A National Weather Service gale warning is in effect until 10 p.m. Sunday, Oct. 18, for offshore Lake Michigan waters near Sheboygan.

In an update issued at 4:44 a.m. Sunday, the weather service office in Milwaukee and Sullivan listed the affected waters as those from Sturgeon Bay to Two Rivers and from Two Rivers to Sheboygan, from five nautical miles offshore to mid-lake.

Forecasters expect southwest winds of 20 to 30 knots, with gusts up to 35 knots, and waves building to 7 to 11 feet.

The weather service advises mariners to alter plans to avoid the hazardous conditions, and for severe conditions to remain in port, seek safe harbor, alter course or secure the vessel. The offshore warning is separate from nearshore small craft advisories, and boaters are urged to check current marine alerts before leaving, since conditions can change.