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.
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 airborne 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.
Haboobs have been observed in the Sahara, Sahel (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, and Kuwait are frequently created by the collapse of a thunderstorm.
African haboobs result from the northward summer shift of the Intertropical Convergence Zone into North Africa, bringing moisture from the Gulf of Guinea.
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.
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 storms on 11 November 1911, 9–11 May 1934, 14 April 1935, and 19 February 1954 having been 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, eastern California, and Texas. They also sometimes occur in the Columbia Basin of Eastern Washington, almost always leading to an impact on the city of Spokane. If these 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.
Dust storms of Titan observed in 2009 and 2010 have been compared to haboobs.However, the convective storm clouds are composed of liquid methane droplets, and the dust is likely composed of organic tholins.
A dust storm, also called a 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.
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.
Sherwood B. Idso is the president of the Center for the Study of Carbon Dioxide and Global Change, which rejects the scientific consensus on climate change. Previously he was a Research Physicist with the U.S. Department of Agriculture's Agricultural Research Service at the U.S. Water Conservation Laboratory in Phoenix, Arizona, where he worked since June 1967. He was also closely associated with Arizona State University over most of this period, serving as an Adjunct Professor in the Departments of Geology, Geography, and Botany and Microbiology. His two sons, Craig and Keith, are, respectively, the founder and vice president of the Center for the Study of Carbon Dioxide and Global Change.
Sir Gilbert Thomas Walker was an English physicist and statistician of the 20th century. Walker studied mathematics and applied it to a variety of fields including aerodynamics, electromagnetism and the analysis of time-series data before taking up a teaching position at the University of Cambridge. Although he had no experience in meteorology, he was recruited for a post in the Indian Meteorological Department where he worked on statistical approaches to predict the monsoons. He developed the methods in the analysis of time-series data that are now called the Yule-Walker equations. He is known for his groundbreaking description of the Southern Oscillation, a major phenomenon of global climate, and for discovering what is named after him as the Walker circulation, and for greatly advancing the study of climate in general. He was also instrumental in aiding the early career of the Indian mathematical prodigy, Srinivasa Ramanujan.
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 or within 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 is an instrument proposed as a method for predicting weather. It consists 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.
A sting jet is a meteorological phenomenon which has been postulated to cause some of the most damaging winds in extratropical cyclones, developing according to the Shapiro-Keyser model of oceanic cyclones.
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 where most 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 Braer Storm 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 from 28 to 30 October 2000. The storm was the fiercest to hit Britain in October since the Great Storm of 1987, with wind gusts reaching 109 mph (175 km/h), and gusting at up to 70 mph (110 km/h) over much of the south of England. Its barometric pressure fell to 941 hPa (27.8 inHg), 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 (28.09 inHg) at RAF Fylingdales. The storm contributed to the 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 northwestern Europe, causing thunderstorms. This meteorological pattern can lead to extreme high temperatures and intense rainfall during the summer months, with potential for flash flooding, damaging hail, and tornado formation. Some of these intense thunderstorms are formed from thermal lows, which 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.
John Sidney Adcock Green (1931–2012) was a British meteorologist.
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.