Flammagenitus (cloud) This is a process not yet fully understood, but is probably in some way associated with charge separation induced by severe turbulence, and, perhaps, by the nature of the particles of ash in the cloud. Large flammagenitus can contain temperatures well below freezing, and the electrostatic properties of any ice that forms may also play a role. A flammagenitus that produces lightning is actually a type of cumulonimbus, a thundercloud, and is called cumulonimbus flammagenitus. The World Meteorological Organization formerly classified flammagenitus and cumulonimbus flammagenitus respectively as cumulus (mediocris or congestus) and cumulonimbus. In 2017, the WMO International Cloud Atlas
Cyclogenesis cloud. The wall cloud is a spinning layer of clouds descending from the mesocyclone. The wall cloud tends to form closer to the center of the mesocyclone. It should be noted the wall clouds do not necessarily need a mesocyclone to form and do not always rotate. As the wall cloud descends, a funnel-shaped cloud may form at its center. This is the first stage of tornado formation. The presence of a mesocyclone is believed to be a key factor in the formation of the strong tornadoes associated with severe thunderstorms. Tornadoes exist on the microscale or low end of