Met Office: CH2 Dense cirrus

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C_H2 Dense cirrus

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Gallery
© R.K. Pilsbury	© W.G. Pendelton
© R.D. Whyman	© F. Norton

Gallery

The cirrus of this specification frequently occurs in entangled sheaves (top left photograph) or in patches thick enough to appear grey when viewed towards the sun (top right). It doesn't usually increase in amount.

Cirrus of C_H 2 may also occur in narrow bands with sproutings like turrets or battlements (bottom left) and is then called cirrus castellanus. Another species (cirrus floccus) takes the form of cirrus in small tufts, the lower part often being more or less ragged (bottom right).

Cirrus of code figure C_H =1 may also be present, but should not predominate.

If any of the cirrus has originated from the upper part of a cumulonimbus, the coding for C_H should be 3. Sometimes the cirrus of C_H 2 develops into thick anvil shapes, which could be mistaken for the C_H 3 of a decaying cumulonimbus.

Classification
Description: Dense cirrus in patches or entangled sheaves, which usually do not increase or cirrus with sproutings in the form of small turrets or battlements or having the appearance of cumuliform tufts.	Designation: C_H=2 (C0)
	Latin name: Cirrus spissatus (Ci spi), Cirrus uncinus (Ci unc), Cirrus castellanus (Ci cas) or Cirrus floccus (Ci flo).