Snow starts this morning.
About mid-day the heavier snow starts, mixed with rain in coastal sections of NYC, Long Island and New Jersey.
Later today, even heavier snow starts, with high winds, into tonight.
Heaviest snow ends before morning tomorrow, except for snow showers and continued strong winds.
What could be different? If the storm gets its act together later than predicted, a little less but still a lot of snow. If the storm gets stronger earlier, less rain, and the heavier snow starts sooner.
See the NWS and other weather sites for details for your area.