Bomb cyclone

From Glossary of Meteorology

bomb cyclone

Also known as “explosive cyclogenesis,” this term refers to a rapidly deepening extratropical surface cyclone with a central pressure that falls on the average of at least 1 hPa h−1 for 24 h, after applying an adjustment to a latitude of 60° using the following equation: r sin(60°)/sin(ϕ), where r is the observed pressure fall (hPa h−1) and ϕ is the cyclone’s latitude. This adjustment accounts for variations in the geostrophic wind speed induced by equivalent pressure gradients at different latitudes. Consequently, it requires a larger pressure drop to qualify as a bomb cyclone at higher latitudes compared to lower latitudes.

This predominantly maritime, cold-season event is usually found approximately 750 km downstream from a mobile 500-hPa trough, within or poleward of the maximum westerlies, and within or ahead of the planetary-scale troughs.

Sanders, F., and J. R. Gyakum, 1980: Synoptic-dynamic climatology of the “bomb”. Mon. Wea. Rev., 108, 1589–1606,<1589:SDCOT>2.0.CO;2.

Term edited 3 July 2023.

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