- A winter storm, described as a “bomb cyclone,” lashed the Northeast, bringing floods, frigid temperatures, and snow to cities across the region.
- The storm’s central pressure dropped to about 951 millibars, which is equivalent to a Category 3 hurricane.
- After the storm, the area is expected to be slapped with an Arctic air mass on Friday evening, plunging temperatures to below zero in New York City.
A winter storm described as a ‘bomb cyclone‘ slammed into New York, New Jersey, and much of southern New England on Thursday, bringing lots of snow, wind, flooding, and frigid temperatures.
The storm has moved on from the Northeast, after leaving thousands without power, causing massive flooding, and killing 12 people. The storm rapidly intensified on Thursday – it dumped around 10 inches of snow in New York City and caused huge floods in Boston, with widespread road and airport closures throughout the region.
New York City received far more snow than the 2-4 inches originally forecast, and Boston experienced a record-high tidal surge. Parts of Long Island, Eastern Massachusetts, and the New Jersey coast received 12 inches of snow by the time the storm moved on from the region.
New York Gov. Andrew Cuomo issued a travel advisory across New York City, Long Island, and Westchester until 4 p.m. on Thursday. On Thursday afternoon, New York Mayor Bill de Blasio declared a winter weather emergency for all of the city’s five boroughs.
But Boston had it worse. A huge storm surge flooded parts of the city and a number of towns on the coast of Massachusetts. Boston is experiencing the highest tide since 1921, according to The National Weather Service. And 76 mile-per-hour gusts were recorded off the coast of Nantucket, close to the storm’s epicenter on Thursday.
Friday morning brought the beginning of a frigid plunge. Temperatures in New York City were sitting around 13 degrees Farenheit as of 11:30 a.m., while Boston saw temperatures around 15 degrees. It’s expected to get much worse: Boston’s temperature will drop to -1 tonight, while New York will hit around 4 degrees.
On Saturday night, temperatures will plunge in Bosto to -6, with the windchill making it feel like -35.
What is a ‘bomb cyclone’?
This isn’t hyperbole – a “weather bomb,” or “bombogenesis,” is the term used by meteorologists for this kind of storm system. The phenomenon gets the ominous label when the central pressure of a low-pressure system drops at least 24 millibars (a unit for measuring atmospheric pressure) within 24 hours.
Bombogenesis occurs when cold, continental air masses meet warm, moisture-rich oceanic air. That can create high winds and heavy precipitation, according to The Weather Channel.
The East Coast storm exceeded the standard bombogenesis rate by several millibars and drop to a minimum pressure of about 950 millibars – equivalent to a Category 3 hurricane. (Hurricane Sandy, which devastated New York City and the New Jersey coast in 2012, had a minimum pressure of 946 millibars when it made landfall.)
Meteorologists consider air pressure to be a measure of a storm’s intensity, meaning this was likely the strongest winter storm to hit the East Coast in decades.
This GIF shows the pressure lows that were projected for the coast of New York and New England on Thursday afternoon, based on models from the interactive forecast site Windy:
After the snow, a deep freeze
Areas as far south as Myrtle Beach, South Carolina and Jacksonville, Florida, saw a bit of snowfall and ice accumulation this week, which ground travel to a halt.
Following the storm, an Arctic air mass has been pulled south, drawn in by the massive air circulation in the storm’s wake.
Though it may seem counterintuitive, it’s actually better that there was heavy snowfall in much of the Northeast, given the plummeting temperatures.
Gary Szatkowski, a meteorologist, explained on Twitter that even a couple of inches of snow can serve as infrastructure insulation, protecting water pipes and subway tracks from extreme cold. Without such snow, water pipes can freeze or burst, which can knock out power and create a cascade of damage.
Despite what President Donald Trump has claimed on Twitter, winter storms – just like hurricanes and heat waves – can be made more severe by climate change. As the White House and Congress gear up to take on infrastructure this year, that’s probably a threat they should keep in mind.