* WHAT. Dangerously hot conditions with heat index values up to 100 possible. * WHERE. Portions of central, south central, southwest, and west central Michigan. * WHEN. From Monday afternoon through Friday evening. * IMPACTS. Heat related illnesses increase significantly during extreme heat and high humidity events. * ADDITIONAL DETAILS. Heat index values near 100 degrees will have a cumulative affect through the course of the week. Temperatures at night will only fall into the 70s. So, the affect of the heat will build through the course of the week.

* WHAT. South winds 15 to 20 knots with gusts up to 30 knots and waves 2 to 5 feet expected. * WHERE. Grand Haven to Manistee. * WHEN. From 2 AM Sunday to 2 AM EDT Monday. * IMPACTS. Conditions will be hazardous to small craft.

* WHAT. High wave action, strong currents, and dangerous swimming conditions expected. Piers may be heavily swamped by waves. * WHERE. Mason, Oceana, Muskegon and Ottawa counties. * WHEN. From 2 AM EDT Sunday through late Sunday night. * IMPACTS. Strong currents can pull swimmers into deeper water and high waves can sweep people off piers.