Editing Cirrus cloud (section)

== Use in forecasting ==
{{See also|Weather forecasting|Tropical cyclone track forecasting}}
[[File:Highcloudsymbols.gif|thumb|upright=1.35|High cloud weather map symbols|left]]
Random, isolated cirrus do not have any particular significance.<ref name="audubon-447"/> A large number of cirrus clouds can be a sign of an approaching [[weather front|frontal system]] or upper air disturbance. The appearance of cirrus signals a change in weather—usually more stormy—in the near future.<ref name="WeatherBattan">{{harvnb|Battan|1974|p=74}}</ref> If the cloud is a ''[[cirrus castellanus cloud|cirrus castellanus]]'', there might be instability at the high altitude level.<ref name="audubon-447">{{harvnb|Audubon|2000|p=447}}</ref> When the clouds deepen and spread, especially when they are of the ''cirrus radiatus'' variety or ''cirrus fibratus'' species, this usually indicates an approaching weather front. If it is a warm front, the cirrus clouds spread out into cirrostratus, which then thicken and lower into [[Altocumulus cloud|altocumulus]] and [[Altostratus cloud|altostratus]]. The next set of clouds are the rain-bearing [[nimbostratus cloud]]s.<ref name="cloud-classification"/><ref name="audubon-447"/><ref name="whiteman-84">{{harvnb|Whiteman|2000|p=84}}</ref> When cirrus clouds precede a [[cold front]], [[squall line]] or [[multicellular thunderstorm]], it is because they are blown off the anvil, and the next clouds to arrive are the cumulonimbus clouds.<ref name="whiteman-84"/> Kelvin-Helmholtz waves indicate extreme wind shear at high levels.<ref name="audubon-447"/> When a jet streak creates a large arc of cirrus, weather conditions may be right for the development of [[winter storm]]s.<ref name="cirrus-arc" />

Within the tropics, 36&nbsp;hours prior to the center passage of a tropical cyclone, a veil of white cirrus clouds approaches from the direction of the cyclone.<ref>{{cite web|author=Central Pacific Hurricane Center|date=23 July 2006|url=http://www.prh.noaa.gov/cphc/pages/FAQ/Observations.php|title=Tropical Cyclone Observations|access-date=5 May 2008|publisher=[[National Oceanic and Atmospheric Administration]]|archive-url=https://web.archive.org/web/20170322035214/http://www.prh.noaa.gov/cphc/pages/FAQ/Observations.php|archive-date=22 March 2017|author-link=Central Pacific Hurricane Center}}</ref> In the mid- to late-19th century, forecasters used these cirrus veils to predict the arrival of hurricanes. In the early 1870s the president of Belén College in [[Havana]], Father [[Benito Vines|Benito Viñes]], developed the first hurricane forecasting system; he mainly used the motion of these clouds in formulating his predictions.<ref>{{harvnb|Sheets|1990|p=190}}</ref> He would observe the clouds hourly from 4:00&nbsp;am to 10:00&nbsp;pm. After accumulating enough information, Viñes began accurately predicting the paths of hurricanes; he summarized his observations in his book ''Apuntes Relativos a los Huracanes de las Antilles'', published in English as ''Practical Hints in Regard to West Indian Hurricanes''.<ref>{{cite news|url=http://www.cubanet.org/CNews/y98/mar98/13e5.htm |publisher=Cable News Network, Inc |title=Father Hurricane |access-date=22 February 2011 |date=11 March 1998 |archive-url=https://web.archive.org/web/20110725212329/http://www.cubanet.org/CNews/y98/mar98/13e5.htm |archive-date=25 July 2011 }}</ref>