If you’re headed downtown for Saturday’s Trayvon Martin rally or soccer matches at the Georgia Dome, you might want to avoid the northbound Downtown Connector, where weekend bridge work could cause huge traffic jams.

“All weekend, up to three lanes will be closed northbound as two different contractors work between I-20 and Andrew Young International Boulevard on bridge painting and bridge joint repairs,” said Mark McKinnon, spokesman for the Georgia Department of Transportation.

“Extreme backups are expected,” McKinnon warned, adding that multiple lane closures also are planned this weekend on the top-end Perimeter and on I-20 in DeKalb County.

Up to three westbound lanes of I-285 will be closed for bridge work between Roswell Road and Ga. 400, McKinnon said. There also will be various rolling lane closures in both directions across the top-end Perimeter for lane striping.

In DeKalb County, two eastbound lanes of I-20 will be closed throughout the weekend between Wesley Chapel and Panola roads for bridge joint work.

All of those road projects are weather permitting, and the weekend forecast doesn’t look very promising for road crews.

Channel 2 meteorologist Karen Minton said conditions should be dry Saturday morning. “After that, it’s going to get rainy,” she said.

Minton said the chance of rain is 50 percent Saturday and Sunday, with highs around 87 and lows of 72 expected both days.

Rainy or not, and roadwork or not, Atlanta police said large crowds are expected in and around downtown because of several major events this weekend.

Quarterfinal CONCACAF Gold Cup soccer matches will be held Saturday at the Georgia Dome, with Panama playing Cuba at 3:30 p.m., followed by a 6:30 p.m. match between Mexico and Trinidad & Tobago.

The nine-day BB&T Atlanta Open tennis tournament begins Saturday at Atlantic Station.

Large crowds are expected for “Justice for Trayvon” National Day of Action Vigil that begins at noon at the Richard B. Russell Federal Building.

Later Saturday, the Cobb Coalition will host a march, rally and vigil for “Justice for Trayvon” from 6 p.m.. to 8:30 p.n. Saturday.

The group plans to march from the Cobb Civic Center, 548 South Marietta Parkway, to the Marietta Square. The rally and vigil will follow on the square, and all three events have the goal of racial healing and understanding within the community, churches, law enforcement and government, organizers said.

The Cobb Coalition is comprised of the Cobb SCLC , the Cobb Immigrant Alliance and other human and civil rights groups.