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Storm Cell
A storm cell is an air mass that contains up and down vertical draft, drafts in convective loops and that moves and reacts as a single entity, functioning as the smallest unit of a storm-producing system. An organized grouping of thunder clouds will thus be considered as a series of storm cells with their up/downdrafts being independent or interfering one with the other. Characteristics A storm cell can extend over an area the size of a few tens of square miles/kilometers and last 30 minutes or so. When the updraft and the environmental wind shear is well coordinated, the size and the duration of the cell can be much greater leading to a supercell. Finally, storm cells can form on the Outflow (meteorology), outflow of previous cells leading to multicellular thunderstorms or mesoscale convective systems. Slow motion of these more intense storm cells or groups of cells can produce large precipitation accumulations and flash flood, or other dangerous phenomena like hail and tornadoes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Storm Cell Over Aegina Greece Sept 2015 04
A storm is any disturbed state of the natural environment or the atmosphere of an astronomical body. It may be marked by significant disruptions to normal conditions such as strong wind, tornadoes, hail, thunder and lightning (a thunderstorm), heavy precipitation (snowstorm, rainstorm), heavy freezing rain (ice storm), strong winds (tropical cyclone, windstorm), wind transporting some substance through the atmosphere such as in a dust storm, among other forms of severe weather. Storms have the potential to harm lives and property via storm surge, heavy rain or snow causing flooding or road impassibility, lightning, wildfires, and vertical and horizontal wind shear. Systems with significant rainfall and duration help alleviate drought in places they move through. Heavy snowfall can allow special recreational activities to take place which would not be possible otherwise, such as skiing and snowmobiling. The English word comes from Proto-Germanic ''*sturmaz'' meaning "noise, tu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Meteorological Society
The American Meteorological Society (AMS) is a scientific and professional organization in the United States promoting and disseminating information about the atmospheric, oceanic, and hydrologic sciences. Its mission is to advance the atmospheric and related sciences, technologies, specifications, applications and services for the benefit of society. Background Founded on December 29, 1919, by Charles F. Brooks, at a meeting of the American Association for the Advancement of Science in St. Louis, and incorporated on January 21, 1920, the American Meteorological Society has a membership of more than 13,000 weather, water, and climate scientists, professionals, researchers, educators, students, and enthusiasts. AMS publishes 12 atmospheric and related oceanic and hydrologic journals (in print and online), sponsors as many as twelve conferences annually, and administers professional certification programs and awards. The AMS Policy and Education programs promote scientific kn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multicellular Thunderstorm
A multicellular thunderstorm cluster is a thunderstorm that is composed of multiple convective cells, each being at a different stage in the life cycle of a thunderstorm. It appears as several anvils clustered together. A cell is an updraft/downdraft couplet. These different cells will dissipate as new cells form and continue the life of the multicellular thunderstorm cluster with each cell taking a turn as the dominant cell in the group. Description The formation of multicellular thunderstorms imply that the updraft in the mother thunderstorm is offset from its downdraft. New cells usually form in the upwind (usually western or southwestern) part of the storm where the downdrafts of the mature cells meet the environmental wind, lifting air parcels and triggering new convection. The mature cells are thus usually in the center of the storm, and dissipating cells are usually in the downwind (usually eastern or northeastern) part of the storm. Characteristics The multicellular ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supercell
A supercell is a thunderstorm characterized by the presence of a mesocyclone, a deep, persistently rotating updraft. Due to this, these storms are sometimes referred to as rotating thunderstorms. Of the four classifications of thunderstorms (supercell, squall line, multi-cell, and single-cell), supercells are the overall least common and have the potential to be the most severe. Supercells are often isolated from other thunderstorms, and can dominate the local weather up to away. They tend to last 2–4 hours. Supercells are often put into three classification types: classic (normal precipitation level), low-precipitation (LP), and high-precipitation (HP). LP supercells are usually found in climates that are more arid, such as the high plains of the United States, and HP supercells are most often found in moist climates. Supercells can occur anywhere in the world under the right pre-existing weather conditions, but they are most common in the Great Plains of the United State ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulse Storm
A pulse storm is a single cell thunderstorm of substantial intensity which only produces severe weather for short periods of time. Such a storm weakens and then generates another short burst – hence "pulse". The term was coined by researchers at the National Severe Storms Laboratory in 1979 to describe a single storm cell briefly becoming severe within a cluster of multi-cellular thunderstorms, but has since been used to describe a variety of isolated and brief thunderstorms with both severe and non-severe characteristics. __TOC__ Description Single cell thunderstorms ordinarily form in environments with low wind shear and moderate instability, with the low wind shear contributing to a short average lifespan of less than an hour. When the instability, calculated by convective available potential energy (CAPE), is strong, the updraft will bring a larger amount of humid air very high above ground and generate a cumulonimbus cloud with high water and ice content. When the rain con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Outflow Boundary
An outflow boundary, also known as a gust front, is a storm-scale or mesoscale meteorology, mesoscale boundary separating thunderstorm-cooled air (Outflow (meteorology), 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 (cold front, dry line, another outflow boundary, etc.). 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. Outflow boundaries create low-level wind shear which can be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shower (precipitation)
A shower is a mode of precipitation characterized by an abrupt start and end, and by rapid variations in intensity. Often strong and short-lived, it comes from Atmospheric convection, convective clouds, like Cumulus congestus cloud, cumulus congestus. A shower will produce rain if the temperature is above the freezing point in the cloud, or snow / ice pellets / snow pellets / hail if the temperature is below it at some point. In a meteorological observation, such as the METAR, they are noted SH giving respectively SHRA, SHSN, SHPL, SHGS and SHGR. Formation Convection occurs when the Earth's surface, especially within a conditionally unstable or moist atmosphere, becomes heated more than its surroundings and in turn leads to significant evaporation. The raised air parcel in a colder environment at altitude will cool, according to the adiabatic thermal gradient, forming clouds, and later precipitation above the lifted condensation level (LCL). Depending on the convective available ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thunder
Thunder is the sound caused by lightning. Depending upon the distance from and nature of the lightning, it can range from a long, low rumble to a sudden, loud crack. The sudden increase in temperature and hence pressure caused by the lightning produces rapid Thermal expansion, expansion of the air in the path of a Lightning strike, lightning bolt. In turn, this expansion of air creates a Shock wave, sonic shock wave, often referred to as a "thunderclap" or "peal of thunder". The scientific study of thunder is known as ''brontology'' and the irrational fear (phobia) of thunder is called ''brontophobia''. Etymology The ''d'' in Modern English ''thunder'' (from earlier Old English ''þunor'') is epenthetic, and is now found as well in Modern Dutch ''donder'' (cf. Middle Dutch ''donre''; also Old Norse ''þorr'', Old Frisian ''þuner'', Old High German ''donar'', all ultimately descended from Proto-Germanic *''þunraz''). In Latin the term was ''tonare'' "to thunder". The name of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lightning
Lightning is a natural phenomenon consisting of electrostatic discharges occurring through the atmosphere between two electrically charged regions. One or both regions are within the atmosphere, with the second region sometimes occurring on the land, ground. Following the lightning, the regions become partially or wholly electrically neutralized. Lightning involves a near-instantaneous release of energy on a scale averaging between 200 megajoules and 7 gigajoules. The air around the lightning flash rapidly heats to temperatures of about . There is an emission of electromagnetic radiation across a wide range of wavelengths, some visible as a bright flash. Lightning also causes thunder, a sound from the shock wave which develops as heated gases in the vicinity of the discharge experience a sudden increase in pressure. The most common occurrence of a lightning event is known as a thunderstorm, though they can also commonly occur in other types of energetic weather systems, such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cumulonimbus
Cumulonimbus () is a dense, towering, vertical cloud, typically forming from water vapor condensing in the lower troposphere that builds upward carried by powerful buoyant air currents. Above the lower portions of the cumulonimbus the water vapor becomes ice crystals, such as snow and graupel, the interaction of which can lead to hail and to lightning formation, respectively. When causing thunderstorms, these clouds may be called thunderheads. Cumulonimbus can form alone, in clusters, or along squall lines. These clouds are capable of producing lightning and other dangerous severe weather, such as tornadoes, hazardous winds, and large hailstones. Cumulonimbus progress from overdeveloped cumulus congestus clouds and may further develop as part of a supercell. Cumulonimbus is abbreviated as Cb. Description Towering cumulonimbus clouds are typically accompanied by smaller cumulus clouds. The cumulonimbus base may extend several kilometres (miles) across, or be as small as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cumulus Congestus
Cumulus congestus or towering cumulus clouds are a species of cumulus that can be based in the low- to middle-height ranges. They achieve considerable vertical development in areas of deep, moist convection. They are an intermediate stage between cumulus mediocris and cumulonimbus, sometimes producing rainshowers, snow, or ice pellets. Precipitation that evaporates before reaching the surface is virga. Description Cumulus congestus clouds are characteristic of unstable regions of atmosphere that are undergoing convection. They are often characterized by sharp outlines and great vertical development. Since strong updrafts produce (and primarily compose) them, the clouds are typically taller than they are wide; cloud tops can reach , or higher in the tropics. Cumulus congestus clouds are formed by the development of cumulus mediocris generally, though they can also be formed from altocumulus castellanus or stratocumulus castellanus, which are forms of cumulus castellanus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Météo-France
Météo-France is the official French meteorological administration, also offering services to Andorra and Monaco. It has the powers of the state and can exercise them in relation to meteorology. Météo-France is in charge of observing, studying, and forecasting weather and monitoring snowpack. The organization also issues weather warnings for the Metropole and the overseas territories. Météo-France is also in charge of recording and predicting the climate. Organisation The organisation was established by decree in June 1993 and is a department of the Ministry of Transportation. It is headquartered in Paris but many domestic operations have been decentralised to Toulouse. Its budget of around €300 million is funded by state grants, aeronautic royalties and sale of commercial services. Météo-France has a particularly strong international presence, and is the French representative at the World Meteorological Organization. The organisation is a leading member of EUM ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
