Runners participating in the 21st annual Komen Atlanta Race for the Cure Saturday morning in Midtown will find nearly perfect weather, with sunny skies and temperatures that will begin the day in the low 50s, a few degrees cooler than normal.

The sunny skies will hang around throughout the weekend, although Channel 2 Action News meteorologist David Chandley said there’s a 20 percent chance of an isolated shower late on Mother’s Day.

Several major roads in Midtown will be shut down Saturday morning for the Race for the Cure, which organizers said is expected to draw 18,000 runners to Atlanta.

Included in the road closures are 5th Street between Spring and West Peachtree streets and 17th Street between West Peachtree and State streets. The north and south exit ramps from I-85 to 17th Street will also be closed from 7:45 a.m. to 10:30 a.m., and race organizers said severe congestion is expected on Spring and West Peachtree streets between 17th and 5th streets.

The 8:30 a.m. race begins and ends at Atlantic Station.

Other major weekend events include Hawks playoff games Friday night and Sunday night at Philips Arena, Georgia State University commencement on Saturday afternoon at the Georgia Dome and Georgia Tech graduation Sunday afternoon at the Dome.

Not far from the Dome, the state Department of Transportation expects a crowd of about 20,000 at Centennial Olympic Park Saturday afternoon for Coca-Cola’s 125th anniversary celebration.

Motorists trying to get into Atlanta will find several metro interstates congested by road construction.

In Cobb and Fulton counties, the ongoing repaving of I-75 in both directions between Cumberland Boulevard and the Techwood/16th Street/14th Street exits will have two and three lanes shut down between 8 a.m. Friday and 5 a.m. Monday. Entrance and exit ramps along that eight-mile stretch of interstate could also be closed at various times throughout the weekend, the DOT warned.

On I-20 in DeKalb County, the DOT will be completing a project that began last year. Mark McKinnon, a spokesman for the DOT, said crews will close the two left westbound lanes of I-20 between Panola and Wesley Chapel roads this weekend “as preparations are made to place the top layer of asphalt on the interstate as part of the resurfacing project that began last summer.”

On the other side of Atlanta, the two left westbound lanes of I-20 will be closed near Six Flags Parkway for work on bridge joints.