New England braces for powerful nor’easter with high winds and snow

Boston and New England will take the brunt of a powerful snowstorm set to sweep the U.S. East Coast starting Friday, but New York City will still get a few inches as the system winds up.

Snow will begin in New York late Friday, bringing as much as 4 inches (10 centimeters) overnight as the nor’easter starts to gain power off the coast, said Rob Carolan, a meteorologist with Hometown Forecast Services, who provides outlooks for Bloomberg Radio. Eastern Long Island, Massachusetts and Boston could get more than a foot of snow and high winds as the storm strengthens. Coastal flooding is also expected.

The storm is expected to intensify so rapidly it could become a so-called bomb cyclone.

“It’s going to be a bomb,” Carolan said. “For parts of southern New England, it’s going to be the largest storm of the season so far.”

The storm’s exact track will determine who suffers the worst of it, but the system’s power will likely disrupt air, rail and ground traffic throughout the Northeast as it rides directly up Interstate 95, the main north-south highway in the eastern U.S.

The Northeast has lagged below normal for snowfall this year, so the storm has the potential to be the biggest in the region this season. Since Dec. 1, Central Park has received 7 inches of snow, or 4.2 inches below normal. Boston, Philadelphia and Washington are all running behind average as well.

The main question is will the heaviest snow fall in southeast Massachusetts along a line from Boston to Providence, or will all of eastern New England get blanketed, Carolan said. Up to 15 inches is expected in the storm’s worst-hit areas.

Cape Cod will likely waver between snow and rain, because warmer-than-normal water temperatures in the Atlantic will moderate the snow.

A storm undergoes a rapid shift known as bombogenesis if its central pressure drops by at least 24 millibars in 24 hours or less. Meteorologists often refer to this process as a storm “bombing out.”

Some models show it dropping 55 millibars in 24 hours, which would be historic, Carolan said.

Before the snow arrives, temperatures will plummet Wednesday night. The low in Manhattan is forecast to drop to 17 degrees Fahrenheit (minus 8 Celsius) overnight, while Philadelphia will see lows of 12, Washington 13 and Boston 3, according to the National Weather Service.