Hybrid low may refer to a number of different meteorological depressions:
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 | This disambiguation page lists articles associated with the title Hybrid low. If an internal link led you here, you may wish to change the link to point directly to the intended article. |
In meteorology, a cyclone (/ˈsaɪ.kloʊn/) is a large scale air mass that rotates around a strong center of low atmospheric pressure. Cyclones are characterized by inward spiraling winds that rotate about a zone of low pressure. The largest low-pressure systems are polar vortices and extratropical cyclones of the largest scale. Warm-core cyclones such as tropical cyclones and subtropical cyclones also lie within the synoptic scale. Mesocyclones, tornadoes, and dust devils lie within smaller mesoscale. Upper level cyclones can exist without the presence of a surface low, and can pinch off from the base of the tropical upper tropospheric trough during the summer months in the Northern Hemisphere. Cyclones have also been seen on extraterrestrial planets, such as Mars, Jupiter, and Neptune. Cyclogenesis is the process of cyclone formation and intensification. Extratropical cyclones begin as waves in large regions of enhanced mid-latitude temperature contrasts called baroclinic zones. These zones contract and form weather fronts as the cyclonic circulation closes and intensifies. Later in their life cycle, extratropical cyclones occlude as cold air masses undercut the warmer air and become cold core systems. A cyclone's track is guided over the course of its 2 to 6 day life cycle by the steering flow of the subtropical jet stream.
A subtropical cyclone is a weather system that has some characteristics of a tropical and an extratropical cyclone.
South Atlantic tropical cyclones are unusual weather events that occur in the Southern Hemisphere. Strong wind shear, which disrupts the formation of cyclones, as well as a lack of weather disturbances favorable for development in the South Atlantic Ocean, make any strong tropical system extremely rare, and Hurricane Catarina in 2004 is the only recorded South Atlantic hurricane in history. South Atlantic storms have developed year-round, with activity peaking during the months from November through May in this basin. Since 2011, the Brazilian Navy Hydrographic Center has assigned names to tropical and subtropical systems in the western side of the basin, near the eastern coast of Brazil, when they have sustained wind speeds of at least 65 km/h (40 mph), the generally accepted minimum sustained wind speed for a disturbance to be designated as a tropical storm in the North Atlantic basin. Below is a list of notable South Atlantic tropical and subtropical cyclones.
A typhoon is a mature tropical cyclone that develops between 180° and 100°E in the Northern Hemisphere. This region is referred to as the Northwestern Pacific Basin, and is the most active tropical cyclone basin on Earth, accounting for almost one-third of the world's annual tropical cyclones. For organizational purposes, the northern Pacific Ocean is divided into three regions: the eastern, central, and western. The Regional Specialized Meteorological Center (RSMC) for tropical cyclone forecasts is in Japan, with other tropical cyclone warning centers for the northwest Pacific in Hawaii, the Philippines and Hong Kong. While the RSMC names each system, the main name list itself is coordinated among 18 countries that have territories threatened by typhoons each year.
Tropical cyclones are ranked on one of five tropical cyclone intensity scales, according to their maximum sustained winds and which tropical cyclone basin(s) they are located in. Only a few scales of classifications are used officially by the meteorological agencies monitoring the tropical cyclones, but some alternative scales also exist, such as accumulated cyclone energy, the Power Dissipation Index, the Integrated Kinetic Energy Index, and the Hurricane Severity Index.
Tropical cyclogenesis is the development and strengthening of a tropical cyclone in the atmosphere. The mechanisms through which tropical cyclogenesis occurs are distinctly different from those through which temperate cyclogenesis occurs. Tropical cyclogenesis involves the development of a warm-core cyclone, due to significant convection in a favorable atmospheric environment.
The 1996 Lake Huron Cyclone, commonly referred to as Hurricane Huron, Cyclone Huron, or the Lake Huron Subtropical Cyclone of 1996, was an extremely rare, strong cyclonic storm system that developed over Lake Huron in September 1996. The system resembled a subtropical cyclone at its peak, having some characteristics of a tropical cyclone. It was the first time such a storm has ever been recorded over the Great Lakes region.
Traditionally, areas of tropical cyclone formation are divided into seven basins. These include the north Atlantic Ocean, the eastern and western parts of the northern Pacific Ocean, the southwestern Pacific, the southwestern and southeastern Indian Oceans, and the northern Indian Ocean. The western Pacific is the most active and the north Indian the least active. An average of 86 tropical cyclones of tropical storm intensity form annually worldwide, with 47 reaching hurricane/typhoon strength, and 20 becoming intense tropical cyclones, super typhoons, or major hurricanes.
The 1975 Pacific Northwest hurricane was an unusual Pacific tropical cyclone that attained hurricane status farther north than any other Pacific hurricane. It was officially unnamed, with the cargo ship Transcolorado providing vital meteorological data in assessing the storm. The twelfth tropical cyclone of the 1975 Pacific hurricane season, it developed from a cold-core upper-level low merging with the remnants of a tropical cyclone on August 31, well to the northeast of Hawaii. Convection increased as the circulation became better defined, and by early on September 2 it became a tropical storm. Turning to the northeast through an area of warm water temperatures, the storm quickly strengthened, and, after developing an eye, it attained hurricane status late on September 3, while located about 1,200 miles (1,950 km) south of Alaska. After maintaining peak winds for about 18 hours, the storm rapidly weakened, as it interacted with an approaching cold front. Early on September 5, it lost its identity near the coast of Alaska.
The 2006 Central Pacific cyclone, also known as Invest 91C or Storm 91C, was an unusual weather system that formed in 2006. Forming on October 30 from a mid-latitude cyclone in the north Pacific mid-latitudes, it moved over waters warmer than normal. The system acquired some features more typical of subtropical and even tropical cyclones. However, as it neared western North America, the system fell apart, dissipating soon after landfall, on November 4. Moisture from the storm's remnants caused substantial rainfall in British Columbia and the Pacific Northwest. The exact status and nature of this weather event is unknown, with meteorologists and weather agencies having differing opinions.
The following outline is provided as an overview of and topical guide to tropical cyclones:
A cold-core low, also known as an upper level low or cold-core cyclone, is a cyclone aloft which has an associated cold pool of air residing at high altitude within the Earth's troposphere, without a frontal structure. It is a low pressure system that strengthens with height in accordance with the thermal wind relationship. If a weak surface circulation forms in response to such a feature at subtropical latitudes of the eastern north Pacific or north Indian oceans, it is called a subtropical cyclone. Cloud cover and rainfall mainly occurs with these systems during the day. Severe weather, such as tornadoes, can occur near the center of cold-core lows. Cold lows can help spawn cyclones with significant weather impacts, such as polar lows, and Kármán vortices. Cold lows can lead directly to the development of tropical cyclones, owing to their associated cold pool of air aloft or by acting as additional outflow channels to aid in further development.
Mediterranean tropical-like cyclones, often referred to as medicanes but sometimes also as Mediterranean cyclones or as Mediterranean hurricanes, are meteorological phenomena observed over the Mediterranean Sea. On a few rare occasions, some storms have been observed reaching the strength of a Category 1 hurricane. The main societal hazard posed by medicanes is not usually from destructive winds, but through life-threatening torrential rains and flash floods.
Tropical Storm Omeka was the latest forming Eastern Pacific named storm since reliable records began in the 1960s. The storm was part of the 2010 Pacific typhoon and hurricane season. On December 18, 2010, the Central Pacific Hurricane Center (CPHC) began monitoring a subtropical cyclone near the International Dateline for possible tropical cyclogenesis. Over the following two days, the system tracked southwestward, entering the Western Pacific basin. It then began to transition into a tropical cyclone. Shortly before crossing the dateline on December 20, the CPHC assessed the system to have become a tropical storm. The storm was assigned the name Omeka several hours later as it moved into the CPHC's area of responsibility – which is from 140°W to the International Dateline. Upon doing so, Omeka attained its peak intensity with winds of 60 mph (100 km/h). Later on December 20, wind shear in the region increased, causing the system to weaken. By December 21, the center of Omeka was devoid of convection and dissipated on the next day. Omeka brushed Lisianski Island with no damage.
Throughout 2006, 133 tropical cyclones formed in seven bodies of water known as tropical cyclone basins. Of these, 80 have been named, including two tropical cyclones in the South Atlantic Ocean, and a tropical cyclone in the Mediterranean Sea, by various weather agencies when they attained maximum sustained winds of 35 knots. The strongest storms of the year were Typhoon Yagi in the Western Pacific, and Cyclone Glenda of the Australian region. The deadliest and costliest storms of the year were a series of five typhoons that struck the Philippines; Chanchu, Bilis, Saomai, Xangsane, and Durian, with most of the damage being caused by Durian of November.
During 2007, tropical cyclones formed within seven different tropical cyclone basins, located within various parts of the Atlantic, Pacific and Indian Oceans. During the year, a total of 129 systems formed with 79 of these developing further and were named by the responsible warning centre. The strongest tropical cyclone of the year was Cyclone George, which was estimated to have a minimum barometric pressure of 902 hPa (26.64 inHg).
The following is a glossary of tropical cyclone terms.
Subtropical Cyclone Katie, unofficially named by researchers, was an unusual weather event in early 2015. After the 2014–15 South Pacific cyclone season had officially ended, a rare subtropical cyclone was identified outside of the basin near Easter Island, during early May, and was unofficially dubbed Katie by researchers. Katie was one of the few tropical or subtropical systems ever observed forming in the far Southeast Pacific, outside of the official basin boundary of 120°W, which marks the eastern edge of RSMC Nadi's and RSMC Wellington's warning areas, during the satellite era. Due to the fact that this storm developed outside of the official areas of responsibility of the warning agencies in the South Pacific, the storm was not officially included as a part of the 2014–15 South Pacific cyclone season. However, the Chilean Navy Weather Service issued High Seas Warnings on the system as an extratropical low.
Throughout 2020, 132 tropical cyclones have formed in bodies of water known as tropical cyclone basins. Of these, 97, including two subtropical cyclones in the South Atlantic Ocean and a tropical-like cyclone in the Mediterranean Sea, have been named by various weather agencies when they attained maximum sustained winds of 35 knots. The strongest storm of the year so far was Goni, peaking with a pressure of 905 hPa (26.72 inHg) and with winds of 315 km/h (196 mph). The deadliest storm of the year was Eta which caused 189 fatalities and another 120 to be missing in Central America and the U.S, while the costliest storm of the year was Laura, with a damage cost around $16.1 billion in the Greater Antilles, The Bahamas, and the Gulf Coast of the United States.
Throughout 2009, 130 tropical cyclones have formed in bodies of water known as tropical cyclone basins. Of these, 81 have been named, including a subtropical cyclone in the South Atlantic Ocean, by various weather agencies when they attained maximum sustained winds of 35 knots. The strongest storm of the year was Typhoon Nida in the Western Pacific Ocean. The deadliest and costliest storm of the year was Typhoon Morakot (Kiko) causing 789 fatalities through its track in the Philippines, Japan, Taiwan, China, and the Korean peninsula.
