Hurricane Sandy is about 505 kilometers (some 310 miles) south-southeast of New York City and moving at 32 kph (about 20 mph) toward the northeastern United States, where it is expected to arrive late in the day on Monday.
Sandy, a Category 1 hurricane, has maximum sustained winds of 140 kph (85 mph), the National Hurricane Center, or NHC, said in its 8:00 a.m. advisory.
The storm is "now moving north-northwestward and accelerating ... expected to bring life-threatening storm surge and coastal hurricane winds plus heavy Appalachian snows," the NHC said.
"Sandy is expected to transition into a frontal or wintertime low pressure system prior to landfall. However ... this transition will not be accompanied by a weakening of the system ... and in fact ... a little strengthening is possible during this process," the NHC said.
The storm "is expected to weaken after moving inland," the National Hurricane Center said.
The hurricane's powerful winds will be felt along the coasts of New Jersey, Delaware, eastern Virginia and the central and southern portions of Chesapeake Bay.
A tropical storm warning is in effect from north of Surf City to Duck, North Carolina, Pamlico and Albemarle Sounds, and Bermuda.
Hurricane-force winds will be felt along the coast from Chincoteague, Virginia, to Chatham, Massachusetts, as well as in Chesapeake Bay, Delaware Bay, the coasts of the northern Delmarva Peninsula, New Jersey, the New York City area, Long Island, Connecticut and Rhode Island," the NHC said.
Forecasters are warning that the storm could cause heavy snowfall in the mountains of western Virginia and eastern Kentucky, as well as in higher elevations on the North Carolina-Tennessee border, and in Maryland, with coastal conditions remaining poor from Florida to New England over the next few days.
Government offices, schools, transit systems and businesses have closed from northern Virginia to New York.
New York City officials ordered the evacuation of more than 370,000 people living in low-lying areas, such as Coney Island in Brooklyn and Battery Park City in Lower Manhattan.
La ONU, las universidades, algunas de las principales entidades financieras y hasta los teatros de Broadway y los museos han anunciado que estarán cerradas hoy, y posiblemente también el martes.
The New York Stock Exchange, or NYSE, which is near the evacuation area, will be closed on Monday and has not made a decision about trading on Tuesday.
"We support the consensus of the markets and the regulatory community that the dangerous conditions developing as a result of Hurricane Sandy will make it extremely difficult to ensure the safety of our people and communities, and safety must be our first priority. We will work with the industry to determine the next steps in restoring trading as soon as the situation permits," the NYSE said.
Flights have been cancelled at airports in the Northeast and Amtrak suspended train service from Washington to Boston.
States of emergency have been declared in nine states from North Carolina to Massachusetts to prepare for the storm.
Power outages are expected across the region and utility crews have been deployed to restore electric service as soon as the storm passes. EFE