NEW YORK: Plunging temperatures after a wet winter storm dumped more than a foot of snow on parts of the U.S. Northeast were expected to flash freeze much of the region on Sunday and make travel dicey during the Martin Luther King Jr. holiday on Monday.
"Any water that remains on the road will freeze into a sheet of ice and make conditions quite hazardous," said Rich Otto, a meteorologist with the National Weather Service (NWS).
Sub-zero temperatures tied to gusting winds prompted the NWS to issue wind chill advisories and warnings for more than 10 states, from North Dakota and other parts of the central United States to East Coast metropolitan centres including Washington, New York and Boston.
It will be a roller-coaster ride for temperatures, with Sunday's warm start melting overnight snow and threatening flooding in areas including southeastern Massachusetts. By evening, temperatures were expected to dive into a dangerous flash freeze.
High temperatures for Monday are forecast at 17 Fahrenheit (minus 8 Celsius) for New York City, and 12 F (minus 11 C) for Boston.
"Behind this winter storm is a lot of cold air that has been dropping south from Canada," said Otto by telephone from College Park, Maryland. "You combine that with winds gusting between 20 and 30 miles an hour and you have pretty dangerous windchills of 10 to 30 below zero."
The storm has already dropped heavy snow in Pennsylvania, although the deepest amount reported was 16 inches (41 cm) in the northern New York town of Lake Desolation, he said. It was headed for Maine, where it was expected to lay a white carpet up to 2 feet deep.
While the mercury will dive in the Northeast, forecasters say it is unlikely to fall below the storm's current low of minus 46 Fahrenheit (minus 43 Celsius) recorded in Cotton, Minnesota.
The wintry weather has contributed to travel disruption across the United States during a busy holiday weekend, with 1,458 flight cancellations and 989 flight delays by mid-morning on Sunday, according to FlightAware.com.
Amtrak cancelled or modified its Sunday train service from Boston to Washington and between Chicago and the East Coast.
(Reporting by Barbara Goldberg; Editing by Lisa Shumaker)