Mammatus cloud. Mammatus, also known as mammatocumulus (meaning "mammary cloud"),[1][2] is a meteorological term applied to a cellular pattern of pouches hanging underneath the base of a cloud.
The name mammatus is derived from the Latin mamma (meaning "udder" or "breast"). According to WMO International Cloud Atlas mamma is a cloud supplementary feature.[3] Characteristics[edit] Mammatus are most often associated with the anvil cloud and also severe thunderstorms. NOAA's National Weather Service. Topic Matrix. Climatic Extremes and Weather Events.