YOUNGSTOWN - People in the Mahoning and Shenango Valleys can expect extreme heat from Sunday afternoon through Tuesday evening, with potential heat index values reaching 104 degrees, according to the National Weather Service.

Forecasters warn that consecutive days of high heat and humidity, combined with limited overnight relief from warm low temperatures, can increase the risk of heat-related illnesses. The heat may persist into Wednesday.

The National Weather Service advises residents to drink ample fluids, stay in air-conditioned environments, remain out of the sun, and check on relatives and neighbors during this period.