A powerful winter storm was sweeping through the East Coast early Saturday, hours after it prompted the governors of New York and New Jersey to issue emergency declarations and forced the cancellation of more than 5,000 flights. As of 3 a.m., snow had been falling in New York, New Jersey and parts of southern New England for several hours. No major power outages had been reported in the Northeast. Yet people up and down the coast were bracing for freezing temperatures, heavy snowfall, treacherous travel conditions and the potential for widespread power failures. In New York, Gov. Kathy Hochul’s emergency declaration for New York City, Long Island, and Rockland and Westchester Counties took effect on Friday night. Five to 10 inches of snow were expected in the city and the mid-Hudson region, and up to 16 inches were forecast to fall on Long Island. The National Weather Service said at midnight that heavy snowfall would accumulate overnight first along the southern coast of New Jersey and later in southern New England, as the storm moved just offshore. It predicted that areas of Massachusetts and Rhode Island could see “whiteout conditions” and as much as two to four inches of snow per hour. In parts of southeastern Massachusetts, forecasters were predicting high winds and up to 24 or even 30 inches of snow. The heaviest snowfall in Massachusetts is expected from about 6 a.m. to 9 a.m., and accumulation totals in the state’s eastern region will likely be the highest of the entire storm system, said Bryce Williams, a meteorologist at the National Weather Service office in Boston. “That’s where the bull's-eye is,” Mr. Williams said by telephone around 2 a.m., as snow piled up on his car in a nearby parking lot. He said that about 2.5 inches had already fallen along some parts of the state’s southern coast. Eastern Massachusetts will probably also see the fiercest winds of the entire system, including hurricane-force gusts over Cape Cod and the island of Nantucket, he added. From The New York Times