This is a light weekend for traffic-generating events but a very big one for work on the Metrorail system, and that’s not just because of the start of the next SafeTrack maintenance project.

We hold off spring for one more weekend. In the Capital Weather Gang forecast, Saturday will be sunny and breezy, with a high temperature in the mid-40s. Sunday will be mainly sunny, and the temperature could rise to about 50.

Sporting events: At Verizon Center, the Wizards play at 7 p.m. Friday, the Capitals at 7 p.m. Saturday and the Wizards again at 5 p.m. Sunday. D.C. United is back at RFK Stadium, with a 7 p.m. game Saturday. Fans who travel by transit will want to check the Metrorail schedules below.

Sprinting out ahead of St. Patrick’s Day, the St. Pat’s Run is scheduled for 8:15 a.m. Sunday. It starts and ends near the Washington Monument and includes a trip around the Tidal Basin and along Independence Avenue SW. See a course map. The events should wrap up about 11 a.m. (Runners, keep in mind that Metrorail doesn’t open until 7 a.m.)

Speaking of the Tidal Basin, the National Park Service is predicting an early bloom for the cherry blossoms, with a peak from March 14 to 17. The National Cherry Blossom Festival moved up its official opening by five days to March 15. All the major traffic-generating events are still on their original schedules. But commuters should anticipate a natural traffic jam: As the blossoms come out, traffic gets extra slow on the 14th Street Bridge and on the roads near the Tidal Basin.

The next edition of SafeTrack affects service on the Blue and Yellow lines, but riders also will encounter significant disruptions on the Red, Orange and Silver lines this weekend.

Red Line. On Saturday and Sunday, free shuttle buses replace trains between Forest Glen and Silver Spring on the east side of the line while crews work on the tracks. Trains are scheduled to operate every 15 minutes between the end of the line at Glenmont and Forest Glen. But many riders probably will want to drive to Silver Spring and start their trips from that station to avoid transferring from train to bus to train. A ride on the shuttle bus will add about 10 minutes to trips.

Between Silver Spring and Shady Grove, the line’s western terminal, trains are scheduled to operate every 10 minutes.

Orange Line. Free shuttle buses replace trains between Smithsonian and Federal Center SW on Saturday and Sunday. In the closed area, crews will work on ceiling tiles, communications cables and tracks. Trains are scheduled to operate every 24 minutes between the Vienna and Smithsonian stations. Between Federal Center SW and New Carrollton, they are scheduled to operate every 15 minutes. The shuttle buses will make a stop at L’Enfant Plaza, where the station’s lower level will be closed for the weekend. It should take about 10 minutes to get from station to station by shuttle bus.

The last trains from New Carrollton are scheduled to leave at 11:19 on Saturday and Sunday nights. That’s 17 minutes earlier than normal.

Silver Line. Trains are scheduled to operate every 24 minutes, but only between the end of the line at Wiehle-Reston East and Ballston. At Ballston, switch to an Orange Line train to continue traveling eastward toward downtown Washington and Prince George’s County.

Blue Line. On Saturday, Metro launches its 13th SafeTrack project, scheduled to continue through April 9. Starting this weekend, trains will share a track between the Braddock Road and Van Dorn Street stations. Riders planning a Blue Line trip also should note the separate disruption between Smithsonian and Federal Center SW, where free shuttle buses will replace trains.

The weekend’s Blue Line trains are scheduled to operate every 24 minutes between Franconia-Springfield and Smithsonian. They will operate every 15 minutes between Federal Center SW and Largo.

Yellow Line. The SafeTrack project means that trains will share a track between Braddock Road and Huntington. They are scheduled to operate every 24 minutes between Huntington and Mount Vernon Square. For a trip farther north toward Fort Totten and Greenbelt, transfer to a Green Line train.

Green Line. It’s the only line with regular weekend service scheduled.

Roosevelt Island parking
The National Park Service has closed Theodore Roosevelt Island’s parking lot for a project that will repave the lot and realign the Mount Vernon Trail. The closing is likely to continue till late spring. Meanwhile, pedestrians still will have access to the island, and bicyclists can bypass construction by using a short detour on the Mount Vernon Trail. Drivers could park at Daingerfield Island and Columbia Island, or use public parking in Rosslyn, which is about a 15-minute walk from Roosevelt Island.