Altocumulus volutus

Altocumulus volutus is a type of altocumulus cloud. This cloud type has the appearance of a single, small, horizontal, rolling line, it is relatively rare compared with its counterpart stratocumulus volutus,^[1] This cloud does not attach to any other cloud. It may or may not appear with altocumulus clouds of different species. When found in a thunderstorm, it forms when cold air from a thunderstorm's downdraft makes the already present warm and moist air rise, expanding and cooling as it rises. It then condenses, although the most likely scenario is that it condenses into a shelf cloud or roll cloud, rather than an altocumulus volutus cloud.^[2] When found in environments where it is not associated with a thunderstorm, it forms because of wind shear (difference of wind speed and direction between the mid-levels of the atmosphere and the surface).^[3]

Altocumulus volutus
Distant altocumulus volutus cloud
Abbreviation	Ac vol
Genus	Altocumulus
Species	Volutus
Altitude	2,000-7,000 m (7,000-23,000 ft)
Appearance	small, single, horizontal, rolling mid-level altocumulus line
Precipitation	None