In 2003, Blizzard Beach was down for rehab from mid-November until around December 26. Also in 2003, WDW reversed the rehab schedule for the water parks. For years, Typhoon Lagoon was closed Nov - Dec and Blizzard Beach was closed from late December until Feb.
I my memory is correct, WDW was going to stay with the 2003 rehab schedule for 2004. It is rumored that TL will be getting new attractions during this year's rehab.