The National Weather Service has issued a tornado warning for the eastern portion of Butler County, as well as a portion of Armstrong County. The tornado watch took effect at 4:33 p.m. Wednesday, May 21, and expires at 5 p.m.

Locations mentioned in the alert include Butler, Chicora, East Butler, Bruin, Eau Claire, Petrolia, Karns City, West Sunbury, Cherry Valley and Moraine State Park.

A tornado warning indicates that a tornado has actually been spotted in the area or on radar, and advises residents to take shelter immediately.