CLEVELAND, OH (MARION COUNTY NOW)—The National Weather Service has issued a heat advisory for portions of north central, northeast, and northwest Ohio, warning of dangerously hot temperatures and high humidity later this week.

The advisory is scheduled to take effect at noon Tuesday and will remain in place until 8 p.m. Thursday.

Forecasters expect heat index values — a measure of how hot it feels when relative humidity is combined with the air temperature — to reach up to 104 degrees across the affected regions. Authorities warn that the combination of high temperatures and humidity could significantly increase the risk of heat-related illnesses.

To stay safe during the advisory, experts recommend drinking plenty of fluids, remaining in air-conditioned rooms, staying out of direct sunlight, and checking on neighbors and relatives.