Looks like across Maryland and south snow began when cloud decks reached around 7,000 ft. Across PA it’s been 4,000ft. Up here it may take til they get down to 2500-3000ft. I’d say it could begin as early as 10Z but meaningful accumulations won’t be til 12-13Z. In these setups too the immediate NYC area as well as western LI always pulls down more dry air from the Connecticut river valley and can take longer to saturate than NW NJ and central and eastern LI