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Pressure system

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	Pressure system
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	Topics Pressure system Topic Home A pressure system is a region of the Earth's atmosphereEarth's atmosphere Earth's atmosphere is a layer of gases surrounding the planet Earth and retained by the Earth's gravity.... where air pressureAtmospheric pressure Atmospheric pressure is the pressure above any area in the Earth's atmosphere caused by the weight of air.... is unusually high or low. High and low pressures develop (and dissipate) constantly due to thermodynamic interactions of temperature differentials in the atmosphere and waterWater Water is a tasteless, odorless substance that is essential to all known forms of life and is known as the universal solve... in oceans, lakes, and other bodies of water. Pressure systems on weather maps On weather maps, which often display weather frontWeather front A weather front is a boundary separating two masses of air of different densities, and is the principal cause of meteorologi... s and pressure systems graphically, low-pressure systems are depicted with a capital L, unless they are tropical storms or tropical cycloneTropical cyclone In meteorology, a tropical cyclone is a storm system fueled by the heat released when moist air rises and condenses.... s (in which case the symbols for those weather systems are used). High-pressure systems are depicted with an H. The steepness of the pressure gradientGradient A generalization of these concepts is the gradient in vector calculus; and this article is mostly about this vector gradient... can be observed according to the density of isobarIsobar The word derives from the two ancient Greek words, ?s??, meaning 'equal', and a???, meaning 'weight'.... s, or lines on the map at which pressure is equal. Low pressure system CyclonicCyclone In meteorology, a cyclone is the rotation of a volume of air around an area of low atmospheric pressure.... properties: in the northern hemisphereNorthern Hemisphere The Northern Hemisphere is the half of a planet's surface that is north of the equator .... , winds around the system move counterclockwise, and in the southern hemisphereSouthern Hemisphere The Southern Hemisphere is the half of a planet's surface that is south of the equator.... they move clockwise. Low pressure systems, additionally, often become junctures of fronts. Most of history's most powerful storms, such as the 1993 North American storm complex1993 North American storm complex Summary The 1993 North American storm complex, also known as the 93 Superstorm, the Blizzard of 1993, or the Storm of... and all tropical cyclones, have been low-pressure cyclonic systems. TornadoTornado A tornado is a violently rotating column of air which is in contact with both a cumulonimbus cloud base and the surface of ... es invariantly have very strong local low-pressure systems at their vorticesVortex A vortex is a spinning, often turbulent, flow with closed streamlines.... . Low pressure sytems are generally warm due to the fact the warm air rises making the system it is on having low pressure. Which is generally the reason for storms and Tropical cyclones. The lowest recorded non-tornadic barometric pressure was 869.96 millibars (25.69 inches of mercury), occurred in the Western Pacific during Typhoon Tip on 12 October, 1979. High-pressure system High pressure systems are associated with clear, cool weather. Around high-pressure systems, winds flow clockwise in the northern hemisphere, counterclockwise in the southern hemisphere. In the northern winterWinter Winter is one of the four seasons of temperate zones.... , high-pressure systems (called Canadian highs or Arctic air masses) often migrate to midlatitude regions such as the North AmericaNorth America North America is a continent in the Earth's northern hemisphere and almost fully in the western hemisphere.... n upper MidwestUpper Midwest The Upper Midwest is a region of the United States with no universally agreed-upon boundary, but it almost always lies withi... , New EnglandNew England New England is a region of the United States located in the northeastern corner of the country.... , and northern EuropeEurope Summary Europe is one of the seven traditional continents of the Earth.... . These create cold snapCold snap Cold snap is used in two ways to describe climate:... s where unseasonably cold and sunny weather are observed. Cold snaps often follow winter warm spells, where temperatures may be as high as 10°C to 20°C (50-68 °F), and often happen suddenly. The most dramatic Arctic cold snaps, observed in the central regions of North AmericaNorth America North America is a continent in the Earth's northern hemisphere and almost fully in the western hemisphere.... involve temperature drops of 25°C (45°F) or more in a few hours. Arctic highs, alone, rarely trigger precipitation because of the cloudless weather they produce. However, in combination with other weather-making systems, the cold air they bring can produce massive snowstorms. High pressure usually means good weather.