Details on the Snowstorm for the Long Island/ NYC Area
Winter Storm Warnings for NW Suffolk, all of Nassau and points north and west from there. Major gradient expected from 10 to 15 inches for interior locations to 8 to 12 inches for NYC to 6 to 10 inches for Nassau to 4 to 7 inches for central to western Suffolk to 2 or 3 inches for eastern Suffolk.
The models are all over the place. First image is the NWS official snow map. The GFS and NAM have less snow for Long Island. Some of the high resolution models are showing huge snow amounts from Nassau westward. The Euro using a 10:1 ratio shows 8 to 14 inches for most of Long Island, but the eurowx.com map using proprietary algorithms lowers that to 3 to 7 inches (second image).
Now for timing... snow will start around midnight tonight and there is a better chance for mixing with sleet and rain tomorrow morning for Suffolk. It should go back to all snow from NW Suffolk and Nassau by early afternoon the latest, and the snow should end from west to east between 11 PM and 3 AM. Best chance for snow-day tomorrow is NW Suffolk and Nassau and areas north and west of there. Potential for delayed openings on Thursday for those locations as well.