Rain showers are moving through the Philadelphia region today, prompting colleges to move commencement ceremonies inside and causing some transit problems.

Several schools, including RowanVillanova and Widener universities, have moved their graduation events due to the forecast.

Rowan's ceremony will no longer be held at Wackar Stadium. The university said ceremonies for its various schools will now be staggered across the campus and throughout the day.

The switch was made "in the interest of safety and comfort," the university's commencement website says.

At Villanova, commencement will now be held indoors in the Pavilion, rather than at Villanova Stadium. A live simulcast will be streamed in the Jake Nevin Field House. Other viewing locations on campus are Bartley and Driscoll halls.

Widener said its graduate commencement ceremony has been moved to the Schwartz Athletic Center.

Villanova and Rowan are scheduled to have high-profile speakers, with Jill Biden, an educator and wife of Vice President Joe Biden, slated to speak at Villanova and New Jersey Gov. Chris Christie set to address Rowan graduates. Attendance for their remarks will require tickets due to limited seating.

Rain had already disrupted commencement events in the region, with West Chester University holding a second ceremony Thursday for graduates who could not walk across the stage at last weekend's event after a rainstorm broke out.

The National Weather Service says a flash flood watch is in effect from 8 a.m. through late this evening. The alert covers the bulk of eastern Pennsylvania and western New Jersey.

The region will see periods of heavy rain, along with the potential for thunderstorms, throughout the day. Most places should see one to two inches of rainfall.

The rain caused some travel-related problems: SEPTA said shuttle buses were running in place of Route 102 trolleys between MacDade Boulevard and Sharon Hill because of flooding. Earlier in the day, Norristown High Speed Line trains were operating only on inbound tracks between Bryn Mawr and Wynnewood Road due to high waters.

Dozens of flights at Philadelphia International Airport were also delayed or canceled. Early this afternoon, the Federal Aviation Administration instituted a ground-delay for the airport, meaning flights to Philadelphia were being held at their departure points.

Flooding is especially likely in urban areas and along small rivers and streams, according to the weather service.

The high temperature today is expected to reach 73 degrees.

Students graduating at schools with ceremonies this weekend, though, should have much more pleasant weather: Forecasters say both Saturday and Sunday are expected to be mostly sunny, with expected highs of 72 and 71 degrees.

For more weather information, see John Bolaris' forecast.

Contact Emily Babay at 215-854-2153 or ebabay@philly.com. Follow @emilybabay on Twitter.
Contact the Breaking News Desk at 215-854-2443 or BreakingNewsDesk@philly.com. Follow @phillynews on Twitter.