They are only calling for 1 to 2 inches of snow at JFK. You can sit on it until about 9 pm tonight. If Delta thins flights you will know at that point if it operates. I suspect the flight will be fine. It’s the drive that would worry me. That is an area where you will know far more than me.
I do think the flights will operate normally. They thin the regional jets first and then flights with easy alternative bookings. STT would have a high priority.