* WHAT...High wave action, strong currents, and dangerous swimming conditions expected. Piers may be heavily swamped by waves. * WHERE...Mason, Oceana, Muskegon, Ottawa, Allegan and Van Buren counties. * WHEN...From this evening through Friday morning. * IMPACTS...Strong currents can pull swimmers into deeper water and high waves can sweep people off piers. * ADDITIONAL DETAILS...Winds will increase this evening out of the southwest building waves to 3 to 6 feet tonight. The waves will persist into the morning hours of Friday. Dangerous waves and currents are expected tonight and Friday morning. Storms that sweep across the lake this evening may reach severe levels.