FZUS53 KLOT 180855 NSHLOT Nearshore Marine Forecast National Weather Service Chicago/Romeoville IL 355 AM CDT Mon May 18 2026 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>742-181515- Winthrop Harbor to Wilmette Harbor IL- Wilmette Harbor to Northerly Island IL- Northerly Island to Calumet Harbor IL- 355 AM CDT Mon May 18 2026 .TODAY...South winds 15 to 25 kt. Showers likely and a chance of thunderstorms this morning, then a slight chance of showers this afternoon. Waves 2 to 4 ft. .TONIGHT...South winds 15 to 25 kt. Slight chance of showers and thunderstorms in the evening, then chance of showers and thunderstorms overnight. Waves 2 to 4 ft. .TUESDAY...Southwest winds 20 to 25 kt becoming west 15 to 25 kt in the afternoon. Chance of showers and thunderstorms. Waves 3 to 5 ft subsiding to 2 to 4 ft. A small craft advisory may be needed. .TUESDAY NIGHT...Northwest winds 15 to 20 kt becoming north overnight. Slight chance of showers in the evening. Waves 2 to 4 ft. $$ LMZ743>745-181515- Calumet Harbor IL to Gary IN-Gary to Burns Harbor IN- Burns Harbor to Michigan City IN- 355 AM CDT Mon May 18 2026 .TODAY...South winds 15 to 25 kt. Showers likely and a chance of thunderstorms. Waves 2 to 4 ft. .TONIGHT...South winds 15 to 25 kt. Slight chance of showers and thunderstorms in the evening, then chance of showers and thunderstorms overnight. Waves 2 to 4 ft. .TUESDAY...Southwest winds 20 to 25 kt becoming west in the afternoon. Chance of showers and thunderstorms in the morning, then showers likely and a chance of thunderstorms in the afternoon. Waves 2 to 4 ft. A small craft advisory may be needed. .TUESDAY NIGHT...Northwest winds 15 to 20 kt becoming north overnight. Chance of showers and slight chance of thunderstorms in the evening. Waves 2 to 4 ft. $$ Ratzer