Accessory cloud types can form at various altitude ranges depending on the main clouds with which they are associated. The World Meteorological Organization classifies most accessory clouds as "supplementary features". The height range classification of a supplementary feature is the same as the parent cloud. As an example, the anvil cloud (supplementary feature incus) forms at high altitude but is not classified by the WMO as a high cloud because of its association with the genus cumulonimbus. It is "very rare" for any accessory cloud to generate its own precipitation. However, the parent cloud may generate precipitation. Precipitation from the parent cloud
Morning Glory cloud long, high, often only above the ground. The cloud often travels at the rate of 10 to 20 metres per second. Sometimes there is only one cloud, sometimes there are up to ten consecutive roll clouds. Three distinct types of Morning Glory clouds have been identified. The Morning Glory is often accompanied by sudden wind squalls, intense low-level wind shear, a rapid increase in the vertical displacement of air parcels, and a sharp pressure jump at the surface. Cloud is continuously formed at the leading edge while being eroded at the trailing edge. Showers or thunderstorms may develop in its