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February 2009 Tornado Outbreak
The February 2009 North American storm complex occurred on February 10 and February 11, 2009, affecting portions of both the Central and Eastern United States. During the two-day period, 15 tornadoes touched down in seven states. Oklahoma was struck by six tornadoes, the most of any state. The first day of the outbreak produced the most tornadoes; the second brought mainly high wind damage and rain or snow in most of the Northeast. The storm system responsible for the tornado outbreak resulted from the unusual congruence of a cold, dry system, originating in the Four Corners and a warm, moist system, moving north out of Texas. Complicating factors included daytime heating and a strong wind field favorable to the creation of circulating thunderstorms. On the second day, the stronger cold front limited discrete supercell activity and the risk of tornadoes decreased significantly. A squall line, however, produced high winds and rain along the river valleys, primaril ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tornadoes Of 2009
This page documents notable tornadoes and tornado outbreaks worldwide in 2009. Strong and destructive tornadoes form most frequently in the United States, Argentina, Brazil, Bangladesh, and Eastern India, but can occur almost anywhere under the right conditions. Tornadoes also develop occasionally in southern Canada during the Northern Hemisphere's summer and somewhat regularly at other times of the year across Europe, Asia, Argentina, Australia and New Zealand. Tornadic events are often accompanied by other forms of severe weather, including strong thunderstorms, strong winds, and hail. In the U.S., there were 1,304 reports of tornadoes received by the Storm Prediction Center (SPC), and 1,159 tornadoes were confirmed to have taken place. Worldwide, 73 fatalities were caused by tornadoes; 22 in the United States, 20 in India, 11 in Argentina, eight in the Philippines, four each in Canada and Brazil, two in Greece and one each in Serbia and Russia. Tornadic activit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Massachusetts
Massachusetts (Massachusett: ''Muhsachuweesut Massachusett_writing_systems.html" ;"title="nowiki/> məhswatʃəwiːsət.html" ;"title="Massachusett writing systems">məhswatʃəwiːsət">Massachusett writing systems">məhswatʃəwiːsət'' English: , ), officially the Commonwealth of Massachusetts, is the most populous state in the New England region of the Northeastern United States. It borders on the Atlantic Ocean and Gulf of Maine to the east, Connecticut and Rhode Island to the south, New Hampshire and Vermont to the north, and New York to the west. The state's capital and most populous city, as well as its cultural and financial center, is Boston. Massachusetts is also home to the urban core of Greater Boston, the largest metropolitan area in New England and a region profoundly influential upon American history, academia, and the research economy. Originally dependent on agriculture, fishing, and trade. Massachusetts was transformed into a manufacturing center during t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hail
Hail is a form of solid precipitation. It is distinct from ice pellets (American English "sleet"), though the two are often confused. It consists of balls or irregular lumps of ice, each of which is called a hailstone. Ice pellets generally fall in cold weather, while hail growth is greatly inhibited during low surface temperatures. Unlike other forms of water ice precipitation, such as graupel (which is made of rime ice), ice pellets (which are smaller and translucent), and snow (which consists of tiny, delicately crystalline flakes or needles), hailstones usually measure between and in diameter. The METAR reporting code for hail or greater is GR, while smaller hailstones and graupel are coded GS. Hail is possible within most thunderstorms (as it is produced by cumulonimbus), as well as within of the parent storm. Hail formation requires environments of strong, upward motion of air within the parent thunderstorm (similar to tornadoes) and lowered heights of the freezing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wind Shear
Wind shear (or windshear), sometimes referred to as wind gradient, is a difference in wind speed and/or direction over a relatively short distance in the atmosphere. Atmospheric wind shear is normally described as either vertical or horizontal wind shear. Vertical wind shear is a change in wind speed or direction with a change in altitude. Horizontal wind shear is a change in wind speed with a change in lateral position for a given altitude. Wind shear is a microscale meteorological phenomenon occurring over a very small distance, but it can be associated with mesoscale or synoptic scale weather features such as squall lines and cold fronts. It is commonly observed near microbursts and downbursts caused by thunderstorms, fronts, areas of locally higher low-level winds referred to as low-level jets, near mountains, radiation inversions that occur due to clear skies and calm winds, buildings, wind turbines, and sailboats. Wind shear has significant effects on the control ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Troposphere
The troposphere is the first and lowest layer of the atmosphere of the Earth, and contains 75% of the total mass of the planetary atmosphere, 99% of the total mass of water vapour and aerosols, and is where most weather phenomena occur. From the planetary surface of the Earth, the average height of the troposphere is in the tropics; in the middle latitudes; and in the high latitudes of the polar regions The polar regions, also called the frigid zones or polar zones, of Earth are the regions of the planet that surround its geographical poles (the North and South Poles), lying within the polar circles. These high latitudes are dominated by floa ... in winter; thus the average height of the troposphere is . The term ''troposphere'' derives from the Greek words ''tropos'' (rotating) and '' sphaira'' (sphere) indicating that rotational turbulence mixes the layers of air and so determines the structure and the phenomena of the troposphere. The rotational friction of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmospheric Instability
Atmospheric instability is a condition where the Earth's atmosphere is generally considered to be unstable and as a result the weather is subjected to a high degree of variability through distance and time. Atmospheric stability is a measure of the atmosphere's tendency to discourage or deter vertical motion, and vertical motion is directly correlated to different types of weather systems and their severity. In unstable conditions, a lifted thing, such as a parcel of air will be warmer than the surrounding air at altitude. Because it is warmer, it is less dense and is prone to further ascent. In meteorology, instability can be described by various indices such as the Bulk Richardson Number, lifted index, K-index, convective available potential energy (CAPE), the Showalter, and the Vertical totals. These indices, as well as atmospheric instability itself, involve temperature changes through the troposphere with height, or lapse rate. Effects of atmospheric instability in mois ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planetary Boundary Layer
In meteorology, the planetary boundary layer (PBL), also known as the atmospheric boundary layer (ABL) or peplosphere, is the lowest part of the atmosphere and its behaviour is directly influenced by its contact with a planetary surface. On Earth it usually responds to changes in surface radiative forcing in an hour or less. In this layer physical quantities such as flow velocity, temperature, and moisture display rapid fluctuations (turbulence) and vertical mixing is strong. Above the PBL is the "free atmosphere", where the wind is approximately geostrophic (parallel to the isobars), while within the PBL the wind is affected by surface drag and turns across the isobars (see Ekman layer for more detail). Cause of surface wind gradient Typically, due to aerodynamic drag, there is a wind gradient in the wind flow ~100 meters above the Earth's surface—the surface layer of the planetary boundary layer. Wind speed increases with increasing height above the ground, starting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ozarks
The Ozarks, also known as the Ozark Mountains, Ozark Highlands or Ozark Plateau, is a physiographic region in the U.S. states of Missouri, Arkansas, Oklahoma and the extreme southeastern corner of Kansas. The Ozarks cover a significant portion of northern Arkansas and most of the southern half of Missouri, extending from Interstate 40 in central Arkansas to Interstate 70 in central Missouri. There are two mountain ranges in the Ozarks: the Boston Mountains of Arkansas and the St. Francois Mountains of Missouri. Buffalo Lookout, the highest point in the Ozarks, is located in the Boston Mountains. Geologically, the area is a broad dome with the exposed core in the ancient St. Francois Mountains. The Ozarks cover nearly , making it the most extensive highland region between the Appalachians and Rockies. Together with the Ouachita Mountains, the area is known as the U.S. Interior Highlands. The Salem Plateau, named after Salem, Missouri, makes up the largest geologic area o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Louisiana
Louisiana , group=pronunciation (French: ''La Louisiane'') is a state in the Deep South and South Central regions of the United States. It is the 20th-smallest by area and the 25th most populous of the 50 U.S. states. Louisiana is bordered by the state of Texas to the west, Arkansas to the north, Mississippi to the east, and the Gulf of Mexico to the south. A large part of its eastern boundary is demarcated by the Mississippi River. Louisiana is the only U.S. state with political subdivisions termed parishes, which are equivalent to counties, making it one of only two U.S. states not subdivided into counties (the other being Alaska and its boroughs). The state's capital is Baton Rouge, and its largest city is New Orleans, with a population of roughly 383,000 people. Some Louisiana urban environments have a multicultural, multilingual heritage, being so strongly influenced by a mixture of 18th century Louisiana French, Dominican Creole, Spanish, French Canadian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Air Mass
In meteorology, an air mass is a volume of air defined by its temperature and humidity. Air masses cover many hundreds or thousands of square miles, and adapt to the characteristics of the surface below them. They are classified according to latitude and their continental or maritime source regions. Colder air masses are termed polar or arctic, while warmer air masses are deemed tropical. Continental and superior air masses are dry, while maritime and monsoon air masses are moist. Weather fronts separate air masses with different density (temperature or moisture) characteristics. Once an air mass moves away from its source region, underlying vegetation and water bodies can quickly modify its character. Classification schemes tackle an air mass' characteristics, as well as modification. Classification and notation The Bergeron classification is the most widely accepted form of air mass classification, though others have produced more refined versions of this scheme over diffe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Great Plains
The Great Plains (french: Grandes Plaines), sometimes simply "the Plains", is a broad expanse of flatland in North America. It is located west of the Mississippi River and east of the Rocky Mountains, much of it covered in prairie, steppe, and grassland. It is the southern and main part of the Interior Plains, which also include the tallgrass prairie between the Great Lakes and Appalachian Plateau, and the Taiga Plains and Boreal Plains ecozones in Northern Canada. The term Western Plains is used to describe the ecoregion of the Great Plains, or alternatively the western portion of the Great Plains. The Great Plains lies across both Central United States and Western Canada, encompassing: * The entirety of the U.S. states of Kansas, Nebraska, North Dakota and South Dakota; * Parts of the U.S. states of Colorado, Iowa, Minnesota, Missouri, Montana, New Mexico, Oklahoma, Texas and Wyoming; * The southern portions of the Canadian provinces of Alberta, Saskatchewan and Man ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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