The National Weather Service issued a severe thunderstorm watch that is in effect until 8 p.m. Sunday for Allegheny and other counties in Pennsylvania
At 4 p.m., the weather service forecast a strong thunderstorm will affect northeastern Allegheny, Butler, extreme northwestern Westmoreland, extreme southeastern Mercer, Lawrence, northeastern Columbiana, Northern Beaver and west central Armstrong counties.
Wind gusts up to 40 mph and hail as big as dimes are possible, the weather service stated.
"Heavy rain will pond water on roads and quickly fill ditches and small streams," the NWS website states.
Among the locations that will be impacted are Wexford, Saxonburg, Beaver Falls, Bessemer, New Castle, Darlington, Harlansburg, Ellwood City, McConnells Mill, Slippery Rock, Moraine State Park and Fombell.
Highways that will be affected, according to the weather service:
I-79 between mile markers 73 and 110;
I-76 between mile markers 1 and 39;
I-376 between mile markers 9 and 31.
Are you experiencing storms in your area? Tell us about it in the comments.