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 is a type of cloud that is tall, dense, and involved in thunderstorms and other bad weather. The clouds can form alone, in clusters, or along a cold front in a squall line. Cumulonimbus cloud in central Oklahoma. ... Cumulonimbus cloud in central Oklahoma. ... Cumulus of fair weather A cloud is a visible mass of condensation droplets or ice crystals suspended in the atmosphere above the surface of the Earth or another planetary body. ... A roll cloud associated with a heavy or severe thunderstorm over Enschede, The Netherlands. ... Composite satellite image showing the progress of a hurricane weather system approaching the east coast of America Weather comprises all the various phenomena that occur in the atmosphere of a planet. ... A guide to the symbols for weather fronts that may be found on a weather map. ... A squall or squall line is a line of thunderstorms with a common leading convection line, or mesocyclone, which tends to create a powerful gust front. ...

Formation

To create a cumulonimbus cloud, you need three ingredients.

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. ...

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 adds more energy to the cloud, which soon becomes self-sustaining. 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. Water vapor or water vapour, also aqueous vapour, is the gas phase of water. ... Condensation can refer to: The change in phase of a substance to a denser phase, such as gas to a liquid. ... A natural, 4 tonne, block of ice on a beach in Iceland Icicles Ice is the solid form of water. ... It has been suggested that Law of universal gravitation be merged into this article or section. ...

Instability between the updrafts and downdrafts causes static electrical charges to build up in the cumulonimbus cloud. The discharge of this electricity causes thunder and lightning. A downdraft is downward moving air, usually the direct result of air convection within the thunderstorm. ... Static electricity is a class of phenomena involving the imbalanced charge present on an object, typically referring to charge with voltages of sufficient magnitude to produce visible attraction, repulsion, and sparks. ... Thunder is the sound of the shockwave caused when lightning instantly heats the air around it to up to 30 000 °C (54 000 °F). ... Lightning over Pentagon City in Arlington County, Virginia Cloud to cloud lightning Lightning is a powerful natural electrostatic discharge produced during a thunderstorm. ...

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. A guide to the symbols for weather fronts that may be found on a weather map. ... A roll cloud associated with a heavy or severe thunderstorm over Enschede, The Netherlands. ... 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. ...

Appearance

Ideal anvil shaped cumulonimbus

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 metres (10,000 to 12,000 feet), its peak can reach up to 23,000 metres (75,000 feet) in extreme cases. Typically, it peaks at a much lower height. Cumulonimbus 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. This anvil shape can precede the main cloud structure for many miles, causing anvil lightning. Image File history File links Download high resolution version (1280x960, 1300 KB)Ideal Anvil Cloud. ... Image File history File links Download high resolution version (1280x960, 1300 KB)Ideal Anvil Cloud. ... Altitude is the elevation of an object from a known level or datum, called zero level. ... Lightning over Pentagon City in Arlington County, Virginia Cloud to cloud lightning Lightning is a powerful natural electrostatic discharge produced during a thunderstorm. ...

Effects

Cumulonimbus

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. Image File history File links Thunderstorm cloud - Cumulonimbus photo from www. ... Image File history File links Thunderstorm cloud - Cumulonimbus photo from www. ... Rain falling For other uses see Rain (disambiguation). ... Convection is the transfer of heat by the motion of or within a fluid. ... A flash flood (also a freshet, considered archaic) is a rapid flooding of low-lying areas, rivers and streams that is caused by the intense rainfall associated with a thunderstorm, or multiple training thunderstorms. ... Wind is the quasi-horizontal movement of air (as opposed to an air current) caused by a horizontal pressure gradient force. ... Solar power describes a number of methods of harnessing energy from the light of the sun. ... Layers of Atmosphere (NOAA) Earths atmosphere is the layer of gases surrounding the planet Earth and retained by the Earths gravity. ... In electronics, a summer is a circuit or system that adds one or more input voltages or currents together (usually by means of operational amplifiers), giving an output equal to the algebraic sum of the inputs. ... Evaporation is the process whereby atoms or molecules in a liquid state (or solid state if the substance sublimes) gain sufficient energy to enter the gaseous state. ...

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. Convection is the transfer of heat by the motion of or within a fluid. ... A downdraft is downward moving air, usually the direct result of air convection within the thunderstorm. ... An aircraft is any machine capable of atmospheric flight. ... This long range radar antenna (approximately 40m (130ft) in diameter) rotates on a track to observe activities near the horizon. ...

The air convection can also form mesocyclones, which can cause hail and tornadoes. A mesocyclone is an area of vertical atmospheric rotation, typically 2-6 miles across. ... A large hailstone Hail is a type of graupel (a form of precipitation) composed of spears or irregular lumps of ice. ... A tornado over land. ...

External link

Wikimedia Commons has more media related to:

Cumulonimbus clouds

• Fine picture of a CB in Germany