Nimbostratus cloud - wikipedia Nimbostratus cloud Nimbostratus cloud Nimbostratus with fractus Abbreviation Ns Symbol Genus Nimbostratus ( rain, layered ) Species none Variety none Altitude below 3,000 m ( below 10,000 ft ) Appearance Dark, widespread, formless layer Precipitation cloud ? Yes, but may be virga Nimbostratus is a stratiform genus formerly classified as `` Family C '' low - level, but now considered by the World Meteorological Organization ( WMO ) to be a middle - or multi-level stratus type.. Although it is usually a low - based cloud, it actually forms most commonly in the middle level of the troposphere and then spreads vertically into the low and high levels. This change in classification would once have made it a `` Family D '' cloud, but this style of nomenclature was discontinued by the WMO in 1956. Nimbostratus usually produces precipitation over a wide area. Nimbo - is from the Latin word nimbus, which denotes precipitation. It has a diffuse cloud base generally found anywhere from near surface in the low levels to about 3,000 m ( 9,800 ft ) in the middle level of the troposphere. Although usually dark at its base, it often appears illuminated from within to a surface observer. Nimbostratus usually has a thickness of about 2000 m. Though found worldwide, nimbostratus occurs more commonly in the middle latitudes. It is coded C 2 on the SYNOP report. Downward - growing nimbostratus can have the same vertical extent as most large upward - growing cumulus, but its horizontal extent tends to be even greater. This sometimes leads to the exclusion of nimbostratus from the group of vertical clouds by some independent meteorologists and educators. Classifications that follow this approach usually show nimbostratus as low - level based on its normal base height range. Species and varieties : Nimbostratus is very thick, opaque, and featureless, so this genus type is not subdivided into species or varieties. Precipitation - based supplementary features : Nimbostratus is a major precipitation cloud and produces the virga or praecipitatio features. The latter can achieve heavy intensity due to the cloud 's vertical depth. Accessory cloud : Pannus frequently forms in precipitation and is coded C 7. Genitus mother clouds : This genus type can form from cumulus and cumulonimbus. Mutatus mother clouds : Nimbostratus can form due to the complete transformation of altocumulus, altostratus and stratocumulus. Contents 1 Formation 2 Forecast 3 Origin of name 4 References 5 External links Formation Nimbostratus occurs along a warm front or occluded front where the slowly rising warm air mass creates nimbostratus along with shallower stratus clouds producing less rain, these clouds being preceded by higher - level clouds such as cirrostratus and altostratus. Often, when an altostratus cloud thickens and descends into lower altitudes, it will become nimbostratus. Nimbostratus, unlike cumulonimbus, is not associated with thunderstorms, however at an unusually unstable warm front caused as a result of the advancing warm air being hot, humid and unstable, cumulonimbus clouds may be embedded within the usual nimbostratus. Lightning from an embedded cumulonimbus cloud may interact with the nimbostratus but only in the immediate area around it. In this situation with lightning and rain occurring it would be hard to tell which type of cloud was producing the rain from the ground, however cumulonimbus tend to produce larger droplets and more intense downpours. The occurrence of cumulonimbus and nimbostratus together is uncommon, and usually only nimbostratus is found at a warm front. Nimbostratus pannus is an accessory cloud of nimbostratus that forms as a ragged layer in precipitation below the main cloud deck. Forecast Nimbostrati often have very few visual features. Usually, nimbostratus is a sign of easily steady to powerful precipitation, as opposed to the shorter period of typically heavier precipitation released by a cumulonimbus cloud. However, precipitation does not occur at ground level in case of virga and accompanies other cloud types. Precipitation may last for several days, depending on the speed of the warm or occluded front it accompanies. A nimbostratus virga cloud is the same as a normal nimbostratus cloud, but the precipitation is virga and it never reaches the ground. Stratus or stratocumulus ( comprising the warm sector of a frontal system ) usually forms when it clears. Origin of name Further information : Cloud § History of cloud science and nomenclature Under Luke Howard 's first systematized study of clouds, carried out in France in 1802, three general cloud forms were established based on appearance and characteristics of formation : cirriform, cumiliform and stratiform. These were further divided into upper and lower types depending on altitude. In addition to these three main types, Howard added two names to designate multiple cloud types joined together : cumulostratus, a blending of cumulus clouds and stratus layers, and nimbus, a complex blending of cirriform, cumuliform, and stratiform clouds with sufficient vertical development to produce significant precipitation. Later, in the 20th Century, an IMC commission for the study of clouds put forward a refined and more restricted definition of the genus nimbus, effectively reclassifying it as a stratiform cloud type. It was then renamed nimbostratus, and published with the new name in the 1932 edition of the International Atlas of Clouds and of States of the Sky. This left cumulonimbus as the only nimbiform type as indicated by its root - name. References Jump up ^ JetStream ( 5 January 2010 ). `` Cloud Classifications ''. National Weather Service. Retrieved 31 January 2011. Jump up ^ World Meteorological Organization, ed. ( 1975 ). Nimbostratus, International Cloud Atlas ( PDF ). I. pp. 37 -- 39. ISBN 92 - 63 - 10407 - 7. Retrieved 26 August 2014. ^ Jump up to : Pretor - Pinney, Gavin ( 2007 ). The Cloudspotter 's Guide : The Science, History, and Culture of Clouds. Perigee. ISBN 0 - 399 - 53345 - 1. Jump up ^ `` cloud : Classification of Clouds ''. Infoplease.com. Jump up ^ Hatheway, Becca ( 2009 ). `` Cloud Types ''. Windows to the Universe, US National Earth Science Teachers Association ( NESTA ). Retrieved 15 September 2011. Jump up ^ UXL, ed. ( 2002 ). `` clouds. UXL Encyclopedia of Science ''. Retrieved 23 November 2014. Jump up ^ World Meteorological Organization, ed. ( 1975 ). Species, International Cloud Atlas ( PDF ). pp. 18 -- 20. Retrieved 26 August 2014. Jump up ^ World Meteorological Organization, ed. ( 1975 ). Varieties, International Cloud Atlas ( PDF ). pp. 20 -- 22. Retrieved 26 August 2014. ^ Jump up to : Dunlop, Storm ( 2003 ). Weather Identification Handbook : The Ultimate Guide for Weather Watchers. Guilford, Connecticut : Globe Pequot. ISBN 1 - 58574 - 857 - 9. Jump up ^ Thompson, Graham ; Turk, Jonathan ( 1993 ). Earth Science and the Environment. Fort Worth : Saunders College Publishing. ISBN 0 - 03 - 075446 - 1. Jump up ^ Lankford, Terry ( 2000 ). Aviation Weather Handbook. McGraw - Hill Professional. ISBN 978 - 0 - 07 - 136103 - 3. Jump up ^ World Meteorological Organization, ed. ( 1975 ). Features, International Cloud Atlas ( PDF ). I. pp. 22 -- 24. ISBN 92 - 63 - 10407 - 7. Retrieved 26 August 2014. External links Wikimedia Commons has media related to Nimbostratus clouds. National Science Digital Library - Nimbostratus Nimbostratus and Other Low Clouds Cloud genera and selected species, supplementary features, and other airborne hydrometeors - WMO Latin terminology except where indicated Extreme - level Polar mesospheric cirriform type Noctilucent Very high - level Polar stratospheric cirriform type Nacreous High - level Tropospheric cirriform, stratiform, and stratocumuliform genera Cirrus ( Ci ) Cirrostratus ( Cs ) Cirrocumulus ( Cc ) General type ( non-WMO terminology ) Aviaticus cloud ( Contrail ) Medium - level Tropospheric stratiform and stratocumuliform genera Altostratus ( As ) Altocumulus ( Ac ) Stratocumuliform species Altocumulus castellanus ( Ac cas ) Low - level Tropospheric stratiform, stratocumuliform and cumuliform genera Stratus ( St ) Stratocumulus ( Sc ) Cumulus ( Cu ) Stratiform and cumuliform species Fractus Cumulus humilis ( Cu hum ) Stratocumulus variants ( non-WMO terminology ) Actinoform cloud Asperitas Moderate vertical Tropospheric stratiform and cumuliform genera Nimbostratus ( Ns ) Cumulus ( Cu ) Cumuliform species Cumulus mediocris ( Cu med ) Cumuliform supplementary features Cumulus Pileus Cumulus Volutus Towering vertical Tropospheric cumulonimbiform genus Cumulonimbus ( Cb ) Cumuliform species Cumulus congestus ( ICAO term Towering cumulus ( Tcu ) ) Cumuliform and cumulonimbiform supplementary features mamma Tuba ( Funnel cloud ) Pileus Arcus ( Shelf ) Cumuliform and cumulonimbiform variants ( non-WMO terminology ) Wall cloud Cumulonimbuus Overshooting top Hot tower Surface based General type Fog Non-height specific General types Accessory cloud Kelvin -- Helmholtz cloud Special Special modifiers Flammagenitus ( cloud ) Homogenitus ( cloud ) Retrieved from `` https://en.wikipedia.org/w/index.php?title=Nimbostratus_cloud&oldid=785786844 '' Categories : Stratus Talk Contents About Wikipedia Беларуская Català Čeština Cymraeg Deutsch Eesti Ελληνικά Español Esperanto Euskara فارسی Français Gaeilge Galego 한국어 Íslenska Italiano עברית Kaszëbsczi Latviešu Lietuvių Magyar Nederlands 日本 語 Norsk Norsk nynorsk Polski Português Română Русский Scots Slovenčina Slovenščina Српски / srpski Srpskohrvatski / српскохрватски Suomi Svenska தமிழ் Türkçe Українська Tiếng Việt 中文 Edit links This page was last edited on 15 June 2017, at 12 : 11. 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Question: what is meant by the term nimbus regarding clouds
Answer: precipitation