Cirrocumulus stratiformis (V-12) Sheets or relatively flat patches of cirrocumulus. Cirrocumulus lenticularis (V-13) Lenticular, or lens-shaped high cloud. Cirrocumulus castellanus (V-14) Cirrocumulus layer with "towers", or turrets joined at the bases. Cirrocumulus floccus (V-15) Very small white heaps with ragged bases and rounded tops. Varieties Opacity-based varieties None (always translucent). Pattern-based varieties Undulatus Cirrocumulus with an undulating base; normally associated with stratiformis and lenticularis species. Stratocumuliform undulatus (V-16) Cirrocumulus stratiformis undulatus (V-17) Cirrocumulus lenticularis undulatus (V-18) Lacunosus Cirrocumulus with large clear holes; normally associated with stratiformis and castellanus species (also with cumuliform floccus species). Stratocumuliform lacunosus Cirrocumulus stratiformis lacunosus (V-19) Cirrocumulus castellanus lacunosus (V-20) Cirrocumulus floccus lacunosus (V-21) Supplementary features Precipitation-based supplementary feature Virga Light precipitation that evaporates well above ground level; mostly seen with species stratiformis, castellanus, and floccus. Cloud-based supplementary feature Mamma Bubble-like downward protuberances; mostly seen with species castellanus. Genitus mother clouds No genitus types. Mutatus mother clouds Cirrocumulus cirromutatus Cirrocumulus cirrostratomutatus Cirrocumulus altocumulomutatus Cirrocumulus homomutatus Results from the transformation of cirrus homogenitus. Genus cirrostratus Abbreviation: Cs Clouds of the genus cirrostratus consist of mostly continuous, wide sheets of cloud that covers a large area of the sky. It is formed when convectively stable moist air cools to saturation at high altitude, forming ice crystals. Frontal cirrostratus is a precursor to rain or snow if it thickens into mid-level altostratus and eventually nimbostratus, as the weather front moves closer to the observer. Species Cirrostratus fibratus (V-22) Cirrostratus sheet with a fibrous appearance, but not as detached as cirrus. Cirrostratus nebulosus (V-23) Featureless, uniform sheet. Varieties Opacity-based varieties None (always translucent) Fibratus pattern-based varieties Cirrostratus fibratus duplicatus (V-24) Separate or semi-merged sheets with one layer slightly above the other. Cirrostratus fibratus undulatus (V-25) Undulating waves. Varieties are not commonly associated with Cs species nebulosus. Supplementary features Supplementary features/accessory clouds: Not associated with cirrostratus. Genitus mother clouds Cirrostratus cirrocumulogenitus Cirrostratus cumulonimbogenitus Mutatus mother clouds Cirrostratus cirromutatus Cirrostratus cirrocumulomutatus Cirrostratus altostratomutatus Cirrostratus homomutatus Results from the transformation of cirrus homogenitus. Mid-level stratocumuliform and stratiform Middle cloud forms from 2 to 7 km (6,500–23,000 ft) in temperate latitudes, and may be composed of water droplets or ice crystals depending on the temperature profile at that altitude range. Genus altocumulus Abbreviation: Ac Mid-level stratocumuliform clouds of the genus altocumulus are not always associated with a weather front but can still bring precipitation, usually in the form of virga which does not reach