Update 11:20 a.m.: President Obama arrived at Pfitnzer Stadium just before 11 a.m. via helicopter. 

Update, 9:30 a.m.: 

The event is unlikely to affect PWCS operations, PWCS Director of Communications Phil Kavits said. 

"Thus far, not aware of any anticipated problems having to do with the president's campaign event," Kavits told Patch. 

Update, Sept. 21: 

The parking lots at the stadium are now all full, Prince William County Police Department advised on Facebook.

"Those attending the event at the P'Nats Stadium must go to the PW Fairgrounds to park and catch a shuttle," the post read. "NO MORE VEHICLES will be allowed to park at the stadium."

Original story: 

President Barack Obama will speak at Potomac Nationals' Pfitzner Stadium on Sept. 21. Here's what to expect if you plan on going or just passing through.

Traffic and parking:

• Media will begin arriving at about 9:30 a.m., and the event is estimated to begin at about 12:45 p.m. Doors open to the public at 9:30 a.m.
• The Prince William County Police Department advised on their Facebook page that drivers not going to the event should find routes that avoid the area around the stadium. If you're not going to the event, avoid driving near the stadium, particularly avoiding Prince William Parkway between Hoadly Road and Old Bridge Road.
• Prince William County Police public information officer Jonathan Perok said in an email to Patch early morning that he did not know of any road closures for the event.
• Satellite parking will be available at the Prince William County Fairgrounds at 10624 Dumfries Rd. in Manassas. "There will be continual shuttle bus service operating from the fairground beginning at 7:30 a.m., as well as after the conclusion of Friday's event," said an email from the Obama campaign. 

For those who want to go:

• Parking at the stadium is limited, the Prince William County Police Department said on their Facebook page. Try to carpool if possible. 
• Expect high security. 
• You can bring your camera to the event, but try to keep belongings to a minimum. 
• Participants will have to go through security as they enter the park.

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