The National Weather Service has issued a flood watch for the entire Delaware Valley due to potential flash floods of low lying areas, streams, creeks and moderate flooding on the Schuylkill River.
The advisory is in effect from Thursday night through Friday morning.
In Northwest Philadelphia, the areas at highest risk of flooding include Main Street in Manayunk, Kelly Drive and Lincoln Drive.
As of noon on Thursday, those roads were clear but that may all change rapidly as the National Weather Service expects to see up to four inches of rain fall on the region through Friday.
Drivers are advised to watch out for washed-out roads and downed utility wires. Residents and businesses in low lying areas with a history of flooding should be prepared to evacuate if needed.