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162-530: The climate is temperate, with precipitation of 600 to 1,200 mm (23.6 to 47.2 in) that is more or less evenly distributed throughout the year, making the soils appropriate for agriculture . The area is also one of the distinct physiography provinces of the larger Paraná – Paraguay plain division. It is considered that the limit of the Pampas plain is to the north with the Atlantic Forest and

324-570: A Cwa tendency (drier winters) in the northwestern edge); a cold semi-arid climate ( BSk ) on the southern and western fringes (like San Luis Province , western La Pampa Province and southern Buenos Aires Province); and an oceanic climate ( Cfb ) in the southeastern part (in the localities of Mar del Plata , Necochea , Tandil and the Sierra de la Ventana mountains, Argentina). Summer temperatures are more uniform than winter temperatures, generally ranging from 28 to 33 °C (82 to 91 °F) during

486-576: A lightning storm , is a storm characterized by the presence of lightning and its acoustic effect on the Earth's atmosphere , known as thunder . Relatively weak thunderstorms are sometimes called thundershowers . Thunderstorms occur in a type of cloud known as a cumulonimbus . They are usually accompanied by strong winds and often produce heavy rain and sometimes snow , sleet , or hail , but some thunderstorms produce little precipitation or no precipitation at all. Thunderstorms may line up in

648-651: A T0 for extremely weak tornadoes to T11 for the most powerful known tornadoes. Doppler radar data, photogrammetry , and ground swirl patterns (cycloidal marks) may also be analyzed to determine intensity and award a rating. Waterspouts have similar characteristics as tornadoes, characterized by a spiraling funnel-shaped wind current that form over bodies of water, connecting to large cumulonimbus clouds. Waterspouts are generally classified as forms of tornadoes, or more specifically, non- supercelled tornadoes that develop over large bodies of water. These spiralling columns of air frequently develop within tropical areas close to

810-499: A channel around 11 micron wavelength and primarily give information about cloud tops. Due to the typical structure of the atmosphere, cloud-top temperatures are approximately inversely related to cloud-top heights, meaning colder clouds almost always occur at higher altitudes. Further, cloud tops with a lot of small-scale variation are likely to be more vigorous than smooth-topped clouds. Various mathematical schemes, or algorithms, use these and other properties to estimate precipitation from

972-481: A deviation in their course at a right angle to the wind shear direction. Thunderstorms result from the rapid upward movement of warm, moist air, sometimes along a front . However, some kind of cloud forcing , whether it is a front, shortwave trough, or another system is needed for the air to rapidly accelerate upward. As the warm, moist air moves upward, it cools, condenses , and forms a cumulonimbus cloud that can reach heights of over 20 kilometres (12 mi). As

1134-705: A dramatic effect on agriculture. All plants need at least some water to survive, therefore rain (being the most effective means of watering) is important to agriculture. While a regular rain pattern is usually vital to healthy plants, too much or too little rainfall can be harmful, even devastating to crops. Drought can kill crops and increase erosion, while overly wet weather can cause harmful fungus growth. Plants need varying amounts of rainfall to survive. For example, certain cacti require small amounts of water, while tropical plants may need up to hundreds of inches of rain per year to survive. In areas with wet and dry seasons, soil nutrients diminish and erosion increases during

1296-404: A high frequency for cloud-to-ground lightning, like Florida, lightning causes several fatalities per year, most commonly to people working outside. Acid rain is also a frequent risk produced by lightning. Distilled water has a neutral pH of 7. "Clean" or unpolluted rain has a slightly acidic pH of about 5.2, because carbon dioxide and water in the air react together to form carbonic acid ,

1458-425: A layer of above-freezing air exists with sub-freezing air both above and below. This causes the partial or complete melting of any snowflakes falling through the warm layer. As they fall back into the sub-freezing layer closer to the surface, they re-freeze into ice pellets. However, if the sub-freezing layer beneath the warm layer is too small, the precipitation will not have time to re-freeze, and freezing rain will be

1620-500: A local thunderstorm. During a thunderstorm, pollen grains can absorb moisture and then burst into much smaller fragments with these fragments being easily dispersed by wind. While larger pollen grains are usually filtered by hairs in the nose, the smaller pollen fragments are able to pass through and enter the lungs, triggering the asthma attack. Most thunderstorms come and go fairly uneventfully; however, any thunderstorm can become severe , and all thunderstorms, by definition, present

1782-764: A paucity of specific symbionts might have exerted a synergistic influence in slowing tree invasion rates ". The World Wildlife Fund divides the Pampas into three distinct ecoregions . The Uruguayan Savanna lies east of the Paraná River , and includes all of Uruguay, most of Entre Ríos and Corrientes provinces in Argentina, and the southern portion of Brazil's state of Rio Grande do Sul. The Humid Pampas include eastern Buenos Aires Province, and southern Entre Ríos Province. The Semiarid Pampas includes western Buenos Aires Province and adjacent portions of Santa Fe, Córdoba, and La Pampa provinces. The Pampas are bounded by

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1944-411: A physical barrier such as a mountain ( orographic lift ). Conductive cooling occurs when the air comes into contact with a colder surface, usually by being blown from one surface to another, for example from a liquid water surface to colder land. Radiational cooling occurs due to the emission of infrared radiation , either by the air or by the surface underneath. Evaporative cooling occurs when moisture

2106-453: A portion of the atmosphere becomes saturated with water vapor (reaching 100% relative humidity ), so that the water condenses and "precipitates" or falls. Thus, fog and mist are not precipitation; their water vapor does not condense sufficiently to precipitate, so fog and mist do not fall. (Such a non-precipitating combination is a colloid .) Two processes, possibly acting together, can lead to air becoming saturated with water vapor: cooling

2268-514: A prominent feature and tracking it from scan to scan. A back-building thunderstorm, commonly referred to as a training thunderstorm , is a thunderstorm in which new development takes place on the upwind side (usually the west or southwest side in the Northern Hemisphere ), such that the storm seems to remain stationary or propagate in a backward direction. Though the storm often appears stationary on radar, or even moving upwind, this

2430-445: A series or become a rainband , known as a squall line . Strong or severe thunderstorms include some of the most dangerous weather phenomena, including large hail, strong winds, and tornadoes . Some of the most persistent severe thunderstorms, known as supercells , rotate as do cyclones. While most thunderstorms move with the mean wind flow through the layer of the troposphere that they occupy, vertical wind shear sometimes causes

2592-567: A single year. A significant portion of the annual precipitation in any particular place (no weather station in Africa or South America were considered) falls on only a few days, typically about 50% during the 12 days with the most precipitation. The Köppen classification depends on average monthly values of temperature and precipitation. The most commonly used form of the Köppen classification has five primary types labeled A through E. Specifically,

2754-409: A slow-falling drizzle , which has been observed as Rain puddles at its equator and polar regions. Precipitation is a major component of the water cycle , and is responsible for depositing most of the fresh water on the planet. Approximately 505,000 km (121,000 cu mi) of water falls as precipitation each year, 398,000 km (95,000 cu mi) of it over the oceans. Given

2916-569: A storm arises quickly and unexpectedly. Preparing the home by removing dead or rotting limbs and trees, which can be blown over in high winds, can also significantly reduce the risk of property damage and personal injury. The National Weather Service (NWS) in the United States recommends several precautions that people should take if thunderstorms are likely to occur: While safety and preparedness often overlap, "thunderstorm safety" generally refers to what people should do during and after

3078-421: A storm. The American Red Cross recommends that people follow these precautions if a storm is imminent or in progress: The NWS stopped recommending the "lightning crouch" in 2008 as it does not provide a significant level of protection and will not significantly lower the risk of being killed or injured from a nearby lightning strike. Thunderstorms occur throughout the world, even in the polar regions, with

3240-752: A subject of research. Although the ice is clear, scattering of light by the crystal facets and hollows/imperfections mean that the crystals often appear white in color due to diffuse reflection of the whole spectrum of light by the small ice particles. The shape of the snowflake is determined broadly by the temperature and humidity at which it is formed. Rarely, at a temperature of around −2 °C (28 °F), snowflakes can form in threefold symmetry—triangular snowflakes. The most common snow particles are visibly irregular, although near-perfect snowflakes may be more common in pictures because they are more visually appealing. No two snowflakes are alike, as they grow at different rates and in different patterns depending on

3402-407: A variety of datasets possessing different formats, time/space grids, periods of record and regions of coverage, input datasets, and analysis procedures, as well as many different forms of dataset version designators. In many cases, one of the modern multi-satellite data sets is the best choice for general use. The likelihood or probability of an event with a specified intensity and duration is called

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3564-683: A weak acid (pH 5.6 in distilled water), but unpolluted rain also contains other chemicals. Nitric oxide present during thunderstorm phenomena, caused by the oxidation of atmospheric nitrogen, can result in the production of acid rain, if nitric oxide forms compounds with the water molecules in precipitation, thus creating acid rain. Acid rain can damage infrastructures containing calcite or certain other solid chemical compounds. In ecosystems, acid rain can dissolve plant tissues of vegetations and increase acidification process in bodies of water and in soil , resulting in deaths of marine and terrestrial organisms. Any thunderstorm that produces hail that reaches

3726-420: Is IC. Occult deposition occurs when mist or air that is highly saturated with water vapour interacts with the leaves of trees or shrubs it passes over. Stratiform or dynamic precipitation occurs as a consequence of slow ascent of air in synoptic systems (on the order of cm/s), such as over surface cold fronts , and over and ahead of warm fronts . Similar ascent is seen around tropical cyclones outside of

3888-410: Is RA, while the coding for rain showers is SHRA. Ice pellets or sleet are a form of precipitation consisting of small, translucent balls of ice. Ice pellets are usually (but not always) smaller than hailstones. They often bounce when they hit the ground, and generally do not freeze into a solid mass unless mixed with freezing rain . The METAR code for ice pellets is PL . Ice pellets form when

4050-465: Is a polar molecule that can carry a charge, so it is capable of creating the charge separation needed to produce lightning). These electrical discharges can be up to a thousand times more powerful than lightning on the Earth. The water clouds can form thunderstorms driven by the heat rising from the interior. The clouds of Venus may also be capable of producing lightning ; some observations suggest that

4212-596: Is a complex of thunderstorms that becomes organized on a scale larger than the individual thunderstorms but smaller than extratropical cyclones , and normally persists for several hours or more. A mesoscale convective system's overall cloud and precipitation pattern may be round or linear in shape, and include weather systems such as tropical cyclones , squall lines , lake-effect snow events, polar lows , and mesoscale convective complexes (MCCs), and they generally form near weather fronts . Most mesoscale convective systems develop overnight and continue their lifespan through

4374-482: Is a grassland biome located in semi-arid to semi-humid climate regions of subtropical and tropical latitudes, with rainfall between 750 and 1,270 mm (30 and 50 in) a year. They are widespread on Africa, and are also found in India, the northern parts of South America, Malaysia, and Australia. The humid subtropical climate zone is where winter rainfall (and sometimes snowfall) is associated with large storms that

4536-480: Is a stable cloud deck which tends to form when a cool, stable air mass is trapped underneath a warm air mass. It can also form due to the lifting of advection fog during breezy conditions. There are four main mechanisms for cooling the air to its dew point: adiabatic cooling, conductive cooling, radiational cooling , and evaporative cooling. Adiabatic cooling occurs when air rises and expands. The air can rise due to convection , large-scale atmospheric motions, or

4698-449: Is a time when air quality improves, freshwater quality improves, and vegetation grows significantly. Soil nutrients diminish and erosion increases. Animals have adaptation and survival strategies for the wetter regime. The previous dry season leads to food shortages into the wet season, as the crops have yet to mature. Developing countries have noted that their populations show seasonal weight fluctuations due to food shortages seen before

4860-582: Is accompanied by plentiful precipitation year-round. The Mediterranean climate regime resembles the climate of the lands in the Mediterranean Basin, parts of western North America, parts of western and southern Australia, in southwestern South Africa and in parts of central Chile. The climate is characterized by hot, dry summers and cool, wet winters. A steppe is a dry grassland. Subarctic climates are cold with continuous permafrost and little precipitation. Precipitation, especially rain, has

5022-620: Is added to the air through evaporation, which forces the air temperature to cool to its wet-bulb temperature , or until it reaches saturation. The main ways water vapor is added to the air are: wind convergence into areas of upward motion, precipitation or virga falling from above, daytime heating evaporating water from the surface of oceans, water bodies or wet land, transpiration from plants, cool or dry air moving over warmer water, and lifting air over mountains. Coalescence occurs when water droplets fuse to create larger water droplets, or when water droplets freeze onto an ice crystal, which

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5184-435: Is an illusion. The storm is really a multi-cell storm with new, more vigorous cells that form on the upwind side, replacing older cells that continue to drift downwind. 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 continuously training set of cells that dropped an enormous quantity of rain upon

5346-437: Is associated with their warm front is often extensive, forced by weak upward vertical motion of air over the frontal boundary which condenses as it cools and produces precipitation within an elongated band, which is wide and stratiform , meaning falling out of nimbostratus clouds. When moist air tries to dislodge an arctic air mass, overrunning snow can result within the poleward side of the elongated precipitation band . In

5508-487: Is equally distributed through the year. Some areas with pronounced rainy seasons will see a break in rainfall mid-season when the Intertropical Convergence Zone or monsoon trough move poleward of their location during the middle of the warm season. When the wet season occurs during the warm season, or summer, rain falls mainly during the late afternoon and early evening hours. The wet season

5670-416: Is filled by 2.5 cm (0.98 in) of rain, with overflow flowing into the outer cylinder. Plastic gauges have markings on the inner cylinder down to 1 ⁄ 4  mm (0.0098 in) resolution, while metal gauges require use of a stick designed with the appropriate 1 ⁄ 4  mm (0.0098 in) markings. After the inner cylinder is filled, the amount inside is discarded, then filled with

5832-401: Is intermittent and often associated with baroclinic boundaries such as cold fronts , squall lines , and warm fronts. Convective precipitation mostly consist of mesoscale convective systems and they produce torrential rainfalls with thunderstorms, wind damages, and other forms of severe weather events. Orographic precipitation occurs on the windward (upwind) side of mountains and is caused by

5994-474: Is issued if a thunderstorm becomes severe, or will soon turn severe. In Canada, a rainfall rate greater than 50 millimetres (2 in) in one hour, or 75 millimetres (3 in) in three hours, is also used to indicate severe thunderstorms. Severe thunderstorms can occur from any type of storm cell. However, multicell , supercell , and squall lines represent the most common forms of thunderstorms that produce severe weather. A mesoscale convective system (MCS)

6156-759: Is known as the Bergeron process . The fall rate of very small droplets is negligible, hence clouds do not fall out of the sky; precipitation will only occur when these coalesce into larger drops. droplets with different size will have different terminal velocity that cause droplets collision and producing larger droplets, Turbulence will enhance the collision process. As these larger water droplets descend, coalescence continues, so that drops become heavy enough to overcome air resistance and fall as rain. Raindrops have sizes ranging from 5.1 to 20 millimetres (0.20 to 0.79 in) mean diameter, above which they tend to break up. Smaller drops are called cloud droplets, and their shape

6318-556: Is known, then the total energy of a thunderstorm can be calculated. In a typical thunderstorm, approximately 5×10 kg of water vapor are lifted, and the amount of energy released when this condenses is 10 joules . This is on the same order of magnitude of energy released within a tropical cyclone, and more energy than that released during the atomic bomb blast at Hiroshima, Japan in 1945 . The Fermi Gamma-ray Burst Monitor results show that gamma rays and antimatter particles ( positrons ) can be generated in powerful thunderstorms. It

6480-525: 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 or direction, the downdraft will be separated from the updraft, and the storm may become a supercell , where the mature stage can sustain itself for several hours. 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, approximately 20–30 minutes into

6642-477: Is made, various networks exist across the United States and elsewhere where rainfall measurements can be submitted through the Internet, such as CoCoRAHS or GLOBE . If a network is not available in the area where one lives, the nearest local weather office will likely be interested in the measurement. A concept used in precipitation measurement is the hydrometeor. Any particulates of liquid or solid water in

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6804-422: Is mainly inflicted by downburst winds, large hailstones, and flash flooding caused by heavy precipitation . Stronger thunderstorm cells are capable of producing tornadoes and waterspouts . There are three types of thunderstorms: single-cell , multi-cell , and supercell . Supercell thunderstorms are the strongest and most severe. Mesoscale convective systems formed by favorable vertical wind shear within

6966-468: Is more of a factor with thunderstorms with heavy precipitation (HP) than with thunderstorms with low precipitation (LP). When thunderstorms merge, which is most likely when numerous thunderstorms exist in proximity to each other, the motion of the stronger thunderstorm normally dictates the future motion of the merged cell. The stronger the mean wind, the less likely other processes will be involved in storm motion. On weather radar , storms are tracked by using

7128-741: Is not falling through the updraft) with a strong, rotating updraft (a " mesocyclone "). These storms normally have such powerful updrafts that the top of the supercell storm cloud (or anvil) can break through the troposphere and reach into the lower levels of the stratosphere . Supercell storms can be 24 kilometres (15 mi) wide. Research has shown that at least 90 percent of supercells cause severe weather . These storms can produce destructive tornadoes , extremely large hailstones (10 centimetres or 4 inches diameter), straight-line winds in excess of 130 km/h (81 mph), and flash floods . In fact, research has shown that most tornadoes occur from this type of thunderstorm. Supercells are generally

7290-412: Is one of the most significant thunderstorm hazards to aircraft. When hail stones exceed 13 millimetres (0.5 in) in diameter, planes can be seriously damaged within seconds. The hailstones accumulating on the ground can also be hazardous to landing aircraft. Wheat, corn, soybeans, and tobacco are the most sensitive crops to hail damage. Hail is one of Canada's most costly hazards. Hailstorms have been

7452-431: Is possible within a cyclone's comma head and within lake effect precipitation bands. In mountainous areas, heavy precipitation is possible where upslope flow is maximized within windward sides of the terrain at elevation. On the leeward side of mountains, desert climates can exist due to the dry air caused by compressional heating. Most precipitation occurs within the tropics and is caused by convection . The movement of

7614-519: Is spherical. As a raindrop increases in size, its shape becomes more oblate , with its largest cross-section facing the oncoming airflow. Contrary to the cartoon pictures of raindrops, their shape does not resemble a teardrop. Intensity and duration of rainfall are usually inversely related, i.e., high intensity storms are likely to be of short duration and low intensity storms can have a long duration. Rain drops associated with melting hail tend to be larger than other rain drops. The METAR code for rain

7776-411: Is suggested that the antimatter positrons are formed in terrestrial gamma-ray flashes (TGF). TGFs are brief bursts occurring inside thunderstorms and associated with lightning. The streams of positrons and electrons collide higher in the atmosphere to generate more gamma rays. About 500 TGFs may occur every day worldwide, but mostly go undetected. In more contemporary times, thunderstorms have taken on

7938-492: Is that grass roots compete for water and exclude tree seedlings. The effect might be increased by heavy, clayed soils which limit tap root penetration. Other causes that have been proposed are fires set by indigenous peoples for land clearance; the existence of heavy-bodied herbivores; and that the pampas are relicts of drier past climates. These explanations have been criticised as mono-causal. "Overall, we expect that low propagule pressure, abiotic stresses, biotic resistance, and

8100-586: Is the most common type of thunderstorm development. Mature thunderstorms are found near the center of the cluster, while dissipating thunderstorms exist on their downwind side. Multicell storms form as clusters of storms but may then evolve into one or more squall lines . While each cell of the cluster may only last 20 minutes, the cluster itself may persist for hours at a time. They often arise from convective updrafts in or near mountain ranges and linear weather boundaries, such as strong cold fronts or troughs of low pressure. These type of storms are stronger than

8262-489: Is the temperature to which a parcel of air must be cooled in order to become saturated, and (unless super-saturation occurs) condenses to water. Water vapor normally begins to condense on condensation nuclei such as dust, ice, and salt in order to form clouds. The cloud condensation nuclei concentration will determine the cloud microphysics. An elevated portion of a frontal zone forces broad areas of lift, which form cloud decks such as altostratus or cirrostratus . Stratus

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8424-457: Is the time of year, covering one or more months, when most of the average annual rainfall in a region falls. The term green season is also sometimes used as a euphemism by tourist authorities. Areas with wet seasons are dispersed across portions of the tropics and subtropics. Savanna climates and areas with monsoon regimes have wet summers and dry winters. Tropical rainforests technically do not have dry or wet seasons, since their rainfall

8586-400: Is typically active when freezing rain occurs. A stationary front is often present near the area of freezing rain and serves as the focus for forcing moist air to rise. Provided there is necessary and sufficient atmospheric moisture content, the moisture within the rising air will condense into clouds, namely nimbostratus and cumulonimbus if significant precipitation is involved. Eventually,

8748-437: Is usually caused by the heavy liquid precipitation that accompanies it. Flash floods are most common in arid regions as well as densely populated urban environments, where few plants, and bodies of water are present to absorb and contain the extra water. Flash flooding can be hazardous to small infrastructure, such as bridges, and weakly constructed buildings. Plants and crops in agricultural areas can be destroyed and devastated by

8910-485: Is warmer than fall in most areas (especially in the west) but significantly colder along the Atlantic. Violent storms are more common as well as wide temperature variations: days of 35 °C (95 °F) can give way to nights of under 5 °C (41 °F) or even frost, all within only a few days. Precipitation ranges from 1,400 millimetres (55 in) in the northeast to about 400 millimetres (16 in) or less in

9072-666: The Doppler on Wheels , vehicles with mounted automated weather stations , weather balloons , and unmanned aircraft to investigate thunderstorms expected to produce severe weather. Lightning is detected remotely using sensors that detect cloud-to-ground lightning strokes with 95 percent accuracy in detection and within 250 metres (820 ft) of their point of origin. Thunderstorms strongly influenced many early civilizations. Greeks believed that they were battles waged by Zeus , who hurled lightning bolts forged by Hephaestus . Some American Indian tribes associated thunderstorms with

9234-490: The Earth's atmosphere . In the mature stage of a thunderstorm, the warmed air continues to rise until it reaches an area of warmer air and can rise no farther. Often this 'cap' is the tropopause . The air is instead forced to spread out, giving the storm a characteristic anvil shape. The resulting cloud is called cumulonimbus incus . The water droplets coalesce into larger and heavier droplets and freeze to become ice particles. As these fall, they melt to become rain. If

9396-438: The Earth's atmosphere . Weaker thunderstorms are steered by winds closer to the Earth's surface than stronger thunderstorms, as the weaker thunderstorms are not as tall. Organized, long-lived thunderstorm cells and complexes move at a right angle to the direction of the vertical wind shear vector. If the gust front, or leading edge of the outflow boundary, races ahead of the thunderstorm, its motion will accelerate in tandem. This

9558-678: The Great Basin and Mojave Deserts . Similarly, in Asia, the Himalaya mountains create an obstacle to monsoons which leads to extremely high precipitation on the southern side and lower precipitation levels on the northern side. Extratropical cyclones can bring cold and dangerous conditions with heavy rain and snow with winds exceeding 119 km/h (74 mph), (sometimes referred to as windstorms in Europe). The band of precipitation that

9720-674: The Great Chaco Plain , to the west with the Pampas Mountains and the Cuyo Region , and to the south with Patagonia . This region has generally low elevations, whose highest levels generally do not exceed 600 metres (2,000 ft) in altitude. The coastal areas and most of the Buenos Aires Province are predominantly plain (with some wetlands ) and the interior areas (mainly in the southern part of

9882-649: The Guanaco have been extirpated completely from this habitat. Mammals that are still fairly present include Brazilian guinea pig , southern mountain cavy , coypu , Pampas fox , Geoffroy's cat , lesser grison , white-eared opossum , Molina's hog-nosed skunk , big lutrine opossum , big hairy armadillo and southern long-nosed armadillo . Bird species of the pampas are ruddy-headed goose , pampas meadowlark , hudsonian godwit , maguari stork , white-faced ibis , white-winged coot , southern screamer , dot-winged crake , curve-billed reedhaunter , burrowing owl and

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10044-655: The Rocky Mountains as part of the North American Monsoon regime. In the Northeast , storms take on similar characteristics and patterns as the Midwest, but with less frequency and severity. During the summer, air-mass thunderstorms are an almost daily occurrence over central and southern parts of Florida. If the quantity of water that is condensed in and subsequently precipitated from a cloud

10206-529: The Thunderbird , who they believed was a servant of the Great Spirit . The Norse considered thunderstorms to occur when Thor went to fight Jötnar , with the thunder and lightning being the effect of his strikes with the hammer Mjölnir . Hinduism recognizes Indra as the god of rain and thunderstorms. Christian doctrine accepts that fierce storms are the work of God. These ideas were still within

10368-550: The United States rainfall climatology over the Great Plains since they bring the region about half of their annual warm season rainfall. The two major ways thunderstorms move are via advection of the wind and propagation along outflow boundaries towards sources of greater heat and moisture. Many thunderstorms move with the mean wind speed through the Earth's troposphere , the lowest 8 kilometres (5.0 mi) of

10530-459: The electromagnetic spectrum that theory and practice show are related to the occurrence and intensity of precipitation. The sensors are almost exclusively passive, recording what they see, similar to a camera, in contrast to active sensors ( radar , lidar ) that send out a signal and detect its impact on the area being observed. Satellite sensors now in practical use for precipitation fall into two categories. Thermal infrared (IR) sensors record

10692-437: The equator , but are less common within areas of high latitude . Flash flooding is the process where a landscape, most notably an urban environment, is subjected to rapid floods. These rapid floods occur more quickly and are more localized than seasonal river flooding or areal flooding and are frequently (though not always) associated with intense rainfall. Flash flooding can frequently occur in slow-moving thunderstorms and

10854-446: The eyewall , and in comma-head precipitation patterns around mid-latitude cyclones . A wide variety of weather can be found along an occluded front, with thunderstorms possible, but usually their passage is associated with a drying of the air mass. Occluded fronts usually form around mature low-pressure areas. Precipitation may occur on celestial bodies other than Earth. When it gets cold, Mars has precipitation that most likely takes

11016-418: The lifted index can be used to assist in determining potential upward vertical development of clouds. Generally, thunderstorms require three conditions in order to form: All thunderstorms, regardless of type, go through three stages: the developing stage , the mature stage , and the dissipation stage . The average thunderstorm has a 24 km (15 mi) diameter. Depending on the conditions present in

11178-468: The monsoon trough , or Intertropical Convergence Zone , brings rainy seasons to savannah regions. Precipitation is a major component of the water cycle , and is responsible for depositing fresh water on the planet. Approximately 505,000 cubic kilometres (121,000 cu mi) of water falls as precipitation each year: 398,000 cubic kilometres (95,000 cu mi) over oceans and 107,000 cubic kilometres (26,000 cu mi) over land. Given

11340-425: The return period or frequency. The intensity of a storm can be predicted for any return period and storm duration, from charts based on historical data for the location. The term 1 in 10 year storm describes a rainfall event which is rare and is only likely to occur once every 10 years, so it has a 10 percent likelihood any given year. The rainfall will be greater and the flooding will be worse than

11502-504: The water vapor in that rising air condenses . When the moisture condenses, it releases energy known as latent heat of condensation, which allows the rising packet of air to cool less than the cooler surrounding air continuing the cloud's ascension. If enough instability is present in the atmosphere, this process will continue long enough for cumulonimbus clouds to form and produce lightning and thunder . Meteorological indices such as convective available potential energy (CAPE) and

11664-448: The 1840s but intensifying after the 1880s, European immigrants began to migrate to the Pampas, first as part of government-sponsored colonization schemes to settle the land and later as tenant farmers "working as either a sharecropper or as paid laborers for absentee landowners" in an attempt to make a living for themselves. However, many immigrants eventually moved to more permanent employment in cities, as industrialization picked up after

11826-475: The 18th century. Beyond the Earth's atmosphere, thunderstorms have also been observed on the planets of Jupiter , Saturn , Neptune , and, probably, Venus . Warm air has a lower density than cool air, so warmer air rises upwards and cooler air will settle at the bottom (this effect can be seen with a hot air balloon ). Clouds form as relatively warmer air, carrying moisture, rises within cooler air. The moist air rises, and, as it does so, it cools and some of

11988-650: The 1930s. As a result, Argentina's history of immigration in Buenos Aires Province is typically associated with cities and urban life, unlike in Entre Ríos Province and Santa Fe Province, where European immigration took on a more rural profile. Precipitation (meteorology) In meteorology , precipitation is any product of the condensation of atmospheric water vapor that falls from clouds due to gravitational pull. The main forms of precipitation include drizzle , rain , sleet , snow , ice pellets , graupel and hail . Precipitation occurs when

12150-696: The Brazilian state of Rio Grande do Sul and Uruguay) have low ranges of hills (like Serras de Sudeste in Brazil and Cuchilla Grande in Uruguay). Low hills covered by grasslands are called coxilhas ( Portuguese pronunciation: [koˈʃiʎɐs] ) in Portuguese and cuchillas ( Spanish pronunciation: [kuˈtʃiʝas] ) in Spanish, and it is the most typical landscape of the countryside areas in

12312-686: The Earth's surface area, that means the globally averaged annual precipitation is 990 millimetres (39 in), but over land it is only 715 millimetres (28.1 in). Climate classification systems such as the Köppen climate classification system use average annual rainfall to help differentiate between differing climate regimes. Global warming is already causing changes to weather, increasing precipitation in some geographies, and reducing it in others, resulting in additional extreme weather . Precipitation may occur on other celestial bodies. Saturn's largest satellite , Titan , hosts methane precipitation as

12474-610: The Earth's surface area, that means the globally averaged annual precipitation is 990 millimetres (39 in). Mechanisms of producing precipitation include convective, stratiform , and orographic rainfall. Convective processes involve strong vertical motions that can cause the overturning of the atmosphere in that location within an hour and cause heavy precipitation, while stratiform processes involve weaker upward motions and less intense precipitation. Precipitation can be divided into three categories, based on whether it falls as liquid water, liquid water that freezes on contact with

12636-481: The Earth's surface, occasionally causing strong winds that are commonly associated with thunderstorms. Thunderstorms can form and develop in any geographic location but most frequently within the mid-latitude , where warm, moist air from tropical latitudes collides with cooler air from polar latitudes. Thunderstorms are responsible for the development and formation of many severe weather phenomena, which can be potentially hazardous. Damage that results from thunderstorms

12798-535: The IR data. The second category of sensor channels is in the microwave part of the electromagnetic spectrum. The frequencies in use range from about 10 gigahertz to a few hundred GHz. Channels up to about 37 GHz primarily provide information on the liquid hydrometeors (rain and drizzle) in the lower parts of clouds, with larger amounts of liquid emitting higher amounts of microwave radiant energy . Channels above 37 GHz display emission signals, but are dominated by

12960-807: The Northern Hemisphere, poleward is towards the North Pole, or north. Within the Southern Hemisphere, poleward is towards the South Pole, or south. Southwest of extratropical cyclones, curved cyclonic flow bringing cold air across the relatively warm water bodies can lead to narrow lake-effect snow bands. Those bands bring strong localized snowfall which can be understood as follows: Large water bodies such as lakes efficiently store heat that results in significant temperature differences (larger than 13 °C or 23 °F) between

13122-475: The Pampas south and west of Buenos Aires . Much of the area is also used for cattle , and more recently, to cultivate vineyards in the Buenos Aires wine region . The area is also used for farming honey using European honeybees . These farming regions are particularly susceptible to flooding during thunderstorms. The weather averages out to be 16 °C (60 °F) year-round in the Pampas. Starting in

13284-500: The Pampas, but it is much more frequent in the southwest than around the Parana and Uruguay Rivers. Temperatures under −5 °C (23 °F) can occur everywhere, but values of −10 °C (14 °F) or lower are confined to the south and west. Snow almost never falls in the northernmost third and is rare and light elsewhere, except for exceptional events in which depths have reached 30 cm (12 in). Springs are very variable; it

13446-515: The Pampas: Human activity has caused major changes to the wildlife of the Pampas. Most big or medium-sized species such as puma , rhea , Capybara , plains viscacha , maned wolf , marsh deer and Pampas deer have lost their habitats especially due to the spread of agriculture and ranching , and are only present in very few relicts of the pampas. Other species, such as the Jaguar and

13608-1000: The action of solid hydrometeors (snow, graupel, etc.) to scatter microwave radiant energy. Satellites such as the Tropical Rainfall Measuring Mission (TRMM) and the Global Precipitation Measurement (GPM) mission employ microwave sensors to form precipitation estimates. Additional sensor channels and products have been demonstrated to provide additional useful information including visible channels, additional IR channels, water vapor channels and atmospheric sounding retrievals. However, most precipitation data sets in current use do not employ these data sources. The IR estimates have rather low skill at short time and space scales, but are available very frequently (15 minutes or more often) from satellites in geosynchronous Earth orbit. IR works best in cases of deep, vigorous convection—such as

13770-414: The air or adding water vapor to the air. Precipitation forms as smaller droplets coalesce via collision with other rain drops or ice crystals within a cloud. Short, intense periods of rain in scattered locations are called showers . Moisture that is lifted or otherwise forced to rise over a layer of sub-freezing air at the surface may be condensed by the low temperature into clouds and rain. This process

13932-429: The amount of rainy days is fairly constant. Very intense thunderstorms are common in the spring and summer, and it has among the most frequent lightning and highest convective cloud tops in the world. The severe thunderstorms produce intense hailstorms , both floods and flash floods , and the most consistently active tornado region outside the central and southeastern US. Climate charts for different locations of

14094-497: The atmosphere are known as hydrometeors. Formations due to condensation, such as clouds, haze , fog, and mist, are composed of hydrometeors. All precipitation types are made up of hydrometeors by definition, including virga , which is precipitation which evaporates before reaching the ground. Particles blown from the Earth's surface by wind, such as blowing snow and blowing sea spray, are also hydrometeors , as are hail and snow . Although surface precipitation gauges are considered

14256-413: The atmosphere due to their mass, and may collide and stick together in clusters, or aggregates. These aggregates are snowflakes, and are usually the type of ice particle that falls to the ground. Guinness World Records list the world's largest snowflakes as those of January 1887 at Fort Keogh , Montana; allegedly one measured 38 cm (15 in) wide. The exact details of the sticking mechanism remain

14418-589: The atmosphere, each of these three stages take an average of 30 minutes. The first stage of a thunderstorm is the cumulus stage or developing stage. During this stage, masses of moisture are lifted upwards into the atmosphere. The trigger for this lift can be solar illumination , where the heating of the ground produces thermals , or where two winds converge forcing air upwards, or where winds blow over terrain of increasing elevation. The moisture carried upward cools into liquid drops of water due to lower temperatures at high altitude, which appear as cumulus clouds. As

14580-484: The average time between observations exceeds three hours. This several-hour interval is insufficient to adequately document precipitation because of the transient nature of most precipitation systems as well as the inability of a single satellite to appropriately capture the typical daily cycle of precipitation at a given location. Since the late 1990s, several algorithms have been developed to combine precipitation data from multiple satellites' sensors, seeking to emphasize

14742-764: The back edge of the rain shield associated with mature squall lines, a wake low can form, which is a mesoscale low pressure area that forms behind the mesoscale high pressure system normally present under the rain canopy, which are sometimes associated with a heat burst . This kind of storm is also known as "Wind of the Stony Lake" ( simplified Chinese : 石湖风 ; traditional Chinese : 石湖風 ; shi2 hu2 feng1) in southern China. Supercell storms are large, usually severe , quasi-steady-state storms that form in an environment where wind speed or wind direction varies with height (" wind shear "), and they have separate downdrafts and updrafts (i.e., where its associated precipitation

14904-531: The best analyses of gauge data take two months or more after the observation time to undergo the necessary transmission, assembly, processing and quality control. Thus, precipitation estimates that include gauge data tend to be produced further after the observation time than the no-gauge estimates. As a result, while estimates that include gauge data may provide a more accurate depiction of the "true" precipitation, they are generally not suited for real- or near-real-time applications. The work described has resulted in

15066-420: The best instantaneous satellite estimate. In either case, the less-emphasized goal is also considered desirable. One key aspect of multi-satellite studies is the ability to include even a small amount of surface gauge data, which can be very useful for controlling the biases that are endemic to satellite estimates. The difficulties in using gauge data are that 1) their availability is limited, as noted above, and 2)

15228-402: The bulk of the occurrences from May through September. Cheyenne, Wyoming , is North America's most hail-prone city with an average of nine to ten hailstorms per season. In South America, areas prone to hail are cities like Bogotá, Colombia. Hail can cause serious damage, notably to automobiles , aircraft, skylights, glass-roofed structures, livestock, and most commonly, farmers' crops . Hail

15390-510: The cause of costly and deadly events throughout history. One of the earliest recorded incidents occurred around the 9th century in Roopkund , Uttarakhand, India. The largest hailstone in terms of maximum circumference and length ever recorded in the United States fell in 2003 in Aurora, Nebraska , United States. A tornado is a violent, rotating column of air in contact with both the surface of

15552-532: The changing temperature and humidity within the atmosphere through which they fall on their way to the ground. The METAR code for snow is SN, while snow showers are coded SHSN. Diamond dust, also known as ice needles or ice crystals, forms at temperatures approaching −40 °C (−40 °F) due to air with slightly higher moisture from aloft mixing with colder, surface-based air. They are made of simple ice crystals, hexagonal in shape. The METAR identifier for diamond dust within international hourly weather reports

15714-447: The cloud droplets will grow large enough to form raindrops and descend toward the Earth where they will freeze on contact with exposed objects. Where relatively warm water bodies are present, for example due to water evaporation from lakes, lake-effect snowfall becomes a concern downwind of the warm lakes within the cold cyclonic flow around the backside of extratropical cyclones . Lake-effect snowfall can be locally heavy. Thundersnow

15876-462: The coding of GS, which is short for the French word grésil. Stones just larger than golf ball-sized are one of the most frequently reported hail sizes. Hailstones can grow to 15 centimetres (6 in) and weigh more than 500 grams (1 lb). In large hailstones, latent heat released by further freezing may melt the outer shell of the hailstone. The hailstone then may undergo 'wet growth', where

16038-431: The danger of lightning . Thunderstorm preparedness and safety refers to taking steps before, during, and after a thunderstorm to minimize injury and damage. Preparedness refers to precautions that should be taken before a thunderstorm. Some preparedness takes the form of general readiness (as a thunderstorm can occur at any time of the day or year). Preparing a family emergency plan, for example, can save valuable time if

16200-537: The day. However, most cities in the Pampas occasionally have high temperatures that push 38 °C (100 °F), as occurs when warm, dry, northerly winds blow from southern Brazil, northern Argentina or Paraguay . Autumn arrives gradually in March and peaks in April and May. In April, highs range from 20 to 25 °C (68 to 77 °F) and lows from 9 to 13 °C (48 to 55 °F). The first frosts arrive in mid-April in

16362-424: The deeper the clouds get, and the greater the precipitation rate becomes. In mountainous areas, heavy snowfall accumulates when air is forced to ascend the mountains and squeeze out precipitation along their windward slopes, which in cold conditions, falls in the form of snow. Because of the ruggedness of terrain, forecasting the location of heavy snowfall remains a significant challenge. The wet, or rainy, season

16524-531: The descending and generally warming, leeward side where a rain shadow is observed. In Hawaii , Mount Waiʻaleʻale , on the island of Kauai, is notable for its extreme rainfall, as it has the second-highest average annual rainfall on Earth, with 12,000 millimetres (460 in). Storm systems affect the state with heavy rains between October and March. Local climates vary considerably on each island due to their topography, divisible into windward ( Koʻolau ) and leeward ( Kona ) regions based upon location relative to

16686-497: The development of organized convection. This term technically applies to a single thunderstorm with one main updraft. Also known as air-mass thunderstorms , these are the typical summer thunderstorms in many temperate locales. They also occur in the cool unstable air that often follows the passage of a cold front from the sea during winter. Within a cluster of thunderstorms, the term "cell" refers to each separate principal updraft. Thunderstorm cells occasionally form in isolation, as

16848-471: The drier Argentine Espinal grasslands, which form a semicircle around the north, west, and south of the Humid Pampas. Winters are cold to mild, and summers are hot and humid. Rainfall is fairly uniform throughout the year but is a little heavier during the summer. Annual rainfall is heaviest near the coast and decreases gradually further inland. Rain during the late spring and summer usually arrives in

17010-637: The earth and a cumulonimbus cloud (otherwise known as a thundercloud) or, in rare cases, the base of a cumulus cloud . Tornadoes come in many sizes but are typically in the form of a visible condensation funnel , whose narrow end touches the earth and is often encircled by a cloud of debris and dust . Most tornadoes have wind speeds between 40 and 110 mph (64 and 177 km/h), are approximately 75 metres (246 ft) across, and travel several kilometers (a few miles) before dissipating. Some attain wind speeds of more than 300 mph (480 km/h), stretch more than 1,600 metres (1 mi) across, and stay on

17172-548: The equator in Colombia are amongst the wettest places on Earth. North and south of this are regions of descending air that form subtropical ridges where precipitation is low; the land surface underneath these ridges is usually arid, and these regions make up most of the Earth's deserts. An exception to this rule is in Hawaii, where upslope flow due to the trade winds lead to one of the wettest locations on Earth. Otherwise,

17334-458: The first harvest, which occurs late in the wet season. Tropical cyclones, a source of very heavy rainfall, consist of large air masses several hundred miles across with low pressure at the centre and with winds blowing inward towards the centre in either a clockwise direction (southern hemisphere) or counterclockwise (northern hemisphere). Although cyclones can take an enormous toll in lives and personal property, they may be important factors in

17496-737: The flow of the Westerlies into the Rocky Mountains lead to the wettest, and at elevation snowiest, locations within North America. In Asia during the wet season, the flow of moist air into the Himalayas leads to some of the greatest rainfall amounts measured on Earth in northeast India. The standard way of measuring rainfall or snowfall is the standard rain gauge, which can be found in 10 cm (3.9 in) plastic and 20 cm (7.9 in) metal varieties. The inner cylinder

17658-429: The force exerted by downburst winds. Downburst winds are usually formed in areas when high pressure air systems of downdrafts begin to sink and displace the air masses below it, due to their higher density. When these downdrafts reach the surface, they spread out and turn into the destructive straight-horizontal winds. Thunderstorm asthma is the triggering of an asthma attack by environmental conditions directly caused by

17820-739: The force of raging water. Automobiles parked within affected areas can also be displaced. Soil erosion can occur as well, exposing risks of landslide phenomena. Downburst winds can produce numerous hazards to landscapes experiencing thunderstorms. Downburst winds are generally very powerful, and are often mistaken for wind speeds produced by tornadoes, due to the concentrated amount of force exerted by their straight-horizontal characteristic. Downburst winds can be hazardous to unstable, incomplete, or weakly constructed infrastructures and buildings. Agricultural crops, and other plants in nearby environments can be uprooted and damaged. Aircraft engaged in takeoff or landing can crash. Automobiles can be displaced by

17982-412: The form of brief heavy showers and thunderstorms. More general rainfall occurs the remainder of the year as cold fronts and storm systems move through. Although cold spells during the winter often send nighttime temperatures below freezing, snow is quite rare. In most winters, a few light snowfalls occur over inland areas. Central Argentina boasts a successful agricultural business, with crops grown on

18144-579: The form of ice needles, rather than rain or snow. Convective rain , or showery precipitation, occurs from convective clouds, e.g. cumulonimbus or cumulus congestus . It falls as showers with rapidly changing intensity. Convective precipitation falls over a certain area for a relatively short time, as convective clouds have limited horizontal extent. Most precipitation in the tropics appears to be convective; however, it has been suggested that stratiform precipitation also occurs. Graupel and hail indicate convection. In mid-latitudes, convective precipitation

18306-427: The form of strong straight-line winds can be expected in areas where the squall line itself is in the shape of a bow echo , within the portion of the line that bows out the most. Tornadoes can be found along waves within a line echo wave pattern , or LEWP, where mesoscale low pressure areas are present. Some bow echoes in the summer are called derechos , and move quite fast through large sections of territory. On

18468-400: The funnel needs to be removed before the event begins. For those looking to measure rainfall the most inexpensively, a can that is cylindrical with straight sides will act as a rain gauge if left out in the open, but its accuracy will depend on what ruler is used to measure the rain with. Any of the above rain gauges can be made at home, with enough know-how . When a precipitation measurement

18630-425: The gauge. Once the snowfall/ice is finished accumulating, or as 30 cm (12 in) is approached, one can either bring it inside to melt, or use lukewarm water to fill the inner cylinder with in order to melt the frozen precipitation in the outer cylinder, keeping track of the warm fluid added, which is subsequently subtracted from the overall total once all the ice/snow is melted. Other types of gauges include

18792-431: The grass genus Stipa are particularly conspicuous. "Pampas grass" ( Cortaderia selloana ) is an iconic species of the Pampas. Vegetation typically includes perennial grasses and herbs . Different strata of grasses occur because of gradients of water availability. Why the pristine pampas were treeless regions has been much debated. Perhaps the most commonly cited explanation is seasonal drought. A related hypothesis

18954-589: The greatest frequency in tropical rainforest areas, where they may occur nearly daily. At any given time, approximately 2,000 thunderstorms are occurring on Earth. Kampala and Tororo in Uganda have each been mentioned as the most thunderous places on Earth, a claim also made for Singapore and Bogor on the Indonesian island of Java . Other cities known for frequent storm activity include Darwin , Caracas, Manila and Mumbai . Thunderstorms are associated with

19116-478: The ground for more than 100 kilometres (dozens of miles). The Fujita scale and the Enhanced Fujita Scale rate tornadoes by damage caused. An EF0 tornado, the weakest category, damages trees but does not cause significant damage to structures. An EF5 tornado, the strongest category, rips buildings off their foundations and can deform large skyscrapers. The similar TORRO scale ranges from

19278-449: The ground is known as a hailstorm. Thunderclouds that are capable of producing hailstones are often seen obtaining green coloration. Hail is more common along mountain ranges because mountains force horizontal winds upwards (known as orographic lifting ), thereby intensifying the updrafts within thunderstorms and making hail more likely. One of the more common regions for large hail is across mountainous northern India, which reported one of

19440-463: The hailstones to the upper part of the cloud. The updraft dissipates and the hailstones fall down, back into the updraft, and are lifted again. Hail has a diameter of 5 millimetres (0.20 in) or more. Within METAR code, GR is used to indicate larger hail, of a diameter of at least 6.4 millimetres (0.25 in). GR is derived from the French word grêle. Smaller-sized hail, as well as snow pellets, use

19602-487: The higher mountains. Windward sides face the east to northeast trade winds and receive much more rainfall; leeward sides are drier and sunnier, with less rain and less cloud cover. In South America, the Andes mountain range blocks Pacific moisture that arrives in that continent, resulting in a desertlike climate just downwind across western Argentina. The Sierra Nevada range creates the same effect in North America forming

19764-410: The highest hail-related death tolls on record in 1888. China also experiences significant hailstorms. Across Europe, Croatia experiences frequent occurrences of hail. In North America, hail is most common in the area where Colorado , Nebraska , and Wyoming meet, known as "Hail Alley". Hail in this region occurs between the months of March and October during the afternoon and evening hours, with

19926-479: The ice crystals the crystals are able to grow to hundreds of micrometers in size at the expense of the water droplets. This process is known as the Wegener–Bergeron–Findeisen process . The corresponding depletion of water vapor causes the droplets to evaporate, meaning that the ice crystals grow at the droplets' expense. These large crystals are an efficient source of precipitation, since they fall through

20088-402: The instability and relative wind conditions at different layers of the atmosphere (" wind shear "). Single-cell thunderstorms form in environments of low vertical wind shear and last only 20–30 minutes. Organized thunderstorms and thunderstorm clusters/lines can have longer life cycles as they form in environments of significant vertical wind shear, normally greater than 25 knots (13 m/s) in

20250-532: The life of the thunderstorm. The downdraft will push down out of the thunderstorm, hit the ground and spread out. This phenomenon is known as a downburst . 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. Thunderstorms in an atmosphere with virtually no vertical wind shear weaken as soon as they send out an outflow boundary in all directions, which then quickly cuts off its inflow of relatively warm, moist air, and kills

20412-454: The liquid outer shell collects other smaller hailstones. The hailstone gains an ice layer and grows increasingly larger with each ascent. Once a hailstone becomes too heavy to be supported by the storm's updraft, it falls from the cloud. Snow crystals form when tiny supercooled cloud droplets (about 10 μm in diameter) freeze. Once a droplet has frozen, it grows in the supersaturated environment. Because water droplets are more numerous than

20574-609: The lowest 6 kilometres (3.7 mi) of the troposphere , which aids the development of stronger updrafts as well as various forms of severe weather. The supercell is the strongest of the thunderstorms, most commonly associated with large hail, high winds, and tornado formation. Precipitable water values of greater than 31.8 millimetres (1.25 in) favor the development of organized thunderstorm complexes. Those with heavy rainfall normally have precipitable water values greater than 36.9 millimetres (1.45 in). Upstream values of CAPE of greater than 800 J/kg are usually required for

20736-453: The mainstream as late as the 18th century. Martin Luther was out walking when a thunderstorm began, causing him to pray to God for being saved and promising to become a monk. Thunderstorms, evidenced by flashes of lightning , on Jupiter have been detected and are associated with clouds where water may exist as both a liquid and ice, suggesting a mechanism similar to that on Earth. (Water

20898-675: The most powerful thunderstorms over the United States occur in the Midwest and the Southern states . These storms can produce large hail and powerful tornadoes. Thunderstorms are relatively uncommon along much of the West Coast of the United States , but they occur with greater frequency in the inland areas, particularly the Sacramento and San Joaquin Valleys of California. In spring and summer, they occur nearly daily in certain areas of

21060-458: The next day. They tend to form when the surface temperature varies by more than 5 °C (9 °F) between day and night. The type that forms during the warm season over land has been noted across North America, Europe, and Asia, with a maximum in activity noted during the late afternoon and evening hours. Forms of MCS that develop in the tropics are found in use either the Intertropical Convergence Zone or monsoon troughs , generally within

21222-485: The northern parts of the Pampas. The highest elevations of the Pampas region are found in the Sierra de la Ventana mountains , in the southern part of Buenos Aires Province, with 1,239 metres (4,065 ft) at the summit of Cerro Tres Picos . The climate of the Pampas is generally temperate, gradually giving way to a more humid subtropical climate in the north ( Cfa , according to the Köppen climate classification , with

21384-526: The occurrence of one thunderstorm can develop an outflow boundary that sets up new thunderstorm development. Such storms are rarely severe and are a result of local atmospheric instability; hence the term "air mass thunderstorm". When such storms have a brief period of severe weather associated with them, it is known as a pulse severe storm. Pulse severe storms are poorly organized and occur randomly in time and space, making them difficult to forecast. Single-cell thunderstorms normally last 20–30 minutes. This

21546-498: The phenomena of thunderstorms and have numerous hazards towards landscapes and populations. One of the more significant hazards lightning can pose is the wildfires they are capable of igniting. Under a regime of low precipitation (LP) thunderstorms, where little precipitation is present, rainfall cannot prevent fires from starting when vegetation is dry as lightning produces a concentrated amount of extreme heat. Direct damage caused by lightning strikes occurs on occasion. In areas with

21708-424: The popular wedge gauge (the cheapest rain gauge and most fragile), the tipping bucket rain gauge , and the weighing rain gauge . The wedge and tipping bucket gauges have problems with snow. Attempts to compensate for snow/ice by warming the tipping bucket meet with limited success, since snow may sublimate if the gauge is kept much above freezing. Weighing gauges with antifreeze should do fine with snow, but again,

21870-490: The precipitation regimes of places they impact, as they may bring much-needed precipitation to otherwise dry regions. Areas in their path can receive a year's worth of rainfall from a tropical cyclone passage. On the large scale, the highest precipitation amounts outside topography fall in the tropics, closely tied to the Intertropical Convergence Zone , itself the ascending branch of the Hadley cell . Mountainous locales near

22032-581: The primary types are A, tropical; B, dry; C, mild mid-latitude; D, cold mid-latitude; and E, polar. The five primary classifications can be further divided into secondary classifications such as rain forest , monsoon , tropical savanna , humid subtropical , humid continental , oceanic climate , Mediterranean climate , steppe , subarctic climate , tundra , polar ice cap , and desert . Rain forests are characterized by high rainfall, with definitions setting minimum normal annual rainfall between 1,750 and 2,000 mm (69 and 79 in). A tropical savanna

22194-406: The remaining rainfall in the outer cylinder until all the fluid in the outer cylinder is gone, adding to the overall total until the outer cylinder is empty. These gauges are used in the winter by removing the funnel and inner cylinder and allowing snow and freezing rain to collect inside the outer cylinder. Some add anti-freeze to their gauge so they do not have to melt the snow or ice that falls into

22356-413: The result at the surface. A temperature profile showing a warm layer above the ground is most likely to be found in advance of a warm front during the cold season, but can occasionally be found behind a passing cold front . Like other precipitation, hail forms in storm clouds when supercooled water droplets freeze on contact with condensation nuclei , such as dust or dirt. The storm's updraft blows

22518-616: The rhea. Invasive species include the European hare , wild boar and house sparrow . Most of the large mammals native to the Pampas became extinct as part of the end-Pleistocene extinction event of most large mammals across the Americas around 12,000 years ago. Notable former inhabitants of the Pampas include the giant elephant-sized ground sloth Megatherium americanum , along side the smaller (though still large) ground sloths Mylodon , Glossotherium Lestodon and Catonyx ,

22680-448: The rhinoceros like ungulate Toxodon , the camel-like Macrauchenia , the gomphothere (elephant-relative) Notiomastodon , the equines Equus neogeus and Hippidion , and the glyptodonts (car-sized relatives of armadillos) Glyptodon and Doedicurus , the bear Arctotherium and the sabertooth cat Smilodon populator . The dominant vegetation types are grassy prairie and grass steppe , in which numerous species of

22842-438: The rising air motion of a large-scale flow of moist air across the mountain ridge, resulting in adiabatic cooling and condensation. In mountainous parts of the world subjected to relatively consistent winds (for example, the trade winds ), a more moist climate usually prevails on the windward side of a mountain than on the leeward or downwind side. Moisture is removed by orographic lift, leaving drier air (see katabatic wind ) on

23004-426: The rising air reaches its dew point temperature, water vapor condenses into water droplets or ice, reducing pressure locally within the thunderstorm cell. Any precipitation falls the long distance through the clouds towards the Earth's surface. As the droplets fall, they collide with other droplets and become larger. The falling droplets create a downdraft as it pulls cold air with it, and this cold air spreads out at

23166-497: The role of a scientific curiosity. Every spring, storm chasers head to the Great Plains of the United States and the Canadian Prairies to explore the scientific aspects of storms and tornadoes through use of videotaping. Radio pulses produced by cosmic rays are being used to study how electric charges develop within thunderstorms. More organized meteorological projects such as VORTEX2 use an array of sensors, such as

23328-508: The same area, resulting in devastating flash flooding . A similar event occurred in Boscastle , England, on 16 August 2004, and over Chennai on 1 December 2015. Each year, many people are killed or seriously injured by severe thunderstorms despite the advance warning . While severe thunderstorms are most common in the spring and summer, they can occur at just about any time of the year. Cloud-to-ground lightning frequently occurs within

23490-526: The single-cell storm, yet much weaker than the supercell storm. Hazards with the multicell cluster include moderate-sized hail, flash flooding, and weak tornadoes. A squall line is an elongated line of severe thunderstorms that can form along or ahead of a cold front . In the early 20th century, the term was used as a synonym for cold front . The squall line contains heavy precipitation , hail , frequent lightning , strong straight line winds, and possibly tornadoes and waterspouts . Severe weather in

23652-450: The south and late May or early June in the north. Winters are generally mild, but cold waves often occur. Typical temperatures range from 12 to 19 °C (54 to 66 °F) during the day, and from 1 to 6 °C (34 to 43 °F) at night. With strong northerly winds, days of over 25 °C (77 °F) can be recorded almost everywhere, and during cold waves, high temperatures can be only 6 °C (43 °F). Frost occurs everywhere in

23814-512: The southern and western edges. It is highly seasonal in the West, with some places recording averages of 120 millimetres (4.7 in) monthly in the summer, and only 20 millimetres (0.79 in) monthly in the winter. The eastern areas have small peaks in the fall and the spring, with relatively rainy summers and winters that are only slightly drier. However, where summer rain falls as short, heavy storms, winter rain falls mostly as cold drizzle, and so

23976-455: The standard for measuring precipitation, there are many areas in which their use is not feasible. This includes the vast expanses of ocean and remote land areas. In other cases, social, technical or administrative issues prevent the dissemination of gauge observations. As a result, the modern global record of precipitation largely depends on satellite observations. Satellite sensors work by remotely sensing precipitation—recording various parts of

24138-565: The strengths and minimize the weaknesses of the individual input data sets. The goal is to provide "best" estimates of precipitation on a uniform time/space grid, usually for as much of the globe as possible. In some cases the long-term homogeneity of the dataset is emphasized, which is the Climate Data Record standard. Alternatively, the High Resolution Precipitation Product aims to produce

24300-443: The strongest type of thunderstorm. In the United States, a thunderstorm is classed as severe if winds reach at least 93 kilometres per hour (58 mph), hail is 25 millimetres (1 in) in diameter or larger, or if funnel clouds or tornadoes are reported. Although a funnel cloud or tornado indicates a severe thunderstorm, a tornado warning is issued in place of a severe thunderstorm warning . A severe thunderstorm warning

24462-424: The surface, or ice. Mixtures of different types of precipitation, including types in different categories, can fall simultaneously. Liquid forms of precipitation include rain and drizzle. Rain or drizzle that freezes on contact within a subfreezing air mass is called "freezing rain" or "freezing drizzle". Frozen forms of precipitation include snow, ice needles , ice pellets , hail , and graupel . The dew point

24624-592: The thunderstorm's further growth. The downdraft hitting the ground creates an outflow boundary . This can cause downbursts, a potential hazardous condition for aircraft to fly through, as a substantial change in wind speed and direction occurs, resulting in a decrease of airspeed and the subsequent reduction in lift for the aircraft. The stronger the outflow boundary is, the stronger the resultant vertical wind shear becomes. There are four main types of thunderstorms: single-cell, multi-cell, squall line (also called multi-cell line) and supercell. Which type forms depends on

24786-453: The tropics and subtropics can be responsible for the development of hurricanes . Dry thunderstorms , with no precipitation, can cause the outbreak of wildfires from the heat generated from the cloud-to-ground lightning that accompanies them. Several means are used to study thunderstorms: weather radar , weather stations , and video photography. Past civilizations held various myths concerning thunderstorms and their development as late as

24948-437: The tropics—and becomes progressively less useful in areas where stratiform (layered) precipitation dominates, especially in mid- and high-latitude regions. The more-direct physical connection between hydrometeors and microwave channels gives the microwave estimates greater skill on short time and space scales than is true for IR. However, microwave sensors fly only on low Earth orbit satellites, and there are few enough of them that

25110-552: The updraft is strong enough, the droplets are held aloft long enough to become so large that they do not melt completely but fall as hail . While updrafts are still present, the falling rain drags the surrounding air with it, creating downdrafts as well. The simultaneous presence of both an updraft and a downdraft marks the mature stage of the storm and produces cumulonimbus clouds. During this stage, considerable internal turbulence can occur, which manifests as strong winds, severe lightning, and even tornadoes . Typically, if there

25272-464: The various monsoon seasons around the globe, and they populate the rainbands of tropical cyclones . 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

25434-539: The warm season between spring and fall. More intense systems form over land than over water. One exception is that of lake-effect snow bands, which form due to cold air moving across relatively warm bodies of water, and occurs from fall through spring. Polar lows are a second special class of MCS. They form at high latitudes during the cold season. Once the parent MCS dies, later thunderstorm development can occur in connection with its remnant mesoscale convective vortex (MCV). Mesoscale convective systems are important to

25596-405: The water surface and the air above. Because of this temperature difference, warmth and moisture are transported upward, condensing into vertically oriented clouds (see satellite picture) which produce snow showers. The temperature decrease with height and cloud depth are directly affected by both the water temperature and the large-scale environment. The stronger the temperature decrease with height,

25758-454: The water vapor condenses into liquid, latent heat is released, which warms the air, causing it to become less dense than the surrounding, drier air. The air tends to rise in an updraft through the process of convection (hence the term convective precipitation ). This process creates a low-pressure zone within and beneath the forming thunderstorm. In a typical thunderstorm, approximately 500 million kilograms of water vapor are lifted into

25920-447: The westerlies steer from west to east. Most summer rainfall occurs during thunderstorms and from occasional tropical cyclones. Humid subtropical climates lie on the east side continents, roughly between latitudes 20° and 40° degrees from the equator. An oceanic (or maritime) climate is typically found along the west coasts at the middle latitudes of all the world's continents, bordering cool oceans, as well as southeastern Australia, and

26082-456: The wet season. Animals have adaptation and survival strategies for the wetter regime. The previous dry season leads to food shortages into the wet season, as the crops have yet to mature. Developing countries have noted that their populations show seasonal weight fluctuations due to food shortages seen before the first harvest, which occurs late in the wet season. Thunderstorm A thunderstorm , also known as an electrical storm or

26244-438: The worst storm expected in any single year. The term 1 in 100 year storm describes a rainfall event which is extremely rare and which will occur with a likelihood of only once in a century, so has a 1 percent likelihood in any given year. The rainfall will be extreme and flooding to be worse than a 1 in 10 year event. As with all probability events, it is possible though unlikely to have two "1 in 100 Year Storms" in

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