U.S. has more snow on the ground now than last year, except in the East

You couldn’t tell that in any of the large cities along the East Coast.

 

Through Tuesday, New York’s Central Park has had a trace of snow, Boston 0.9 inch, and Washington and Philadelphia nothing at all, according to National Weather Service records.

 

It isn’t surprising, because across the contiguous 48 states, December was the warmest on record. While January readings have chilled the region from Boston to Washington, they are still lingering above normal levels in the large eastern cities, the weather service said.

 

To understand the temperatures, just look to the equatorial Pacific Ocean, where a warming of the sea’s surface and a ruffling of the atmosphere above it have upset winter weather patterns over the U.S.

 

“It’s a classic El Niño pattern,” National Weather Service Director Louis Uccellini said in an interview at the American Meteorological Society’s annual meeting in New Orleans.

 

Warmer air came in off the Pacific, where it got a boost crossing the mountains of the western U.S. and brought about the spring-like December, Uccellini said. Since then, cold has begun to descend from the Pole and sweep into the central U.S., due in part to another weather system known as the Arctic Oscillation, which operates independently of El Niño.

 

Typically, an El Niño is supposed to mean a mild winter for the Northeast. This is where things get interesting. One of the hallmarks of an El Niño is wet Pacific storms that sweep across the southern U.S., often picking up more moisture in the Gulf of Mexico before moving up and over the Atlantic coast off Washington, New York and Boston.