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A haboob (Arabic : هَبوب, romanized: habūb, lit. 'blasting/drifting') is a type of intense dust storm carried on an atmospheric gravity current, also known as a weather front. Haboobs occur regularly in dry land area regions throughout the world.
The romanization of Arabic writes written and spoken Arabic in the Latin script in one of various systematic ways. Romanized Arabic is used for a number of different purposes, among them transcription of names and titles, cataloging Arabic language works, language education when used in lieu of or alongside the Arabic script, and representation of the language in scientific publications by linguists. These formal systems, which often make use of diacritics and non-standard Latin characters and are used in academic settings or for the benefit of non-speakers, contrast with informal means of written communication used by speakers such as the Latin-based Arabic chat alphabet.
Literal translation, direct translation, or word-for-word translation is a translation of a text done by translating each word separately, without looking at how the words are used together in a phrase or sentence.
A dust storm, also called sandstorm, is a meteorological phenomenon common in arid and semi-arid regions. Dust storms arise when a gust front or other strong wind blows loose sand and dirt from a dry surface. Fine particles are transported by saltation and suspension, a process that moves soil from one place and deposits it in another.
During thunderstorm formation, winds move in a direction opposite to the storm's travel, and they move from all directions into the thunderstorm. When the storm collapses and begins to release precipitation, wind directions reverse, gusting outward from the storm and generally gusting the strongest in the direction of the storm's travel.
When this downdraft of cold air, or downburst, reaches the ground, it blows dry, loose silt and clay (collectively, dust) up from the desert, creating a wall of sediment that precedes the storm cloud. This wall of dust can be up to 100 km (62 mi) wide and several kilometers in elevation. At their strongest, haboob winds often travel at 35–100 km/h (22–62 mph), and they may approach with little or no warning. Often rain does not appear at ground level as it evaporates in the hot, dry air (a phenomenon known as virga). The evaporation cools the rushing air even further and accelerates it. Occasionally, when the rain does persist, it can contain a considerable quantity of dust. Severe cases are called mud storms. Eye and respiratory system protection is advisable for anyone who must be outside during a haboob. Moving to shelter is highly advised during a strong event.
A downburst is a strong ground-level wind system that emanates from a point source above and blows radially, that is, in straight lines in all directions from the point of contact at ground level. Often producing damaging winds, it may be confused with a tornado, where high-velocity winds circle a central area, and air moves inward and upward; by contrast, in a downburst, winds are directed downward and then outward from the surface landing point.
In meteorology, a virga is an observable streak or shaft of precipitation falling from a cloud that evaporates or sublimates before reaching the ground. A shaft of precipitation that does not evaporate before reaching the ground is a precipitation shaft. At high altitudes the precipitation falls mainly as ice crystals before melting and finally evaporating; this is often due to compressional heating, because the air pressure increases closer to the ground. It is very common in deserts and temperate climates. In North America, it is commonly seen in the Western United States and the Canadian Prairies. It is also very common in the Middle East, Australia, and North Africa.
Haboobs have been observed in the Sahara desert (typically Sudan, where they were named and described), as well as across the Arabian Peninsula, throughout Kuwait, and in the most arid regions of Iraq.Haboob winds in the Arabian Peninsula, Iraq, Kuwait are frequently created by the collapse of a thunderstorm.
Sudan or the Sudan, officially the Republic of the Sudan, is a country in Northeast Africa. It is bordered by Egypt to the north, the Red Sea to the northeast, Eritrea to the east, Ethiopia to the southeast, South Sudan to the south, the Central African Republic to the southwest, Chad to the west, and Libya to the northwest. It has a population of 43 million people and occupies a total area of 1,886,068 square kilometres, making it the third-largest country in Africa. Sudan's predominant religion is Islam, and its official languages are Arabic and English. The capital is Khartoum, located at the confluence of the Blue and White Nile. Since 2011, Sudan is the scene of ongoing military conflict in its regions South Kordofan and the Blue Nile.
The Arabian Peninsula, or simply Arabia, is a peninsula of Western Asia situated northeast of Africa on the Arabian plate. From a geographical perspective, it is considered a subcontinent of Asia.
Kuwait, officially the State of Kuwait, is a country in Western Asia. Situated in the northern edge of Eastern Arabia at the tip of the Persian Gulf, it shares borders with Iraq and Saudi Arabia. As of 2016, Kuwait has a population of 4.5 million people: 1.3 million are Kuwaitis and 3.2 million are expatriates. Expatriates account for 70% of the population.
African haboobs result from the northward summer shift of the inter-tropical front into North Africa, bringing moisture from the Gulf of Guinea.
North Africa is a region encompassing the northern portion of the African continent. There is no singularly accepted scope for the region, and it is sometimes defined as stretching from the Atlantic shores of Mauritania in the west, to Egypt's Suez Canal and the Red Sea in the east. Others have limited it to the countries of Algeria, Morocco, and Tunisia, a region that was known by the French during colonial times as "Afrique du Nord" and is known by Arabs as the Maghreb. The most commonly accepted definition includes Morocco, Algeria, Tunisia, Libya, Egypt, and Sudan, the 6 countries that shape the top North of the African continent. Meanwhile, "North Africa", particularly when used in the term North Africa and the Middle East, often refers only to the countries of the Maghreb and Libya. Egypt, being also part of the Middle East, is often considered separately, due to being both North African and Middle Eastern at the same time.
The Gulf of Guinea is the northeasternmost part of the tropical Atlantic Ocean between Cape Lopez in Gabon, north and west to Cape Palmas in Liberia. The intersection of the Equator and Prime Meridian is in the gulf.
Haboobs in Australia may be frequently associated with cold fronts. The deserts of Central Australia, especially near Alice Springs, are particularly prone to haboobs, with sand and debris reaching several kilometers into the sky and leaving up to 30 centimetres (1 ft) of sand in the haboob's path.
A cold front is the leading edge of a cooler mass of air, replacing at ground level a warmer mass of air, which lies within a fairly sharp surface trough of low pressure. It forms in the wake of an extratropical cyclone, at the leading edge of its cold air advection pattern, which is also known as the cyclone's dry conveyor belt circulation. Temperature differences across the boundary can exceed 30 °C (54 °F) from one side to the other. When enough moisture is present, rain can occur along the boundary. If there is significant instability along the boundary, a narrow line of thunderstorms can form along the frontal zone. If instability is less, a broad shield of rain can move in behind the front, which increases the temperature difference across the boundary. Cold fronts are stronger in the fall and spring transition seasons and weakest during the summer.
Central Australia, also known as the Alice Springs Region, is one of the five regions in the Northern Territory of Australia. The term Central Australia is used to describe an area centred on Alice Springs. It is sometimes referred to as Centralia; likewise the people of the area are sometimes called Centralians. The region is located in the southern part of the Northern Territory spanning from the west on the Western Australian Border to the east on the Queensland border.
Alice Springs is the third-largest town in the Northern Territory of Australia. Known as Stuart until 31 August 1933, the name Alice Springs was given by surveyor William Whitfield Mills after Alice, Lady Todd, wife of the telegraph pioneer Sir Charles Todd. Now colloquially known as The Alice or simply Alice, the town is situated roughly in Australia's geographic centre. It is nearly equidistant from Adelaide and Darwin.
As with haboobs in the Middle East, haboob occurrences in North America are often created by the collapse of a thunderstorm. This is a local or mesoscale event, and at times of extreme drought they can originate in agricultural regions. Some of the most famous dust storms of the Dust Bowl and similar conditions later were in fact synoptic scale events typically generated by a strong cold frontal passage, with 14 April 1935, 9–11 May 1934, 19 February 1954, and 11 November 1911 being particularly vivid examples.
The arid and semiarid regions of North America—in fact, any dry region—may experience haboobs. In North America, the most common terms for these events are either dust storm or sandstorm. In the U.S., they frequently occur in the deserts of Arizona, including around the cities of Yuma and Phoenix;in New Mexico, including Albuquerque; in eastern California, and in Texas. They also sometimes occur in the Columbia Basin, of Eastern Washington, almost always leading to an impact with the city of Spokane. If the storms are strong enough, they can reach as far east as Post Falls and Moscow, in North Idaho.
Global dust storms on Mars have been compared to haboobs on Earth.
A dry line is a line across a continent that separates moist air and dry air. One of the most prominent examples of such a separation occurs in central North America, especially Texas, Oklahoma, and Kansas, where the moist air from the Gulf of Mexico meets dry air from the desert south-western states. The dry line is an important factor in severe weather frequency in the Great Plains of North America. It typically lies north-south across the High Plains states in the warm sector of an extratropical cyclone and stretches into the Canadian Prairies during the spring and early summer. The dry line is also important for severe convective storms in other regions of the world, such as northern India. In general, thunderstorms and other forms of severe weather occur on the moist side of the dryline.
The Burns' Day Storm was an extremely violent windstorm that took place on 25–26 January 1990 over north-western Europe. It is one of the strongest European windstorms on record. This storm has received different names as there is no official list of such events in Europe. Starting on the birthday of Scottish poet Robert Burns, it caused widespread damage and hurricane-force winds over a wide area. The storm was responsible for 47 deaths, although figures have ranged from 89 to over 100.
An outflow boundary, also known as a gust front, is a storm-scale or mesoscale boundary separating thunderstorm-cooled air (outflow) from the surrounding air; similar in effect to a cold front, with passage marked by a wind shift and usually a drop in temperature and a related pressure jump. Outflow boundaries can persist for 24 hours or more after the thunderstorms that generated them dissipate, and can travel hundreds of kilometers from their area of origin. New thunderstorms often develop along outflow boundaries, especially near the point of intersection with another boundary. Outflow boundaries can be seen either as fine lines on weather radar imagery or else as arcs of low clouds on weather satellite imagery. From the ground, outflow boundaries can be co-located with the appearance of roll clouds and shelf clouds.
Keith Anthony Browning is a British meteorologist who worked at Imperial College London, the Met Office, and the University of Reading departments of meteorology. His work with Frank Ludlam on the supercell thunderstorm at Wokingham, UK in 1962 was the first detailed study of such a storm. His well regarded research covered many areas of mesoscale meteorology including developing the theory of the sting jet. Arguably his greatest talent is his intuitive understanding of complex three-dimensional meteorological processes which he has described more simply using conceptual models.
Ensemble forecasting is a method used in numerical weather prediction. Instead of making a single forecast of the most likely weather, a set of forecasts is produced. This set of forecasts aims to give an indication of the range of possible future states of the atmosphere. Ensemble forecasting is a form of Monte Carlo analysis. The multiple simulations are conducted to account for the two usual sources of uncertainty in forecast models: (1) the errors introduced by the use of imperfect initial conditions, amplified by the chaotic nature of the evolution equations of the atmosphere, which is often referred to as sensitive dependence on initial conditions; and (2) errors introduced because of imperfections in the model formulation, such as the approximate mathematical methods to solve the equations. Ideally, the verified future atmospheric state should fall within the predicted ensemble spread, and the amount of spread should be related to the uncertainty (error) of the forecast. In general, this approach can be used to make probabilistic forecasts of any dynamical system, and not just for weather prediction.
The Lemon technique is a method used by meteorologists using weather radar to determine the relative strength of thunderstorm cells in a vertically sheared environment. It is named for Leslie R. Lemon, the co-creator of the current conceptual model of a supercell. The Lemon technique is largely a continuation of work by Keith A. Browning, who first identified and named the supercell.
The storm glass or chemical weather glass was an instrument which was proposed as a method for predicting weather. It consisted of a special liquid placed inside a sealed transparent glass. The state of crystallization within the liquid was believed to be related to the weather. The inventor is unknown but the device became popular in the 1860s after being promoted by Admiral Robert FitzRoy who claimed that
if fixed, undisturbed, in free air, not exposed to radiation, fire, or sun, but in the ordinary light of a well-ventilated room or outer air, the chemical mixture in a so-called storm-glass varies in character with the direction of the wind, not its force, specially from another cause, electrical tension.
Outflow, in meteorology, is air that flows outwards from a storm system. It is associated with ridging, or anticyclonic flow. In the low levels of the troposphere, outflow radiates from thunderstorms in the form of a wedge of rain-cooled air, which is visible as a thin rope-like cloud on weather satellite imagery or a fine line on weather radar imagery. Low-level outflow boundaries can disrupt the center of small tropical cyclones. However, outflow aloft is essential for the strengthening of a tropical cyclone. If this outflow is undercut, the tropical cyclone weakens. If two tropical cyclones are in proximity, the upper level outflow from the system to the west can limit the development of the system to the east.
The Great Flood of 1968 was a flood caused by a pronounced trough of low pressure which brought exceptionally heavy rain and thunderstorms to South East England and France in mid-September 1968, with the worst on Sunday 15 September 1968, and followed earlier floods in South West England during July. This was likely the severest inland flood experienced in the Home Counties during the last 100 years.
A dry thunderstorm is a thunderstorm that produces thunder and lightning, but most or all of its precipitation evaporates before reaching the ground. Dry lightning refers to lightning strikes occurring in this situation. Both are so common in the American West that they are sometimes used interchangeably. The latter term is a technical misnomer since lightning itself is neither wet nor dry.
The Braer Storm of January 1993 was the most intense extratropical cyclone ever recorded over the northern Atlantic Ocean. Developing as a weak frontal wave on 8 January 1993, the system moved rapidly northeast. The combination of the absorption of a second low-pressure area to its southeast, a stronger than normal sea surface temperature differential along its path, and the presence of a strong jet stream aloft led to a rapid strengthening of the storm, with its central pressure falling to an estimated 914 hPa on 10 January. Its strength was well predicted by forecasters in the United Kingdom, and warnings were issued before the low initially developed.
Cyclone Oratia, was an unusually deep European windstorm which affected Western Europe early in the year for a storm of this type. The storm was the fiercest to hit Britain in October since the Great Storm of 1987, with wind gusts reaching 109 mph, and gusting at up to 90 mph over much of the south of England. Its barometric pressure fell to 941 hPa, over the North Sea making it one of the deepest lows recorded in the country in October. The lowest land-based pressure observation reached 951.2 hPa at RAF Fylingdales, which is not lower than the UK record October value of 946.8 hPa observed at Cawdor Castle on 14 October 1981. Three tornadoes were reported from this storm. The storm contributed to the ongoing Autumn 2000 western Europe floods.
The Spanish Plume is a weather pattern in which a plume of warm air moves from the Iberian plateau or the Sahara to northwest Europe giving rise to severe thunderstorms. This meteorological pattern can lead to extreme high temperatures and intense rainfall during the summer months, with potential for flash flooding, damaging hail storms, and tornado formation. Some of these intense thunderstorms are formed from thermal lows. Thermal lows are also known as heat lows. Thermal lows can be semipermanent features around some parts of Europe, particularly in the summer season. These thermal lows can be developed or created around Spain, Portugal, France etc., during the summer season because of the intense heat. Thermal low pressure can be located around the world, particularly in the summer or in tropical regions.
Norman A. Phillips was an American meteorologist notable for his contributions to geophysical fluid dynamics. In 1956, he developed a mathematical model that could realistically depict monthly and seasonal patterns in the troposphere, which became the first successful general circulation model of climate.
Crown flash is a rarely observed weather phenomenon involving "The brightening of a thunderhead crown followed by the appearance of aurora-like streamers emanating into the clear atmosphere". The current hypothesis for why the phenomenon occurs is that sunlight is reflecting off or refracting through tiny ice crystals above the crown of a cumulonimbus cloud. These ice crystals are aligned by the strong electro-magnetic effects around the cloud, so the effect may appear as a tall streamer, pillar of light, or resemble a massive flash of a searchlight / flashlight beam through the clouds. When the electro-magnetic field is disturbed by electrical charging or discharges within the cloud, the ice crystals are re-orientated causing the light pattern to shift, at times very rapidly and appearing to 'dance' in a strikingly mechanical fashion. The effect may also sometimes be known as a "leaping sundog". As with sundogs, the observer would have to be in a specific position to see the effect, which is not a self-generated light such as seen in a lightning strike or aurora, but rather a changing reflection/refraction of the sunlight.
Professor John Alan Chalmers was a British atmospheric physicist based at Durham University. He is well known for his contributions to atmospheric electricity, particularly an internationally-respected textbook, and, outside his scientific work, for his involvement with Scouting. This led to him being widely known to his colleagues by the nickname, "Skip", a commonly used term for the leader of a Scout troop.
Mavis Kathleen Hinds (1929–2009) was an English meteorologist who, together with Fred Bushby, pioneered the use of computers to carry out meteorological calculations in the UK. She studied Mathematics at University College London (UCL) and on graduating joined the UK Meteorological (Met) Office in 1951, attending their Initial Forecasting Course that year. She went on to work with Bushby in using the Lyons Electronic Office (LEO), an early computer developed by J. Lyons & Co of Cadby Hall, London, becoming an expert in writing, running and correcting computer programs for weather forecasting. She was seen at that time as one of the first prominent female meteorologists and also the first to play a leading role in the development of Numerical Weather Prediction, not only in the UK but also worldwide.
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