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 \(-5\ ^{\,\unicode{x26ac}}\text{C}\); vertical velocities usually \(< 0.1\ \text{m s}^{-1}\).
PAC, 1990, 62, 2167. (Glossary of atmospheric chemistry terms (Recommendations 1990)) on page 2180 [Terms] [Paper]