The nor’easter about to tear up the U.S. East Coast with near-hurricane-force winds and fast-falling snow — as much as 10 inches of it in New York and more in Boston — is almost certain to intensify so rapidly that it will meet the definition of a bomb cyclone as it roars north. The technical term is “bombogenesis,” and it means the central pressure of a storm, a measure of its power, drops by at least 24 millibars in 24 hours.
The key ingredient of a weather bomb is the collision of cooler air with much warmer air, and that is on hand. A cold front from Canada dropped temperatures to a low of 17° Fahrenheit (-8° Celsius) in New York City’s Central Park overnight Wednesday into Thursday, while in the Atlantic Ocean, the water is warmer than normal. Cape May in New Jersey recorded a water temperature of 46°F, and in Georges Bank off Massachusetts, the ocean was 44.6°F, according to the National Data Buoy Center. Not exactly balmy, but enough to provide the grist for the bombogenesis mill.