PITTSBURGH (KDKA) — The National Weather Service has issued a heat advisory for Allegheny, Armstrong, Beaver, Butler, Fayette, Greene, Lawrence, Washington and Westmoreland Counties.

The advisory is set to take effect Sunday from 12:00 p.m. to 8:00 p.m. the same day. NWS says heat-related illnesses could be caused by weather conditions, with temperatures expected to reach up to 100 degrees Fahrenheit.

The NWS advises people to stay inside, stay hydrated and check up on friends and family. Outdoor activities should be readjusted while the advisory is in place, and if someone is suffering heatstroke, the correct action to take is to call 911.