FACTOID # 1: Idaho produces more milk than Iowa, Indiana and Illinois combined.
 
 Home   Encyclopedia   Statistics   States A-Z   Flags   Maps   FAQ   About 
 
WHAT'S NEW
 

SEARCH ALL

FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:

 

 

(* = Graphable)

 

 


Encyclopedia > Tropical Depression
Cyclone Catarina, a rare South Atlantic tropical cyclone viewed from the International Space Station on March 26, 2004.
Cyclone Catarina, a rare South Atlantic tropical cyclone viewed from the International Space Station on March 26, 2004.

In meteorology, a tropical cyclone (also referred to as a tropical depression, tropical storm, typhoon, or hurricane depending on strength and geographical context) is a type of low pressure system which generally forms in the tropics. While they can be highly destructive, tropical cyclones are an important part of the atmospheric circulation system, which moves heat from the equatorial region toward the higher latitudes. Image File history File links Download high resolution version (1000x662, 320 KB) http://eol. ... Image File history File links Download high resolution version (1000x662, 320 KB) http://eol. ... A South Atlantic tropical cyclone is an unusual weather event which occurs in the southern Atlantic Ocean, south of the equator. ... ISS Statistics Crew: 2 As of August 21, 2005 Perigee: 352. ... Satellite image of Hurricane Hugo with a polar low visible at the top of the image. ... A low pressure area, or a low for short, is a region where the atmospheric pressure is lowest with relation to the surrounding area. ... The tropics are the geographic region of the Earth centered on the equator and limited in latitude by the two tropics: the Tropic of Cancer in the northern hemisphere and the Tropic of Capricorn in the southern hemisphere. ... Cyclone - Wikipedia, the free encyclopedia /**/ @import /skins-1. ... Atmospheric circulation is the large-scale movement of air, and the means (together with the ocean circulation, which is smaller [1]) by which heat is distributed on the surface of the Earth. ... The equator is an imaginary circle drawn around a planet (or other astronomical object) at a distance halfway between the poles. ...

Contents


Terms for tropical cyclones

Eye of Typhoon Odessa, Pacific Ocean, August 1985
Eye of Typhoon Odessa, Pacific Ocean, August 1985

Terms used in weather reports for tropical cyclones that have surface winds over 64 knots (73.6 mph) or 32 m/s vary by region: Image File history File links Download high resolution version (640x640, 63 KB)Eye of Typhoon Odessa, Pacific Ocean August 1985. ... Image File history File links Download high resolution version (640x640, 63 KB)Eye of Typhoon Odessa, Pacific Ocean August 1985. ... Kikyo is the prettiest anime girl/priestess!! ... This article is about the year. ... Some knots: 1. ... Miles per hour is a unit of speed, expressing the number of international miles covered per hour. ... Metre per second (U.S. spelling: meter per second) is an SI derived unit of both speed (scalar) and velocity (vector), defined by distance in metres divided by time in seconds. ...

  • Hurricane: Atlantic basin and North Pacific Ocean east of the dateline
  • Typhoon: Northwest Pacific west of the dateline
  • Severe tropical cyclone: Southwest Pacific west of 160°E and the southeast Indian Ocean east of 90°E
  • Severe cyclonic storm: North Indian Ocean
  • Tropical cyclone: Southwest Indian Ocean and the South Pacific east of 160°E.
  • Cyclone (unofficially): South Atlantic Ocean

There are many regional names for tropical cyclones, including Bagyo in the Philippines and Taino in Haiti. The Atlantic Basin includes the main body of the Atlantic Ocean, the Gulf of Mexico and the Caribbean Sea, but ommits other bodies of water considered to be a part of the Atlantic Ocean in the broad sense, such as the Mediteranean Sea. ... The International Date Line around 180° The International Date Line is an imaginary line on the surface of the Earth, which offsets the hours that are added or subtracted as one travels east or west through successive time zones. ...


Etymology

The word typhoon has two possible origins:

  • From the Chinese 大風 (daaih fūng (Cantonese); dà fēng (Mandarin)) which means "great wind". (The Chinese term as 颱風 táifēng, and 台風 taifu in Japanese, has an independent origin traceable variously to 風颱, 風篩 or 風癡 hongthai, going back to Song 宋 (960-1278) and Yuan 元(1260-1341) dynasties. The first record of the character 颱 appeared in 1685's edition of Summary of Taiwan 臺灣記略).
  • From Urdu, Persian or Arabic ţūfān (طوفان) < Greek tuphōn (Τυφών).

Portuguese tufão is also related to typhoon. See tuphōn for more information. This article is on all of the Yue dialects. ... This article is on all of the Northern Chinese dialects. ... Wind is the roughly horizontal movement of air (as opposed to an air current) caused by uneven heating of the Earths surface. ... This article needs to be cleaned up to conform to a higher standard of quality. ... Persian (فارسی = Fârsi . ... Arabic (; , less formally, ) is the largest member of the Semitic branch of the Afro-Asiatic language family (classification: South Central Semitic) and is closely related to Hebrew and Aramaic. ... Typhon (Typhaon, Typhoeus, Typhus), in Greek mythology, was the final son of Gaia, this time with Tartarus, the offspring of the Earth and the cavernous void beneath: But when Zeus had driven the Titans from heaven, huge Earth bare her youngest child Typhoeus of the love of —Hesiod, Theogony 820... Typhon (Typhaon, Typhoeus, Typhus), in Greek mythology, was the final son of Gaia, this time with Tartarus, the offspring of the Earth and the cavernous void beneath: But when Zeus had driven the Titans from heaven, huge Earth bare her youngest child Typhoeus of the love of —Hesiod, Theogony 820...


The word hurricane is derived from the name of a native Caribbean Amerindian storm god, Huracan, via Spanish huracán. The Caribbean, (Spanish: Caribe; French: Caraïbe or more commonly Antilles; Dutch: Cariben or Caraïben, or more commonly Antillen) or the West Indies, is a group of islands and countries which are in or border the Caribbean Sea which lies on the Caribbean Plate. ... Native Americans (also Indians, Aboriginal Peoples, American Indians, First Nations, Alaskan Natives, or Indigenous Peoples of America) are the indigenous inhabitants of The Americas prior to the European colonization, and their modern descendants. ... God is the term used to denote the Supreme Being ascribed by monotheistic religions to be the creator, ruler and/or the sum total of, existence. ... In Maya mythology, Huracan (one legged) was a wind, storm and fire god and one of the creator deities who participated in all three attempts at creating humanity. ...


The word cyclone is from the Greek "κύκλος", meaning "circle." An Egyptian word Cykline meaning to "to spin" has been cited as a possible origin. [citation needed]


Overall mechanics of a tropical cyclone

Hurricanes form when the energy released by the condensation of moisture in rising air causes a positive feedback loop. The air heats up, rising further, which leads to more condensation. The air flowing out of the top of this “chimney” drops towards the ground, forming powerful winds.
Hurricanes form when the energy released by the condensation of moisture in rising air causes a positive feedback loop. The air heats up, rising further, which leads to more condensation. The air flowing out of the top of this “chimney” drops towards the ground, forming powerful winds.

Structurally, a tropical cyclone is a large, rotating system of clouds, wind and thunderstorms. Its primary energy source is the release of the heat of condensation from water vapor condensing at high altitudes, the heat ultimately derived from the sun. Therefore, a tropical cyclone can be thought of as a giant vertical heat engine supported by mechanics driven by physical forces such as the rotation and gravity of the Earth. Continued condensation leads to higher winds, continued evaporation, and continued condensation, feeding back into itself. This gives rise to factors that give the system enough energy to be self-sufficient and cause a positive feedback loop where it can draw more energy as long as the source of heat, warm water, remains. Factors such as a continued lack of equilibrium in air mass distribution would also give supporting energy to the cyclone. The orbital revolution of the Earth causes the system to spin, an effect known as the Coriolis force, giving it a cyclone characteristic and affecting the trajectory of the storm. Image File history File links http://earthobservatory. ... Positive feedback is a type of feedback. ... In cybernetics and control theory, feedback is a process whereby some proportion or in general, function, of the output signal of a system is passed (fed back) to the input. ... Cumulus of fair weather A cloud is a visible mass of condensed droplets or ice crystals suspended in the atmosphere above the surface of the Earth or another planetary body. ... Wind is the roughly horizontal movement of air (as opposed to an air current) caused by uneven heating of the Earths surface. ... A roll cloud associated with a heavy or severe thunderstorm over Enschede, The Netherlands. ... The heat of vaporization is a physical property of substances. ... Condensation is the change in phase of a substance to a denser phase, such as gas (or vapor) to a liquid. ... The Sun is the star at the center of our Solar system. ... In engineering and thermodynamics, a heat engine performs the conversion of heat energy to mechanical work by exploiting the temperature gradient between a hot source and a cold sink. Heat is transferred to the sink from the source, and in this process some of the heat is converted into work. ... Rotation of a plane, seen as the rotation of the terrain relative to the plane (exposure time 1. ... It has been suggested that gravitation be merged into this article or section. ... Earth is the third planet from the Sun. ... Positive feedback is a type of feedback. ... In cybernetics and control theory, feedback is a process whereby some proportion or in general, function, of the output signal of a system is passed (fed back) to the input. ... Look up equilibrium in Wiktionary, the free dictionary. ... In physics, the Coriolis effect is an inertial force first described by Gaspard-Gustave Coriolis, a French scientist, in 1835. ...


The factors to form a tropical cyclone include a pre-existing weather disturbance, warm tropical oceans, moisture, and relatively light winds aloft. If the right conditions persist and allow it to create a feedback loop by maximizing the energy intake possible, for example, such as high winds to increase the rate of evaporation, they can combine to produce the violent winds, incredible waves, torrential rains, and floods associated with this phenomenon. A flood (in Old English flod, a word common to Teutonic languages; compare German Flut, Dutch vloed from the same root as is seen in flow, float) is an overflow of water, an expanse of water submerging land, a deluge. ...


Condensation as a driving force is what primarily distinguishes tropical cyclones from other meteorological phenomena, and because this is strongest in a tropical climate, this defines the initial domain of the tropical cyclone. By contrast, mid-latitude cyclones, for example, draw their energy mostly from pre-existing horizontal temperature gradients in the atmosphere. In order to continue to drive its heat engine, a tropical cyclone must remain over warm water, which provides the atmospheric moisture needed. The evaporation of this moisture is accelerated by the high winds and reduced atmospheric pressure in the storm, resulting in a positive feedback loop. As a result, when a tropical cyclone passes over land, its strength diminishes rapidly. Condensation is the change in phase of a substance to a denser phase, such as gas (or vapor) to a liquid. ... The tropics are the geographic region of the Earth centered on the equator and limited in latitude by the two tropics: the Tropic of Cancer in the north and the Tropic of Capricorn in the southern hemisphere. ... In the above two images, the scalar field is in black and white, black representing higher values, and its corresponding gradient is represented by blue arrows. ...


Scientists at the National Center for Atmospheric Research estimate that a hurricane releases heat energy at the rate of 50 to 200 trillion watts -- about the amount of energy released by exploding a 10-megaton nuclear bomb every 20 minutes [1]. The numeral trillion refers to one of two number values, depending on the context of where and how it is being used. ... The watt (symbol: W) is the SI derived unit of power. ... The mushroom cloud of the atomic bombing of Nagasaki, Japan, in 1945 lifted nuclear fallout some 18 km (60,000 feet) above the epicenter. ...


While the most obvious motion of clouds is toward the center, tropical cyclones also develop an upper-level (high-altitude) outward flow of clouds. These originate from air that has released its moisture and is expelled at high altitude through the "chimney" of the storm engine. This outflow produces high, thin cirrus clouds that spiral away from the center. The high cirrus clouds may be the first signs of an approaching hurricane.


Formation

Waves in the trade winds in the Atlantic Ocean—areas of converging winds that move along the same track as the prevailing wind—create instabilities in the atmosphere that may lead to the formation of hurricanes.
Waves in the trade winds in the Atlantic Ocean—areas of converging winds that move along the same track as the prevailing wind—create instabilities in the atmosphere that may lead to the formation of hurricanes.

The formation of tropical cyclones is the topic of extensive ongoing research, and is still not fully understood. Five factors are necessary to make tropical cyclone formation possible: Image File history File links http://earthobservatory. ...

  1. Sea surface temperatures above 26.5 degrees Celsius (79.7 degrees Fahrenheit) to at least a depth of 50 meters (164 feet). The moisture in the air above the warm water is the energy source for tropical cyclones.
  2. Upper-atmosphere conditions conducive to thunderstorm formation. Temperature in the atmosphere must decrease quickly with height, and the mid-troposphere must be relatively moist.
  3. A pre-existing weather disturbance. This is most frequently provided by tropical waves—non-rotating areas of thunderstorms that move through tropical oceans.
  4. A distance of approximately 10 degrees or more from the equator, so that the Coriolis effect is strong enough to initiate the cyclone's rotation. (2004's Hurricane Ivan was the strongest storm to form closer than 10 degrees from the equator; it started forming at 9.7 degrees north.)
  5. Low vertical wind shear (change in wind speed or direction over height). High wind shear can break apart the vertical structure of a tropical cyclone.

Tropical cyclones occasionally form despite not meeting these conditions. It has been suggested that Centigrade be merged into this article or section. ... Fahrenheit is a temperature scale named after the German physicist Gabriel Fahrenheit (1686–1736), who proposed it in 1724. ... metre or meter, see meter (disambiguation) The metre is the basic unit of length in the International System of Units. ... This article is about a foot as a unit of length. ... A roll cloud associated with a heavy or severe thunderstorm over Enschede, The Netherlands. ... The Troposphere is the lowermost portion of Earths atmosphere and the one in which most weather phenomena occur. ... It has been suggested that Easterly wave be merged into this article or section. ... The equator is an imaginary circle drawn around a planet (or other astronomical object) at a distance halfway between the poles. ... A low pressure system over Iceland The Coriolis effect is an apparent deflection of a moving object in a rotating frame of reference. ... 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... Hurricane Ivan was the ninth named storm, the sixth hurricane, the fourth major hurricane, and the strongest hurricane of the 2004 Atlantic hurricane season. ... Wind shear is a difference in wind speed and/or direction between two points in the atmosphere. ...


Only specific weather disturbances can result in tropical cyclones. These include:

  1. Tropical waves, or easterly waves, which, as mentioned above, are westward moving areas of convergent winds. This often assists in the development of thunderstorms, which can develop into tropical cyclones. Most tropical cyclones form from these. A similar phenomenon to tropical waves are West African disturbance lines, which are squally lines of convection that form over Africa and move into the Atlantic.
  2. Tropical upper tropospheric troughs, which are cold-core upper level lows. A warm-core tropical cyclone may result when one of these (on occasion) works down to the lower levels and produces deep convection.
  3. Decaying frontal boundaries may occasionally stall over warm waters and produce lines of active convection. If a low level circulation forms under this convection, it may develop into a tropical cyclone.

... A satellite composite image of Africa Africa is the worlds second-largest and second most populous continent, after Asia. ... The troposphere is the lowermost portion of Earths atmosphere and the one in which most weather phenomena occur. ... Convection is the transfer of heat by currents within a fluid. ...

Times of formation

Tropical storms and hurricanes by month, for the period 1944-2005
(North Atlantic region)
Month Total Average
January–April 4 0.1
May 8 0.1
June 35 0.6
July 58 0.9
August 173 2.8
September 224 3.6
October 114 1.8
November 33 0.5
December 7 0.1
Source: NOAA + additions for 2001-05

Worldwide, tropical cyclone activity peaks in late summer when water temperatures are warmest. However, each particular basin has its own seasonal patterns. Summer is a season, defined by convention in meteorology as the whole months of June, July, and August, in the Northern hemisphere, and the whole months of December, January, and February, in the Southern hemisphere. ...


In the North Atlantic, a distinct hurricane season occurs from June 1 to November 30, sharply peaking from late August through September. The statistical peak of the North Atlantic hurricane season is September 10. The Northeast Pacific has a broader period of activity, but in a similar timeframe to the Atlantic. The Northwest Pacific sees tropical cyclones year-round, with a minimum in February and a peak in early September. In the North Indian basin, storms are most common from April to December, with peaks in May and November. June 1 is the 152nd day of the year in the Gregorian calendar (153rd in leap years), with 213 days remaining. ... November 30 is the 334th day (335th on leap years) of the year in the Gregorian calendar, with 31 days remaining, as the final day of November. ... September 10 is the 253rd day of the year (254th in leap years). ...


In the Southern Hemisphere, tropical cyclone activity begins in late October and ends in May. Southern Hemisphere activity peaks in mid-February to early March. Southern Hemisphere The Southern Hemisphere is the half of a planets surface (or celestial sphere) that is south of the equator (the word hemisphere literally means half ball). On Earth it contains four continents (part of Africa, Oceania, most of South America, and Antarctica) and four oceans (South Atlantic...


Worldwide, an average of 80 tropical cyclones form each year.


Locations of formation

Most tropical cyclones form in a worldwide band of thunderstorm activity called the Intertropical convergence zone (ITCZ). The thunderstorms of the Intertropical Convergence Zone form a line across the eastern Pacific Ocean. ...


Nearly all of them form between 10 and 30 degrees of the equator and 87% form within 20 degrees of it. Because the Coriolis effect initiates and maintains tropical cyclone rotation, such cyclones almost never form or move within about 10 degrees of the equator [2], where the Coriolis effect is weakest. However, it is possible for tropical cyclones to form within this boundary if there is another source of initial rotation. These conditions are extremely rare, and such storms are believed to form at most once per century. Hurricane Ivan of 2004 developed within 10 degrees of the equator. A combination of a pre-existing disturbance, upper level divergence and a monsoon-related cold spell led to Typhoon Vamei at only 1.5 degrees north of the equator in 2001. It is estimated that such conditions occur only once every 400 years. The equator is an imaginary circle drawn around a planet (or other astronomical object) at a distance halfway between the poles. ... A low pressure system over Iceland The Coriolis effect is an apparent deflection of a moving object in a rotating frame of reference. ... Hurricane Ivan was the ninth named storm, the sixth hurricane, the fourth major hurricane, and the strongest hurricane of the 2004 Atlantic hurricane season. ... 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... Monsoon in the Vindhya, a mountain chain in central India A monsoon is a periodic wind, especially in the Indian Ocean and southern Asia. ... The 2001 Pacific typhoon season has no official bounds; it ran year-round in 2001, but most tropical cyclones tend to form in the northwestern Pacific Ocean between June and December. ... 2001: A Space Odyssey. ...


Major basins

There are seven main basins of tropical cyclone formation:

  • North Atlantic Basin: The most-studied of all tropical basins, it includes the Atlantic Ocean, the Caribbean Sea, and the Gulf of Mexico. Tropical cyclone formation here varies widely from year to year, ranging from over twenty to one per year. The average is about ten. The United States Atlantic coast, Mexico, Central America, the Caribbean Islands and Bermuda are frequently affected by storms in this basin. Venezuela, the south-east of Canada and Atlantic "Macaronesian" islands are also occasionally affected. The U.S. National Hurricane Center (NHC) based in Miami, Florida, issues forecasts for storms for all nations in the region; the Canadian Hurricane Centre, based in Halifax, Nova Scotia, also issues forecasts and warnings for storms expected to affect Canadian territory and waters. Hurricanes that strike Mexico, Central America, and Caribbean island nations, often do intense damage, as hurricanes are deadlier over warmer water. Additionally, they can hit the coast of the U.S., especially Florida, North Carolina, the U.S. Gulf Coast and occasionally New Jersey, New York and New England (usually hurricanes weaken to tropical storms before they reach these northern regions). The coast of Atlantic Canada receives hurricane landfalls on rare occasion, such as Hurricane Juan in 2003. Many of the more intense Atlantic storms are Cape Verde-type hurricanes, which form off the west coast of Africa near the Cape Verde islands.
  • Western North Pacific Ocean: Tropical storm activity in this region frequently affects China, Japan, the Philippines, and Taiwan, but also many other countries in South-East Asia, such as Vietnam, South Korea and Indonesia, plus numerous Oceanian islands. This is by far the most active basin, accounting for one-third of all tropical cyclone activity in the world. The eastern coasts of Taiwan and Philippines also have the highest tropical cyclone landfall frequency in the world. National meteorology organizations and the Joint Typhoon Warning Center (JTWC) are responsible for issuing forecasts and warnings in this basin.
  • Eastern North Pacific Ocean: This is the second most active basin in the world, and the most dense (a large number of storms for a small area of ocean). Storms that form here can affect western Mexico, Hawaii, northern Central America, and on extremely rare occasions, California. In the U.S., the Central Pacific Hurricane Center is responsible for forecasting the western part of this area while the National Hurricane Center is responsible for the eastern part.
  • South Western Pacific Ocean: Tropical activity in this region largely affects Australia and Oceania, and is forecast by Australia and Papua New Guinea.
  • Northern Indian Ocean: This basin is divided into two areas, the Bay of Bengal and the Arabian Sea, with the Bay of Bengal dominating (5 to 6 times more activity). This basin's season has an interesting double peak; one in April and May before the onset of the monsoon, and another in October and November just after. Hurricanes which form in this basin have historically cost the most lives — most notably, the 1970 Bhola cyclone killed 200,000. Nations affected by this basin include India, Bangladesh, Sri Lanka, Thailand, Myanmar, and Pakistan, and all of these countries issue regional forecasts and warnings. Rarely, a tropical cyclone formed in this basin will affect the Arabian Peninsula.
  • Southeastern Indian Ocean: Tropical activity in this region affects Australia and Indonesia, and is forecast by those nations.
  • Southwestern Indian Ocean: This basin is the least understood, due to a lack of historical data. Cyclones forming here impact Madagascar, Mozambique, Mauritius, and Kenya, and these nations issue forecasts and warnings for the basin.

Map of Central America and the Caribbean The Caribbean Sea is a tropical body of water adjacent to the Atlantic Ocean and southeast of the Gulf of Mexico. ... Gulf of Mexico in 3D perspective. ... Commonly, Central America is the region of North America located between the southern border of Mexico and the northwest border of Colombia, in South America. ... This is a list of inhabited islands in the Caribbean. ... Macaronesia Macaronesia is a modern invented collective name for several groups of islands in the North Atlantic Ocean near Europe and North Africa belonging to three countries: Portugal, Spain, and Cape Verde. ... The U.S. National Hurricane Center is the division of National Weather Services Tropical Prediction Center responsible for tracking and predicting the likely behavior of tropical depressions, tropical storms and hurricanes. ... This article is about the city in Florida. ... Official language(s) English Capital Tallahassee Largest city Jacksonville Area  - Total  - Width  - Length  - % water  - Latitude  - Longitude Ranked 22nd 170,451 km² 260 km 800 km 17. ... The Canadian Hurricane Centre operated by Environment Canada exists to advise Canadians on the threat of hurricanes and tropical storms. ... Please read first: This article is about the Nova Scotia community. ... Motto: Munit Haec et Altera Vincit (Latin: One defends and the other conquers) Official languages English Capital Halifax Largest city Halifax Lieutenant-Governor Myra Freeman Premier John Hamm (PC) Parliamentary representation  - House seat  - Senate seats 11 10 Area  - Total  - % water Ranked 12th 55,283 km² 3. ... Commonly, Central America is the region of North America located between the southern border of Mexico and the northwest border of Colombia, in South America. ... The Caribbean, (Spanish: Caribe; French: Caraïbe or more commonly Antilles; Dutch: Cariben or Caraïben, or more commonly Antillen) or the West Indies, is a group of islands and countries which are in or border the Caribbean Sea which lies on the Caribbean Plate. ... Official language(s) English Capital Tallahassee Largest city Jacksonville Area  - Total  - Width  - Length  - % water  - Latitude  - Longitude Ranked 22nd 170,451 km² 260 km 800 km 17. ... Official language(s) English Capital Raleigh Largest city Charlotte Area  - Total  - Width  - Length  - % water  - Latitude  - Longitude Ranked 28th 139,509 km² 805 km 240 km 9. ... Regional definitions vary from source to source. ... Official language(s) None defined, English de facto Capital Trenton Largest city Newark Area  - Total  - Width  - Length  - % water  - Latitude  - Longitude Ranked 47th 22,608 km² 110 km 240 km 14. ... Official language(s) None, English de facto Capital Albany Largest city New York City Area  - Total  - Width  - Length  - % water  - Latitude  - Longitude Ranked 27th 141,205 km² 455 km 530 km 13. ... First Flag of New England, 1686-c. ... Atlantic Canada consists of the four Canadian provinces on the Atlantic Ocean: Newfoundland and Labrador, New Brunswick, Nova Scotia, and Prince Edward Island. ... Hurricane Juan was a hurricane that made landfall at Prospect, Nova Scotia, 30 km (20 miles) southwest of Halifax at 12:10 a. ... 2003 (MMIII) was a common year starting on Wednesday of the Gregorian calendar. ... Hurricane Ivan, a category 5 Cape Verde-type hurricane A Cape Verde-type hurricane is an Atlantic hurricane that develops near the Cape Verde islands, off the west coast of Africa. ... A satellite composite image of Africa Africa is the worlds second-largest and second most populous continent, after Asia. ... Oceania is a geographical (often geopolitical) region consisting of numerous countries and territories – mostly islands – in the Pacific Ocean. ... The Joint Typhoon Warning Center (JTWC) is a division of the United States Navys Naval Pacific Meteorology and Oceanography Center in Pearl Harbor, Hawaii. ... Official language(s) Hawaiian and English Capital Honolulu Largest city Honolulu Area  - Total  - Width  - Length  - % water  - Latitude  - Longitude Ranked 43rd 28,337 km² n/a km 2,450 km 41. ... Commonly, Central America is the region of North America located between the southern border of Mexico and the northwest border of Colombia, in South America. ... Official language(s) English Capital Sacramento Largest city Los Angeles Area  - Total  - Width  - Length  - % water  - Latitude  - Longitude Ranked 3rd 410,000 km² 402. ... On September 11, 1992, Hurricane Iniki caused more than USD $3 billion of damage in Hawaii. ... The US National Hurricane Center is the division of National Weather Services Tropical Prediction Center responsible for tracking and predicting the likely behavior of tropical depressions, tropical storms and hurricanes. ... Oceania is a geographical (often geopolitical) region consisting of numerous countries and territories – mostly islands – in the Pacific Ocean. ... A map showing the location of the Bay of Bengal. ... Map of the Arabian Sea. ... Monsoon in the Vindhya, a mountain chain in central India A monsoon is a periodic wind, especially in the Indian Ocean and southern Asia. ... The Bhola cyclone made landfall in East Pakistan (now Bangladesh) on 13 November 1970. ... The Arabian Peninsula The Arabian Peninsula is a peninsula in Southwest Asia at the junction of Africa and Asia consisting mainly of desert. ...

Unusual formation areas

Hurricane Vince on October 9, 2005 at 2300 UTC near the Madeira Islands.
Hurricane Vince on October 9, 2005 at 2300 UTC near the Madeira Islands.

The following areas spawn tropical cyclones only very rarely. Image File history File links Hurricane_Vince_October_9_2005_2300_UTC.jpg Description Hurricane Vince on October 9, 2005 at 2300 UTC. Vince was a very rare tropical cyclone, forming near the Madeira Islands. ... Image File history File links Hurricane_Vince_October_9_2005_2300_UTC.jpg Description Hurricane Vince on October 9, 2005 at 2300 UTC. Vince was a very rare tropical cyclone, forming near the Madeira Islands. ... October 9 is the 282nd day of the year in the Gregorian calendar (283rd in Leap years). ... 2005 (MMV) was a common year starting on Saturday of the Gregorian calendar. ... Location Motto of the autonomous region: Das ilhas, as mais belas e livres (Portuguese: Of the islands, the most beautiful and free) Official language Portuguese Capital Funchal Other towns Porto Santo, Machico, Santa Cruz, Câmara de Lobos, Santana, Ribeira Brava, Caniço Area 797 km² Population  - Total (1991)  - Density...

  • Southern Atlantic Ocean: A combination of cooler waters, the lack of an ITCZ, and wind shear makes it very difficult for the Southern Atlantic to support tropical activity. However, three tropical cyclones have been observed here — a weak tropical storm in 1991 off the coast of Africa, Hurricane Catarina (sometimes also referred to as Aldonça), which made landfall in Brazil in 2004 as a Category 1 hurricane, and a smaller storm in January 2004, east of Salvador, Brazil. The January storm is thought to have reached tropical storm intensity based on scatterometre winds.
  • Central North Pacific: Shear in this area of the Pacific Ocean severely limits tropical development. However, this region is commonly frequented by tropical cyclones that form in the much more favorable Eastern North Pacific Basin.
  • Eastern South Pacific: Tropical cyclone formation is rare in this region; when they do form, it is frequently linked to El Niño episodes. Most of the storms that enter this region formed farther west in the Southwest Pacific. They affect the islands of Polynesia in exceptional instances.
  • Mediterranean Sea: Storms which appear similar to tropical cyclones in structure sometimes occur in the Mediterranean basin. Such cyclones formed in September 1947, September 1969, January 1982, September 1983, and January 1995. However, there is debate on whether these storms were tropical in nature.
  • Northeastern Atlantic Ocean: In October 2005, Hurricane Vince formed near Madeira, then moved northeastward, passing south of the Portuguese south coast, and made landfall in southwestern Spain as a tropical depression. Vince's origin was the northernmost in the eastern Atlantic ever recorded, and Vince was the first storm in recorded history to reach the Iberian Peninsula as a tropical cyclone, i.e. before being transformed into an extratropical low or absorbed into other systems of low pressure.
  • Australia: SW Pacific Basin includes the eastern part of Australia and the Fiji area.
  • Australia: SE Indian Basin includes the eastern part of the Indian ocean and the northern and western part of the Australian basin.
  • Southern South China Sea Tropical cyclones normally do not develop in the Southern South China Sea due to its close proximity to the equator. Areas within ten degrees laditude of the equator do not experience a significant coriolis force, a vital ingredient in tropical cyclone formation. However, in December 2001, Typhoon Vamei formed in the Southern South China Sea and made landfall in Malaysia. It caused flooding in southern Malaysia and some damage in Singapore. It formed from a thunderstorm formation in Borneo that moved into the South China Sea.
  • The Great Lakes A storm system that appeared similar to a tropical cyclone formed in 1996 on Lake Huron it formed an eye and could have breifly been sub-tropical.

Wind shear is a difference in wind speed and/or direction between two points in the atmosphere. ... 1991 (MCMXCI) is a common year starting on Tuesday of the Gregorian calendar. ... A satellite composite image of Africa Africa is the worlds second-largest and second most populous continent, after Asia. ... A South Atlantic tropical cyclone is an unusual weather event which occurs in the southern Atlantic Ocean, south of the equator. ... 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... 2004 : January - February - March - April - May - June - July - August - September - October - November - December- → January 31, 2004 The United States defence budget is set to exceed US$400 billion next year—an almost 7% increase—according to budget proposals inadvertently posted on the Pentagons website. ... Salvador and Baía de Todos os Santos from space, April 1997 Morning Street Scene, Bahia, Brazil, about 1900 Salvador (in full, São Salvador da Baía de Todos os Santos, meaning Holy Savior of the Bay of All Saints) is a city on the northeast coast of Brazil... Polynesia is generally defined as the islands within the triangle Polynesia (from Greek: πολύς many, νῆσος island) is a large grouping of over 1,000 islands scattered over the central and southern Pacific Ocean. ... Satellite image The Mediterranean Sea is a part of the Atlantic Ocean almost completely enclosed by land, on the north by Europe, on the south by Africa, and on the east by Asia. ... 1947 (MCMXLVII) was a common year starting on Wednesday (link will take you to calendar). ... 1969 (MCMLXIX) was a common year starting on Wednesday For other uses, see Number 1969. ... 1982 (MCMLXXXII) is a common year starting on Friday of the Gregorian calendar. ... 1983 (MCMLXXXIII) is a common year starting on Saturday of the Gregorian calendar. ... 1995 (MCMXCV) was a common year starting on Sunday of the Gregorian calendar. ... The 2005 Atlantic hurricane season officially began June 1, 2005 and officially ended on November 30, 2005 although effectively the season persisted into January of 2006 due to continued storm activity. ... The NHCs archive on Hurricane Vince. ... For other uses of the word, see Madeira (disambiguation) Madeira Islands location. ... topographic map of the Iberian Peninsula The Iberian Peninsula, or Iberia, is located in the extreme southwest of Europe. ... The 2001 Pacific typhoon season has no official bounds; it ran year-round in 2001, but most tropical cyclones tend to form in the northwestern Pacific Ocean between June and December. ... Borneo and Sulawesi Borneo (politically divided between Indonesia, Malaysia and Brunei) is the third largest island in the world. ... The Great Lakes from space The Great Lakes are a group of five large lakes on or near the United States-Canadian border. ... 1996 (MCMXCVI) is a leap year starting on Monday of the Gregorian calendar, and was designated the International Year for the Eradication of Poverty. ... The Great Lakes from space; Lake Huron is the third from the left. ... A subtropical cyclone is a weather system that has some characteristics of a tropical cyclone and some characteristics of an extratropical cyclone. ...

Average Season

Basin Season Start Season End Tropical Storms (34-63 knots) Tropical Cyclones (>63 knots) Category 3+ Tropical Cyclones (>95 knots)
Northwest Pacific Year Round Year Round 26.7 16.9 8.5
Northeast Pacific May November 16.3 9.0 4.1
Southwest Indian October May 13.3 6.7 2.7
North Atlantic June November 10.6 5.9 2.0
Australia Southwest Pacific October May 10.6 4.8 1.9
Australia Southeast Indian October May 7.3 3.6 1.6
North Indian April December 5.4 2.2 0.4

Structure and classification

Structure of a hurricane
Structure of a hurricane

A strong tropical cyclone consists of the following components. Image File history File links File links The following pages link to this file: Tropical cyclone ...

  • Surface low: All tropical cyclones rotate around an area of low atmospheric pressure near the Earth's surface. The pressures recorded at the centers of tropical cyclones are among the lowest that occur on Earth's surface at sea level.
  • Warm core: Tropical cyclones are characterized and driven by the release of large amounts of latent heat of condensation as moist air is carried upwards and its water vapor condenses. This heat is distributed vertically, around the center of the storm. Thus, at any given altitude (except close to the surface where water temperature dictates air temperature) the environment inside the cyclone is warmer than its outer surroundings.
  • Central Dense Overcast (CDO): The Central Dense Overcast is a dense shield of very intense thunderstorm activity that make up the inner portion of the hurricane. This contains the eye wall, and the eye itself. The classic hurricane contains a symmetrical CDO, which means that it is perfectly circular and round on all sides.
  • Eye: A strong tropical cyclone will harbor an area of sinking air at the center of circulation. Weather in the eye is normally calm and free of clouds (however, the sea may be extremely violent). Eyes are home to the coldest temperatures of the storm at the surface, and the warmest temperatures at the upper levels. The eye is normally circular in shape, and may range in size from 8 km to 200 km (5 miles to 125 miles) in diameter. In weaker cyclones, the CDO covers the circulation center, resulting in no visible eye.
  • Eyewall: A band around the eye of greatest wind speed, where clouds reach highest and precipitation is heaviest. The heaviest wind damage occurs where a hurricane's eyewall passes over land.
  • Outflow: The upper levels of a tropical cyclone feature winds headed away from the center of the storm with an anticyclonic rotation. Winds at the surface are strongly cyclonic, weaken with height, and eventually reverse themselves. Tropical cyclones owe this unique characteristic to the warm core at the center of the storm.

A low pressure area, or a low for short, is a region where the atmospheric pressure is lowest with relation to the surrounding area. ... diurnal (daily) rhythm of air pressure in northern Germany (black curve is air pressure) Atmospheric pressure is the pressure above any area in the Earths atmosphere caused by the weight of air. ... Earth is the third planet from the Sun. ... For considerations of sea level change, in particular rise associated with possible global warming, see sea level rise. ... The heat of vaporization is a physical property of substances. ... A roll cloud associated with a heavy or severe thunderstorm over Enschede, The Netherlands. ... Eye of Typhoon Odessa, Pacific Ocean, August 1985 The eyewall is the region of a tropical cyclone where the winds are the highest, the clouds reach furthest into the atmosphere and the precipitation is the heaviest. ... In meteorology, an anticyclone is a weather phenomenon associated with atmospheric high pressure. ... For the 1928 film, see The Wind. ...

Intensities of tropical cyclones

Tropical cyclones are classified into three main groups: tropical depressions, tropical storms, and a third group whose name depends on the region.


A tropical depression is an organized system of clouds and thunderstorms with a defined surface circulation and maximum sustained winds of less than 17 metres per second (33 knots, 38 mph, or 62 km/h). It has no eye, and does not typically have the spiral shape of more powerful storms. It is already becoming a low-pressure system, however, hence the name "depression". The metre (Commonwealth English) or meter (American English) (symbol: m) is the SI base unit of length. ... A knot is a unit of bullshit, abbreviated kt or kn. ...


A tropical storm is an organized system of strong thunderstorms with a defined surface circulation and maximum sustained winds between 17 and 33 meters per second (34–63 knots, 39–73 mph, or 62–117 km/h). At this point, the distinctive cyclonic shape starts to develop, though an eye is usually not present. Government weather services assign first names to systems that reach this intensity (thus the term named storm).


At hurricane and typhoon intensity, a tropical cyclone tends to develop an eye, an area of relative calm (and lowest atmospheric pressure) at the center of the circulation. The eye is often visible in satellite images as a small, circular, cloud-free spot. Surrounding the eye is the eyewall, an area about 10 to 50 miles (16 to 80 kilometers) wide in which the strongest thunderstorms and winds circulate around the storm's center. Eye of Typhoon Odessa, Pacific Ocean, August 1985 The eyewall is the region of a tropical cyclone where the winds are the highest, the clouds reach furthest into the atmosphere and the precipitation is the heaviest. ...


The circulation of clouds around a cyclone's center imparts a distinct spiral shape to the system. Bands or arms may extend over great distances as clouds are drawn toward the cyclone. The direction of the cyclonic circulation depends on the hemisphere; it is counterclockwise in the Northern Hemisphere, clockwise in the Southern Hemisphere. Maximum sustained winds in the strongest tropical cyclones have been measured at more than 85 m/s (165 knots, 190 mph, 305 km/h). Intense, mature hurricanes can sometimes exhibit an inward curving of the eyewall top that resembles a football stadium: this phenomenon is thus sometimes referred to as stadium effect. Insert non-formatted text here The Northern Hemisphere is the half of a planets surface (or celestial sphere) that is north of the equator (the word hemisphere literally means half ball). On the Earth, the Northern Hemisphere contains most of the land and population. ... Southern Hemisphere The Southern Hemisphere is the half of a planets surface (or celestial sphere) that is south of the equator (the word hemisphere literally means half ball). On Earth it contains four continents (part of Africa, Oceania, most of South America, and Antarctica) and four oceans (South Atlantic... This picture, taken by Scott A. Dommin, a typhoon/hurricane hunter, presents the stadium effect of Super Typhoon Forrest (1983) as seen from a distance The stadium effect is a rare phenomenon appearing in hurricanes in which the inward curvature of the cumulonimbi top forming the eyewall of the hurricane...


Eyewall replacement cycles naturally occur in intense tropical cyclones. When cyclones reach peak intensity they usually - but not always - have an eyewall and radius of maximum winds that contract to a very small size, around 5 to 15 miles. At this point, some of the outer rainbands may organize into an outer ring of thunderstorms that slowly moves inward and robs the inner eyewall of its needed moisture and momentum. During this phase, the tropical cyclone is weakening (i.e. the maximum winds die off a bit and the central pressure goes up). Eventually the outer eyewall replaces the inner one completely and the storm can be the same intensity as it was previously or, in some cases, even stronger. Eye of Typhoon Odessa, Pacific Ocean, August 1985 The eyewall is the region of a tropical cyclone where the winds are the highest, the clouds reach furthest into the atmosphere and the precipitation is the heaviest. ...


Categories and ranking

Hurricanes are ranked according to their maximum winds using the Saffir-Simpson Hurricane Scale. A Category 1 storm has the lowest maximum winds, a Category 5 hurricane has the highest. The rankings are not absolute in terms of effects. Lower-category storms can inflict greater damage than higher-category storms, depending on factors such as local terrain and total rainfall. For instance, a Category 2 hurricane that strikes a major urban area will likely do more damage than a large Category 5 hurricane that strikes a mostly rural region. In fact, tropical systems of less than hurricane strength can produce significant damage and human casualties, especially from flooding and landslides. The Saffir-Simpson Hurricane Scale is a scale classifying most Western Hemisphere tropical cyclones that exceed the levels of tropical depression and tropical storm and thereby become hurricanes. ...


The National Hurricane Center classifies hurricanes of Category 3 and above as Major Hurricanes. The Joint Typhoon Warning Center classifies typhoons with wind speeds of at least 150 mi/h (67 m/s or 241 km/h, equivalent to a strong Category 4 storm) as Super Typhoons. The U.S. National Hurricane Center is the division of National Weather Services Tropical Prediction Center responsible for tracking and predicting the likely behavior of tropical depressions, tropical storms and hurricanes. ... The Joint Typhoon Warning Center (JTWC) is a division of the United States Navys Naval Pacific Meteorology and Oceanography Center in Pearl Harbor, Hawaii. ...


The definition of sustained winds recommended by the World Meteorological Organization (WMO) and used by most weather agencies is that of a 10-minute average. The U.S. weather service defines sustained winds based on 1-minute average speed measured about 10 meters (33 ft) above the surface. The World Meteorological Organization (WMO) is an intergovernmental organization with a membership of 187 Member States and Territories. ...


Other storm systems

An extratropical cyclone is a storm that derives energy from horizontal temperature differences, which are typical in higher latitudes. A tropical cyclone can become extratropical as it moves toward higher latitudes if its energy source changes from heat released by condensation to differences in temperature between air masses. From space, extratropical storms have a characteristic "comma-shaped" cloud pattern. Extratropical cyclones can also be dangerous because their low-pressure centers cause powerful winds. Extratropical is a term used in advisories and tropical summaries to indicate that a cyclone has lost its tropical characteristics. ... A comma ( , ) is a punctuation mark. ...


In the United Kingdom and Europe, some severe northeast Atlantic cyclonic depressions are referred to as "hurricanes," even though they rarely originate in the tropics. These European windstorms can generate hurricane-force winds but are not given individual names. However, two powerful extratropical cyclones that ravaged France, Germany, and the United Kingdom in December 1999, "Lothar" and "Martin", were named due to their unexpected power (equivalent to a category 1 or 2 hurricane). In British Shipping Forecasts, winds of force 12 on the Beaufort scale are described as "hurricane force." World map showing Europe A satellite composite image of Europe Europe is conventionally considered one of the seven continents which, in this case, is more a cultural and political distinction than a physiogeographic one. ... A European windstorm is a severe cyclonic storm that tracks across the North Atlantic towards northwestern Europe in the winter months. ... 1999 is a common year starting on Friday Anno Domini (or the Current Era), and was designated the International Year of Older Persons by the United Nations. ... The Shipping Forecast is a regular feature of BBC Radio 4 and is provided by the UK Meteorological Office on behalf of the Maritime and Coastguard Agency. ... The Beaufort scale is an empirical measure for the intensity of the wind based mainly on sea-state or wave conditions. ...


There is also a polar counterpart to the tropical cyclone, called a polar low. Polar lows are similar in behavior and size to tropical cyclones, although generally much shorter lived. ...


Movement and track

Large-scale winds

Although tropical cyclones are large systems generating enormous energy, their movements over the earth's surface are often compared to that of leaves carried along by a stream. That is, large-scale winds—the streams in the earth's atmosphere—are responsible for moving and steering tropical cyclones. The path of motion is referred to as a tropical cyclone's track.


The major force affecting the track of tropical systems in all areas are winds circulating around high-pressure areas. Over the North Atlantic Ocean, tropical systems are steered generally westward by the east-to-west winds on the south side of the Bermuda High, a persistent high-pressure area over the North Atlantic. Also, in the area of the North Atlantic where hurricanes form, trade winds, which are prevailing westward-moving wind currents, steer tropical waves (precursors to tropical depressions and cyclones) westward from off the African coast toward the Caribbean and North America. The trade winds are a pattern of wind found in bands around Earths equatorial region. ...


Coriolis effect

The earth's rotation also imparts an acceleration (termed the Coriolis Acceleration or Coriolis Effect). This acceleration causes cyclonic systems to turn towards the poles in the absence of strong steering currents (i.e. in the north, the northern part of the cyclone has winds to the west, and the Coriolis force pulls them slightly north. The southern part is pulled south, but since it is closer to the equator, the Coriolis force is a bit weaker there). Thus, tropical cyclones in the Northern Hemisphere, which commonly move west in the beginning, normally turn north (and are then usually blown east), and cyclones in the Southern Hemisphere are deflected south, if no strong pressure systems are counteracting the Coriolis Acceleration. The Coriolis acceleration also initiates cyclonic rotation, but it is not the driving force that brings this rotation to high speeds. (Much of that is due to the conservation of angular momentum - air is drawn in from an area much larger than the cyclone such that the tiny angular velocity of that air will be magnified greatly when the distance to the storm center shrinks.) A low pressure system over Iceland The Coriolis effect is an apparent deflection of a moving object in a rotating frame of reference. ... In physics the angular momentum of an object with respect to a reference point is a measure for the extent to which, and the direction in which, the object rotates about the reference point. ...


Interaction with high and low pressure systems

Finally, when a tropical cyclone moves into higher latitude, its general track around a high-pressure area can be deflected significantly by winds moving toward a low-pressure area. Such a track direction change is termed recurve. A hurricane moving from the Atlantic toward the Gulf of Mexico, for example, will recurve to the north and then northeast if it encounters winds blowing northwestward toward a high-pressure system passing over North Africa. Many tropical cyclones along the coast. East Coast and in the Gulf of Mexico are eventually forced toward the northeast by high-pressure areas which move from west to east over North Africa. Gulf of Mexico in 3D perspective. ...


Forecasting

Hurricane Epsilon strengthened and organized in the Central North Atlantic Ocean despite highly unfavorable conditions. This unusual system defied most NHC forecasts and demonstrated the difficulties of predicting tropical cyclones.
Enlarge
Hurricane Epsilon strengthened and organized in the Central North Atlantic Ocean despite highly unfavorable conditions. This unusual system defied most NHC forecasts and demonstrated the difficulties of predicting tropical cyclones.

Because of the forces that affect tropical cyclone tracks, accurate track predictions depend on determining the position and strength of high- and low-pressure areas, and predicting how those areas will change during the life of a tropical system. Image File history File links Download high resolution version (3032x2007, 942 KB) Summary This view of Hurricane Epsilon in the Atlantic Ocean was photographed at 15:36:18 GMT on Dec. ... Image File history File links Download high resolution version (3032x2007, 942 KB) Summary This view of Hurricane Epsilon in the Atlantic Ocean was photographed at 15:36:18 GMT on Dec. ... The 2005 Atlantic hurricane season officially began June 1, 2005 and officially ended on November 30, 2005 although effectively the season persisted into January of 2006 due to continued storm activity. ... The US National Hurricane Center is the division of National Weather Services Tropical Prediction Center responsible for tracking and predicting the likely behavior of tropical depressions, tropical storms and hurricanes. ...


With their understanding of the forces that act on tropical cyclones, and a wealth of data from earth-orbiting satellites and other sensors, scientists have increased the accuracy of track forecasts over recent decades. High-speed computers and sophisticated simulation software allow forecasters to produce computer models that forecast tropical cyclone tracks based on the future position and strength of high- and low-pressure systems. But while track forecasts have become more accurate than 20 years ago, scientists say they are less skillful at predicting the intensity of tropical cyclones. They attribute the lack of improvement in intensity forecasting to the complexity of tropical systems and an incomplete understanding of factors that affect their development.


Landfall

Officially, "landfall" is when a storm's center (the center of the eye, not its edge) reaches land. Naturally, storm conditions may be experienced on the coast and inland well before landfall. In fact, for a storm moving inland, the landfall area experiences half the storm before the actual landfall. For emergency preparedness, actions should be timed from when a certain wind speed will reach land, not from when landfall will occur.


For a list of notable and unusual landfalling hurricanes, see list of notable tropical cyclones. This is a list of notable tropical cyclones, subdivided by basin and reason for notability. ...


Dissipation

A tropical cyclone can cease to have tropical characteristics in several ways:

  • It moves over land, thus depriving it of the warm water it needs to power itself, and quickly loses strength. Most strong storms become disorganized areas of low pressure within a day or two of landfall. There is, however, a chance they could regenerate if they manage to get back over open warm water. If a storm is over mountains for even a short time, it can rapidly lose strength. This is, however, the cause of many storm fatalities, as the dying storm unleashes torrential rainfall, and in mountainous areas, this can lead to deadly mudslides. The storm loses strength slower over flatter or marshy areas than over mountainous terrain which disrupts the surface circulation of the storm more.
  • It remains in the same area of ocean for too long, sucking up all the warm water. Without warm surface water, the storm cannot survive.
  • It experiences wind shear, causing the convection to lose direction and the heat engine to break down.
  • It can be weak enough to be consumed by another area of low pressure, disrupting it and joining to become a large area of non-cyclonic thunderstorms. (Such, however, can re-strengthen the non-tropical system as a whole.)
  • It enters colder waters. This does not necessarily mean the death of the storm, but the storm will lose its tropical characteristics. These storms are extratropical cyclones.
  • An outer eye wall forms (typically around 50 miles from the center of the storm), choking off the convection toward the inner eye wall. Such weakening is generally temporary unless it meets other conditions above.

Even after a tropical cyclone is said to be extratropical or dissipated, it can still have tropical storm force (or occasionally hurricane force) winds and drop several inches of rainfall. When a tropical cyclone reaches higher latitudes or passes over land, it may merge with weather fronts or develop into a frontal cyclone, also called extratropical cyclone. In the Atlantic ocean, such tropical-derived cyclones of higher latitudes can be violent and may occasionally remain at hurricane-force wind speeds when they reach Europe as a European windstorm. Mudslide in La Conchita, California A mudslide is a landslide of mud. ... Freshwater marsh in Florida In geography, a marsh is a type of wetland, featuring grasses, rushes, reeds, typhas, sedges, and other herbaceous plants (possibly with low-growing woody plants) in a context of shallow water. ... Wind shear is a difference in wind speed and/or direction between two points in the atmosphere. ... Extratropical is a term used in advisories and tropical summaries to indicate that a cyclone has lost its tropical characteristics. ... A guide to the symbols for weather fronts that may be found on a weather map: 1. ... A low pressure area, or a low for short, is a region where the atmospheric pressure is lowest with relation to the surrounding area. ... Extratropical is a term used in advisories and tropical summaries to indicate that a cyclone has lost its tropical characteristics. ... A European windstorm is a severe cyclonic storm that tracks across the North Atlantic towards northwestern Europe in the winter months. ...


Artificial dissipation

In the 1960s and 1970s, the United States government attempted to weaken hurricanes in its Project Stormfury by seeding selected storms with silver iodide. It was thought that the seeding would disrupt the storm's eyewall, causing it to collapse and thus reduce the winds. The winds of Hurricane Debbie dropped as much as 30 percent, but then regained their strength after each of two seeding forays. In an earlier episode, disaster struck when a hurricane east of Jacksonville, Florida, was seeded, promptly changed its course, and smashed into Savannah, Georgia. Because there was so much uncertainty about the behavior of these storms, the federal government would not approve seeding operations unless the hurricane had a less than 10 percent chance of making landfall within 48 hours. This placed severe restrictions on the project, and when the Navy pulled out in 1972, it all but killed any further attempts at hurricane seeding in the Atlantic. Project Stormfury was an attempt to weaken hurricanes by using cloud seeding in the eyewall of these storms. ... Cloud seeding is the attempt to change the amount or type of precipitation that falls out of clouds or the structure of clouds by dispersing substances into the air which allow water droplets or ice crystals to form more easily. ... Silver iodide (chemical symbol: AgI) is a chemical compound used in photography and cloud seeding. ... Nickname: Where Florida Begins Motto: Official website: http://www. ... Nickname: The Coastal Empire or The Hostess City Motto: Official website: Savannah, Georgia Location Government County Chatham Mayor Otis S. Johnson Geographical characteristics Area Total 202. ... 1972 (MCMLXXII) was a leap year that started on a Tuesday. ...


It was later discovered that eyewall disruption happens naturally as part of eyewall replacement cycles, and so the success of the program was impossible to gauge. Eye of Typhoon Odessa, Pacific Ocean, August 1985 The eyewall is the region of a tropical cyclone where the winds are the highest, the clouds reach furthest into the atmosphere and the precipitation is the heaviest. ...


Other approaches have been suggested over time, including cooling the water under a tropical cyclone by towing icebergs into the tropical oceans; dropping large quantities of ice into the eye at very early stages so that latent heat is absorbed by ice at the entrance (storm cell perimeter bottom) instead of heat energy being converted to kinetic energy at high altitudes vertically above; covering the ocean in a substance that inhibits evaporation; or blasting the cyclone apart with nuclear weapons. These approaches all suffer from the same flaw: tropical cyclones are simply too large for any of them to be practical [3]. However, it has been suggested by some that we can change the course of a storm during its early stages of formation, (detailed by an article, Controlling Hurricanes, Scientific American, 2005), such as using satellite to alter the environmental conditions or, more realistically, spreading degradable film of oil over the ocean, which prevent water vapor from fueling the storm. An iceberg (a partial loan translation to Dutch ijsberg, berg being the Dutch word for mountain) is a large piece of ice that has broken off from a snow-formed glacier or ice shelf and is floating in open water. ...


Monitoring, observation and tracking

Intense tropical cyclones pose a particular observation challenge. As they are a dangerous oceanic phenomenon, weather stations are rarely available on the site of the storm itself. Surface level observations are generally available only if the storm is passing over an island or a coastal area, or it has overtaken an unfortunate ship. Even in these cases, real-time measurement taking is generally possible only in the periphery of the cyclone, where conditions are less catastrophic. A technician checks data from a weather station. ...


It is however possible to take in-situ measurements, in real-time, by sending specially equipped reconnaissance flights into the cyclone. In the Atlantic basin, these flights are regularly flown by US government hurricane hunters [4]. The aircraft used are WC-130 Hercules and WP-3D Orions, both four-engine turboprop cargo aircraft. These aircraft fly directly into the cyclone and take direct and remote-sensing measurements. The aircraft also launch GPS dropsondes inside the cyclone. These sondes measure temperature, humidity, pressure, and especially winds between flight level and the ocean's surface. Hurricane Hunters is the nickname given to two groups that fly instrumented aircraft into Atlantic tropical cyclones (hurricanes) to collect data. ... The WC-130 Hercules is a high-wing, medium-range aircraft flown by the Air Force Reserve Command for weather reconnaissance missions. ... Categories: Stub | Special-purpose aircraft ... A schematic diagram showing the operation of a turboprop engine. ... A device created by National Center for Atmospheric Research (NCAR) to more accurately track tropical storm conditions. ...


A new era in hurricane observation began when a remotely piloted Aerosonde, a small drone aircraft, was flown through Tropical Storm Ophelia as it passed Virginia's Eastern Shore during the 2005 hurricane season. This demonstrated a new way to probe the storms at low altitudes that human pilots seldom dare[5].


Tropical cyclones far from land are tracked by weather satellites using visible light and infrared bands. These satellite images are received regularly on half hour intervals. As the hurricane approaches land, the cyclone can also be imaged remotely by a nationwide system of Doppler radar. Land-based Doppler radars play a crucial role during landfall because they give forecasters the ability to see the storms location and intensity minute by minute. A weather satellite is a type of artificial satellite that is primarily used to monitor the weather and climate of the Earth. ... The optical spectrum (light or visible spectrum) is the portion of the electromagnetic spectrum that is visible to the human eye. ... Image of a small dog taken in mid-infrared (thermal) light (false color) Infrared (IR) radiation is electromagnetic radiation of a wavelength longer than that of visible light, but shorter than that of microwave radiation. ... Doppler radar uses the Doppler effect to return additional information from a radar system. ...


Recently, university researchers have begun to deploy mobile weather stations fortified to withstand hurricane-force winds. The two largest programs are the Florida Coastal Monitoring Program [6] and the Wind Engineering Mobile Instrumented Tower Experiment [7]. During landfall, the NOAA Hurricane Research Division compares and quality controls reconnaissance aircraft data—which include flight-level, GPS sonde and stepped frequency microwave radiometer wind speed estimates—to wind speed data transmitted in real-time from weather stations erected near or at the coast. The National Hurricane Center uses these data to evaluate conditions at landfall and to verify its forecasts.


Naming of tropical cyclones

Storms reaching tropical storm strength (winds exceeding 17 metres per second, 38 mph, or 62 km/h) are given names, to assist in recording insurance claims, to assist in warning people of the coming storm, and to further indicate that these are important storms that should not be ignored. These names are taken from lists which vary from region to region and are drafted a few years ahead of time. The lists are decided upon, depending on the regions, either by committees of the World Meteorological Organization (called primarily to discuss many other issues), or by national weather services involved in the forecasting of the storms.


Each year, the names of particularly destructive storms (if there were any) are "retired" and new names are chosen to take their place.

Because of their long-term persistence, and the need for a unique identifier in issuing forecasts and warnings, tropical cyclones are given names. ...

Naming schemes

The WMO's Regional Association IV Hurricane Committee selects the names for Atlantic Basin and central and eastern Pacific storms.


In the Atlantic and Eastern North Pacific regions, feminine and masculine names are assigned alternately in alphabetic order during a given season. The "gender" of the season's first storm also alternates year to year: the first storm of an odd-numbered year gets feminine name, while the first storm of an even-numbered year gets a masculine name. Six lists of names are prepared in advance, and each list is used once every six years. Five letters — "Q," "U," "X," "Y" and "Z" — are omitted in the Atlantic; only "Q" and "U" are omitted in the Eastern Pacific, so the format accommodates 21 or 24 named storms in a hurricane season. Names of storms may be retired by request of affected countries if they have caused extensive damage. The affected countries then decide on a replacement name of the same gender (and if possible, the same ethnicity) as the name being retired.


If there are more than 21 named storms in an Atlantic season or 24 named storms in an Eastern Pacific season, the rest are named as letters from the Greek alphabet: the 22nd storm is called "Alpha," the 23rd "Beta," and so on. This was first necessary during the 2005 season when the names Alpha, Beta, Gamma, Delta, Epsilon, and Zeta were all used. There is no precedent for a storm named with a Greek Letter causing enough damage to justify retirement; how this situation would be handled is unknown. Note: This article contains special characters. ... The 2005 Atlantic hurricane season officially began June 1, 2005 and officially ended on November 30, 2005 although effectively the season persisted into January of 2006 due to continued storm activity. ...

Further information: List of notable tropical cyclones This is a list of notable tropical cyclones, subdivided by basin and reason for notability. ...


In the Central North Pacific region, the name lists are maintained by the Central Pacific Hurricane Center in Honolulu, Hawaii. Four lists of Hawaiian names are selected and used in sequential order without regard to year. On September 11, 1992, Hurricane Iniki caused more than USD $3 billion of damage in Hawaii. ... Nickname: Motto: Official website: Location Location of Honolulu within the City & County of Honolulu, Hawaii. ... Hawaiian is the ancestral language of the indigenous people of the Hawaiian Islands, the Hawaiians, a Polynesian people. ...


In the Western North Pacific, name lists are maintained by the WMO Typhoon Committee. Five lists of names are used, with each of the 14 nations on the Typhoon Committee submitting two names to each list. Names are used in the order of the countries' English names, sequentially without regard to year. Japan Meteorological Agency uses a secondary naming system in Western North Pacific that numbers a typhoon on the order it formed, resetting on December 31 of every year. The Typhoon Songda in September 2004 is internally called the typhoon number 18 and is recorded as the typhoon 0418 with 04 taken from the year. Japan Meteorological Agency (気象庁) is a government agency, which is a central place responsible for gathering and reporting weather data and forecasts in Japan. ...


The Australian Bureau of Meteorology maintains three lists of names, one for each of the Western, Northern and Eastern Australian regions. There are also Fiji region and Papua New Guinea region names. The Bureau of Meteorology is an Australian government organisation responsible for providing weather services to Australia and surrounding areas. ...


The Seychelles Meteorological Service maintains a list for the Southwest Indian Ocean.


History of tropical cyclone naming

For several hundred years after Europeans arrived in the West Indies, hurricanes there were named after the saint's day on which the storm struck. The Caribbean or the West Indies is a group of islands in the Caribbean Sea. ... The calendar of saints is a traditional Christian method of organising a liturgical year on the level of days by associating each day with a saint, and referring to the day as the saints day of that saint. ...


The practice of giving storms people's names was introduced by Clement Lindley Wragge, an Anglo-Australian meteorologist at the end of the 19th century. He used feminine names, the names of politicians who had offended him, and names from history and mythology. Portrait of Clement Lindley Wragge. ... Meteorology is the scientific study of the atmosphere that focuses on weather processes and forecasting. ...


During World War II, tropical cyclones were given feminine names, mainly for the convenience of the forecasters and in a somewhat ad hoc manner. For a few years afterwards, names from the Joint Army/Navy Phonetic Alphabet were used. Combatants Allied Powers Axis Powers Commanders {{{commander1}}} {{{commander2}}} Strength {{{strength1}}} {{{strength2}}} Casualties 17 million military deaths 7 million military deaths {{{notes}}} World War II, also known as the Second World War (sometimes WW2 or WWII or World War Two), was a mid-20th century conflict that engulfed much of the... Ad hoc is a Latin phrase which means for this [purpose]. It generally signifies a solution that has been tailored to a specific purpose, such as a tailor-made suit, a handcrafted network protocol, and specific-purpose equation and things like that. ... The Joint Army/Navy Phonetic Alphabet was developed in 1941 and was used by all branches of the United States military until the promulgation of the NATO phonetic alphabet in 1956, which replaced it. ...


The modern naming convention came about in response to the need for unambiguous radio communications with ships and aircraft. As transportation traffic increased and meteorological observations improved in number and quality, several typhoons, hurricanes or cyclones might have to be tracked at any given time. To help in their identification, beginning in 1953 the practice of systematically naming tropical storms and hurricanes was initiated by the United States National Hurricane Center, and is now maintained by the WMO. 1953 (MCMLIII) is a common year starting on Thursday. ... The US National Hurricane Center is the division of National Weather Services Tropical Prediction Center responsible for tracking and predicting the likely behavior of tropical depressions, tropical storms and hurricanes. ... The World Meteorological Organization (WMO) is an intergovernmental organization with a membership of 187 Member States and Territories. ...


In keeping with the common English language practice of referring to inanimate objects such as boats, trains, etc., using the female pronoun "she," names used were exclusively feminine. The first storm of the year was assigned a name beginning with the letter "A", the second with the letter "B", etc. However, since tropical storms and hurricanes are primarily destructive, some considered this practice sexist. The National Weather Service responded to these concerns in 1979 with the introduction of masculine names to the nomenclature. It was also in 1979 that the practice of preparing a list of names before the season began. The names are usually of English, French or Spanish origin in the Atlantic basin, since these are the three predominant languages of the region where the storms typically form. The English language is a West Germanic language that originates in England. ... The sign of the headquarters of the National Association Opposed To Woman Suffrage Sexism is commonly considered to be discrimination against people based on their sex rather than their individual merits, but can also refer to any and all differentiations based on sex. ... The National Weather Service (NWS) is one of the six scientific agencies that make up the National Oceanic and Atmospheric Administration (NOAA) of the United States government. ... This page refers to the year 1979. ... The English language is a West Germanic language that originates in England. ...


Renaming of tropical cyclones

In most cases, a tropical cyclone retains its name throughout its life. However, a tropical cyclone may be renamed in several occasions.


1. A tropical storm enters the southwestern Indian Ocean from the east


In the south Indian Ocean, RSMC la Reunion names a tropical storm once it crosses 90°E from the east, even though it has been named. In this case, the Joint Typhoon Warning Center (JTWC) will put two names together with a hyphen. The Joint Typhoon Warning Center (JTWC) is a division of the United States Navys Naval Pacific Meteorology and Oceanography Center in Pearl Harbor, Hawaii. ...


Examples: Bertie-Alvin (2005) The 2005-06 Southern Hemisphere tropical cyclone season runs from late October and ends in May, reaching its peak mid-February to early March. ... 2005 (MMV) was a common year starting on Saturday of the Gregorian calendar. ...


2. A tropical storm crosses from the Atlantic into the Pacific, or vice versa, before 2001


It was the policy of National Hurricane Center (NHC) to rename a tropical storm which crossed from Atlantic into Pacific, or vice versa. The U.S. National Hurricane Center is the division of National Weather Services Tropical Prediction Center responsible for tracking and predicting the likely behavior of tropical depressions, tropical storms and hurricanes. ...


Examples: Cesar-Douglas (1996), Joan-Miriam (1988) Hurricane Cesar was the third named storm of the 1996 Atlantic hurricane season. ... 1996 (MCMXCVI) is a leap year starting on Monday of the Gregorian calendar, and was designated the International Year for the Eradication of Poverty. ... ... 1988 (MCMLXXXVIII) was a leap year starting on a Friday of the Gregorian calendar. ...


In 2001, when Iris moved across Central America, NHC mentioned that Iris would retain its name if it regenerated in the Pacific. However, the Pacific tropical depression developed from the remnants of Iris was called Fifteen-E instead. The depression later became tropical storm Manuel.


NHC explained that Iris had dissipated as a tropical cyclone prior to entering the eastern North Pacific basin; the new depression was properly named Fifteen-E, rather than Iris.


In 2003, when Larry was about to move across Mexico, NHC attempted to provide greater clarity:

Should Larry remain a tropical cyclone during its passage over Mexico into the Pacific, it would retain its name. However, a new name would be given if the surface circulation dissipates and then regenerates in the Pacific.

Up to now, there has been no tropical cyclone retaining its name during the passage from Atlantic to Pacific, or vice versa.


3. Uncertainties of the continuation


When the remnants of a tropical cyclone redevelop, the redeveloping system will be treated as a new tropical cyclone if there are uncertainties of the continuation, even though the original system may contribute to the forming of the new system.


Example: TD 10-TD 12 (2005) The 2005 Atlantic hurricane season officially began June 1, 2005 and officially ended on November 30, 2005 although effectively the season persisted into January of 2006 due to continued storm activity. ... Hurricane Katrina was the eleventh named tropical storm, fifth hurricane, third major hurricane, and first Category 5 hurricane of the 2005 Atlantic hurricane season. ... The 2005 Atlantic hurricane season officially began June 1, 2005 and officially ended on November 30, 2005 although effectively the season persisted into January of 2006 due to continued storm activity. ...


4. Human faults


Sometimes, there may be human faults leading to the renaming of a tropical cyclone.


Example: Ken-Lola (1989) The 1989 Pacific typhoon season has no official bounds; it ran year-round in 1989, but most tropical cyclones tend to form in the northwestern Pacific Ocean between June and December. ... The 1989 Pacific typhoon season has no official bounds; it ran year-round in 1989, but most tropical cyclones tend to form in the northwestern Pacific Ocean between June and December. ...


Effects

The aftermath of Hurricane Katrina in Gulfport, Mississippi. Katrina was the most costly tropical cyclone in United States history.
The aftermath of Hurricane Katrina in Gulfport, Mississippi. Katrina was the most costly tropical cyclone in United States history.

A mature tropical cyclone can release heat at a rate upwards of 6x1014 watts [8]. Tropical cyclones on the open sea cause large waves, heavy rain, and high winds, disrupting international shipping and sometimes sinking ships. However, the most devastating effects of a tropical cyclone occur when they cross coastlines, making landfall. A tropical cyclone moving over land can do direct damage in four ways. ImageMetadata File history File links Download high resolution version (3008x2000, 2706 KB) Hurricane Katrina damage in Long Beach, Mississippi, which is west of Gulfport and east of Pass Christian. ... ImageMetadata File history File links Download high resolution version (3008x2000, 2706 KB) Hurricane Katrina damage in Long Beach, Mississippi, which is west of Gulfport and east of Pass Christian. ... Hurricane Katrina was the eleventh named tropical storm, fifth hurricane, third major hurricane, and first Category 5 hurricane of the 2005 Atlantic hurricane season. ... Gulfport is a city located in Harrison County, Mississippi. ...

  • High winds - Hurricane strength winds can damage or destroy vehicles, buildings, bridges, etc. High winds also turn loose debris into flying projectiles, making the outdoor environment even more dangerous.
  • Storm surge - Tropical cyclones cause an increase in sea level, which can flood coastal communities. This is the worst effect, as cyclones claim 80% of their victims when they first strike shore.
  • Heavy rain - The thunderstorm activity in a tropical cyclone causes intense rainfall. Rivers and streams flood, roads become impassable, and landslides can occur.
  • Tornado activity - The broad rotation of a hurricane often spawns tornadoes. While these tornadoes are normally not as strong as their non-tropical counterparts, they can still cause tremendous damage.
Graphic illustrating storm surge
Graphic illustrating storm surge

Often, the secondary effects of a tropical cyclone are equally damaging. They include: Wind is the roughly horizontal movement of air (as opposed to an air current) caused by uneven heating of the Earths surface. ... ... Rain falling For other uses see Rain (disambiguation). ... A roll cloud associated with a heavy or severe thunderstorm over Enschede, The Netherlands. ... Union City, Oklahoma tornado (1973) A tornado is a violent spinning storm typically shaped like a funnel with the narrow end on the ground. ... Image File history File links http://earthobservatory. ...

  • Disease - The wet environment in the aftermath of a tropical cyclone, combined with the destruction of sanitation facilities and a warm tropical climate, can induce epidemics of disease which claim lives long after the storm passes. One of the most common post-hurricane injuries is stepping on a nail in storm debris, leading to a risk of tetanus or other infection. Infections of cuts and bruises can be greatly amplified by wading in sewage-polluted water.
  • Power outages - Tropical cyclones often knock out power to tens or hundreds of thousands of people (or occasionally millions if a large urban area is affected), prohibiting vital communication and hampering rescue efforts.
  • Transportation difficulties - Tropical cyclones often destroy key bridges, overpasses, and roads, complicating efforts to transport food, clean water, and medicine to the areas that need it.

Nail or nails can mean Look up nail in Wiktionary, the free dictionary. ... Tetanus is a serious and often fatal disease caused by the neurotoxin tetanospasmin which is produced by the Gram-positive, obligate anaerobic bacterium Clostridium tetani. ... The Lachine Canal, in Montreal, is badly polluted Pollution is the release of harmful environmental contaminants, or the substances so released. ...

Beneficial effects of tropical cyclones

Although cyclones take an enormous toll in lives and personal property, they may bring much-needed precipitation to otherwise dry regions. Hurricane Allen ended the Texas drought of 1980. Hurricane Camille averted drought conditions and ended water deficits along much of its path. Hurricane Floyd did the same thing in New Jersey in 1999. The destruction caused by Camille on the Gulf coast spurred redevelopment as well, greatly increasing local property values. On the other hand, disaster response officials point out that redevelopment encourages more people to live in clearly dangerous areas subject to future deadly storms (as shown by the effects of Hurricane Katrina). Of course, many former residents and businesses do relocate to inland areas away from the threat of future hurricanes as well. ... Hurricane Camille was a Category 5 hurricane that struck the United States at peak intensity near the mouth of the Mississippi River on the night of August 17 during the 1969 Atlantic hurricane season, causing catastrophic damage. ... Hurricane Floyd was the sixth named storm, fourth hurricane, and third major hurricane in the 1999 Atlantic hurricane season. ... Hurricane Katrina was the eleventh named tropical storm, fifth hurricane, third major hurricane, and first Category 5 hurricane of the 2005 Atlantic hurricane season. ...


Hurricanes also help to maintain global heat balance by moving warm, moist tropical air to the mid-latitudes and polar regions.


Long term trends in cyclone activity

While the number of storms in the Atlantic has increased since 1995, there seems to be no signs of a global trend; the annual global number of tropical cyclones remains about 90 ± 10. [9].


Atlantic storms are certainly becoming more destructive financially, since five of the ten most expensive storms in United States history have occurred since 1990. This can to a large extent be attributed to the number of people living in susceptible coastal area, and massive development in the region since the last surge in Atlantic hurricane activity in the 1960s. This article is about the year. ...


Often in part because of the threat of hurricanes, many coastal regions had sparse population between major ports until the advent of automobile tourism; therefore, the most severe portions of hurricanes striking the coast often went unmeasured. The combined effects of ship destruction and remote landfall severely limit the number of intense hurricanes in the official record before the era of hurricane reconnaissance aircraft and satellite meteorology. Although the record shows a distinct increase in the number and strength of intense hurricanes, therefore, experts regard the early data as suspect.


The number and strength of Atlantic hurricanes may undergo a 50-70-year cycle. Although more common since 1995, few above-normal hurricane seasons occurred during 1970-1994. Destructive hurricanes struck frequently from 1926-60, including many major New England hurricanes. A record 21 Atlantic tropical storms formed in 1933, only recently exceeded in 2005. Tropical hurricanes occurred infrequently during the seasons of 1900-1925; however, many intense storms formed 1870-1899. During the 1887 season, 19 tropical storms formed, of which a record 4 occurred after 1 November and 11 strengthened into hurricanes. Few hurricanes occurred in the 1840s to 1860s; however, many struck in the early 1800s, including an 1821 storm that made a direct hit on New York City which some historical weather experts say may have been as high as Category 4 in strength. November 1 is the 305th day of the year (306th in leap years) in the Gregorian Calendar, with 60 days remaining. ... 1821 was a common year starting on Monday (see link for calendar). ... Nickname: The Big Apple Motto: Official website: City of New York Location Location in the state of New York Government Counties (Boroughs) Bronx (The Bronx) New York (Manhattan) Queens (Queens) Kings (Brooklyn) Richmond (Staten Island) Mayor Michael Bloomberg (R) Geographical characteristics Area Total 468. ...


These unusually active hurricane seasons predated satellite coverage of the Atlantic basin that now enables forecasters to see all tropical cyclones. Before the satellite era began in 1961, tropical storms or hurricanes went undetected unless a ship reported a voyage through the storm. The official record, therefore, probably misses many storms in which no ship experienced gale-force winds, recognized it as a tropical storm (as opposed to a high-latitude extra-tropical cyclone, a tropical wave, or a brief squall), returned to port, and reported the experience.


Global warming?

A common question is whether global warming can or will cause more frequent or more fierce tropical cyclones. So far, virtually all climatologists seem to agree that a single storm, or even a single season, cannot clearly be attributed to a single cause such as global warming or natural variation [10]. The question is thus whether a statistical trend in frequency or strength of cyclones exists. The U.S. National Oceanic and Atmospheric Administration says in their Hurricane FAQ that "it is highly unlikely that global warming has (or will) contribute to a drastic change in the number or intensity of hurricanes." [11]. Global mean surface temperatures 1856 to 2005 Mean temperature anomalies during the period 1995 to 2004 with respect to the average temperatures from 1940 to 1980 Global warming is an increase in the average temperature of the Earths atmosphere and oceans. ... Climatology is the science that studies climates and investigates their phenomena and causes. ... A statistic (singular) is the result of applying a statistical algorithm to a set of data. ... Look up Trend in Wiktionary, the free dictionary Wikiquote has a collection of quotations related to: Trend The word trend has a number of possible meanings: In statistics, a trend is a long-term movement in time series data after other components have been accounted for. ... Motto: Official (Latin): E pluribus unum (1789 to 1956) (Translated: Out of Many, One) In God We Trust (1956 to present) Anthem: The Star-Spangled Banner Capital Washington, D.C. Largest city New York City Official language(s) None at federal level; English de facto Government  â€¢ President  â€¢ Vice President Federal... The National Oceanic and Atmospheric Administration (NOAA) is a scientific agency of the United States Department of Commerce focused on the conditions of the oceans and the atmosphere. ...


Regarding strength, a similar conclusion was consensus until recently. This consensus is now questioned by K. Emanuel (2005) (Nature 436, 686–688, preprint). In this article, K. Emanuel states that the potential hurricane destructiveness, a measure which combines strength, duration, and frequency of hurricanes, "is highly correlated with tropical sea surface temperature, reflecting well-documented climate signals, including multidecadal oscillations in the North Atlantic and North Pacific, and global warming." K. Emanuel further predicts "a substantial increase in hurricane-related losses in the twenty-first century". Kerry Emanuel is an American Professor of Meteorology currently working at MIT in Boston. ...


Along similar lines, P.J. Webster et al. published an article in Science 309, 1844-1846 examining "changes in tropical cyclone number, duration, and intensity" over the last 35 years, a period where satellite data is available. The main finding is that while the number of cyclones "decreased in all basins except the North Atlantic during the past decade" there is a "large increase in the number and proportion of hurricanes reaching categories 4 and 5". I.e., while the number of cyclones decreased overall, the number of very strong cyclones increased.


Both Emanuel and Webster et al., consider the sea surface temperature as of key importance in the development of cyclones. The question then becomes: what caused the observed increase in sea surface temperatures? In the Atlantic, it could be due to the Atlantic Multidecadal Oscillation (AMO), a 50–70 year pattern of temperature variability. K. Emanuel, however, found the recent temperature increase was outside the range of previous oscillations. So, both a natural variation (such as the AMO) and global warming could have made contributions to the warming of the tropical Atlantic over the past decades, but an exact attribution is so far impossible to make. [12] Upper: AMO index: the ten-year running mean of detrended Atlantic sea surface temperature anomaly (SSTA, °C) north of the equator. ...


While Emanuel analyzes total annual energy dissipation, Webster et al. analyze the slightly less relevant percentage of hurricanes in the combined categories 4 and 5, and find that this percentage has increased in each of six distinct hurricane basins: North Atlantic, North East and North West Pacific, South Pacific, and North and South Indian. Because each individual basin may be subject to intra-basin oscillations similar to the AMO, any single-basin statistic remains open to question. But if the local oscillations are not synchronized by some as-yet-unidentified global oscillation, the independence of the basins allows joint statistical tests that are more powerful than any set of individual basin tests. Unfortunately Webster et al. do not undertake any such test.


Under the assumption that the six basins are statistically independent except for the effect of global warming, Stoft has carried out the obvious paired t-test and found that the null-hypothesis of no impact of global warming on the percentage of category 4 & 5 hurricanes can be rejected at the 0.1% level—there is only a 1 in 1000 chance of simultaneously finding the observed six increases in the cat-4&5 percentages. This statistic needs refining because the variables being tested are not normally distributed with equal variances, but it may provide the best evidence yet that the impact of global warming on hurricane intensity has been detected. A t-test is any statistical hypothesis test in which the test statistic has a Students t-distribution if the null hypothesis is true. ...


Notable cyclones

Main article: List of notable tropical cyclones

Tropical cyclones that cause massive destruction are fortunately rare, but when they happen, they can cause damage in the thousands of lives and the billions of dollars. This is a list of notable tropical cyclones, subdivided by basin and reason for notability. ... This article is about general United States currency. ...


The deadliest tropical cyclone on record hit the densely populated Ganges Delta region of East Pakistan (now Bangladesh) on November 13, 1970, likely as a Category 3 tropical cyclone. It killed an estimated 500,000 people. The North Indian basin has historically been the deadliest, with three storms since 1900 killing over 100,000 people, each in Bangladesh. [13] The Bhola cyclone made landfall in East Pakistan (now Bangladesh) on 13 November 1970. ... Ganges Delta The Ganges Delta is a river delta in the south Asia region of Bengal, consisting of Bangladesh and the state of West Bengal, India. ... It has been suggested that East Bengal (province) be merged into this article or section. ... November 13 is the 317th day of the year (318th in leap years) in the Gregorian Calendar, with 48 days remaining. ... 1970 (MCMLXX) was a common year starting on Thursday. ... Category 3 can refer to either: Category 3 cable used for carrying data Category 3 hurricanes on the Saffir-Simpson Hurricane Scale. ...


In the Atlantic basin, at least two storms have killed more than 10,000 people. Hurricane Mitch during the 1998 Atlantic hurricane season caused severe flooding and mudslides in Honduras, killing about 18,000 people and changing the landscape enough that entirely new maps of the country were needed. The Galveston Hurricane of 1900, which made landfall at Galveston, Texas as an estimated Category 4 storm, killed 8,000 to 12,000 people, and remains the deadliest natural disaster in the history of the United States. The deadliest Atlantic storm on record was the Great Hurricane of 1780, which killed about 22,000 people in the Antilles. The Atlantic Basin includes the main body of the Atlantic Ocean, the Gulf of Mexico and the Caribbean Sea, but ommits other bodies of water considered to be a part of the Atlantic Ocean in the broad sense, such as the Mediteranean Sea. ... Hurricane Mitch was one of the most powerful tropical cyclones ever observed, with maximum sustained winds of 180 mph (290 km/h). ... First storm formed: Jul. ... ... The Strand The City of Galveston is the county seat of Galveston County located along the Gulf Coast region in the U.S. state of Texas within the Greater Houston area. ... The Great Hurricane of 1780 is considered the deadliest Atlantic tropical cyclone of all time. ... The Antilles now generally refers to the islands of the Caribbean or West Indies, except the Bahamas. ...

The relative sizes of Typhoon Tip, Tropical Cyclone Tracy, and the United States.
The relative sizes of Typhoon Tip, Tropical Cyclone Tracy, and the United States.

The most intense storm on record was Typhoon Tip in the northwestern Pacific Ocean in 1979, which had a minimum pressure of only 870 mbar and maximum sustained wind speeds of 190 mph (305 km/h). It weakened before striking Japan. Tip does not hold the record for fastest sustained winds in a cyclone alone alone; Typhoon Keith in the Pacific, and Hurricane Camille and Hurricane Allen in the North Atlantic currently share this record as well [14], although recorded wind speeds that fast are suspect, since most monitoring equipment is likely to be destroyed by such conditions. Illustrating the extremes in tropical cyclone sizes. ... Super Typhoon Tip was the most intense and largest tropical cyclone on record. ... This page refers to the year 1979. ... A millibar (mbar, also mb) is 1/1000th of a bar, a unit for measurement of pressure. ... The tenth of eleven TCs to attain super typhoon intensity in the western North Pacific during 1997, Keith formed at low latitudes in the Marshall Islands. ... Hurricane Camille was a Category 5 hurricane that struck the United States at peak intensity near the mouth of the Mississippi River on the night of August 17 during the 1969 Atlantic hurricane season, causing catastrophic damage. ... ...


Camille was the only storm to actually strike land while at that intensity, making it, with 190 mph (305 km/h) sustained winds and 210 mph (335 km/h) gusts, the strongest tropical cyclone of record to ever hit land. For comparison, these speeds are encountered at the center of a strong tornado, but Camille was much larger and long-lived than any tornado. Union City, Oklahoma tornado (1973) A tornado is a violent spinning storm typically shaped like a funnel with the narrow end on the ground. ...


Typhoon Nancy in 1961 had recorded wind speeds of 213 mph (343 km/h), but recent research indicates that wind speeds from the 1940s to the 1960s were gauged too high, and this is no longer considered the fastest storm on record. [15] Similarly, a gust caused by Typhoon Paka over Guam was recorded at 236 mph (380 km/h); however, this reading had to be discarded, since the anemometer was damaged by the storm. Had it been confirmed, this would be the strongest non-tornadic wind ever recorded at the Earth's surface. (The current record is held by a non-hurricane wind registering 231 mph (372 km/h) at Mount Washington in New Hampshire.) [16] 1961 (MCMLXI) was a common year starting on Sunday (link will take you to calendar). ... ... Anemometer installation on roof of Deconism Gallery, using three size 6, schedule 40 pipes in their original uncut 20 foot (6 m) lengths. ... Union City, Oklahoma tornado (1973) A tornado is a violent spinning storm typically shaped like a funnel with the narrow end on the ground. ... Earth is the third planet from the Sun. ... Mount Washington (formerly Agiocochook) is, at 6,288 ft. ... Official language(s) English Capital Concord Largest city Manchester Area  - Total  - Width  - Length  - % water  - Latitude  - Longitude Ranked 46th 24,239 km² 110 km 305 km 3. ...


Tip was also the largest cyclone on record, with a circulation 1,350 miles (2,170 km) wide. The average tropical cyclone is only 300 miles (480 km) wide. The smallest storm on record, 1974's Cyclone Tracy, which devastated Darwin, Australia, was roughly 30 miles (50 km) wide. [17] 1974 (MCMLXXIV) is a common year starting on Tuesday (click on link for calendar). ... ... Darwin is the territorial capital and most populous city of the Northern Territory. ...


Hurricane Iniki in 1992 was the most powerful storm to strike Hawaii in recorded history, hitting Kauai as a Category 4 hurricane, killing six and causing $3 billion in damage. Hurricane Iniki (Hawaiian for Enid) was the most powerful hurricane to strike the state of Hawaii and the Hawaiian Islands in recorded history, and at the time was one of the most costly hurricanes in the United States. ... 1992 (MCMXCII) was a leap year starting on Wednesday. ... Official language(s) Hawaiian and English Capital Honolulu Largest city Honolulu Area  - Total  - Width  - Length  - % water  - Latitude  - Longitude Ranked 43rd 28,337 km² n/a km 2,450 km 41. ... Kauai (usually called Kauai outside the Hawaiian Islands) is the oldest and fourth largest of the main Hawaiian Islands, having an area of 1,446 km² . Known also as the Garden Isle, Kauai lies 105 miles (170 kilometers) across the Kauai Channel, northwest of Oahu. ...

The first recorded South Atlantic hurricane
The first recorded South Atlantic hurricane

On March 26, 2004, Cyclone Catarina became the first recorded South Atlantic hurricane. Previous South Atlantic cyclones in 1991 and 2004 reached only tropical storm strength. Hurricanes may have formed there prior to 1960 but were not observed until weather satellites began monitoring the Earth's oceans in that year. Summary Image of Cyclone Catarina on March 26, 2004, the first South Atlantic hurricane ever recorded. ... Summary Image of Cyclone Catarina on March 26, 2004, the first South Atlantic hurricane ever recorded. ... March 26 is the 85th day of the year in the Gregorian Calendar (86th in leap years). ... 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... Hurricane Catarina redirects here, but should not be confused with Hurricane Katrina Cyclone Catarina was an extremely rare South Atlantic tropical cyclone. ... A South Atlantic tropical cyclone is an unusual weather event which occurs in the southern Atlantic Ocean, south of the equator. ... 1991 (MCMXCI) is a common year starting on Tuesday of the Gregorian calendar. ... 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... 1960 (MCMLX) was a leap year starting on Friday (link will take you to calendar). ... A weather satellite is a type of artificial satellite that is primarily used to monitor the weather and climate of the Earth. ...


A tropical cyclone need not be particularly strong to cause memorable damage; Tropical Storm Allison in June 2001 had its name retired for killing 41 people and causing over $5 billion damage in East Texas, even though it never became a hurricane; the damage from Allison was mostly due to flooding, not winds or storm surge. Hurricane Jeanne in 2004 was only a tropical storm when it made a glancing blow on Haiti, but the flooding and mudslides it caused killed over 3,000 people. 2 B C D E F G 9 H I J K L M N O Categories: | | | | | | | ... 2001: A Space Odyssey. ... Red counties show the core of East Texas, counties shown as pink may or may not be included in East Texas, and thus their inclusion varies from source to source. ... ... Hurricane Jeanne was the tenth named storm, the seventh hurricane, and the fifth major hurricane of the 2004 Atlantic hurricane season. ... 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ...


On August 29, 2005, Hurricane Katrina made landfall in Louisiana and Mississippi. The U.S. National Hurricane Center, in its August review of the tropical storm season stated that Katrina is probably the worst natural disaster in U.S. history. Its death toll is above 1300, mainly from flooding and the aftermath. It is also estimated to have caused an estimated $40 to $120 billion in damages. Before that, the most costly (in money, not human terms) storm had been 1992's Hurricane Andrew, which caused an estimated $25 billion in damage in Florida. August 29 is the 241st day of the year in the Gregorian Calendar (242nd in leap years), with 124 days remaining. ... 2005 (MMV) was a common year starting on Saturday of the Gregorian calendar. ... Hurricane Katrina was the eleventh named tropical storm, fifth hurricane, third major hurricane, and first Category 5 hurricane of the 2005 Atlantic hurricane season. ... Official language(s) English and French Capital Baton Rouge Largest city New Orleans at last census; probably Baton Rouge since Hurricane Katrina Area  - Total  - Width  - Length  - % water  - Latitude  - Longitude Ranked 31st 134,382 km² 210 km 610 km 16 29°N to 33°N 89°W to 94°W Population... To meet Wikipedias quality standards, this article or section may require cleanup. ... 1992 (MCMXCII) was a leap year starting on Wednesday. ... Hurricane Andrew was one of the most destructive hurricanes ever to hit the United States. ... Official language(s) English Capital Tallahassee Largest city Jacksonville Area  - Total  - Width  - Length  - % water  - Latitude  - Longitude Ranked 22nd 170,451 km² 260 km 800 km 17. ...


See also

Look up Tropical cyclone in Wiktionary, the free dictionary
   
Tropical cyclones Portal

Wikipedia does not have an article with this exact name. ... Wiktionary logo Wiktionary is a sister project to Wikipedia intended to be a free wiki dictionary (including thesaurus and lexicon) in every language. ... Image File history File links Portal. ... A neutercane is an antiquated meteorological term that was used between 1972 and 1973 by the National Hurricane Center. ... Hot Tower in Hurricane Bonnie 1998. ... Polar lows are similar in behavior and size to tropical cyclones, although generally much shorter lived. ... Eye of Typhoon Odessa, Pacific Ocean, August 1985 The eyewall is the region of a tropical cyclone where the winds are the highest, the clouds reach furthest into the atmosphere and the precipitation is the heaviest. ... A subtropical cyclone is a weather system that has some characteristics of a tropical cyclone and some characteristics of an extratropical cyclone. ... Cyclone - Wikipedia, the free encyclopedia /**/ @import /skins-1. ... In meteorology, an anticyclone (i. ... Catastrophe modeling (also known as cat modeling) is the process of using computer-assisted calculations to estimate the losses that could be sustained by a portfolio of properties due to a catastrophic event such as a hurricane or earthquake. ... The Saffir-Simpson Hurricane Scale is a scale classifying most Western Hemisphere tropical cyclones that exceed the levels of tropical depression and tropical storm and thereby become hurricanes. ... ... The following is a list of Pacific hurricane seasons. ... The following is a list of Pacific typhoon seasons. ... The following is a list of North Indian cyclone seasons. ... This is a list of notable tropical cyclones, subdivided by basin and reason for notability. ... // Introduction Tornadoes, cyclones, and other strong winds damage or destroy many buildings. ... Supplies and food Gas powered chain saw Gasoline Water-1 gallon of clean drinking water per person, enough for 2 weeks. ...

External links

Wikimedia Commons has media related to:

Image File history File links Commons-logo. ... The Wikimedia Commons (also called Commons or Wikicommons) is a repository of free content images, sound and other multimedia files. ...

Tracking and Warning

Regional Specialized Meteorological Centers

A map showing the location of the Bay of Bengal. ... Map of the Arabian Sea. ...

Past storms

  • Yearly World Tropical Storm Summary - About 10 years of origins and tracks, in color, up to present. Broken up by year and region; for example "Atlantic, 2005"
  • The Hurricane Hut - Information on all past storms to 1950, along with images and individual storm summaries.
  • Unisys historical and contemporary hurricane track data e.g. Atlantic 1968
  • United States Tropical Cyclone Rainfall Climatology - About 20 years of tropical cyclone histories with an emphasis on storm total rainfall, in color, up to present. Broken up by year and region
  • Hurricanes of the 1970s, including survivor stories and 1980s
  • Worldwide tropical cyclone tracks, 1979-1988
  • the EM-DAT International Disaster Database

Learning Resources

  • Create-a-Cane Interactive fun site from NOAA, allows to specify conditions and see how they impact storm formation
  • NASA Hurricane Web Page - Data, research, science & multimedia resources from NASA
  • WMO guide on cyclone terminology
  • NOVA scienceNOW: Hurricanes
  • Mariner's Guide for Hurricane Awareness (pdf)
  • The Hurricane Hut - Information on tropical cyclones, as well as information on hurricane naming, and all Atlantic storms 1950-2005

Miscellaneous

  • WebCamPlaza Big collection of hurricane webcams.
  • www.worldhurricanes.com- Lates news from the WN network.
  • Tropical Cyclones - Chapter from the online edition of Nathaniel Bowditch's American Practical Navigator
  • Hurricane Alley - tracking
  • Live Hurricane Talk and Information Archive
  • NOAA's Tropical Cyclone FAQ
  • Hurricanes & climate change
  • Global climatology of tropical cyclones
  • Caribbean Hurricane Network
  • 1995 Mediterranean "Hurricane"
  • Atlantic hurricanes track animations
  • Tropical cyclone pictures and movies, from the United Kingdom Met Office
  • Global Warming & Hurricanes - Review based on latest articles in Science and Nature. Graph of trends in 6 hurricane basins.
  • Hurricane Havens Handbook for the North Atlantic Ocean
  • Typhoon Havens Handbook for the Western Pacific and Indian Oceans
  • Tropical Storm Risk
  • Hurricanes, global warming, and global politics
  • Steve Gregory's Blog at Weather Underground
  • Dr. Jeff Masters Blog at Weather Underground
  • Hurricane Dictionary Hurricane and Tropical Storms
  • Natural Disasters - Hurricanes Great research site for kids.

Memorial statue for Nathaniel Bowditch, in Mount Auburn Cemetery, Cambridge, Massachusetts. ...



  Results from FactBites:
 
Tropical depression - definition of Tropical depression in Encyclopedia (4745 words)
Warm core: tropical cyclones are characterized and driven by the release of large amounts of latent heat of condensation as moist air is carried upwards and its water vapor condenses.
Tropical cyclones that cause massive destruction are fortunately rare, but when they happen, they can cause damage in the thousands of lives and the billions of dollars.
Tropical cyclones with winds exceeding 17 metres per second are given names, to assist in recording insurance claims, to assist in warning people of the coming storm, and to further indicate that these are important storms that should not be ignored.
FAQ : HURRICANES, TYPHOONS, AND TROPICAL CYCLONES (281 words)
Disturbances associated with perturbations in the wind field and progressing through the tropics from east to west are also known as easterly waves.
A tropical cyclone in which the maximum sustained wind speed (using the U.S. 1 minute average standard) is 33 kt (38 mph, 17 m/s).
A tropical cyclone in which the maximum sustained surface wind speed (using the U.S. 1 minute average standard) ranges from 34 kt (39 mph,17.5 m/s) to 63 kt (73 mph, 32.5 m/s).
  More results at FactBites »

 
 

COMMENTARY     


Share your thoughts, questions and commentary here
Your name
Your comments

Want to know more?
Search encyclopedia, statistics and forums:

 


Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 1022, m