Altocumulus (From Latin
Altus, "high",
cumulus, "heaped") is a middle-altitude
cloud genus that belongs to the
stratocumuliform physical category characterized by globular masses or rolls in layers or patches, the individual elements being larger and darker than those of
cirrocumulus and smaller than those of
stratocumulus. Like other cumuliform and stratocumuliform clouds, altocumulus signifies
convection. It is usually white or grey, and often occurs in sheets or patches with wavy, rounded masses or rolls. A sheet of partially conjoined altocumulus perlucidus is sometimes found preceding a weakening warm front, where the altostratus is starting to fragment, resulting in patches of altocumulus perlucidus between the areas of altostratus. Altocumulus is also commonly found between the warm and cold fronts in a depression, although this is often hidden by lower clouds.