The National Weather Service Pittsburgh issued a severe thunderstorm warning for the southwestern part of Butler County including Portersville, Zelienople, Callery and Saxonburg that is in effect until 4:45 p.m. Wednesday.

Prior to the warning, the service issued a severe thunderstorm watch for the entire county and parts of southwestern Pennsylvania, eastern Ohio and northern West Virginia that is in effect until 10 p.m. Wednesday.

The area under the thunderstorm warning could experience winds of up to 60 miles per hour and hail the size of pennies, in addition to possible storms.

The region affected by the severe thunderstorm watch could experience scattered gusts of up to 65 miles per hour and isolated hail storms, and frequent lightning is possible.