GRAND HAVEN, Mich. (AP) - The National Weather Service is warning swimmers about risky weekend conditions at some of the Michigan's most popular Lake Michigan beaches. Swimmers are likely to find high waves, possible rip currents and strong winds, from Friday through Saturday afternoon, especially at beaches from Ottawa to Mason counties. The weather service is specifically pointing at Grand Haven State Park in Grand Haven and Pere Marquette State Park in Muskegon. High waves will cover piers. Water hazards are also posted from Manistee north to Leelanau counties.