Altocumulus castellanus is a family B type cloud.
Altocumulus castellanus is named for its tower-like projections that billow upward from the base of the cloud. The base of the cloud can form at as low as 6500 feet, or as high as 20,000 feet.
Castellanus clouds are a sign of turbulence, and are usually followed by bad weather, continued development of castellanus clouds can produce cumulonimbus clouds.
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