Disney has announced that there will be a special fireworks show on January 19, 2012 at Disney's Hollywood Studios called, "Rock the Night Fireworks Spectacular" at 7pm.
No word on what exactly the fireworks will be compromised of, although it's likely it will be similar to the special fireworks seen on New Years Eve and July Fourth. Given the name, it wouldn't surprise us to see Mulch, Sweat and Shears be a part of the show, although that's speculation.
Keep in mind that Fantasmic! is currently under refurbishment through February 12, 2012.
UPDATE: Some attractions will close early due to the fireworks. Toy Story Midway Mania will close at 5, Great Movie Ride and One Man's Dream at 5:30. All three will likely reopen for Extra Magic Hours between 7-10pm.