C_M3 Semi-transparent altocumulus

Click the small image for full size version.

Gallery
© C.S. Broomfield	© C.S. Broomfield
© D. Philips

The coding C_M=3 is used to report altocumulus at a single level, the greater part of which is sufficiently transparent to reveal the position of the sun and moon. The clouds do not progressively invade the sky, and the individual elements change very little.

The clouds usually appear white or grey with shading, although the evening sun produces a yellowing effect, as seen in the bottom photograph.

These thin altocumulus clouds usually produce a corona.

Classification
Description: Altocumulus, the greater part of which is semi-transparent and the various elements of the cloud change only slowly.	Designation: CM=3 (C3)
	Latin name: Altocumulus translucidus (Ac tr) [plus other varieties].

Related pages: Cloud classification | C_L guide | C_M guide | C_H guide | Cloud index