UPDATE: Dec. 22, 2012 at 6 a.m.> System maintenance on Blue, Expo lines completed ahead of schedule. Trains are running normal operations with no residual delays. ^GA

Here’s the service alert and media advisory from Metro — this will impact those returning home from the Clippers game on Friday night:

Metro Rail System Maintenance on Friday Night and Saturday Morning December 21-22.

Metro work crews will conduct system maintenance on Flower St. in downtown Los Angeles, impacting the Metro Blue Line and Expo Line. The work will begin at 9 p.m., Friday, Dec, 21, and continue through 7 a.m. on Saturday, Dec. 22.

Trains will run on one track in the area. Patrons can expect service delays of 20 to 30 minutes during that time and should plan travel time accordingly. Metro apologizes for the inconvenience and strives to minimize delays or disruption of service.

Follow @metroLAalerts on Twitter for frequent updates. Link to updated planned service advisory reports at metro.net. (http://www.metro.net/service/advisories/rail/)