Cyclogenesis is the development or strengthening of cyclonic circulation in the atmosphere (a low-pressure area).[1] Cyclogenesis is an umbrella term for at least three different processes, all of which result in the development of some sort of cyclone, and at any size from the microscale to the synoptic scale.
The process in which an extratropical cyclone undergoes a rapid drop in atmospheric pressure (24 millibars or more) in a 24-hour period is referred to as explosive cyclogenesis, and is usually present during the formation of a nor'easter.[2] Similarly, a tropical cyclone can undergo rapid intensification.
The anticyclonic equivalent, the process of formation of high-pressure areas, is anticyclogenesis.[3] The opposite of cyclogenesis is cyclolysis.