https://doi.org/10.1351/goldbook.S06041
A layer of patches composed of laminae or globular masses arranged in groups, lines or waves and having a soft, grey appearance; very often the rolls are so close together that their edges join and give the undersurface a wavy character; the process of formation (cumulogenesis) involves the spreading out of the tops of cumulus clouds, the latter having disappeared; \(<2000\ \mathrm{m}\); usually warmer than \(\pu{-5 ^{\circ}C}\); vertical velocities usually \(< 0.1\ \text{m s}^{-1}\).