Altocumulus floccus

Altocumulus means “high cumulus.” Floccus refers to tufts of wool. These mid-level clouds remind us of tufts of wool. They form when the mid-level of the atmosphere is conditionally unstable; meaning if clouds form the heat released by condensing water vapor create clouds with towers - altocumulus. The unstable layer isn’t very deep. In this photo we can see the cloud towers only penetrate a shallow layer overhead. No rain fell and the clouds dissipated. Sometimes these clouds grow large enough to develop into thunderstorms - if the air mass has a deep unstable layer. Photo copyright by Craig Johnson taken in Cedar Falls, Iowa looking west.