Philadelphia police issued an advisory Wednesday night urging residents to stay indoors in the midst of a heavy storm that reportedly dumped more than three inches of rain on the city.

Police warned drivers to exercise extreme caution when encountering road flooding, which could be accompanied by swift water. Those who become trapped in their vehicles are advised to call 911 and to remain in their cars until help arrives.

Police also reminded parents of the dangers associated with the city's creeks and streams, including the Wissahickon and Pennypack. During and after heavy rains, the waterways are susceptible to flash flooding, which has caused deaths in years past.

The National Weather Service on Wednesday issued flood warnings for creeks and streams in Philadelphia County, as well as for the Schuylkill River. Those hazards were expected to persist until Thursday morning, according to a National Weather Service bulletin.