Future radar from the HRRR model from 2 PM to 2 AM:

This gives the general idea even though there probably won't be as much snow at the end as this model is showing, but basically rain will change to freezing rain or freezing drizzle later this afternoon into early evening on Long Island from northwest to southeast and then mix with sleet and possibly a little snow at the end as temperatures drop to 20 degrees overnight. Be careful on untreated roads/surfaces later.