Cyclogenesis

Cyclogenesis is the formation and intensification of a low-pressure system, the development of cyclonic circulation around a falling-pressure center. Extratropical cyclogenesis is driven by baroclinic instability along the polar front, where strong horizontal temperature gradients and an upper-level jet-stream trough convert available potential energy into the kinetic energy of the storm. Tropical cyclogenesis is a warm-core, convectively driven process instead. Rapid deepening, a fall of at least 24 hPa in 24 hours at 60 degrees latitude, defines explosive cyclogenesis, or a bomb cyclone. The deepest North Atlantic and North Pacific lows form this way in winter.