Meteorologists sometimes warn that a storm could “bomb out” or become a bomb cyclone when turbulent conditions—whipping winds and heavy snow—are in the forecast.
The term points to storms that undergo a process called “bombogenesis.” The U.S. National Oceanic and Atmospheric Administration defines bombogenesis as occurring when a storm’s central pressure drops at least 24 millibars in 24 hours, and those storms are sometimes referred to as bomb cyclones.
Storm intensity is measured by central pressure, so the lower the pressure, the stronger the storm. Such rapidly strengthening storms can produce heavy rain, blizzard conditions and intense winds, creating dangerous conditions including downed trees and power outages.
Andrew Orrison, a meteorologist with the National Weather Service in College Park, Maryland, said that when people hear the phrase on a nighttime weather report, it usually signals “quite a bit of active weather going on.”
Orrison also said bomb cyclones can happen in any season, but they mainly occur during fall and winter when frigid air from the Arctic can creep south and clash with warmer air masses. He said “It’s really the clash of those air masses that really kind of helps to generate the areas of low pressure in the first place.”
In North America, Orrison pointed to areas that can be prone to bomb cyclones, including Alaska, the Pacific Northwest and the Great Lakes region. He said it is “not common to get bomb cyclones at lower latitudes” and that “generally speaking,” a bomb cyclone would not typically stretch across the southern United States.
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