* WHAT. Heat index values of 100 to 104 degrees are expected at times this week with variability each day due to clouds and scattered showers and storms. * WHERE. Portions of north central, northeast, and northwest Ohio and northwest Pennsylvania. * WHEN. Until 8 PM EDT Friday. * IMPACTS. Hot temperatures and high humidity may cause heat illnesses. The prolonged nature of the heat may increase heat stress with time.

* WHAT. Prolonged dangerous hot conditions are likely. Heat index values ranging from 105 to 110 degrees are expected. Little relief will be observed at night with temperatures ranging from 70 to 75 degrees. * WHERE. Beaver, Fayette, Washington, Allegheny, Butler, and Westmoreland Counties. * WHEN. Until 8 PM EDT Friday. * IMPACTS. Heat related illnesses increase significantly during extreme heat and high humidity events.

* WHAT. Heat index values ranging from 100 to 105 degrees. * 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 Friday. * IMPACTS. Hot temperatures and high humidity may cause heat illnesses.