Arcus cloud Arcus cloud An arcus cloud is a low, horizontal cloud formation, usually appearing as an accessory cloud to a cumulonimbus. Roll clouds and shelf clouds are the two main types of arcus. Arcus clouds most frequently form along the leading edge or "gust fronts" of thunderstorm outflow; some of the most dramatic arcus formations mark the gust fronts of derecho-producing convective systems. Roll clouds also may arise in the absence of thunderstorms, forming along the shallow cold air currents of some sea breeze boundaries and cold fronts. A shelf cloud is a low, horizontal, wedge-shaped arcus cloud. A shelf cloud
Stratocumulus cloud with two or more layers or sheets. Stratocumulus duplicatus is common on species lenticularis or lenticular cloud. Stratocumulus Lacunosus clouds are very uncommon. They only occur when there are localized downdrafts striking through the stratocumuliform cloud. Stratocumulus Mamma is a type of mammatus cloud. Stratocumulus Virga is a form of precipitation that evaporates in mid-air and doesn't reach the ground. Stratocumulus Praecipitatio is a form of precipitation that reaches the ground as light rain or snow. Stratocumulus Cumulomutatus the specific type of stratocumulus clouds, are flat and elongated. They form in the evening, when updrafts caused by convection decrease making