From Glossary of Meteorology


A cloud variety occurring in a layer, patch, or extensive sheet, the greater part of which is sufficiently translucent to reveal the position of the sun, or through which higher clouds may be discerned.

This variety is found in the genera altocumulus, altostratus, stratocumulus, and stratus, and is usually a modification of the species stratiformis or lenticularis. (Note: With the exception of cirrus spissatus, all cirriform clouds are inherently translucent.)
See cloud classification.

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