Altostratus undulatus cloud

Infobox Cloud
name = Altostratus undulatus cloud
image location = Cirrus and Altostratus undulatus.jpg


abbreviation = As
symbol = CM_5.png genus= Alto- ("high"), -stratus ("layered")
species= undulatus ("waves")
variety=
altitude_m = 2400-6100
altitude_ft = 8,000-20,000
level=medium
appearance = undulated
precipitation = Usually no

The altostratus undulatus is a type of low altocumulus cloud with signature undulations within it. These undulations may be visible (usually as "wavy bases"), but frequently they are indiscernible to the naked eye. These formations will generally appear in the early stages of destabilizing return flows, especially over the southern plains of the United States, when the surface temperature is still relatively cool. [http://www.stormeyes.org/tornado/SkyPix/asundula.htm] The wavy strips of clouds are generally near an inversion surface.

Also referred to as "billow clouds," "windrow clouds," or "wave clouds," variations of the undulatus can be elements that have merged or single elements that have stretched through the sky. They often run parallel, but can also appear to interweave across the sky, especially if dual wave systems are seen (also referred to as biundulatus). Gravity waves aligned normally to the direction of the wind can show wide, near-parallel cloud strips. [http://amsglossary.allenpress.com/glossary/search?id=undulatus1]

ee also

* Weather
* Atmosphere
* Cloud types

External links

* [http://amsglossary.allenpress.com/glossary/ American Meteorological Society's "Glossary of Meteorology"]
* [http://www.stormeyes.org/ Stormeyes] , a website for storm watchers (and storm chasers)
* [http://www.weather-photography.com/index.php Weather Photography]