Well, you won't like this (IOW it won't help) but I'd say you have about a 55-45 chance that it will be open on time. There are so many unknowns - like weather over the course of the closure - that it's almost impossible to be spot on with these predictions. But, I think you have a slight nod in your favor, as they usually do build in some cushion to the schedule to allow for some unforeseen issues. If it helps, by that time in the closure calendar, they will have gotten about as efficient and practiced with the handicapped operation as possible, so it should go as smoothly as it can, even if it doesn't open on time. And you can certainly watch that flight over the course of the closure to see how it performs as the 27th approaches. To be on the safe side, I wouldn't plan anything important around scheduled arrival time on the 27th.