Forecasters said this could one for the record books.
"This one doesn't come along every day. This is going to be a dangerous winter storm," said Alan Dunham, meteorologist for the National Weather Service in Taunton, Mass. "Wherever you need to get to, get there by Friday afternoon and don't plan on leaving."
The snow is expected to start Friday morning, with the heaviest amounts falling at night and into Saturday. Wind gusts could reach 65 mph. Widespread power failures were feared, along with flooding in coastal areas still recovering from superstorm Sandy in October.
Boston could get more than 2 feet of snow, while New York City was expecting 10 to 14 inches. Mayor Michael Bloomberg said plows and 250,000 tons of salt were being put on standby. To the south, Philadelphia was looking at a possible 4 to 6 inches.
"We hope forecasts are exaggerating the amount of snow, but you never can tell," Mr. Bloomberg said, adding that at least the bad weather is arriving on a weekend, when the traffic is lighter and snowplows can clean up the streets more easily.
Amtrak said its Northeast trains will stop running Friday afternoon. The organizers of New York's Fashion Week – a closely watched series of fashion shows held under a big tent – said they will have extra crews to help with snow removal and will turn up the heat and add an extra layer to the venue.