A tornado watch has been issued for counties in Delaware, New Jersey and Pennsylvania until 1 a.m. Sunday.
By 7 p.m., storms had begun to light up. Hail fell in western Chester County.
It was pouring rain with lightning in Center City Philadelphia by 8 p.m.
The National Weather Service issued flood advisories, in addition to the tornado watch.
A rainy Mother's Day is also expected for Sunday, with temperatures in the mid 60s.
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SATURDAY: Scattered thunderstorms developing this afternoon. A few storms may be severe. Low: 81 High: 55
SUNDAY: Cloudy with occasional rain showers. Low: 54 High: 59
MONDAY: Showers and thunderstorms late. Low: 63 High: 79
TUESDAY: Mostly cloudy. Low: 65 High: 87
WEDNESDAY: Scattered thunderstorms. Low: 60 High: 69