Nimbostratus cloud
166737
220539092
2008-06-20T10:30:13Z
196.25.43.208
{{Expand|date=March 2007}}
{{Infobox Cloud
| name = Nimbostratus cloud
| image location = Nov20-05-Nimbostratus.jpg
| image name =Heavy nimbostratus cover with some cumuliform fractus.
| abbreviation = Ns
| distributed = worldwide
| symbol = CM_2.png
| genus= Nimbo- (''rain'')<br /> -stratus (''layered'')
| species= cloud
| variety= cloudy
| altitude_m = below 2,400
| altitude_ft = below 8,000
| level = low
| appearance = Dark, Widespread, formless layer
| precipitation = Yes, but may be [[virga]]
}}
Nimbo is from the Latin word "nimbus" meaning rain. A '''Nimbostratus''' is a [[cloud]] of the class characterized by a formless layer that is almost uniformly dark gray; it is a rain cloud of the layer type, of medium altitude, usually developing above 6500 ft (2000 m) as defined by the [[WMO]]. It may drop below 2000m and is classified in some nations as low level cloud. Nimbostratus block a great amount of [[sunlight]] as a result of its characteristic dense structure. Nimbostratus usually has a thickness of 6,500-10,000 ft (2,000-3,000 meters), but can vary from 15,000 ft (4,500 m) to 3,500 ft (1,000 m) in thickness. In rare cases, nimbostratus can be very thin and accompanied by a separate layer of [[Altostratus cloud|altostratus]] divided by a cloudless layer.
The base of a nimbostratus [[Cloud_base|base]] cloud is dimmed by precipitation and is usually not clearly visible. In most cases, nimbostratus is accompanied by [[Fractus_cloud|pannus]] clouds, which develop under layer of nimbostratus. If [[Fractus_cloud|pannus]] layer is completely opaque, presence of precipitation indicates presence of nimbostratus. The [[Fractus cloud|pannus]] movement is slow and uniform under nimbostratus.
[[Image:Nimbostratus.jpg|thumb|300px|left|Nimbostratus has very few visual features.]]
Nimbostratus, [[Stratus cloud|stratus]], [[Altostratus cloud|altostratus]] and [[stratocumulus]] clouds all have a smooth gray appearance. Usually, nimbostratus is a sign of steady moderate to heavy precipitation. However, precipitation does not occur at ground level in case of [[virga]] and accompanies other cloud types. There are a number of features allowing the observer to distinguish nimbostratus from other clouds:
* [[Stratus cloud|Stratus clouds]] bring much lighter precipitation (drizzle) than nimbostratus;
* [[Altostratus cloud|Altostratus clouds]] are lighter in color and less opaque than nimbostratus, so sunlight can be seen through them;
* [[Cirrostratus cloud|Cirrostratus clouds]] never bring precipitation and have a thin, whitish, veil-like structure, characteristic for cirrus;
* [[Stratocumulus]] bring only light precipitation and have clearly visible [[Cloud_base|base]] with easely distinguished separate cloud elements.
Moreover, large and low [[cumulonimbus cloud]] covering most of sky can be mistaken for nimbostratus. In this case, nimbostratus can be distinguished by lighter, constant precipitation.
Other typical precipitation-bearing clouds are [[cumulonimbus cloud|cumulonimbus]].
==External links==
{{commonscat|Nimbostratus clouds}}
*[http://www.clouds-online.com Clouds-Online.com Cloud Atlas with many photos and description of the different cloud genus]
* [http://www.nsdl.arm.gov/Library/glossary.shtml#Nimbostratus National Science Digital Library - Nimbostratus]
* [http://www.uwsp.edu/geo/faculty/ritter/geog101/textbook/atmospheric_moisture/clouds_3.html Nimbostratus and Other Low Clouds]
{{Cloud types}}
[[Category:Cloud types]]
[[ca:Nimbostratus]]
[[cs:Nimbostratus]]
[[de:Nimbostratus]]
[[el:Μελανοστρώματα]]
[[es:Nimbostratus]]
[[fr:Nimbostratus]]
[[gl:Nimbostratus]]
[[ko:난층운]]
[[it:Nembostrato]]
[[he:נימבוסטרטוס]]
[[nl:Nimbostratus]]
[[ja:乱層雲]]
[[no:Nimbostratus]]
[[nn:Nimbostratus]]
[[pl:Nimbostratus]]
[[pt:Nimbostratus]]
[[sk:Nimbostratus]]
[[sl:Nimbostratus]]
[[fi:Laaja sadepilvi]]
[[sv:Nimbostratus]]
[[uk:Шарувато-дощові хмари]]