The Pennsylvania National Guard was on standby for central and eastern Pennsylvania, expected to see the worst of the flooding, with a potential for evacuations, Gov. Ed Rendell said Thursday. The state announced scattered roadway closures in eastern Pennsylvania.
Rendell ordered the Pennsylvania Emergency Management Agency to open its emergency operations center Thursday afternoon so state agencies could assist communities and residents dealing with heavy rainfall statewide.
"People who live along streams and creeks know the dangers of rapidly rising water," he said. "In light of the forecast, these residents ... should take immediate steps to prepare before the situation becomes an emergency."
The National Weather Service predicted that the Philadelphia area would receive four to six inches of rainfall overnight, potentially resulting in the Schuylkill River's second-worst flooding on record by Friday afternoon.
In Philadelphia, Mayor Michael Nutter announced the opening of two shelters in flood-prone neighborhoods that could take up two 300 people each if needed.
Transit officials also were preparing for possible weather-related delays during the Friday morning commute.
On Thursday, a downed tree forced the Southeastern Pennsylvania Transportation Authority to suspend service on one of its regional rail lines. The agency warned commuters of what could be extensive delays Friday. Philadelphia International Airport was reporting weather-related delays of up to two hours.
In central Pennsylvania, many Lancaster County schools and government buildings closed early Thursday due to the heavy rains.
Much of eastern Pennsylvania was under flood warnings as storms could bring as much as six inches of rain before leaving the area on Friday. The National Weather Service issued a tornado watch Thursday for counties stretching from Philadelphia west to York and north to Allentown.
Torrential downpours in Lancaster County stranded motorists in rising waters, poured into homes and businesses and flooded roadways Thursday afternoon. County commissioners declared a state of emergency and emergency crews rescued dozens of people, some standing on the roofs of their cars as water rose around them. No injuries were reported.
In Schuylkill County, the borough of Pine Grove declared a state of emergency and some citizens were being evacuated Thursday, said Janet Curtis of the American Red Cross in Pottsville.
The weather service predicted the Susquehanna River would rise above flood stage by Saturday morning in Wilkes-Barre, leading to minor flooding there.
If the rain continues as forecasts predict, the Schuylkill River in Reading will crest Friday evening at 21½ feet, well above the flood stage of 13 feet, said Brian Gottschall of the Berks County Department of Emergency Services.
That would be the third-highest level on record, trailing only Tropical Storm Agnes in 1972 and the storm of 2006, Gottschall said. Both caused heavy damage in the area, he said.
The Delaware and Lehigh rivers in the Lehigh Valley area also were expected to spill over their banks Friday, with minor flooding predicted.
