Mammatus Clouds

These globular clouds usually form underneath the base of a cumulonimbus cloud and are associated with strong thunderstorms. The globular lobes clump together to form small patches that last only a few minutes, but can also cover the entire sky lasting up to a few hours. These clouds form differently than most as they form in sinking air instead of rising air. The name translates to mamma and means "mammary cloud" as they resemble the shape of a female breast.