Based on the overnight model runs, this will be a very strong storm, but Long Island will not get the worst of it. Snow should begin around 10:00 tomorrow night and end 6 PM Tuesday. Based on the projected track, it looks like 2 to 4 inches for Suffolk (with as much as 5 inches for extreme eastern Suffolk) and 1 to 3 inches for Nassau. I have included the Euro snow map which shows 6 to 8 inches for Boston and over a foot of snow for most of Maine.
Image from eurowx.com