 to 4 ft. $$ Lenning