Editing Cloud (section)

====High-level====
[[File:Cirrus sky panorama.jpg|thumb|High [[cirrus cloud|cirrus]] upper-left merging into [[cirrostratus]] right and some [[cirrocumulus]] far right]]

High clouds form at altitudes of {{convert|10000|to|25000|ft|abbr=on|order=flip|-2}} in the [[polar region]]s, {{convert|16500|to|40000|ft|abbr=on|order=flip|-2}} in the [[temperate regions]], and {{convert|20000|to|60000|ft|abbr=on|order=flip|-2}} in the [[tropics]].<ref name="Definitions" /> All cirriform clouds are classified as high, thus constitute a single genus ''cirrus'' (Ci). Stratocumuliform and stratiform clouds in the high altitude range carry the prefix ''cirro-'', yielding the respective genus names ''cirrocumulus'' (Cc) and ''cirrostratus'' (Cs). If limited-resolution satellite images of high clouds are analyzed without supporting data from direct human observations, distinguishing between individual forms or genus types becomes impossible, and they are collectively identified as ''high-type'' (or informally as ''cirrus-type'', though not all high clouds are of the cirrus form or genus).<ref name="Cloud type identification">{{Cite web |year=2015 |editor-last=Colorado State University Dept. of Atmospheric Science |title=Cloud type identification by satellites |url=http://rammb.cira.colostate.edu/wmovl/VRL/Texts/SATELLITE_METEOROLOGY/CHAPTER-2.PDF |archive-url=https://web.archive.org/web/20060411213048/http://rammb.cira.colostate.edu/wmovl/VRL/Texts/SATELLITE_METEOROLOGY/CHAPTER-2.PDF |archive-date=11 April 2006 |url-status=live |access-date=30 December 2015 |publisher=[[Colorado State University]]}}</ref>

* Genus [[Cirrus cloud|cirrus]] (Ci) – these are mostly fibrous wisps of delicate, white, cirriform, ice crystal clouds that show up clearly against the blue sky.<ref name="cirrus" /> Cirrus are generally non-convective except castellanus and floccus subtypes which show limited convection. They often form along a high altitude [[jetstream]]<ref name="Jetstream clouds">{{Cite journal |last=Vincent J. Schaefer |date=October 1952 |title=Cloud Forms of the Jet Stream |journal=Tellus |volume=5 |issue=1 |pages=27–31 |bibcode=1953Tell....5...27S |doi=10.1111/j.2153-3490.1953.tb01032.x}}</ref> and at the very leading edge of a frontal or low-pressure disturbance where they may merge into cirrostratus. This high-level cloud genus does not produce precipitation.<ref name="wmo-cloud classifications">{{Cite web |year=1995 |editor-last=World Meteorological Organization |title=WMO cloud classifications |url=http://www.weatheranswer.com/public/Clouds_WMO.pdf |archive-url=https://web.archive.org/web/20050226160200/http://www.weatheranswer.com/public/Clouds_WMO.pdf |archive-date=26 February 2005 |url-status=live |access-date=1 February 2012}}</ref>
* Genus [[cirrocumulus]] (Cc) – this is a pure white high stratocumuliform layer of limited convection. It is composed of ice crystals or supercooled water droplets appearing as small unshaded round masses or flakes in groups or lines with ripples like sand on a beach.<ref name="cirrocumulus">{{Cite web |year=2017 |editor-last=World Meteorological Organization |title=Cirrocumulus, International Cloud Atlas |url=https://cloudatlas.wmo.int/clouds-genera-cirrocumulus.html |access-date=16 May 2017}}</ref><ref name="YDN-364">{{Cite book |last1=Miyazaki |first1=R. |title=Proceedings Ninth Pacific Conference on Computer Graphics and Applications. Pacific Graphics 2001 |last2=Yoshida |first2=S. |last3=Dobashi |first3=Y. |last4=Nishita |first4=T. |year=2001 |isbn=978-0-7695-1227-3 |pages=363 |chapter=A method for modeling clouds based on atmospheric fluid dynamics |citeseerx=10.1.1.76.7428 |doi=10.1109/PCCGA.2001.962893 |s2cid=6656499}}</ref> Cirrocumulus occasionally forms alongside cirrus and may be accompanied or replaced by cirrostratus clouds near the leading edge of an active weather system. This genus-type occasionally produces virga, precipitation that evaporates below the base of the cloud.<ref name="Mackerel sky">{{Cite web |title=Mackerel sky |url=http://www.weatheronline.co.uk/reports/wxfacts/Sometimes-a-bit-fishy.htm |access-date=21 November 2013 |publisher=Weather Online}}</ref>
* Genus [[cirrostratus]] (Cs) – cirrostratus is a thin nonconvective stratiform ice crystal veil that typically gives rise to halos caused by refraction of the [[sunlight|Sun's rays]]. The Sun and Moon are visible in clear outline.<ref name="cirrostratus">{{Cite web |year=2017 |editor-last=World Meteorological Organization |title=Cirrostratus, International Cloud Atlas |url=https://cloudatlas.wmo.int/clouds-genera-cirrostratus.html |access-date=16 May 2017}}</ref> Cirrostratus does not produce precipitation, but often thickens into altostratus ahead of a warm front or low-pressure area, which sometimes does.<ref name="Altostratus">{{Cite book |url=https://archive.org/details/manualonobservat00worl/page/35 |title=Altostratus, International Cloud Atlas |year=1975 |isbn=978-92-63-10407-6 |editor-last=World Meteorological Organization |volume=I |pages=[https://archive.org/details/manualonobservat00worl/page/35 35–37] |publisher=Secretariat of the World Meteorological Organization |access-date=26 August 2014}}</ref>