Met Office: CH3 Dense cirrus from cumulonimbus

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C_H3 Dense cirrus from cumulonimbus

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Gallery
© G Barrett	© R.K. Pilsbury
© C.J. Richards

Gallery

The code figure C_H =3 is used only when the observer is reasonably certain that at least one of the dense cirrus clouds in the sky originated from the upper part of a cumulonimbus. It may be possible to see this development, if a watch can be kept on the sky. Such cirrus clouds frequently have hairy or frayed edges and are often in the form of an anvil. These clouds are sufficiently thick to veil the sun, obscure its outline or even hide it. In winter, this form of cirrus can occur well below 20,000 ft.

Other cirrus clouds may also be present. The three photographs show typical examples and in the bottom one, a grey patch of stratocumulus formed from the spreading out of cumulus (C_L 4) can be seen below the cirrus.

Classification
Description: Dense cirrus, often in the form of an anvil, being the remains of the upper parts of cumulonimbus.	Designation: C_H=3 (C0)
Latin name: Cirrus spissatus cumulonimbogenitus (Ci spi cbgen).

Classification

Description:
Dense cirrus, often in the form of an anvil, being the remains of the upper parts of cumulonimbus.

Designation:
C_H=3 (C0)

Latin name:
Cirrus spissatus cumulonimbogenitus (Ci spi cbgen).