A possibly "historic" storm took aim at New England with heavy snow and blizzard conditions forecast for New York and along the densely populated northeast coast.
The National Weather Service predicted a "major winter storm" for Friday into Saturday and said New York City was in the mix for blizzard conditions, which combine sustained strong winds and snowfall.
"Two weather systems from the polar and subtropical jet streams will combine to produce a major and potentially historic winter storm," the NWS said.
The storm was expected to pound Boston particularly hard, but forecasters said the system should blow through later Saturday, with milder temperatures to follow.
"The storm should reach its peak intensity early Saturday morning just east of Cape Cod," the weather service said, forecasting between one and two feet (30 to 60 centimeters) of snow across the region.
Strong winds of 25-35 miles (40-56 kilometers) per hour, with hurricane-strength gusts of up to 75 miles per hour, were expected, creating deep drifts.
Forecasters said New York would see accumulations of more than a foot of snow, while Boston, where schools were ordered closed, was due to be buried under as much as two feet, with far more in the drifts.
New York Mayor Michael Bloomberg said city schools would remain open, but the famous Staten Island ferry would operate on a reduced schedule, and residents were advised to prepare for worse.
"Due to potential power outages and transportation difficulties, New Yorkers are advised to stock up on potential supplies, including medicine," Bloomberg said.
The Friday commute and air travel in the region were expected to see snarl-ups, while wet, freezing snow on power lines was likely to knock out electricity in some areas.
"Many people could be caught offguard Friday evening," commercial weather service AccuWeather said, warning of "potentially dangerous" conditions.
"Strong winds will not only cause whiteout conditions and massive drifts, but also coastal flooding and power outages. Gusts can approach hurricane force in coastal areas."