Categories: Atmospheric science stubs | Cumulus Cumulus mediocris clouds, as seen from a plane window. ... This article or section does not adequately cite its references or sources. ... Cirrus uncinus is a type of cirrus cloud. ... A KHI on the planet Saturn, formed at the interaction of two bands of the planets atmosphere Kelvin-Helmholtz instability can occur when velocity shear is present within a continuous fluid or when there is sufficient velocity difference across the interface between two fluids. ... Cirrostratus showing an extremely large halo. ... A cirrocumulus is a high-altitude cloud, usually occurring at 20,000-40,000 ft (6,000-12,000 m). ... A pileus (Latin for cap) is a small, horizontal cloud that can appear above a cumulus or cumulonimbus cloud, giving the parent cloud a characteristic hoodlike appearance. ... Contrails are condensation trails (sometimes vapour trails): artificial cirrus clouds made by the exhaust of aircraft engines or wingtip vortices which precipitate a stream of tiny ice crystals in moist, frigid upper air. ... Altostratus is a cloud belonging to a class characterized by a generally uniform gray sheet or layer, lighter in color than nimbostratus and darker than cirrostratus. ... Image provided by Simon Eugster The altostratus undulatus is a type of low altocumulus cloud with signature undulations within it. ... An Altocumulus is a cloud belonging to a class characterized by globular masses or rolls in layers or patches, the individual elements being larger and darker than those of cirrocumulus and smaller than those of stratocumulus. ... The altocumulus undulatus is a mid-level cloud (about 8000 - 20,000 ft or 2400 - 6100 m), usually white or grey with layers or patches containing undulations that resemble waves or ripples in water. ... A mackerel sky is an indicator of moisture (the cloud) and instability (the cumulus form) at intermediate levels (2400-6100 m, 8000-20,000 ft). ... Altocumulus Castellanus is a family B type cloud. ... Lenticular clouds, technically known as altocumulus standing lenticularis, are stationary lens-shaped clouds that form at high altitudes, normally aligned at right-angles to the wind direction. ... A stratus cloud (St) is a cloud belonging to a class characterized by horizontal pictures with a uniform butt, as opposed to convective clouds that are as tall or taller than wide (these are termed cumulus clouds). ... Nimbostratus has very few features. ... Cumulus humilis is what is commonly referred to as fair weather cumulus. In hot countries and over mountainous terrain these clouds occur at up to 6000 meters altitude, though elsewhere they are typically found lower. ... A stratocumulus cloud belongs to a class characterized by large dark, rounded masses, usually in groups, lines, or waves, the individual elements being larger than those in altocumuli, and the whole being at a lower altitude, usually below 2,400 m (8,000 ft). ... Cumulonimbus (Cb) is a type of cloud that is tall, dense, and involved in thunderstorms and other intense weather. ... A cumulonimbus incus cloud has a characteristic anvil-top shape. ... Cumulonimbus calvus is an moderately tall cumulonimbus cloud which is capable of precipitation, but has not yet reached the height where it forms into a cumulonimbus incus (anvil-top). ... Mammatus clouds in Tulsa, Oklahoma, 1973 Cumulonimbus with mammatus formed after Hurricane Catarina in Santa Catarina, Brazil, 2004 Another view of the post-Catarina mammatus formation Mammatus (also known as mamma or mammatocumulus) is a meteorological term applied to a cellular pattern of pouches hanging underneath the base of a... Cumulus congestus clouds are characteristic of unstable areas of the atmosphere which are undergoing convection. ... Cumulus castellanus (from L castellanus, castle) is a type of cumulus cloud that is distinctive because it displays multiple towers arising from its top, indicating significant vertical air movement. ... Pyrocumulus, or fire cumulus, is a dense cumuliform cloud usually found at an altitude of 1500 m. ... The pyrocumulonimbus (pyroCb) is a type of cloud formed above a source of heat such as a wildfire or industrial plant. ...