Editing Cloud (section)

====Cloud-based supplementary features====
''Incus'' is the most type-specific supplementary feature, seen only with cumulonimbus of the species capillatus. A [[cumulonimbus incus]] cloud top is one that has spread out into a clear anvil shape as a result of rising air currents hitting the stability layer at the [[tropopause]] where the air no longer continues to get colder with increasing altitude.<ref name="cumulonimbus-incus">{{Cite web |date=5 August 2009 |title=Cumulonimbus Incus |url=http://epod.usra.edu/blog/2009/08/cumulonimbus-incus.html |access-date=23 October 2012 |publisher=Universities Space Research Association}}</ref>

The ''mamma'' feature forms on the bases of clouds as downward-facing bubble-like protuberances caused by localized downdrafts within the cloud. It is also sometimes called ''mammatus'', an earlier version of the term used before a standardization of Latin nomenclature brought about by the World Meteorological Organization during the 20th century. The best-known is [[cumulonimbus with mammatus]], but the mamma feature is also seen occasionally with cirrus, cirrocumulus, altocumulus, altostratus, and stratocumulus.<ref name="features" />

A ''tuba'' feature is a cloud column that may hang from the bottom of a cumulus or cumulonimbus. A newly formed or poorly organized column might be comparatively benign, but can quickly intensify into a funnel cloud or tornado.<ref name="features" /><ref name="Aerographer">{{Cite web |last=Aerographer/Meteorology |year=2012 |title=Roll cloud formation on cumulonimbus |url=http://meteorologytraining.tpub.com/14269/css/14269_27.htm |url-status=dead |archive-url=https://web.archive.org/web/20130518082044/http://meteorologytraining.tpub.com/14269/css/14269_27.htm |archive-date=18 May 2013 |access-date=5 July 2012}}</ref><ref name="Dunlop79">{{harvnb|Dunlop|2003|p=79}}</ref>

An ''[[Arcus cloud|arcus]]'' feature is a roll cloud with ragged edges attached to the lower front part of cumulus congestus or cumulonimbus that forms along the leading edge of a squall line or thunderstorm outflow.<ref name="Ludlum473">{{Cite book |last=Ludlum |first=David McWilliams |url=https://archive.org/details/audubonsocietyfi00ludl/page/473 |title=National Audubon Society Field Guide to Weather |publisher=Alfred A. Knopf |year=2000 |isbn=978-0-679-40851-2 |page=[https://archive.org/details/audubonsocietyfi00ludl/page/473 473] |oclc=56559729}}</ref> A large arcus formation can have the appearance of a dark menacing arch.<ref name="features" />

Several new supplementary features have been formally recognized by the [[World Meteorological Organization]] (WMO). The feature ''fluctus'' can form under conditions of strong atmospheric wind shear when a stratocumulus, altocumulus, or cirrus cloud breaks into regularly spaced crests. This variant is sometimes known informally as a [[Kelvin–Helmholtz cloud|Kelvin–Helmholtz (wave) cloud]]. This phenomenon has also been observed in cloud formations over other planets and even in the Sun's atmosphere.<ref>{{Cite web |last=Fox |first=Karen C. |date=30 December 2014 |title=NASA's Solar Dynamics Observatory Catches "Surfer" Waves on the Sun |url=http://www.nasa.gov/mission_pages/sunearth/news/sun-surfing.html |website=NASA-The Sun-Earth Connection: Heliophysics |publisher=NASA |access-date=20 November 2014 |archive-date=20 November 2021 |archive-url=https://web.archive.org/web/20211120110428/https://www.nasa.gov/mission_pages/sunearth/news/sun-surfing.html |url-status=dead }}</ref> Another highly disturbed but more chaotic wave-like cloud feature associated with stratocumulus or altocumulus cloud has been given the Latin name ''asperitas''. The supplementary feature ''cavum'' is a circular fall-streak hole that occasionally forms in a thin layer of supercooled altocumulus or cirrocumulus. Fall streaks consisting of virga or wisps of cirrus are usually seen beneath the hole as ice crystals fall out to a lower altitude. This type of hole is usually larger than typical lacunosus holes. A ''murus'' feature is a cumulonimbus wall cloud with a lowering, rotating cloud base that can lead to the development of tornadoes. A ''cauda'' feature is a tail cloud that extends horizontally away from the murus cloud and is the result of air feeding into the storm.<ref name=ICA2017/>