List of cloud types explained

The list of cloud types groups all genera as high (cirro-, cirrus), middle (alto-), multi-level (nimbo-, cumulo-, cumulus), and low (strato-, stratus). These groupings are determined by the altitude level or levels in the troposphere at which each of the various cloud types is normally found. Small cumulus are commonly grouped with the low clouds because they do not show significant vertical extent. Of the multi-level genus-types, those with the greatest convective activity are often grouped separately as towering vertical. The genus types all have Latin names.

The genera are also grouped into five physical forms. These are, in approximate ascending order of instability or convective activity: stratiform sheets; cirriform wisps and patches; stratocumuliform patches, rolls, and ripples; cumuliform heaps, and cumulonimbiform towers that often have complex structures. Most genera are divided into species with Latin names, some of which are common to more than one genus. Most genera and species can be subdivided into varieties, also with Latin names, some of which are common to more than one genus or species. The essentials of the modern nomenclature system for tropospheric clouds were proposed by Luke Howard, a British manufacturing chemist and an amateur meteorologist with broad interests in science, in an 1802 presentation to the Askesian Society. Very low stratiform clouds that touch the Earth's surface are given the common names fog and mist, which are not included with the Latin nomenclature of clouds that form aloft in the troposphere.

Above the troposphere, stratospheric and mesospheric clouds have their own classifications with common names for the major types and alpha-numeric nomenclature for the subtypes. They are characterized by altitude as very high level (polar stratospheric) and extreme level (polar mesospheric). Three of the five physical forms in the troposphere are also seen at these higher levels, stratiform, cirriform, and stratocumuliform, although the tops of very large cumulonimbiform clouds can penetrate the lower stratosphere.

Cloud identification and classification: Order of listed types

In section two of this page (Classification of major types), height ranges are sorted in approximate descending order of altitude expressed in general terms. On the cross-classification table, forms and genus types (including some genus sub-types) are shown from left to right in approximate ascending order of instability.

In sections three to five, terrestrial clouds are listed in descending order of the altitude range of each atmospheric layer in which clouds can form:

mesospheric layer;
stratospheric layer;
tropospheric layer.
- Within the troposphere, the cloud levels are listed in descending order of altitude range.
  - Non-vertical genus types (including some genus sub-types) are sorted into approximate descending order of altitude of the cloud bases.
  - Vertical or multi-level genera and genus sub-types can be based in the low or middle levels and are therefore placed between the non-vertical low and mid-level genus types and sub-types. These thick clouds are listed in approximate descending order of altitude of the cloud tops.
    - The species associated with each genus type are listed in approximate ascending order of instability where applicable.
    - The constituent varieties and associated supplementary features and mother clouds for each genus or species are arranged in approximate order of frequency of occurrence.
    - A count of basic tropospheric variants that result from the division and subdivision of genus types into species and varieties is shown as a number in parentheses from V-1 (variant 1) through V-93 after each variety, after nimbostratus that has no sub-types, and after certain species that are not always dividable into varieties.

In section six, the cloud types in the general lists and the mother clouds in the applicable classification table are sorted in alphabetical order except where noted. The species table shows these types sorted from left to right in approximate ascending order of the convective instability of each species. The table for supplementary features has them arranged in approximate descending order of frequency of occurrence.

In section seven, extraterrestrial clouds can be found in the atmospheres of other planets in our solar system and beyond. The planets with clouds are listed (not numbered) in order of their distance from the sun, and the clouds on each planet are in approximate descending order of altitude.

Cloud cross-classification throughout the homosphere

The table that follows is very broad in scope much like the cloud genera template near the bottom of the article and upon which this table is partly based. There are some variations in styles of nomenclature between the classification scheme used for the troposphere (strict Latin except for surface based aerosols) and the higher levels of the homosphere (common terms, some informally derived from Latin). However, the schemes presented here share a cross-classification of physical forms and altitude levels to derive the 10 tropospheric genera,^[1] the fog and mist that forms at surface level, and several additional major types above the troposphere. The cumulus genus includes four species that indicate vertical size which can affect the altitude levels.

	Stratiform non-convective	Cirriform mostly non-convective	Stratocumuliform limited-convective	Cumuliform free-convective	Cumulonimbiform strong-convective
Extreme-level	Noctilucent (NLC) veils	Noctilucent billows or whirls	Noctilucent bands
Very high-level^[2]	Nitric acid & water polar stratospheric (PSC)	Cirriform nacreous PSC	Lenticular nacreous PSC
High-level	Cirrostratus (Cs)	Cirrus (Ci)	Cirrocumulus (Cc)
Mid-level	Altostratus (As)		Altocumulus (Ac)
Towering vertical^[3]				Cumulus congestus (Cu con)	Cumulonimbus (Cb)
Multi-level or moderate vertical	Nimbostratus(Ns)			Cumulus mediocris (Cu med)
Low-level	Stratus (St)		Stratocumulus (Sc)	Cumulus humilis (Cu hum) or fractus (Cu fr)
Surface-level	Fog or mist

Mesospheric cloud identification and classification

Clouds that form in the mesosphere come in a variety of forms such as veils, bands, and billows, but are not given Latin names based on these characteristics. These clouds are the highest in the atmosphere and are given the Latin-derived name noctilucent which refers to their illumination during deep twilight rather than their physical forms. They are sub-classified alpha-numerically and with common terms according to specific details of their physical structures.

Extreme-level stratiform, stratocumuliform, and cirriform

Noctilucent clouds are thin clouds that come in a variety of forms based from about 80kmto(-)85kmkm (50milesto(-)53mileskm) and occasionally seen in deep twilight after sunset and before sunrise.^[4] ^[5]

Type 1 : Veils, very tenuous stratiform; resembles cirrostratus or poorly defined cirrus.

Stratospheric cloud identification and classification

Polar stratospheric clouds form at very high altitudes in polar regions of the stratosphere. Those that show mother-of-pearl colors are given the name nacreous.^[6]

Very high-level stratiform

Nitric acid and water polar stratospheric : Sometimes known as type 1, a thin sheet-like cloud resembling cirrostratus or haze. Contains supercooled nitric acid and water droplets; sometimes also contains supercooled sulfuric acid in ternary solution.

Very high-level cirriform and stratocumuliform

Nacreous polar stratospheric cloud (mother of pearl): Sometimes known as type 2, a thin usually cirriform or lenticular (stratocumuliform) looking cloud based from about 18kmto(-)30kmkm (11milesto(-)20mileskm) and seen most often between sunset and sunrise.^[6] Consists of ice crystals only.

Troposphere cloud identification and classification

Tropospheric clouds are divided into physical forms defined by structure, and levels defined by altitude range. These divisions are cross-classified to produce ten basic genus-types. They have Latin names as authorized by the World Meteorological Organization (WMO) that indicate physical structure, altitude or étage, and process of formation.

High-level cirriform, stratocumuliform, and stratiform

High clouds form in the highest and coldest region of the troposphere from about 5 to 12 km (16,500 to 40,000 ft) in temperate latitudes.^[7] ^[8] At this altitude water almost always freezes so high clouds are generally composed of ice crystals or supercooled water droplets.

Genus cirrus

Abbreviation: Ci

Cirriform clouds tend to be wispy and are mostly transparent or translucent. Isolated cirrus do not bring rain; however, large amounts of cirrus can indicate an approaching storm system eventually followed by fair weather.

There are several variations of clouds of the cirrus genus based on species and varieties:

Species

Cirrus fibratus (V-1): High clouds having the traditional "mare's tail" appearance. These clouds are long, fibrous, and curved, with no tufts or curls at the ends.

Varieties

Opacity-based: None; always translucent except species spissatus which is inherently opaque.^[10]

Supplementary features

Precipitation-based: Not associated with cirrus.

Genitus mother clouds:

Mutatus mother cloud:

Genus cirrocumulus

Abbreviation: Cc.^[7]

High-level stratocumuliform clouds of the genus cirrocumulus form when moist air at high tropospheric altitude reaches saturation, creating ice crystals or supercooled water droplets. Limited convective instability at the cloud level gives the cloud a rolled or rippled appearance. Despite the lack of a strato- prefix, layered cirrocumulus is physically a high stratocumuliform genus.^[12]

High stratocumuliform species

Cirrocumulus stratiformis^[13] (V-12): Sheets or relatively flat patches of cirrocumulus.

Varieties

Opacity-based varieties: None (always translucent).

Supplementary features

Precipitation-based supplementary feature:

Genus cirrostratus

Abbreviation: Cs^[7]

Clouds of the genus cirrostratus consist of mostly continuous, wide sheets of cloud that covers a large area of the sky. It is formed when convectively stable moist air cools to saturation at high altitude, forming ice crystals.^[14] Frontal cirrostratus is a precursor to rain or snow if it thickens into mid-level altostratus and eventually nimbostratus, as the weather front moves closer to the observer.

Species

Cirrostratus fibratus^[13] (V-22): Cirrostratus sheet with a fibrous appearance, but not as detached as cirrus.

Varieties

Opacity-based varieties: None (always translucent)^[10]

Supplementary features

Supplementary features/accessory clouds: Not associated with cirrostratus.^[11]

Genitus mother clouds:

Mid-level stratocumuliform and stratiform

Middle cloud forms from 2 to 7 km (6,500–23,000 ft) in temperate latitudes, and may be composed of water droplets or ice crystals depending on the temperature profile at that altitude range.^[8]

Genus altocumulus

Abbreviation: Ac^[7]

Mid-level stratocumuliform clouds of the genus altocumulus are not always associated with a weather front but can still bring precipitation, usually in the form of virga which does not reach the ground. Layered forms of altocumulus are generally an indicator of limited convective instability, and are therefore mainly stratocumuliform in structure.

Mid-level stratocumuliform species

Altocumulus stratiformis: Always dividable into opacity-based varieties. Sheets or relatively flat patches of altocumulus.

Varieties

Opacity-based varieties:

Supplementary features

Precipitation-based supplementary feature:

Genus altostratus

Abbreviation: As^[7]

Stratiform clouds of the genus altostratus form when a large convectively stable air mass is lifted to condensation in the middle level of the troposphere, usually along a frontal system. Altostratus can bring light rain or snow. If the precipitation becomes continuous, it may thicken into nimbostratus which can bring precipitation of moderate to heavy intensity.

Species

No differentiated species (always nebulous).^[9]

Varieties

Opacity-based varieties:

Supplementary features

Precipitation-based supplementary features:

Towering vertical cumulonimbiform and cumuliform (low to mid-level cloud base)

Clouds with upward-growing vertical development usually form below 2km (01miles),^[8] but can be based as high as 2.5km (01.6miles) in temperate climates, and often much higher in arid regions.

Genus cumulonimbus: Towering vertical

Abbreviation: Cb^[7]

Clouds of the genus cumulonimbus have very-dark-gray-to-nearly-black flat bases and very high tops that can penetrate the tropopause. They develop from cumulus when the air mass is convectively highly unstable. They generally produce thunderstorms, rain or showers, and sometimes hail, strong outflow winds, and/or tornadoes at ground level.

Species

Cumulonimbus calvus (V-57): Cumulonimbus with high domed top.

Varieties

No varieties (always opaque and does not form in patterns visible from surface level).^[9] ^[10]

Supplementary features

Precipitation-based supplementary features: Associated with calvus and capillatus species.

Genus cumulus: Towering vertical

Abbreviations: Cu con (cumulus congestus) or Tcu (towering cumulus)^[16]

Species

Cumulus congestus^[9] (V-59): These large cumulus clouds have flat dark grey bases and very tall tower-like formations with tops mostly in the high level of the troposphere. The International Civil Aviation Organization (ICAO) designates this species as towering cumulus (Tcu).

Varieties

Opacity-based varieties: None (always opaque).

Supplementary features

Precipitation-based supplementary features:

Multi-level stratiform and moderate vertical cumuliform (low to mid-level cloud base)

Genus nimbostratus: Multi-level

Abbreviation: Ns^[7] (V-60)

Clouds of the genus nimbostratus tend to bring constant precipitation and low visibility. This cloud type normally forms above 2km (01miles)^[8] from altostratus cloud but tends to thicken into the lower levels during the occurrence of precipitation. The top of a nimbostratus deck is usually in the middle level of the troposphere.

Species

No differentiated species (always nebulous).^[9]

Varieties

No varieties (always opaque and never forms in patterns).^[9] ^[10]

Supplementary features

Precipitation-based supplementary features:

Genus cumulus: Moderate vertical

Abbreviation: Cu^[7]

Moderate vertical cumulus is the product of free convective air mass instability. Continued upward growth suggests showers later in the day.

Species

Cumulus mediocris (V-61): Moderate vertical clouds with flat medium grey bases and higher tops than cumulus humilis.^[9]

Varieties

Opacity-based varieties: None (always opaque)

Pattern-based variety:

Supplementary features

Precipitation-based supplementary features:

Virga: Accompanied by precipitation that evaporates before reaching the ground.

Low-level stratocumuliform, cumuliform, and stratiform

Low cloud forms from near surface to ca. 2km (01miles) and are generally composed of water droplets.^[8]

Genus stratocumulus

Abbreviation: Sc^[7]

Clouds of the genus stratocumulus are lumpy, often forming in slightly unstable air, and they can produce very light rain or drizzle.

Species

Stratocumulus stratiformis: Always dividable into opacity-based varieties. Sheets or relatively flat patches of stratocumulus

Varieties

Stratocumuliform opacity-based varieties:

Supplementary features

Precipitation-based supplementary features: Usually associated with species stratiformis and castellanus.

Genus cumulus (little vertical extent)

Abbreviation: Cu

These are fair weather cumuliform clouds of limited convection that do not grow vertically. The vertical height from base to top is generally less than the width of the cloud base. They appear similar to stratocumulus but the elements are generally more detached and less wide at the base.

Species

Cumulus fractus (V-86): Ragged shreds of cumulus clouds.

Varieties

Opacity-based varieties: None (always opaque except species fractus which is always translucent).^[10]

Supplementary features and accessory clouds

Not commonly seen with cumulus fractus or humilis.^[11]

Genitus mother clouds

Genus stratus

Abbreviation: St^[7]

Clouds of the genus stratus form in low horizontal layers having a ragged or uniform base. Ragged stratus often forms in precipitation while more uniform stratus forms in maritime or other moist stable air mass conditions. The latter often produces drizzle. Stratus that touches the Earth's surface is given the common name, fog, rather than a Latin name that applies only to clouds that form and remain aloft in the troposphere.

Species

Stratus nebulosus: Uniform fog-like low cloud.

Varieties

Nebulosus opacity-based varieties:

Supplementary features

Precipitation-based supplementary feature:

Tropospheric cloud types with Latin etymologies where applicable

Cloud types are sorted in alphabetical order except where noted.

WMO genera

Altocumulus (altus and cumulus): Latin for "high heap": Applied to mid-level stratocumuliform.

WMO species

Castellanus (Cas): Latin for "castle-like": Applies to stratocumuliform (Sc cas, Ac cas, Cc cas) and dense cirriform (Ci cas) with a series of turret shapes – indicates air mass instability.

The division of genus types into species is as shown in the following table. The genus types (including some cumulus sub-types) are arranged from top to bottom in the left column in approximate descending order of average overall altitude range. The species are sorted from left to right in approximate ascending order of instability or vertical extent of the forms to which each belongs:

Stratiform species,
Cirriform species,
Stratocumuliform species,
Cumuliform species,
Cumulonimbiform species.

These ordinal instability numbers appear in each box where a particular genus has a particular species.

Level	Species (L-R)	Abbrev.		Neb	Fib	Unc	Spi	Str	Len	Vol	Flo	Cas	Fra	Hum	Med	Con	Cal	Cap
Level	Genus name	Species name L-R	(no species)	Nebulosus	Fibratus	Uncinus	Spissatus	Stratiformis	Lenticularis	Volutus	Floccus	Castellanus	Fractus	Humilis	Mediocris	Congestus	Calvus	Capillatus
High	Cirrus	Ci			(2)	(2)	(2)				(2)	(2)
	Cirrocumulus	Cc						(3)	(3)		(3)	(3)
	Cirrostratus	Cs		(1)	(1)
Middle	Altocumulus	Ac						(3)	(3)	(3)	(3)	(3)
Middle	Altostratus	As	(1)
Towering vertical	Cumulonimbus (5)	Cb															(5)	(5)
Towering vertical	Cumulus congestus	Cu con or Tcu														(4)
Moderate vertical	Nimbostratus	Ns	(1)
Moderate vertical	Cumulus mediocris	Cu med													(4)
Low	Stratocumulus	Sc						(3)	(3)	(3)	(3)	(3)
	Cumulus humilis	Cu hum											(4)	(4)
	Stratus	St		(1)									(1)

WMO varieties

Opacity-based:

The following table shows the cloud varieties arranged across the top of the chart from left to right in approximate descending order of frequency of appearance. The genus types and some sub-types associated with each variety are sorted in the left column from top to bottom in approximate descending order of average overall altitude range. Where applicable, the genera and varieties are cross-classified to show the species normally associated with each combination of genus and variety. The exceptions comprise the following: Altostratus that have varieties but no species so the applicable boxes are marked without specific species names; cumulus congestus, a species that has its own altitude characteristic but no varieties; cumulonimbus that have species but no varieties, and nimbostratus that has no species or varieties. The boxes for genus and species combinations that have no varieties are left blank.

Level	Name	Abbrev.	Tra	Per	Opa	Dup	Und	Rad	Lac	Int	Ver
Level	Name	Abbrev.	Translucidus	Perlucidus	Opacus	Duplicatus	Undulatus	Radiatus	Lacunosus	Intortus	Vertebratus
High	Cirrus	Ci				Fib Unc		Fib Unc		Fib	Fib
	Cirrocumulus	Cc					Str Len		Str, Cas Flo
	Cirrostratus	Cs				Fib	Fib
Middle	Altocumulus	Ac	Str	Str	Str	Str Len	Str Len	Str	Str, Cas Flo
Middle	Altostratus	As	+		+	+	+	+
Towering vertical	Cumulonimbus	Cb
Towering vertical	Cumulus congestus	Cu con or Tcu
Moderate vertical	Nimbostratus	Ns
Moderate vertical	Cumulus mediocris	Cu med						Med
Low	Stratocumulus	Sc	Str	Str	Str	Str Len	Str Len	Str	Str, Cas Flo
	Cumulus humilis	Cu hum						Hum
	Stratus	St	Neb		Neb		Neb

WMO supplementary features

Precipitation-based supplementary features:

The supplementary features are associated with particular genera as follows. They are sorted from left to right in approximate decreasing order of frequency of occurrence for each of three categories. The genus types and some sub-types are arranged from top to bottom in approximate descending order of average overall altitude range. Each box is marked where a particular genus or sub-type has a particular supplementary feature.

Level	Name	Class	Precipitation-based		Cloud-based				Accessory cloud
Level	Name	Abbrev.	Virga	Praecipitatio	Incus	Mamma	Arcus	Tuba	Pannus	Pileus	Velum
High	Cirrus	Ci				+
	Cirrocumulus	Cc	+			+
	Cirrostratus	Cs
Middle	Altocumulus	Ac	+			+
Middle	Altostratus	As	+	+		+			+
Towering vertical	Cumulonimbus	Cb	+	+	+	+	+	+	+	+	+
Towering vertical	Cumulus congestus	Cu con or Tcu	+	+		+	+		+	+	+
Moderate vertical	Nimbostratus	Ns	+	+					+
Moderate vertical	Cumulus mediocris	Cu med	+	+		+				+	+
Low	Stratocumulus	Sc	+	+		+
	Cumulus humilis	Cu hum		+
	Stratus	St

Genitus mother clouds

Altocumulogenitus: Formed by the partial transformation of altocumulus mother cloud.

Other genitus clouds

Cataractagenitus (cataracta-/pertaining to a river cataract): Formed from the mist at a waterfall, the downdraft caused from the cloud is counteracted by the ascending air displacement from the waterfall and may go on to form other types of clouds such as cumulus cataractagenitus.^[18]

Mutatus mother clouds

Nomenclature works the same way as for genitus mother clouds except for the mutatus suffix to indicate the complete rather than the partial transformation of the original cloud type. e.g. Altocumulomutatus – formed by the complete transformation of altocumulus mother cloud. The possible combinations of genera and mother clouds can be seen in this table. The genitus and mutatus clouds are each sorted from left to right in alphabetical order. The genus types and some sub-types are arranged from top to bottom in approximate descending order of average overall altitude range. Each box is marked where a particular genus or sub-type has a particular genitus or mutatus mother cloud.

Level	Name	Class	Genitus mother										Mutatus mother
		Abbrev.	Ac	As	Ci	Cc	Cs	Cu	Cb	Ns	St	Sc	Ac	As	Ci	Cc	Cs	Cu	Cb	Ns	St	Sc
		Abbrev.	altocumulo	altostrato	cirro	cirrocumulo	cirrostrato	cumulo	cumulonimbo	nimbostrato	strato	stratocumulo	altocumulo	altostrato	cirro	cirrocumulo	cirrostrato	cumulo	cumulonimbo	nimbostrato	strato	stratocumulo
High	Cirrus	Ci	+			+			+								+
	Cirrocumulus	Cc											+		+		+
	Cirrostratus	Cs				+			+				+		+	+
Middle	Altocumulus	Ac						+	+					+		+				+	+
Middle	Altostratus	As	+						+								+			+
Towering vertical	Cumulonimbus	Cb	+	+				+		+		+						+
Towering vertical	Cumulus congestus	Cu con or Tcu
Moderate vertical	Nimbostratus	Ns						+	+				+	+								+
Moderate vertical	Cumulus mediocris	Cu med	+									+									+	+
Low	Stratocumulus	Sc		+				+	+	+			+							+	+
	Cumulus humilis	Cu hum						+	+	+												+
	Stratus	St	+									+									+	+

Informal terms recently accepted for WMO classification with Latin nomenclature

Aviaticus cloud: Persistent condensation trails (contrails) formed by ice crystals originating from water vapor emitted by aircraft engines. Usually resembles cirrus; recognized as a WMO genitus cloud cirrus homogenitus (man-made). Further transformation into cirrus, cirrocumulus, or cirrostratus homomutatus is possible depending on atmospheric stability and wind shear.

WMO and informal terms related to free-convective cloud types and storms

Accessory cloud (WMO supplementary feature) – secondary cloud that is associated with but separate from a main cloud.
Anvil (WMO supplementary feature incus) – the anvil top of a cumulonimbus cloud.
Anvil dome (WMO supplementary feature incus) – the overshooting top on a Cb that is often present on a supercell.
Anvil rollover – (slang) circular protrusion attached to underside of anvil.

Arcus cloud (WMO supplementary feature) – arch or a bow shape, attached to cumulus, thick with ragged edges.
Backsheared anvil – (slang) anvil that spreads upwind, indicative of extreme weather.
Clear slot or dry slot (informal term) – an evaporation of clouds as a rear flank downdraft descends and dries out cloud and occludes around a mesocyclone.
Cloud tags (WMO species fractus) – ragged detached portions of cloud.
Collar cloud (WMO velum accessory cloud) – ring shape surrounding upper part of wall cloud.
Condensation funnel (WMO supplementary feature tuba) – the cloud of a funnel cloud aloft or a tornado.
Altocumulus castellanus (WMO genus and species) – castle crenellation-shaped altocumulus clouds.
Cumulus (WMO genus) – heaped clouds.
Cumulus castellanus – (informal variation of WMO genus and species cumulus congestus) cumulus with tops shaped like castle crenellations.
Cumulus congestus (WMO genus and species) – considerable vertical development and heaped into cauliflower shapes.
Cumulus fractus (WMO genus and species) – ragged detached portions of cumulus cloud.
Cumulus humilis (WMO genus and species) – small, low, flattened cumulus, early development.
Cumulus mediocris (WMO genus and species) – medium-sized cumulus with bulges at the top.
Cumulus pileus (WMO genus and accessory cloud) – capped, hood-shaped cumulus cloud.
Cumulus praecipitatio (WMO genus and supplementary feature) – cumulus whose precipitation reaches the ground.
Cumulus radiatus (WMO genus and variety) – cumulus arranged in parallel lines that appear to converge near the horizon.

Cumulus tuba (WMO genus and supplementary feature) – column hanging from the bottom of cumulus.
Cumulonimbus (WMO genus) – heaped towering rain-bearing clouds that stretch to the upper levels of the troposphere.
Cumulonimbus calvus (WMO genus and species) – cumulonimbus with round tops like cumulus congestus.
Cumulonimbus capillatus (WMO genus and species) – Cb with cirriform top.
Cumulonimbus incus (WMO genus and supplementary feature) – Cb capillatus with anvil top.
Cumulonimbus mamma (WMO genus and supplementary feature) – Cb with pouch-like protrusions that hang from under anvil or cloud base.
Cumulonimbus pannus (WMO genus and accessory cloud) – shredded sections attached to main Cb cloud.
Cumulonimbus pileus (WMO genus and accessory cloud) – capped, hood-shaped cloud above a cumulonimbus cloud.
Cumulonimbus praecipitatio (WMO genus and supplementary feature) – Cb whose precipitation reaches the ground.
Cumulonimbus tuba (WMO genus and supplementary feature) – column hanging from the bottom of cumulonimbus.
Debris cloud (informal term) – rotating "cloud" of debris found at base of tornado.
Funnel cloud (WMO supplementary feature tuba) – rotating funnel of cloud hanging from under Cb, not making contact with ground.
Hail fog (informal term) – a shallow surface layer of fog that sometimes forms in vicinity of deep hail accumulation, can be very dense.
Hot tower (informal term) – a tropical cumulonimbus cloud that penetrates the tropopause.
Inflow band (informal term) – a laminar band marking inflow to a Cb, can occur at lower or mid levels of the cloud.
Inverted cumulus (informal variation of WMO supplementary feature mamma) – cumulus which has transferred momentum from an exceptionally intense Cb tower and is convectively growing on the underside of an anvil.
Knuckles (informal variation of WMO supplementary feature mamma) – lumpy protrusion that hangs from edge or underside of anvil.
Pyrocumulus and Pyrocumulonimbus– intense ground-heat cloud proposed for WMO classification (see above).
Rope – (slang) narrow, sometimes twisted funnel type cloud seen after a tornado dissipates.
Rope cloud (informal term) – A narrow, long, elongated line of cumulus clouds that sometimes develop at the leading edge of an advancing cold front that is often visible in satellite imagery.^[20]
Scud cloud (informal term for WMO species fractus) – ragged detached portions of cloud that usually form in precipitation.
Shelf cloud (informal term for WMO supplementary feature arcus) – wedge-shaped cloud often attached to the underside of Cb.
Stratus fractus (WMO genus and species) – ragged detached portions of stratus cloud that usually form in precipitation (see also scud cloud).
Striations (informal term for WMO accessory cloud velum) – a groove or band of clouds encircling an updraft tower, indicative of rotation.
Tail cloud (informal term) – an area of condensation consisting of laminar band and cloud tags extending from a wall cloud towards a precipitation core.
Towering cumulus (TCu) -aviation term for WMO genus and species cumulus congestus, a large cumulus cloud with great vertical development, usually with a cauliflower-like appearance, but lacking the characteristic anvil of a Cb.
Wall cloud (informal term) – distinctive fairly large lowering of the rain-free base of a Cb, often rotating.

Other planets

Venus

Thick overcast clouds of sulfur dioxide and carbon dioxide in three main layers at altitudes of 45 to 65 km that obscure the planet's surface and can produce virga.^[21]

Stratiform: Overcast opaque clouds sheets.

Mars

Clouds resembling several terrestrial types can be seen over Mars and are believed to be composed of water-ice.^[23] ^[24]

Extremely high cirriform: Noctilucent clouds are known to form near the poles at altitudes similar to or higher than the same type of clouds over Earth.^[25]

Jupiter and Saturn

Cloud decks in parallel bands of latitude at and below the tropopause alternately composed of ammonia crystals and ammonium hydrosulfate.

Cirriform: Bands of cloud resembling cirrus located mainly in the highest of three main layers that cover Jupiter.^[26]

Uranus and Neptune

Cloud layers composed mainly of methane gas.^[30]

Cirriform: High wispy formations resembling cirrus.

External links

Notes and References

Web site: World Meteorological Organization . Cloud Identification Guide, International Cloud Atlas . 2017 . 4 April 2017.
Web site: World Meteorological Organization . Upper atmospheric clouds, International Cloud Atlas . 2017 . 31 July 2017.
Web site: de Valk, Paul . van Westhrenen, Rudolf . Carbajal Henken, Cintia . 2010 . Automated CB and TCU detection using radar and satellite data: from research to application . 15 September 2011 . dead . https://web.archive.org/web/20111116001457/http://www.eumetsat.int/Home/Main/AboutEUMETSAT/Publications/ConferenceandWorkshopProceedings/2010/groups/cps/documents/document/pdf_conf_p57_s7_08_devalk_v.pdf . 16 November 2011 .
Book: World Meteorological Organization . Noctilucent, International Cloud Atlas . I . 1975 . 66 . 92-63-10407-7 . 26 August 2014 .
Book: Michael Gadsden. Pekka Parviainen. amp. Observing Noctilucent Clouds. September 2006. International Association of Geomagnetism & Aeronomy. 9. 31 January 2011. dead. https://web.archive.org/web/20081031003710/http://www.iugg.org/IAGA/iaga_pages/pdf/ONC_Sep06.pdf. 31 October 2008.
Web site: Les Cowley . Nacreous and polar stratospheric clouds. Atmospheric optics, atoptics.co.uk . 2011 . 7 November 2014.
Web site: Clouds Online . Cloud Atlas . 2012 . 1 February 2012.
Web site: Cloud Classifications . JetStream . . 5 January 2010 . 31 January 2011 . 29 November 2017 . https://web.archive.org/web/20171129134821/https://oceanservice.noaa.gov/education/yos/resource/JetStream/synoptic/clouds_max.htm . dead .
Web site: Boyd, Sylke . Clouds – Species and Varieties . 2008 . 4 February 2012 . University of Minnesota . dead . https://web.archive.org/web/20101230041442/http://www.morris.umn.edu/~sboyd/weather/cloudsystems/Clouds_files/speciesandvarieties.htm . December 30, 2010 .
Web site: Aerographer/Meteorology . 2012 . Cloud Variety . 2 July 2012 . meteorologytraining.tpub.com . dead . https://web.archive.org/web/20121221005913/http://meteorologytraining.tpub.com/14269/css/14269_20.htm . 21 December 2012 .
Book: World Meteorological Organization. Features, International Cloud Atlas. I. 1975. 22–24. 92-63-10407-7. 26 August 2014.
Burroughs, William James; Crowder, Bob (January 2007). Weather, p.216. Fog City Press, San Francisco. .
Book: World Meteorological Organization. Species, International Cloud Atlas. I. 1975. 17–20. 92-63-10407-7. 26 August 2014.
Burroughs, William James; Crowder, Bob (January 2007). Weather, p.215. Fog City Press, San Francisco. .
Web site: Cumulonimbus Incus . Universities Space Research Association . 5 August 2009 . 23 October 2012.
Web site: de Valk . Paul . van Westhrenen . Rudolf . Carbajal Henken . Cintia . amp . 2010 . Automated CB and TCU detection using radar and satellite data: from research to application . 2011-09-15 . dead . https://web.archive.org/web/20111116001457/http://www.eumetsat.int/Home/Main/AboutEUMETSAT/Publications/ConferenceandWorkshopProceedings/2010/groups/cps/documents/document/pdf_conf_p57_s7_08_devalk_v.pdf . 2011-11-16.
Web site: World Meteorological Organization . Cloud Atlas . 1995 . 2014-08-26 . https://web.archive.org/web/20160725172359/http://library.wmo.int/pmb_ged/wmo_407_en-v1.pdf . 2016-07-25 . dead .
Web site: Cataractagenitus International Cloud Atlas Section 2.1.3.6.5. International Cloud Atlas.
Web site: Final Report . Task Team On Revision of the International Cloud Atlas . 2013 . 2014-10-06 . World Meteorological Organization.
Web site: Rope Cloud in the Gulf of Mexico « CIMSS Satellite Blog .
Web site: Montmessin . Franck . Clouds in the terrestrial planets . dead . 2013 . 2013-11-05 . http://arquivo.pt/wayback/20160516112808/http://www.congrex.nl/09a05/1010_Montmessin.pdf . 2016-05-16.
Web site: Shiga . David . Mysterious waves seen in Venus's clouds . 2006 . 2013-11-05 . New Scientist.
Web site: Clouds Move Across Mars Horizon. 19 September 2008. 15 April 2011. National Aeronautics and Space Administration. Phoenix Photographs. 2 June 2016. https://web.archive.org/web/20160602213811/http://www.nasa.gov/mission_pages/phoenix/images/press/16145-animated.html. dead.
Web site: NASA SP-441: Viking Orbiter Views of Mars. National Aeronautics and Space Administration. 26 January 2013.
Web site: SPACE.com staff . Mars Clouds Higher Than Any On Earth . SPACE.com . 2006-08-28 . 2008-10-19.
Web site: Phillips . Tony . Big Mystery: Jupiter Loses a Stripe . Nasa Headline News – 2010 . . 20 May 2010 . 15 April 2011 . 20 April 2011 . https://web.archive.org/web/20110420012725/http://science.nasa.gov/science-news/science-at-nasa/2010/20may_loststripe/ . dead .
Book: Dougherty . Michele . Esposito . Larry . Saturn from Cassini-Huygens . Springer . 527635272 . 1st . November 2009 . 978-1-4020-9216-9 . 118.
Web site: Ingersoll . A.P. . Dowling . T.E . Gierasch . P.J. . Orton . G.S. . Read . P.L. . Sanchez-Lavega . A. . Showman . A.P. . Simon-Miller . A.A. . Vasavada . A.R. . Dynamics of Jupiter's Atmosphere . Lunar & Planetary Institute . 2007-02-01.
Web site: Monterrey Institute for Research in Astronomy . Saturn . 2006-08-11 . 2011-01-31.
Web site: Neptune's Atmosphere: Composition, Climate, & Weather . Nola Taylor Redd . 2012 . Space.com . 2013-11-05.

List of cloud types explained

Cloud identification and classification: Order of listed types

Cloud cross-classification throughout the homosphere

Mesospheric cloud identification and classification

Extreme-level stratiform, stratocumuliform, and cirriform

Stratospheric cloud identification and classification

Very high-level stratiform

Very high-level cirriform and stratocumuliform

Troposphere cloud identification and classification

High-level cirriform, stratocumuliform, and stratiform

Genus cirrus

Species

Varieties

Supplementary features

Genus cirrocumulus

High stratocumuliform species

Varieties

Supplementary features

Genus cirrostratus

Species

Varieties

Supplementary features

Mid-level stratocumuliform and stratiform

Genus altocumulus

Mid-level stratocumuliform species

Varieties

Supplementary features

Genus altostratus

Species

Varieties

Supplementary features

Towering vertical cumulonimbiform and cumuliform (low to mid-level cloud base)

Genus cumulonimbus: Towering vertical

Species

Varieties

Supplementary features

Genus cumulus: Towering vertical

Species

Varieties

Supplementary features

Multi-level stratiform and moderate vertical cumuliform (low to mid-level cloud base)

Genus nimbostratus: Multi-level

Species

Varieties

Supplementary features

Genus cumulus: Moderate vertical

Species

Varieties

Supplementary features

Low-level stratocumuliform, cumuliform, and stratiform

Genus stratocumulus

Species

Varieties

Supplementary features

Genus cumulus (little vertical extent)

Species

Varieties

Supplementary features and accessory clouds

Genus stratus

Species

Varieties

Supplementary features

Tropospheric cloud types with Latin etymologies where applicable

WMO genera

WMO species

WMO varieties

WMO supplementary features

Genitus mother clouds

Other genitus clouds

Mutatus mother clouds

Informal terms recently accepted for WMO classification with Latin nomenclature

WMO and informal terms related to free-convective cloud types and storms

Other planets

Venus

Mars

Jupiter and Saturn

Uranus and Neptune

See also

External links

Notes and References