to free-convective cloud types and storms Accessory cloud (WMO supplementary feature) – secondary cloud that is associated with but separate from a main cloud. Anvil (WMO supplementary feature incus) – the anvil top of a cumulonimbus cloud. Anvil dome (WMO supplementary feature incus) – the overshooting top on a Cb that is often present on a supercell. Anvil rollover – (slang) circular protrusion attached to underside of anvil. Arcus cloud (WMO supplementary feature) – arch or a bow shape, attached to cumulus, thick with ragged edges. Backsheared anvil – (slang) anvil that spreads upwind, indicative of extreme weather. Clear slot or dry slot (informal term) – an evaporation of clouds as a rear flank downdraft descends and dries out cloud and occludes around a mesocyclone. Cloud tags (WMO species fractus) – ragged detached portions of cloud. Collar cloud (WMO velum accessory cloud) – ring shape surrounding upper part of wall cloud. Condensation funnel (WMO supplementary feature tuba) – the cloud of a funnel cloud aloft or a tornado. Altocumulus castellanus (WMO genus and species) – castle crenellation-shaped altocumulus clouds. Cumulus (WMO genus) – heaped clouds. Cumulus castellanus – (informal variation of WMO genus and species cumulus congestus) cumulus with tops shaped like castle crenellations. Cumulus congestus (WMO genus and species) – considerable vertical development and heaped into cauliflower shapes. Cumulus fractus (WMO genus and species) – ragged detached portions of cumulus cloud. Cumulus humilis (WMO genus and species) – small, low, flattened cumulus, early development. Cumulus mediocris (WMO genus and species) – medium-sized cumulus with bulges at the top. Cumulus pileus (WMO genus and accessory cloud) – capped, hood-shaped cumulus cloud. Cumulus praecipitatio (WMO genus and supplementary feature) – cumulus whose precipitation reaches the ground. Cumulus radiatus (WMO genus and variety) – cumulus arranged in parallel lines that appear to converge near the horizon. Cumulus tuba (WMO genus and supplementary feature) – column hanging from the bottom of cumulus. Cumulonimbus (WMO genus) – heaped towering rain-bearing clouds that stretch to the upper levels of the troposphere. Cumulonimbus calvus (WMO genus and species) – cumulonimbus with round tops like cumulus congestus. Cumulonimbus capillatus (WMO genus and species) – Cb with cirriform top. Cumulonimbus incus (WMO genus and supplementary feature) – Cb capillatus with anvil top. Cumulonimbus mamma (WMO genus and supplementary feature) – Cb with pouch-like protrusions that hang from under anvil or cloud base. Cumulonimbus pannus (WMO genus and accessory