Cloud If the air becomes more unstable, the cloud tends to grow vertically into the species "mediocris", then "congestus", the tallest cumulus species which is the same type that the International Civil Aviation Organization refers to as 'towering cumulus'. With highly unstable atmospheric conditions, large cumulus may continue to grow into cumulonimbus "calvus" (essentially a very tall congestus cloud that produces thunder), then ultimately into the species "capillatus" when supercooled water droplets at the top of the cloud turn into ice crystals giving it a cirriform appearance. All cloud varieties fall into one of two main groups. One group identifies the
Cirrocumulus cloud this may also be seen in conjunction with showers and thunderstorms). If it is seen after rain it usually means improving weather. Cirrocumulus cloud Cirrocumulus is one of the three main genus-types of high-altitude tropospheric clouds, the other two being cirrus and cirrostratus. They usually occur at an altitude of to . Like lower altitude cumuliform and stratocumuliform clouds, cirrocumulus signifies convection. Unlike other high-altitude-tropospheric clouds like cirrus and cirrostratus, cirrocumulus includes a small amount of liquid water droplets, although these are in a supercooled state. Ice crystals are the predominant component, and typically, the ice crystals cause the supercooled