Met Office: CM8 Altocumulus with tufts or sproutings

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C_M8 Altocumulus with tufts or sproutings

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Gallery
© R.K. Pilsbury
© D.M.G. Buchanan
© R.N. Hughes

Gallery

Two species of altocumulus are coded under C_M8.

Altocumulus floccus clouds (top photograph) occur as white or grey scattered tufts with rounded and slightly bulging upper parts. These clouds resemble very small ragged cumulus and are often accompanied by fibrous trials of virga from their bases.

Altocumulus castellanus is pictured in the other two photographs. This species has sproutings in the form of small towers or battlements and the cumiliform appearance is more marked than in altocumulus floccus. The cloud elements have a common base and appear to be arranged in lines. These characteristics are evident when the cloud is seen from the side.

Altocumulus castellanus may develop into large cumulus C_L2 or sometimes cumulonimbus C_L3 or 9. Altocumulus floccus sometimes results from the dissipation of the base of altocumulus catellanus and may itself dissipate, leaving behind very white trails of cirrus. Both these types are associated with developing thundery conditions affecting a large area, as opposed to thunderstorms arising from locally generated cumulonimbus clouds.

Classification
Description: Altocumulus with sproutings in the form of small towers or battlements or having the appearance of cumuliform tufts.	Designation: C_M=8 (C3)
Latin name: Altocumulus castellanus (Ac cas) or Altocumulus floccus (Ac flo).

Classification

Description:
Altocumulus with sproutings in the form of small towers or battlements or having the appearance of cumuliform tufts.

Designation:
C_M=8 (C3)

Latin name:
Altocumulus castellanus (Ac cas) or Altocumulus floccus (Ac flo).