* WHAT. Maximum heat index values around 100. * WHERE. A portion of central Pennsylvania. * WHEN. Until 8 PM EDT this evening. * IMPACTS. Hot temperatures and high humidity may cause an increase in heat-related illnesses. * ADDITIONAL DETAILS. The risk of heat-related impacts is expected to reach its highest level this afternoon. The early season heat persisting over multiple days combined with light winds, limited cloud cover, and very warm nights will exacerbate heat stress.

* WHAT. Peak heat index values around 100 degrees expected this afternoon. * WHERE. Portions of north central, northeast, and northwest Ohio and northwest Pennsylvania. * WHEN. Until 8 PM EDT this evening. * IMPACTS. Hot temperatures and high humidity may cause heat illnesses. The prolonged nature of the heat may increase heat stress with time.

* WHAT. Peak heat index values around 100 degrees expected this afternoon. * WHERE. Portions of north central, northeast, and northwest Ohio and northwest Pennsylvania. * WHEN. Until 8 PM EDT this evening. * IMPACTS. Hot temperatures and high humidity may cause heat illnesses. The prolonged nature of the heat may increase heat stress with time.

* WHAT. Heat index values near 100. * WHERE. A portion of central Pennsylvania. * WHEN. Until 8 PM EDT this evening. * IMPACTS. Hot temperatures and high humidity may cause heat illnesses.

* WHAT. High risk of rip currents expected. * WHERE. In Ohio, Cuyahoga, Lake and Ashtabula Lakeshore Counties. In Pennsylvania, Northern Erie County. * WHEN. From Sunday afternoon through Sunday evening. * IMPACTS. Wind and wave action will cause currents on the lakeshore. Swimmers should not enter the water. Currents can carry swimmers away from shore through a sand bar and along structures extending out into the lake.

* WHAT. West winds 15 to 25 knots and waves 2 to 5 feet expected. * WHERE. The nearshore waters of Lake Erie from Avon Point OH to Ripley NY. * WHEN. From 1 PM to 8 PM EDT Sunday. * IMPACTS. Conditions will be hazardous to small craft.

* WHAT. Heat index values 95 to 100. * WHERE. Portions of east central Ohio, northwest, southwest, and western Pennsylvania, and northern and the northern panhandle of West Virginia. * WHEN. Until 8 PM EDT this evening. * IMPACTS. Hot temperatures and high humidity may cause heat illnesses. * ADDITIONAL DETAILS. Although afternoon thunderstorms have provided cooling relief across many parts of the region, a return to hot and humid conditions will again return on Tuesday and continue throughout the week.