A shelf cloud associated with a heavy or severe thunderstorm over Enschede, The Netherlands. or Eanske in the local dialect ( Twents) is a Municipality and a city in the eastern Netherlands, in the province of Overijssel, in the The Netherlands ( Dutch:, ˈnedərlɑnt is the European part of the Kingdom of the Netherlands, which consists of the Netherlands the Netherlands

A thunderstorm, also called an electrical storm or lightning storm, is a form of weather characterized by the presence of lightning and its attendant thunder. A storm is any disturbed state of an astronomical body's atmosphere, especially affecting its surface and strongly implying Severe weather. Lightning is an atmospheric discharge of Electricity, which typically occurs during Thunderstorms and sometimes during volcanic eruptions or Thunder is the sound made by Lightning. Depending on the nature of the lightning and distance of the listener it can range from a sharp ^[1]

Life cycle

Airflow diagrams showing three stages of a thunderstorm life cycle.

Warm air is less concentrated than cool air, so warm air rises within cooler air, similar to hot air balloons. The hot air balloon is the oldest successful human-carrying Flight technology Clouds form as warm air carrying moisture rises within cooler air. As the warm air rises, it cools. The moist water vapour begins to condense. General properties of water vapor Evaporation/sublimation Whenever a water molecule leaves a surface it is said to have evaporated Condensation is the change of the physical state of aggregation (or simply state of matter from gaseous phase into liquid phase When the moisture condenses, this releases energy that keeps the air warmer than its surroundings, so that it continues to rise. If enough instability is present in the atmosphere, this process will continue long enough for cumulonimbus clouds to form, which support lightning and thunder. In Meteorology, convective available potential energy ( CAPE) sometimes simply available potential energy ( APE) is the amount of Energy Cumulonimbus (Cb is a type of Cloud that is tall dense and involved in Thunderstorms and other intense Weather.

All thunderstorms, regardless of type, go through three stages: the cumulus stage, the mature stage, and the dissipation stage. Depending on the conditions present in the atmosphere, these three stages can take anywhere from 20 minutes to several hours to occur.

Cumulus stage

The first stage of a thunderstorm is the cumulus stage, or developing stage. In this stage, masses of moisture are lifted upwards into the atmosphere. The trigger for this lift can be insolation heating the ground producing thermals, areas where two winds converge forcing air upwards, or where winds blow over terrain of increasing elevation. Insolation is a measure of Solar radiation energy received on a given surface area in a given time A thermal column (or thermal) is a column of rising Air in the lower altitudes of the Earth's atmosphere. The moisture rapidly cools into liquid drops of water, which appears as cumulus clouds. As the water vapor condenses into liquid, latent heat is released which warms the air, causing it to become less dense than the surrounding dry air. In Thermochemistry, latent heat is the amount of Energy in the form of Heat released or absorbed by a substance during a change of phase The air tends to rise in an updraft through the process of convection (hence the term convective precipitation). Convection in the most general terms refers to the movement of molecules within Fluids (i In Meteorology, precipitation (also known as one class of hydrometeors, which are atmospheric water phenomena is any product of the condensation of atmospheric This creates a low-pressure zone beneath the forming thunderstorm. A low pressure area, or " low " is a region where the Atmospheric pressure is lower in relation to the surrounding area In a typical thunderstorm, some 5×10⁸ kg of water vapour are lifted, and the amount of energy released when this condenses is about equal to the energy used by a city (US-2002) of 100,000 during a month. In Physics and other Sciences energy (from the Greek grc ἐνέργεια - Energeia, "activity operation" from grc ἐνεργός The United States of America —commonly referred to as the

Mature stage

Anvil shaped thundercloud in the mature stage

In the mature stage of a thunderstorm, the warmed air continues to rise until it reaches existing air which is warmer, and the air can rise no further. Often this 'cap' is the tropopause. The tropopause is in the atmosphere between the Troposphere and the Stratosphere. The air is instead forced to spread out, giving the storm a characteristic anvil shape. The resulting cloud is called cumulonimbus incus. A cumulonimbus incus (Latin incus, "anvil" is a Cumulonimbus cloud which has reached the level of stratospheric stability and has formed The water droplets coalesce into heavy droplets and freeze to become ice particles. Coalescence is the process by which two or more droplets or particles merge during contact to form a single daughter droplet (or bubble As these fall they melt to become rain. If the updraft is strong enough, the droplets are held aloft long enough to be so large that they do not melt completely and fall as hail. Hail is a form of precipitation which consists of balls or irregular lumps of ice (hailstones While updrafts are still present, the falling rain creates downdrafts as well. The simultaneous presence of both an updraft and downdrafts marks the mature stage of the storm, and during this stage considerable internal turbulence can occur in the storm system, which sometimes manifests as strong winds, severe lightning, and even tornadoes. In Fluid dynamics, turbulence or turbulent flow is a fluid regime characterized by chaotic Stochastic property changes A tornado is a violent rotating column of air which is in contact with both the surface of the earth and a Cumulonimbus cloud or in rare cases the base of a Cumulus

Typically, if there is little wind shear, the storm will rapidly enter the dissipating stage and 'rain itself out', but if there is sufficient change in wind speed and/or direction the downdraft will be separated from the updraft, and the storm may become a supercell, and the mature stage can sustain itself for several hours. Wind shear, sometimes referred to as windshear or Wind gradient, is a difference in Wind speed and direction over a relatively

In certain cases however, even with little wind shear, if there is enough atmospheric support and instability in place for the thunderstorm to feed on, it may even maintain its mature stage a bit longer than most storms.

Dissipating stage

In the dissipation stage, the thunderstorm is dominated by the downdraft. If atmospheric conditions do not support super cellular development, this stage occurs rather quickly, some 20-30 minutes into the life of the thunderstorm. The downdraft will push down out of the thunderstorm, hit the ground and spread out. The cool air carried to the ground by the downdraft cuts off the inflow of the thunderstorm, the updraft disappears and the thunderstorm will dissipate.

Classification

A single cell thunderstorm.

There are four main types of thunderstorms: single cell, multicell, squall line (also called multicell line) and supercell. Which type forms depends on the instability and relative wind conditions at different layers of the atmosphere ("wind shear"). Wind shear, sometimes referred to as windshear or Wind gradient, is a difference in Wind speed and direction over a relatively

Single cell

This term technically applies to a single thunderstorm with one main updraft. Within a cluster of thunderstorms, the term "cell" refers to each separate principal updraft.

Thunderstorm cells can and do form in isolation to other cells. Such storms are rarely severe and are a result of local atmospheric instability; hence the term "air mass thunderstorm". These are the typical summer thunderstorm in many temperate locales. They also occur in the cool unstable air which often follows the passage of a cold front from the sea during winter. A weather front is a boundary separating two masses of air of different densities, and is the principal cause of meteorological phenomena.

While most single cell thunderstorms move, there are some unusual circumstances where they remain stationary. When this happens, catastrophic flooding is possible. In Rapid City, South Dakota, in 1972, an unusual alignment of winds at various levels of the atmosphere combined to produce a continuous, stationary cell which dropped an enormous quantity of rain, resulting in devastating flash flooding ^[2]. Rapid City is the second-largest city in the US state of South Dakota, and the County seat of Pennington County. A similar event occurred in Boscastle, England on 16 August 2004 ^[3]. Boscastle (Kastell Boterel is a Village and fishing port on the north coast of Cornwall, United Kingdom. Events 1384 - The Hongwu Emperor of Ming China, Emperor Dong hears a case of a couple who tore paper money bills while fighting "MMIV" redirects here For the Modest Mouse album see " Baron von Bullshit Rides Again "

Multicell cluster

Multi cell storms form as clusters of storms but may then evolve into an organized line or lines of storms. They often arise from convective updrafts in or near mountain ranges and linear weather boundaries, usually strong cold fronts or troughs of low pressure.

Multicell lines

Multicell line storms, commonly referred to as "squall lines", occur when multi cellular storms form in a line rather than clusters. A squall line is a line of severe thunderstorms that can form along and/or ahead of a Cold front. They can be hundreds of miles long, move swiftly, and be preceded by a gust front. An outflow boundary is a Storm-scale or mesoscale boundary separating Thunderstorm -cooled air ( outflow) from the surrounding Air; Heavy rain, hail, lightning, very strong winds and even isolated tornadoes can occur over a large area in a squall line. ^[4] Bow echoes can form within squall lines, bringing with them even higher winds. A bow echo is a term describing the characteristic radar return from a Mesoscale convective system that is shaped like an archer’s bow.

An unusually powerful type of squall line called a derecho occurs when an intense squall line travels for several hundred miles, often leaving widespread damage over thousands of square miles. derecho ( from Spanish: " derecho " meaning "right" is a widespread and long-lived violent convectively induced straight-line windstorm that is

Occasionally, squall lines also form near the outer rain band of tropical cyclones. The squall line is propelled by its own outflow, which reinforces continuous development of updrafts along the leading edge.

This kind of storm is also known as "Wind of the Stony Lake" (Traditional Chinese:石湖風, Simplified Chinese: 石湖风) in southern China. ^[5]

See also: List of derecho events

Supercell

Main article: Supercell

The setting sun illuminates the top of a classic anvil-shaped thunderstorm cloud in eastern Nebraska, United States. The following is a list of notable Derecho events. See also Severe thunderstorm Tornado List A supercell is a severe thunderstorm with a deep continuously rotating updraft (a Mesocyclone) Nebraska ( is a state located on the Great Plains of the Midwestern United States and The United States of America —commonly referred to as the

Supercell storms are large, severe quasi-steady-state storms which feature wind speed and direction that vary with height ("wind shear"), separate downdrafts and updrafts (i. A supercell is a severe thunderstorm with a deep continuously rotating updraft (a Mesocyclone) e. , precipitation is not falling through the updraft) and a strong, rotating updraft (a "mesocyclone"). A mesocyclone is a Vortex of air approximately 2 to 10 km in diameter (the Mesoscale of meteorology within a convective Storm These storms normally have such powerful updrafts that the top of the cloud (or anvil) can break through the troposphere and reach into the lower levels of the stratosphere and can be 15 miles (24 km) wide. These storms produce destructive tornadoes, sometimes F3 or higher, extremely large hailstones (4 inch or 10 cm diameter), straight-line winds in excess of 80 mph (130 km/h), and flash floods. The Fujita scale ( F-Scale) or Fujita-Pearson scale, is a scale for rating Tornado intensity based on the damage tornadoes inflict on human-built structures A flash flood is a rapid flooding of geomorphic lowlying areas - washes rivers and streams In fact, most tornadoes occur from this kind of thunderstorm. ^[6]

Severe thunderstorm

A severe thunderstorm is a term designated to a thunderstorm that has reached a predetermined level of severity. Often this level is determined by the storm being strong enough to inflict wind or hail damage. In the United States, a storm is considered severe if winds reach over 50 knots (58 mph or 93 km/h), hail is ¾ inch (2 cm) diameter or larger, or if a funnel cloud or tornadoes are spotted. ^[7] Though a funnel cloud or tornado indicates the presence of a severe thunderstorm, a tornado warning would then be issued in place of a severe thunderstorm warning. A tornado warning is an alert issued by government weather services to warn an area that a Tornado may be Imminent. See Severe weather terminology for a comprehensive article on this term and related weather terms

In Canada, a severe thunderstorm is defined as either having tornadoes, wind gusts of 90 km/h or greater, hail of 2 centimetres in diameter or greater, a rainfall rate greater than 50 millimetres in 1 hour or 75 millimetres in 3 hours. ^[8]

Severe thunderstorms can occur from any type of thunderstorm, however multicell and squall lines represent the most common forms. Supercells are often the most powerful type of severe thunderstorm.

Back-building thunderstorm

A back-building thunderstorm is a thunderstorm in which new development takes place on the upwind side (usually the west or southwest side in North America), such that the storm seems to remain stationary or propagate in a backward direction. Although the storm often appears to be stationary or even moving upwind on radar, this is actually an illusion. The storm in reality is a multi-cell storm with new, more vigorous, cells being formed on the upwind side replacing older cells which continue to drift downstream. ^[9]

Mesoscale Convective System

Multicell or squall line systems may form within a meteorologically important feature known as Mesoscale Convective System (MCS) stretching for hundreds of kilometres. A mesoscale convective system ( MCS) is a complex of Thunderstorms that becomes organized on a scale larger than the individual thunderstorms and normally persists The Mesoscale Convective Complex is a closely related phenomenon. A mesoscale convective complex (MCC is a unique kind of Mesoscale convective system which is defined by characteristics observed in infrared Satellite imagery. They are large enough to have a pronounced effect on the upper-level and surface weather pattern and may influence forecasts over a large area. MCS systems are common in the Midwestern United States and the Canadian Prairies during the summer months and produce much of the region's important agricultural rainfall. The Canadian Prairies is a region in western Canada, which may correspond to several different definitions natural or political ^[10] Prior to the discovery of the MCS phenomenon, the individual thunderstorms were thought of as independent entities, each being effectively impossible to predict. The MCS is amenable to forecasting, and a meteorologist can predict with high accuracy the percentage of the MCS that will be affected by thunderstorms. However, the meteorologist still cannot predict exactly where each thunderstorm will occur within the MCS.

Energy

Thunderstorm, Garajau, Madeira

If the quantity of water that is condensed in and subsequently precipitated from a cloud is known, then the total energy of a thunderstorm can be calculated. History See also History of Madeira Pre-Portuguese times Pliny mentions certain Purple Islands the position of which with reference to the In an average thunderstorm, the energy released amounts to about 10,000,000 kilowatt-hours (3. 6×10¹³ joule), which is equivalent to a 20-kiloton nuclear warhead. The joule (written in lower case ˈdʒuːl or /ˈdʒaʊl/ (symbol J) is the SI unit of Energy measuring heat, Electricity A nuclear weapon is an explosive device that derives its destructive force from Nuclear reactions either fission or a combination of fission and fusion. A large, severe thunderstorm might be 10 to 100 times more energetic. ^[11]

Where thunderstorms occur

Example of a cold front

Thunderstorms occur throughout the world, even in the polar regions, with the greatest frequency in tropical rainforest areas, where they may occur nearly daily. The Tropics are centered on the Equator and limited in Latitude by the Tropic of Cancer in the northern hemisphere at approximately 23°26' (23 Rainforests are Forests characterized by high Rainfall with definitions setting minimum normal annual rainfall between 1750–2000 mm (68-78 inches Kampala and Tororo in Uganda have each been mentioned as the most thunderous places on Earth,^[12] an accolade which has also been bestowed upon Bogor on Java, Indonesia or Singapore. Kampala is the Capital city of Uganda. With a population of 1208544 (2002 it is the largest city in Uganda For the Japanese yam see Dioscorea opposita. For the Sgt Frog character see Tororo (Sgt The Republic of Uganda is a Landlocked country in East Africa. Bogor is a city in West Java with a population of approximately 800000 people in the CBD area and 2000000 in suburban area bringing a total of 3 million population Java (Jawa is an Island of Indonesia and the site of its Capital city Jakarta. The Republic of Indonesia ( (Republik Indonesia is a Country in Southeast Asia. Singapore Thunderstorms are associated with the various monsoon seasons around the globe, and they populate the rainbands of all tropical cyclones. A monsoon is a seasonal prevailing wind which lasts for several months A tropical cyclone is a storm system characterized by a low pressure center and numerous Thunderstorms that produce strong winds and Flooding In temperate regions, they are most frequent in spring and summer, although they can occur along or ahead of cold fronts at any time of year. They may also occur within a cooler air mass following the passage of a cold front over a relatively warmer body of water. Thunderstorms are rare in polar regions because of cold surface temperatures.

Some of the most powerful and dangerous thunderstorms occur over the United States, particularly in the Midwest and the southern states. The Southern United States &mdashcommonly referred to as the American South, Dixie, or simply the South &mdashconstitutes a large distinctive These storms can produce large hail and powerful tornadoes. Thunderstorms are relatively uncommon along much of the West Coast of the United States,^[13] but they occur with greater frequency in the inland areas, particularly the Sacramento and San Joaquin Valleys of California. The " West Coast " " Western Seaboard " or " Pacific Seaboard " are terms for the westernmost coastal states of the Western United States The Sacramento Valley is the portion of the California Central Valley that lies to the north of the San Joaquin-Sacramento Delta in the U The San Joaquin Valley (ˌsæn wɑːˈkiːn refers to the area of the Central Valley of California that lies south of the Sacramento-San Joaquin Delta California ( is a US state on the West Coast of the United States, along the Pacific Ocean. Furthermore, in spring and summer, they occur nearly daily in certain areas of the Rocky Mountains. Mountain peaks of the Rocky Mountains The Rocky Mountains, often called the Rockies, are a Mountain range in western North America. In the Northeast, storms take on similar characteristics and patterns as the Midwest, only less frequently and severely. The Northeast is a region of the United States. As defined by the U Probably the most thunderous region outside of the Tropics is Florida. Florida ( is a state located in the southeastern region of the United States, bordering Alabama to the northwest and Georgia to the During the summer, violent thunderstorms are an almost daily occurrence over central and southern parts of the state. In more contemporary times, thunderstorms have taken on the role of a curiosity. Every spring, storm chasers head to the Great Plains of the United States and the Canadian Prairies to explore the visual and scientific aspects of storms and tornadoes. Storm chasing is broadly defined as the pursuit of any severe weather condition regardless of motive The Great Plains are the broad expanse of Prairie and Steppe which lie east of the Rocky Mountains in the United States and Canada

Lightning

Cloud to ground lightning over Pentagon City in Arlington, Virginia

Fork lightning over Tamworth, New South Wales in Australia

Lightning is an electrical discharge that occurs in a thunderstorm. The Commonwealth of Virginia ( is an American state Tamworth is a city in the New England region of New South Wales, Australia Lightning is an atmospheric discharge of Electricity, which typically occurs during Thunderstorms and sometimes during volcanic eruptions or It can be seen in the form of a bright streak (or bolt) from the sky. Lightning occurs when an electrical charge is built up within a cloud. Electric charge is a fundamental conserved property of some Subatomic particles which determines their Electromagnetic interaction. When a large enough charge is built up, a large discharge will occur and can be seen as lightning. The temperature of a lightning bolt can be hotter than the surface of the sun. Although the lightning is extremely hot, the short duration makes it not necessarily fatal. Contrary to the popular idea that lightning does not strike twice in the same spot, some people have been struck by lightning over three times, and skyscrapers like the Empire State Building have been struck numerous times in the same storm. The Empire State Building is a 102-story Art Deco Skyscraper in New York City at the intersection of Fifth Avenue and West 34th Street ^[14] There are several types of lightning:

• In-cloud lightning is the most common. It is lightning within a cloud and is sometimes called intra-cloud or sheet lightning.
• Cloud to ground lightning is when a bolt of lightning from a cloud strikes the ground. This form poses the greatest threat to life and property.
• Ground to cloud lightning is when a lightning bolt is induced from the ground to the cloud.
• Cloud to cloud lightning is rarely seen and is when a bolt of lightning arches from one cloud to another.
• Ball lightning is extremely rare and has several hypothesized explanations. Ball lightning is an atmospheric electrical phenomenon the physical nature of which is still Controversial. It is seen in the form of a 20 to 200 centimeter ball.
• Cloud to air lightning is when lightning from a cloud hits air of a different charge.
• Dry lightning is a misnomer which refers to a thunderstorm whose precipitation does not reach the ground. Dry lightning is a term which is used to refer to lightning strikes occurring without precipitation

Mythology

Thunderstorms have had a lasting and powerful influence on early civilizations. Romans thought them to be battles waged by Jupiter, who hurled lightning bolts forged by Vulcan. Ancient Rome was a Civilization that grew out of a small agricultural community founded on the Italian Peninsula as early as the 10th century BC In Roman mythology, Jupiter was the king of the gods and the god of Sky and Thunder. In ancient Roman religion and Hellenic neopaganism, Vulcan is the god of beneficial and hindering fire including the fire of Volcanoes He is also Thunderstorms were associated with the Thunderbirds, held by Native Americans to be a servant of the Great Spirit. The Thunderbird is a Legendary creature in North American indigenous peoples' history and culture For indigenous peoples in the United States other than Hawaii and Alaska see also Native Americans in the United States. The Great Spirit is a conception of a Supreme being prevalent among some Native American and First Nations cultures ^[15]

See also

• Cumulonimbus
• Severe thunderstorm warning
• Severe thunderstorm watch
• Supercell
• Thunder
• Tornado warning
• Tornado watch

References

Further reading

• Evans, Jeffry S. : Examination of Derecho Environments Using Proximity Soundings. [1]
• J. V. Iribarne and W. L. Godson, Atmospheric Thermodynamics, published by D. Reidel Publishing Company, Dordrecht, the Netherlands, 1973, 222 pages
• M K Yau and R. Dordrecht (population 119649 in 2004 or in English (and locally colloquially Dordt, is a city and municipality in the Dutch province of South The Netherlands ( Dutch:, ˈnedərlɑnt is the European part of the Kingdom of the Netherlands, which consists of the Netherlands the Netherlands R. Rogers, Short Course in Cloud Physics, Third Edition, published by Butterworth-Heinemann, January 1, 1989, 304 pages. New Year See also New Year The Ancient Romans began their consular year on January 1st since 153 BC Year 1989 ( MCMLXXXIX) was a Common year starting on Sunday (link displays 1989 Gregorian calendar) EAN 9780750632157 ISBN 0-7506-3215-1

External links

• Anatomy of a thunderstorm
• Thunderstorm photography in Germany
• Electronic Journal of Severe Storms Meteorology
• Social & Economic Costs of Thunderstorms & High Winds from "NOAA Socioeconomics" website initiative