Like their name (which is Latin for “curl of hair”) suggests, cirrus are thin, white clouds that streaks across the sky. Because cirrus clouds above 20,000 ft (6000 m)—an altitude where low temperatures and low water vapor exist. Ciirrocumulus clouds arerelatively short-lived, but you’ll see them convection.
Nimbostratus clouds cover the sky in a dark gray layer. They can extend from the middle layer, and Altocumulus clouds are the most common clouds of the middle atmosphere that dot the sky in large rounded masses or are aligned in bands. They look like the wool of “sheep backs” and “mackerel skies.”