Behind the Forecast: What is a bomb cyclone?

LOUISVILLE, Ky. (WAVE) - Bombogenesis. It’s a term that has been all over social media and in the television news cycle for the past few years. But, what does it mean?

The National Oceanic and Atmospheric Association defines bombogenesis as “when a midlatitude cyclone rapidly intensifies, dropping at least 24 millibars over 24 hours.” Millibars are a measure of atmospheric pressure. The lower the atmospheric pressure drops, the stronger the storm.

It’s a combination of the words bomb and cyclogenesis. Cyclogenesis defines the development and strengthening of an area of low pressure.

When a strong jet stream in the upper levels of the atmosphere interacts with an existing area of low pressure near a supply of warm, moist air, bombogenesis can occur. The jet stream sucks air from the storm’s column of rising air, strengthening the low at the surface.

Bombogenesis is most common from October through March due to the large temperature gradient between the mid and high latitudes. In the United States, bombogenesis can occur over the Plains when warm air from the south meets cold air diving down from Canada. Some of the most well-known cases of bombogenesis happen in the Northeast. Cold continental air meets the warm water of the Gulf Stream in the Atlantic, causing storms to strengthen significantly very quickly. These are the nor’easters that become big weather news in the colder months.

Near hurricane-force winds, heavy precipitation (rain, snow, or anything in between), flooding, and even intense lightning can occur in a bomb cyclone.

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