“Due to the surprising performance of Avatar and Sherlock Holmes, the total domestic haul for the 12.25 to 12.27 weekend could surpass the record-breaking weekend of July 18-20, 2008, which saw the release of The Dark Knight and Mamma Mia!,” reports boxoffice.com‘s Phil Contrino.

Weekend grosses could exceed $270 million by Sunday night, which would easily top the $260 million earned over the Knight/Momma weekend.

By Sunday night Avatar will have made $72 million for the weekend and $209,268,053 since it opened on 12.18. The mostly loathsome and despicable Sherlock Holmes will have pulled in $70,000,000 (two million less than Avatarhah!), Alvin and the Chipmunks: The Squeakquel will have $45 million in the bank. It’s Complicated will end up with $22,500,000, and Up In the Air with $13 million for the weekend and a $25,762,000 cume. The Blind Side will pocket $12 million for a $184,658,000 cume.

“Estimates have a tendency to fall on Monday,” Contrino cautions, “which means if some of the weekend’s strongest performers suffer a decline when actuals are released on Monday the ’08 record would hold. Either way, 2009 is ending with a bang.”