"Even if people are carpooling, that's going to be a boatload of cars in the area," said Tom Walsh, public information officer for Lower Merion police.
Police may have to temporarily close roads in the area, including Hagys Ford and Hollow Roads, he said. They have told schools and residents in the areas to expect big crowds.
Specter, 82, died Sunday at his home in Philadelphia's East Falls section. The former senator, who represented Pennsylvania for 30 years in Washington, had been battling non-Hodgkin's lymphoma, his family said. He was first diagnosed with the disease in 2005 and announced Aug. 28 that it had returned.
The son of an uneducated Jewish salesman who moved his family to the Midwest, Specter grew up to become an Ivy League-educated statesman who played roles in some of the nation's most pivotal political dramas. They ranged from the investigation into President John F. Kennedy's assassination, where he developed the "single-bullet" theory, to the Supreme Court confirmation hearings for Clarence Thomas, in which Specter aggressively questioned witness Anita Hill, angering women and liberals.
He was one of America's most notable Jewish politicians, and a rare Republican who switched parties late in his career so that he could, as he famously said, get reelected. He was "fiercely Jewish," he said, and recalled growing up in Russell, Kan., where he and his sister were the only Jewish children in school. Local grocers would call the sheriff down on his salesman father for taking their business, and the family would be hustled out of town.
Specter's Senate career ended in 2010 after he lost the Democratic primary to Rep. Joe Sestak. Known as a combative opponent and boss, he took up an unlikely hobby in retirement: stand-up comedy.
"Arlen Specter was a great senator who lived his life the way he died, with dignity and courage," Biden, who as a Delaware senator often rode with Specter on the train to Washington, said in a statement. "He was my friend and I admired him a great deal."
On Monday, Gov. Corbett ordered flags at the Capitol and all state facilities to fly at half-staff until sundown Tuesday in Specter's honor, and the White House announced it would do the same.
The Jewish Federation of Greater Philadelphia called Specter "a true humanitarian who gave generously of his time and resources to charitable causes that improved the lives of countless individuals and families." The federation also praised Specter as a passionate advocate for Israel.
The Consulate General of Israel to the Mid-Atlantic Region noted Specter's strong support, saying he was "a true friend of Israel" and an advocate for Soviet Jews who suffered religious persecution.
"The senator fought to safeguard individual liberties and combated hate crimes," the statement said.
He is survived by his wife, Joan, and son, Shanin.
Har Zion is at 1500 Hagys Ford Rd., less than a mile from the Gladwyne exit of the Schuylkill Expressway. The family requests that donations be made to Philadelphia University or a charity of the donor's choosing.
Contact Kathy Boccella at 610-313-8123, firstname.lastname@example.org, or follow @kmboccella on Twitter.