Future radar with more details for Long Island on the snowstorm:
The latest snow maps are in my previous post, and I also included the snow map in the app at the top of the "Quick LI Weather" section, so let's discuss the details for Long Island. The new 18Z Euro run did hold steady with the snowfall totals on Long Island, but at this range, it's best to look at the higher resolution models.
The start time should be around 4 PM for western Nassau and around 6 PM out towards the east end. With dry air in place initially, it will take a while before the snow makes it all the way to the surface before evaporating, so the radar may show snow overhead, but you may not see it snowing by you initially.
There will be a heavy thumping of snow tomorrow evening between around 7 PM and midnight where most of our accumulations will occur with snowfall rates of 1 to 2 inches per hour.
The wind will also be increasing throughout the evening with gusts exceeding 40 mph from the ENE towards midnight.
The snow will change to sleet and then rain from southeast to northwest between midnight and 2 AM, and we may even get into the dry slot after that time.
It should all change back to snow from west to east between 5 AM and 7 AM from west to east with additional light accumulations possible.
The snow should taper off to snow showers and flurries and end from west to east between around 10 AM and Noon.
Here is the simulated future radar from 3 PM tomorrow to 10 AM Thursday from the HRRR model to give you the general idea. There will be subtle changes though most likely.