If JFK remains closed no planes will be allowed to land expect in dire emergency. An airlines' flight plan, will have two or three alternate airports to divert to. Most flights are on approach about 300 miles from their destination and it would be at that point where decisions about landing are made. I would hate to hazard a guess where a flight will land in this storm, but it normally has to be an airport not affected by the storm and can land lots of plans quickly and handle wide bodies — it might be 1000 miles away - I remember once flying to Denver and being diverted to SFO
landing in a storm