Cloud atlas

The ten genera, fifteen species and nine varieties of the WMO International Cloud Atlas, with symbols and abbreviations.

Varieties

Transparency and arrangement. A cloud may show several at once.

intwisted

Filaments curved and tangled in an irregular fashion.

Applies toCi

vevertebrae

Elements arranged like ribs, a fish skeleton or vertebrae.

Applies toCi

unwaved

Undulations in a sheet or layer, whether continuous or in separate elements.

Applies toCc Cs Ac As Sc St

raradiating

Broad parallel bands that appear to converge on a point on the horizon through perspective.

Applies toCi Ac As Sc Cu

lafull of holes

A thin layer perforated with rounded holes, giving a net or honeycomb look.

Applies toCc Ac Sc

dudoubled

Superposed patches or layers at slightly different levels.

Applies toCi Cs Ac As Sc

trtranslucent

Translucent enough over most of its extent to reveal the position of the sun or moon.

Applies toAc As Sc St

peallowing light through

An extensive layer with distinct gaps between the elements, showing sky or higher cloud.

Applies toAc Sc

opopaque

Opaque over most of its extent, masking the sun or moon completely.

Applies toAc As Sc St