Editing Altocumulus castellanus cloud

{{Short description|Type of altocumulus cloud}}
{{Infobox Cloud
| name = Altocumulus castellanus
| image location = Hiranandani-Gardens-3.jpg
| image name = Altocumulus castellanus clouds, with higher [[altocumulus floccus]]
| abbreviation = Ac cas
| symbol         = Clouds CM 8.svg
| genus= Altocumulus (''high'', ''heaped'')
| species=castellanus (''castle'')
| variety= * Duplicatus
* Lacunosus
* Opacus
* Perlucidus
* Radiatus
* Translucidus
* Undulatus
| altitude_m = 2,000 - 6,000
| altitude_ft = 6,500 - 20,000
| level = medium
| appearance=Middle-altitude [[Stratocumulus]] clouds arranged in groups with rising towers, turrets.
| precipitation = Virga only.
| thickness      = 
| Ice content    = 
}}

In meteorology, '''Altocumulus castellanus''' or '''Altocumulus castellatus'''<ref>{{Cite web|url=https://cloudatlas.wmo.int/en/appendix-3-history-of-cloud-nomenclature.html#cirrus|title = Appendix 3 - History of cloud nomenclature}}</ref> (ACCAS) is a cloud type named for its tower-like projections that billow upwards from the base of the cloud. The base of the cloud can form as low as 2,000 metres (6,500 feet), or as high as 6,000 metres (20,000 feet). They are very similar to cumulus congestus clouds, but at a higher level and with the cloud heaps joined at the base.

[[Castellanus]] clouds are evidence of mid-atmospheric instability and a high mid-altitude [[lapse rate]].<ref name="weather.com glossary">{{cite web|url=http://www.weather.com/glossary/a.html#accs|title=weather.com - Glossary|accessdate=2008-12-06| archiveurl= https://web.archive.org/web/20081207113332/http://www.weather.com/glossary/a.html| archivedate= 7 December 2008}}</ref> They may be a harbinger of heavy showers and thunderstorms and, if surface-based [[convection]] can connect to the mid-[[troposphere|tropospheric]] unstable layer, continued development of Castellanus clouds can produce [[cumulonimbus cloud|cumulonimbus]] clouds.

Altocumulus castellanus clouds are typically accompanied by moderate [[turbulence]] as well as potential [[icing conditions]]. For these reasons, flight through these clouds is often best avoided by aircraft.<ref name="nasaquest">{{cite web|url=http://quest.arc.nasa.gov/aero/virtual/demo/weather/tutorial/tutorial5c.html|title=Weather Tutorial Page 4c - Clouds (NASA Quest)|accessdate=2008-12-06|archive-url=https://web.archive.org/web/20061005134258/http://quest.arc.nasa.gov/aero/virtual/demo/weather/tutorial/tutorial5c.html|archive-date=2006-10-05|url-status=dead}}</ref>

==References==
{{reflist}}

==External links==
* [http://australiasevereweather.com/photography/altocucastellanus.html Altocumulus Castellanus (Source: Australiasevereweather.com)]

{{Cloud types}}

[[Category:Cumulus]]
[[Category:Gliding technology]]