Long Island is a very tricky place to forecast. I’d argue one of the most difficult in the northeast. South shore and east end (forks) versus the north shore in Nassau county. I remember several storms where the north shore managed to stay all snow, while the Hampton got cold rain and sleet. When Long Island manages to stay all snow, they get pummeled. It is ideally placed for bands off the Atlantic from benchmark lows. You can see it with this storm. Those deep greens and yellows off the shoreline heading due north for the island. Incredible.
Hell, I moved only 25 mins north of my old house here in Maryland and the difference is night and day. DC is a crazy phenomenon of its own. So, so unlucky with dry air.