Here is today's video forecast. It shows the powerful storm off New England but outlines the recovery from the extreme cold that starts tomorrow.
This map depicts the circulation around the "blizzacane" off the East Coast. The storm brought about 4 inches to the Washington area, 6 inches to Cape May, N.J., and flurries from New York City to Boston. However, out at Nantucket, Mass., winds gusted to 80 mph in the midst of heavy snow, so it could be called a blizzacane (no, there is no such official term).
In Boston and New York City, the cold may feel most harsh late tomorrow and tomorrow evening. The temperatures will not have hit bottom by then, but gusty winds will sharpen the chill.
One concern: the chance of cold frontal snow squalls that could move all the way to the East Coast tomorrow night. Sudden snow squalls have been implicated in chain reaction collisions that turn deadly and damaging.
These two maps show the change from the very, very cold flow likely this Saturday to the much milder Pacific-origin westerly flow later next week.
When we look more closely, we see a variety of disturbances embedded in the main current, each capable of temporarily increasing or cutting off the chance of snow. This map shows the setup:
This map shows the circulation around the offshore storm and a larger but less intense storm moving into the Great Lakes. With this sprawling storm likely to be in the region for several days, the weather can vary widely.
...speculation about a snowstorm Monday or Tuesday, and one is still possible. However, timing and placement remain elusive. This map shows the GFS ensemble mean "solution" for Tuesday morning showing snow just off the New England coast. Watch this story evolve on accuweather.com all weekend.