Originally Posted by
MSPeconomist
..BTW, if it's within 72 hours of departure, even if it's within the 24 hours, IIRC you cannot cancel.
True, but in this EXACT situation if OP is within 24 of booking and 72 of departure he is entitled to a free change.
Even though the weather looks to be a false alarm, the waiver is still intact for what would have to be a Monday flight through ATL.