A flood watch for the Philadelphia area and a winter storm warning for Northeastern Pennsylvania have been issued by the National Weather Service.
In addition, a little snow could fall in the Philadelphia area tomorrow afternoon.
Today's continuing rainfall could total several inches by tomorrow morning. The flood watch is for Southeastern Pennsylvania, New Jersey and Delaware.
Although the Delaware River should "stay well within its banks ... tributary streams such as the Perkiomen, Neshaminy and Chester Creeks could experience minor flooding," according to the service's statement.
"In addition, the smaller rivers such as the Schuylkill, Raritan and Passaic Rivers could experience three-quarters to near bankfull conditions."
The heaviest rain should start mid to late afternoon today, and continue overnight, letting up by daybreak, said Gary Szatkowski, chief meteorologist for the weather service's Mount Holly office.
Meanwhile, areas north of Allentown are expected to see potentially treacherous conditions, with sleet and freezing rain, followed by a changeover to snow.
"Snow and sleet accumulations of 2 to 4 inches are possible," according to the winter storm warning.
Rain is likely in the Philadelphia area tomorrow morning and early afternoon, followed by a chance of snow showers.
"New snow accumulation of less than one inch possible," states the weather service forecast.
Probably a lot less, said Szatkowski.
"As the storm system pulls out, we may see a little on the back end of it," he said. "But I wouldn't look for anything to stick."
He didn't foresee any significant accumulation in any parts of the Philadelphia area.
Skies are expected to be mostly clear Saturday, Sunday and Monday, with temperatures rising from highs in the upper 30s on Saturday to the upper 50s on Sunday.
For more on the forecast, go to http://go.philly.com/weather.