Cumulonimbus (Cb) is a type of cloud that is tall, dense, and involved in thunderstorms and other intense weather. The clouds can form alone, in clusters, or along a cold front in a squall line. Cumulonimbus clouds form from cumulus clouds (namely from cumulus congestus) and can further develop to a supercell, a severe thunderstorm with special features. Image File history File linksMetadata Wagga-Cumulonimbus. ... // High-level clouds Cirrus Clouds (from above) Abbreviation: Ci Cirrus clouds form above 16,500 feet (5,000 m), in the cold region of the troposphere. ... The metre (American English:meter) is a measure of length. ... A foot (plural: feet or foot;[1] symbol or abbreviation: ft or, sometimes, ′ – a prime) is a unit of length, in a number of different systems, including English units, Imperial units, and United States customary units. ... Cumulus mediocris clouds, as seen from a plane window. ... // High-level clouds Cirrus Clouds (from above) Abbreviation: Ci Cirrus clouds form above 16,500 feet (5,000 m), in the cold region of the troposphere. ... Nimbostratus virga In meteorology, virga is precipitation that falls from a cloud but evaporates before reaching the ground. ... Cumulus mediocris clouds, as seen from a plane window. ... A shelf cloud associated with a heavy or severe thunderstorm over Enschede, The Netherlands. ... Weather is a term that encompasses phenomena in the atmosphere of a planet. ... In meteorology, a weather front is a boundary between two air masses with differing characteristics (e. ... A squall is a sudden, sharp increase in wind speed which usually is associated with active weather, such as rain showers, thunderstorms, or heavy snow. ... This article or section does not adequately cite its references or sources. ... Cumulus congestus clouds are characteristic of unstable areas of the atmosphere which are undergoing convection. ... Satellite view of a supercell A supercell is a severe thunderstorm with a deep rotating updraft (a mesocyclone) [1]. Supercell thunderstorms are the largest, most severe class of single-cell thunderstorms. ...

Formation

Three ingredients are needed for the formation of a perfect cumulonimbus cloud:

1. Plenty of moisture.
2. A mass of warm unstable air.
3. A source of energy to lift the warm, moist air mass rapidly upward.

Typically, the clouds form around front lines, near oceans where sea breezes provide the storm energy, or over mountains which push the air upwards. A guide to the symbols for weather fronts that may be found on a weather map: 1. ...

When the warm air rises above the typically cooler air above it, it starts to cool and the water vapor condenses into water droplets. This condensation heats the surrounding air by releasing latent heat, thus continuing the rise of air. As the air mass continues to rise, the water droplets continue to cool and form ice crystals. Gravity causes these droplets and crystals to start to fall, causing a downward movement to compete with the upward lift. It has been suggested that multiple sections of steam be merged into this article or section. ... Water vapor condensing over a cup of hot tea Condensation is the change in matter of a substance to a denser phase, such as a gas (or vapor) to a liquid. ... In thermochemistry, latent heat is the amount of energy in the form of heat released or absorbed by a substance during evaporation. ... Snowflakes by Wilson Bentley, 1902 Ice is the name given to any one of the 14 known solid phases of water. ... Gravity is a force of attraction that acts between bodies that have mass. ...

Instability between the updrafts and downdrafts causes static electrical charges to build up within the cumulonimbus cloud. The discharge of this electricity causes thunder and lightning. It has been suggested that Thermal be merged into this article or section. ... Static electricity is a class of phenomena involving the net charge present on an object; typically referring to charged object with voltages of sufficient magnitude to produce visible attraction, repulsion, and sparks. ... Thunder is the sound made by lightning. ... This article needs additional references or sources for verification. ...

Anvil tops of thunderclouds visible over the Pacific Ocean, as seen from the International Space Station

During the spring and summer, cumulonimbus clouds are more likely to form in the afternoon, due to the heating of the earth's surface. However, they can also form along a cold front when the warm buoyant air is forced upward by the heavier cold air mass that cuts under the warmer air like a wedge. This can happen at any time of the year, as demonstrated by thunderstorms that happen in conjunction with snowstorms in the winter. Image File history File links Size of this preview: 800 × 545 pixelsFull resolution (3032 × 2064 pixel, file size: 759 KB, MIME type: image/jpeg) // This view of Earths horizon as the sun sets over the Pacific Ocean was taken by an Expedition 7 crew member onboard the International Space... Image File history File links Size of this preview: 800 × 545 pixelsFull resolution (3032 × 2064 pixel, file size: 759 KB, MIME type: image/jpeg) // This view of Earths horizon as the sun sets over the Pacific Ocean was taken by an Expedition 7 crew member onboard the International Space... International Space Station insignia ISS Statistics Crew: 3 As of June 20, 2007 Perigee: 319. ... In meteorology, a weather front is a boundary between two air masses with differing characteristics (e. ... A winter storm is a storm where the dominant forms of precipitation are forms that occur only at cold temperatures, such as snow or sleet, or a rainstorm where ground temperatures are cold enough to allow ice to form. ...

Cumulonimbus are sometimes mistaken for their parent, cumulus congestus. The distinctive feature of cumulonimbus is its frozen top, consisting of ice crystals, contrary to Cumulus cloud, which is formed entirely by water droplets. Frozen top of cumulonimbus loses puffy shape, resembles Cirrostratus and appears as homogeneous or fibrous-edged cirriform or as flat 'anvil'. The line between Cumulus cloud and cumulonimbus can be drawn at the moment, when cloud top reaches temperature of approximately minus 10 degrees Celsius and cirriforms are clearly seen. However, this does not apply to cumulonimbus calvus, which are closer by structure to cumulus clouds and are a intermediate form between cumulus congestus and cumulonimbus. Cumulus congestus clouds are characteristic of unstable areas of the atmosphere which are undergoing convection. ... This article or section does not adequately cite its references or sources. ... Cirrostratus showing an extremely large halo. ... Cumulus can also refer to Cumulus Media (also known as Cumulus Broadcasting) A cumulus cloud is a cloud belonging to a class characterized by dense individual elements in the form of puffs, mounds or towers, with flat bases and tops that often resemble cauliflower. ... Cumulonimbus calvus is an moderately tall cumulonimbus cloud which is capable of precipitation, but has not yet reached the height where it forms into a cumulonimbus incus (anvil-top). ... This article or section does not adequately cite its references or sources. ... Cumulus congestus clouds are characteristic of unstable areas of the atmosphere which are undergoing convection. ...

Appearance

Cumulonimbus cloud in central Oklahoma. The updraft is the large cloud mass at the center of the photo. The anvil is the flat layer at the top. The downdraft is the rainy area to the right.

Cumulonimbus clouds usually form from cumulus clouds at a much lower height, thus making them, like cumulus clouds, grow vertically instead of horizontally, thus giving the cumulonimbus its mushroom shape. The base of a cumulonimbus can be several miles across, and it can be tall enough to occupy middle as well as low altitudes; though formed at an altitude of about 3,000 to 4,000 meters (10,000 to 12,000 feet), its peak can reach up to 23,000 meters (75,000 feet) in extreme cases. Typically, it peaks at a much lower height. Cumulonimbus cloud in central Oklahoma. ... Cumulonimbus cloud in central Oklahoma. ... Official language(s) None Capital Oklahoma City Largest city Oklahoma City Area  Ranked 20th  - Total 69,960 sq mi (181,196 km²)  - Width 230 miles (370 km)  - Length 298 miles (480 km)  - % water 1. ... It has been suggested that Thermal be merged into this article or section. ... Altitude is the elevation of an object from a known level or datum. ...

Well-developed cumulonimbus clouds are also characterized by a flat, anvil-like top (the anvil dome), caused by straight line winds at the higher altitudes which shear off the top of the cloud, as well as by an inversion over the thunderstorm caused by rising temperatures above the tropopause. This anvil shape can precede the main cloud structure for many miles, causing anvil lightning. This article or section does not cite its references or sources. ... The tropopause is a boundary region in the atmosphere between the troposphere and the stratosphere. ... This article needs additional references or sources for verification. ...

Cumulonimbus clouds can be subdivided into several species:

• Cumulonimbus calvus - cloud with puffy top, looking like cumulus congestus, but larger;
• Cumulonimbus capillatus - cloud with cirrus-like, fibrous-edged top;
• Cumulonimbus incus - subtype of Cumulonimbus capillatus, with flat anvil-like top.

Cumulonimbus capillatus incus

Cumulonimbus calvus is an moderately tall cumulonimbus cloud which is capable of precipitation, but has not yet reached the height where it forms into a cumulonimbus incus (anvil-top). ... A cumulonimbus incus cloud has a characteristic anvil-top shape. ... Image File history File links Download high-resolution version (2348x965, 476 KB) Cumulonimbus capillatus incus floating over Swifts Creek, Victoria in Australia. ... Image File history File links Download high-resolution version (2348x965, 476 KB) Cumulonimbus capillatus incus floating over Swifts Creek, Victoria in Australia. ...

Effects

Exeptionally clearly developed single-cell Cumulonimbus incus, gusts will happen near and under it

Cumulonimbus storm cells can produce heavy rain (particularly of a convective nature) and flash flooding, as well as straight-line winds. Most storm cells die after about 20 minutes, when the precipitation causes more downdraft than updraft, causing the energy to dissipate. If there is enough solar energy in the atmosphere, however (on a hot summer's day, for example), the moisture from one storm cell can evaporate rapidly — resulting in a new cell forming just a few miles from the former one. This can cause thunderstorms to last for several hours. This multicell cloud structure exists until cold downdraft preceeding cumulonimbus at ground level flows before cloud at distance sufficient to disrupt updraft (5-10 kilometers). From this moment on, cumulonimbus cloud quickly degrades and dissipates, forming cirrus spissatus, dense anvil-like cirrus, stratocumulus diurnalis or stratocumulus vesperalis. Image File history File links Thunderstorm cloud - Cumulonimbus photo from www. ... Image File history File links Thunderstorm cloud - Cumulonimbus photo from www. ... Rain is a type of precipitation which forms when separate drops of water fall to the Earths surface from clouds. ... Convection in the most general terms refers to the internal movement of currents within fluids (i. ... Lower Antelope Canyon was carved out of sandstone by flash floods A Flash Flood is a rapid flooding of geomorphic low-lying areas (washes), rivers and streams, caused by the intense rainfall associated with a thunderstorm, or multiple training thunderstorms. ... Straight-line winds are very strong winds that produce damage, demonstrating a lack of a rotational damage pattern. ... Solar power describes a number of methods of harnessing energy from the light of the sun. ... Layers of Atmosphere - not to scale (NOAA)[3] Earths atmosphere is a layer of gases surrounding the planet Earth and retained by the Earths gravity. ... Summer is one of the four seasons of the year. ... This article or section is in need of attention from an expert on the subject. ... This article or section does not adequately cite its references or sources. ...

Cumulonimbus clouds sometimes form mammatus clouds. Mammatus clouds in Tulsa, Oklahoma, 1973 Cumulonimbus with mammatus formed after Hurricane Catarina in Santa Catarina, Brazil, 2004 Another view of the post-Catarina mammatus formation Mammatus (also known as mamma or mammatocumulus) is a meteorological term applied to a cellular pattern of pouches hanging underneath the base of a...

Cumulonimbus clouds contain severe convection currents, with very high, unpredictable winds, particularly in the vertical plane (updrafts and downdrafts). They are therefore extremely dangerous to aircraft. Smaller, propeller-driven planes cannot cope with the conditions and must fly around them; larger jet aircraft fly over the smaller ones and around larger examples. Larger planes are also equipped with weather radar and wind shear detectors to help guide them through, in the event that they need to pass through such clouds to land. Look up aircraft in Wiktionary, the free dictionary. ... This long range radar antenna, known as ALTAIR, is used to detect and track space objects in conjunction with ABM testing at the Ronald Reagan Test Site on the Kwajalein atoll. ... It has been suggested that this article or section be merged with wind gradient. ...

The air convection can also form mesocyclones, which can cause hail and tornadoes. It has been suggested that this article or section be merged into Supercell. ... This does not cite any references or sources. ... A tornado in central Oklahoma. ...

See also

• Cumulus congestus cloud
• Cumulonimbus calvus
• Cumulonimbus incus
• Pyrocumulonimbus
• Supercell
• Mammatus cloud
• Funnel cloud
• Storm
• Tornado
• Pileus (meteorology)

Cumulus congestus clouds are characteristic of unstable areas of the atmosphere which are undergoing convection. ... Cumulonimbus calvus is an moderately tall cumulonimbus cloud which is capable of precipitation, but has not yet reached the height where it forms into a cumulonimbus incus (anvil-top). ... A cumulonimbus incus cloud has a characteristic anvil-top shape. ... The pyrocumulonimbus (pyroCb) is a type of cloud formed above a source of heat such as a wildfire or industrial plant. ... Satellite view of a supercell A supercell is a severe thunderstorm with a deep rotating updraft (a mesocyclone) [1]. Supercell thunderstorms are the largest, most severe class of single-cell thunderstorms. ... Mammatus clouds in Tulsa, Oklahoma, 1973 Cumulonimbus with mammatus formed after Hurricane Catarina in Santa Catarina, Brazil, 2004 Another view of the post-Catarina mammatus formation Mammatus (also known as mamma or mammatocumulus) is a meteorological term applied to a cellular pattern of pouches hanging underneath the base of a... A funnel cloud. ... A shelf cloud associated with a heavy or severe thunderstorm over Enschede, Netherlands A storm is any disturbed state of an astronomical bodys atmosphere, especially affecting its surface, and strongly implying severe weather. ... A tornado in central Oklahoma. ... A pileus (Latin for cap) is a small, horizontal cloud that can appear above a cumulus or cumulonimbus cloud, giving the parent cloud a characteristic hoodlike appearance. ...

External links

Wikimedia Commons has media related to:

Cumulonimbus clouds

• Fine picture of a CB in Germany

Image File history File links Commons-logo. ... The Wikimedia Commons (also called Wikicommons) is a repository of free content images, sound and other multimedia files. ...