* WHAT. Heat index values of 95 to 100 degrees expected throughout the week. Low temperatures in the 70s at night will provide little relief from the heat. * WHERE. Portions of northern Indiana and southwest Michigan. * WHEN. Until 8 PM EDT /7 PM CDT/ Friday. * IMPACTS. Hot temperatures and high humidity may cause heat illnesses to occur. * ADDITIONAL DETAILS. Heat stress increases with the number of consecutive hot days. While heat indices may be slightly lower Today because of cloud cover and chances for showers and storms, hot conditions are forecast again for Wednesday through Saturday. The effects of heat are most impactful for more vulnerable urban populations.

* WHAT. Heat index values of 95 to 100 degrees expected throughout the week. Low temperatures in the 70s at night will provide little relief from the heat. * WHERE. Portions of northern Indiana and southwest Michigan. * WHEN. Until 8 PM EDT /7 PM CDT/ Friday. * IMPACTS. Hot temperatures and high humidity may cause heat illnesses to occur. * ADDITIONAL DETAILS. Heat stress increases with the number of consecutive hot days. While heat indices may be slightly lower Today because of cloud cover and chances for showers and storms, hot conditions are forecast again for Wednesday through Saturday. The effects of heat are most impactful for more vulnerable urban populations.

* WHAT. High wave action, strong currents, and dangerous swimming conditions expected. Piers may be heavily swamped by waves. * WHERE. Mason, Oceana and Muskegon counties. * WHEN. From 8 AM EDT Tuesday through Wednesday afternoon. * IMPACTS. Strong currents can pull swimmers into deeper water and high waves can sweep people off piers. * ADDITIONAL DETAILS. The southern side of any structures will be the most dangerous areas with the south to southwest winds.

* WHAT. South winds 15 to 25 knots and waves 3 to 5 feet expected. * WHERE. Grand Haven to Manistee. * WHEN. From 8 AM Tuesday to 4 PM EDT Wednesday. * IMPACTS. Conditions will be hazardous to small craft.

* WHAT. Heat index values up to 100. * WHERE. Portions of central, south central, southwest, and west central Michigan. * WHEN. Until 8 PM EDT Friday. * IMPACTS. Hot temperatures and high humidity may cause heat illnesses.