Size

One measure of the size of a tropical cyclone is determined by measuring the distance from its center of circulation to its outermost closed isobar, also known as its ROCI. A contour line (also Level set, isopleth, isoline, isogram or isarithm) of a function of two If the radius is less than two degrees of latitude or 222 kilometres (138 mi), then the cyclone is "very small" or a "midget". Latitude, usually denoted symbolically by the Greek letter phi ( Φ) gives the location of a place on Earth (or other planetary body north or south of the Radii between 3 and 6 latitude degrees or 333 kilometres (207 mi) to 666 kilometres (414 mi) are considered "average sized". "Very large" tropical cyclones have a radius of greater than 8 degrees or 888 kilometres (552 mi). ^[13] Other methods of determining a tropical cyclone's size include measuring the radius of gale force winds and measuring the radius at which its relative vorticity field decreases to 1×10^-5 s^-1 from its center. Vorticity is a mathematical concept used in Fluid dynamics. It can be related to the amount of " circulation " or "rotation" (or more strictly the ^[14][15]

Mechanics

Tropical cyclones form when the energy released by the condensation of moisture in rising air causes a positive feedback loop over warm ocean waters. Positive feedback, sometimes referred to as "cumulative causation" is a Feedback loop system in which the system responds to perturbation in the same direction ^[16]

A tropical cyclone's primary energy source is the release of the heat of condensation from water vapor condensing at high altitudes, with solar heating being the initial source for evaporation. The enthalpy of vaporization, (symbol \Delta{}_{v}H also known as the heat of vaporization or heat of evaporation, is the Energy required Condensation is the change of the physical state of aggregation (or simply state of matter from gaseous phase into liquid phase Solar heating is the usage of Solar energy to provide process space or Water heating. Therefore, a tropical cyclone can be visualized as a giant vertical heat engine supported by mechanics driven by physical forces such as the rotation and gravity of the Earth. A heat engine is a physical or theoretical device that converts Thermal energy to mechanical output A rotation is a movement of an object in a circular motion A two- Dimensional object rotates around a center (or point) of rotation Gravitation is a natural Phenomenon by which objects with Mass attract one another ^[17] In another way, tropical cyclones could be viewed as a special type of mesoscale convective complex, which continues to develop over a vast source of relative warmth and moisture. A mesoscale convective complex (MCC is a unique kind of Mesoscale convective system which is defined by characteristics observed in infrared Satellite imagery. Condensation leads to higher wind speeds, as a tiny fraction of the released energy is converted into mechanical energy;^[18] the faster winds and lower pressure associated with them in turn cause increased surface evaporation and thus even more condensation. Much of the released energy drives updrafts that increase the height of the storm clouds, speeding up condensation. An updraft or downdraft ( air pocket) is the vertical movement of Air as a Weather related phenomenon ^[19] This positive feedback loop continues for as long as conditions are favorable for tropical cyclone development. Positive feedback, sometimes referred to as "cumulative causation" is a Feedback loop system in which the system responds to perturbation in the same direction Tropical cyclogenesis is the technical term describing the development and strengthening of a Tropical cyclone in the Atmosphere. Factors such as a continued lack of equilibrium in air mass distribution would also give supporting energy to the cyclone. The rotation of the Earth causes the system to spin, an effect known as the Coriolis effect,^[20] giving it a cyclonic characteristic and affecting the trajectory of the storm. In physics the Coriolis effect is an apparent deflection of moving objects when they are viewed from a Rotating frame of reference. ^[21]

What primarily distinguishes tropical cyclones from other meteorological phenomena is deep convection as a driving force. Convection in the most general terms refers to the movement of molecules within Fluids (i ^[22] Because convection is strongest in a tropical climate, it defines the initial domain of the tropical cyclone. A tropical climate is a kind of Climate typical in the Tropics. By contrast, mid-latitude cyclones draw their energy mostly from pre-existing horizontal temperature gradients in the atmosphere. Extratropical cyclones, sometimes called mid-latitude cyclones or wave cyclones, are a group of Cyclones defined as synoptic scale low In Vector calculus, the gradient of a Scalar field is a Vector field which points in the direction of the greatest rate of increase of the scalar ^[22] To continue to drive its heat engine, a tropical cyclone must remain over warm water, which provides the needed atmospheric moisture to maintain the positive feedback loop running. When a tropical cyclone passes over land, it is cut off from its heat source and its strength diminishes rapidly. ^[23]

Chart displaying the drop in surface temperature in the Gulf of Mexico as Hurricanes Katrina and Rita passed over

The passage of a tropical cyclone over the ocean can cause the upper layers of the ocean to cool substantially, which can influence subsequent cyclone development. The Gulf of Mexico ( Spanish: Golfo de México) is the ninth largest Body of water in the world Hurricane Katrina of the 2005 Atlantic hurricane season was the costliest hurricane, as well as one of the five deadliest in the history of the United States Hurricane Rita was the fourth-most intense Atlantic hurricane ever recorded and the most intense Tropical cyclone ever observed in the Gulf of Mexico Cooling is primarily caused by upwelling of cold water from deeper in the ocean due to the wind stresses the storm itself induces upon the sea surface. Additional cooling may come in the form of cold water from falling raindrops. Cloud cover may also play a role in cooling the ocean, by shielding the ocean surface from direct sunlight before and slightly after the storm passage. All these effects can combine to produce a dramatic drop in sea surface temperature over a large area in just a few days. ^[24]

Scientists at the US National Center for Atmospheric Research estimate that a tropical cyclone releases heat energy at the rate of 50 to 200 exajoules (10¹⁸ J) per day,^[19] equivalent to about 1 PW (10¹⁵ watt). The National Center for Atmospheric Research ( NCAR) is a non-governmental U The joule (written in lower case ˈdʒuːl or /ˈdʒaʊl/ (symbol J) is the SI unit of Energy measuring heat, Electricity This rate of energy release is equivalent to 70 times the world energy consumption of humans and 200 times the world-wide electrical generating capacity,^[19] or to exploding a 10-megaton nuclear bomb every 20 minutes. A nuclear weapon is an explosive device that derives its destructive force from Nuclear reactions either fission or a combination of fission and fusion. ^[25]

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. ^[17] This outflow produces high, thin cirrus clouds that spiral away from the center. Cirrus clouds are characterized by thin wisplike strands often accompanied by tufts leading to their common (non-standard name of 'mare's tail' These high cirrus clouds may be the first signs of an approaching tropical cyclone. ^[26]

Major basins and related warning centers

Main articles: Tropical cyclone basins, Regional Specialized Meteorological Centre, and Tropical Cyclone Warning Centre

Basins and WMO Monitoring Institutions[27] Basin Responsible RSMCs and TCWCs Northern Atlantic National Hurricane Center Northeastern Pacific National Hurricane Center North Central Pacific Central Pacific Hurricane Center Northwestern Pacific Japan Meteorological Agency Northern Indian Ocean Indian Meteorological Department Southwestern Indian Ocean Météo-France South and Southwestern Pacific Fiji Meteorological Service Meteorological Service of New Zealand† Papua New Guinea National Weather Service† Bureau of Meteorology† (Australia) Southeastern Indian Ocean Bureau of Meteorology† (Australia) Meteorological and Geophysical Agency† (Indonesia) †: Indicates a Tropical Cyclone Warning Centre

Map of the cumulative tracks of all tropical cyclones during the 1985–2005 time period. Northwestern Pacific Ocean See also Pacific typhoon The Northwest Pacific Ocean is the most active basin on the planet A Regional Specialized Meteorological Centre (also Regional Specialized Meteorological Center and Regional Specialised Meteorological Centre) is responsible for the A Tropical Cyclone Warning Centre is one of six regional warning centers that are part of the World Meteorological Organization Tropical cyclone programme and act The US National Hurricane Center, located at Florida International University in Miami Florida, is the division of National Weather Service The US National Hurricane Center, located at Florida International University in Miami Florida, is the division of National Weather Service The Central Pacific Hurricane Center of the United States National Weather Service is the official body responsible for tracking and issuing Tropical cyclone The or JMA, is the Japanese government's Weather service Charged with gathering and reporting weather data and forecasts in Japan it is a semi-autonomous The India Meteorological Department (IMD also referred to as the Met Office is a Government of India organisation that is responsible for meteorological observations weather Météo-France is the French national meteorological service The organisation was established by decree in June 1993 and is a department of the Ministry of Transportation The Fiji Meteorological Service is a Department of the government of Fiji responsible for providing Weather forecasting and is based in Nadi. Meteorological Service of New Zealand Limited ( MetService) has been in existence since 1992 when it was established as a State-Owned Enterprise. The Bureau of Meteorology is an Executive Agency of the Australian Government responsible for providing weather services to Australia and surrounding areas The Bureau of Meteorology is an Executive Agency of the Australian Government responsible for providing weather services to Australia and surrounding areas The Pacific Ocean west of the International Date Line sees more tropical cyclones than any other basin, while there is almost no activity in the Atlantic Ocean south of the Equator. The Pacific Ocean is the largest of the Earth 's Oceanic divisions The equator (sometimes referred to colloquially as "the Line") is the intersection of the Earth 's surface with the plane perpendicular to the

Map of all tropical cyclone tracks from 1945 to 2006. Equal-area projection.

There are six Regional Specialized Meteorological Centres (RSMCs) worldwide. A Regional Specialized Meteorological Centre (also Regional Specialized Meteorological Center and Regional Specialised Meteorological Centre) is responsible for the These organizations are designated by the World Meteorological Organization and are responsible for tracking and issuing bulletins, warnings, and advisories about tropical cyclones in their designated areas of responsibility. Additionally, there are six Tropical Cyclone Warning Centres (TCWCs) that provide information to smaller regions. A Tropical Cyclone Warning Centre is one of six regional warning centers that are part of the World Meteorological Organization Tropical cyclone programme and act ^[28] The RSMCs and TCWCs are not the only organizations that provide information about tropical cyclones to the public. The Joint Typhoon Warning Center (JTWC) issues advisories in all basins except the Northern Atlantic for the purposes of the United States Government. The Joint Typhoon Warning Center (JTWC is a joint United States Navy &ndash United States Air Force task force located at Naval Maritime Forecast Center The federal government of the United States is the central United States Governmental body established by the United States Constitution. ^[29] The Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) issues advisories and names for tropical cyclones that approach the Philippines in the Northwestern Pacific to protect the life and property of its citizens. The Philippine Atmospheric Geophysical and Astronomical Services Administration ( Filipino: Pangasiwaang Pilipino sa Palingkurang Atmosperiko Heopisikal at Astronomiko The Philippines ( Filipino: Pilipinas, officially known as the Republic of the Philippines (fil ''Republika ng Pilipinas'' RP ^[30] The Canadian Hurricane Centre (CHC) issues advisories on hurricanes and their remnants for Canadian citizens when they affect Canada. The Canadian Hurricane Centre (CHC is a division of the Meteorological Service of Canada, an agency of Canada's Department of the Environment, which exists to advise ^[31]

On March 26, 2004, Cyclone Catarina became the first recorded South Atlantic cyclone and subsequently struck southern Brazil with winds equivalent to Category 2 on the Saffir-Simpson Hurricane Scale. Events 1026 - Pope John XIX crowns Conrad II as Holy Roman Emperor. "MMIV" redirects here For the Modest Mouse album see " Baron von Bullshit Rides Again " Cyclone Catarina is one of several informal names for a South Atlantic tropical cyclone that hit southeastern Brazil in late March 2004 A South Atlantic Tropical cyclone is an unusual weather event |utc_offset = -2 to -4 |time_zone_DST = BRST |utc_offset_DST = -2 to -5 |cctld The Saffir-Simpson Hurricane Scale is a classification used for most Western Hemisphere Tropical cyclones that exceed the intensities of Tropical depressions As the cyclone formed outside the authority of another warning center, Brazilian meteorologists initially treated the system as an extratropical cyclone, although subsequently classified it as tropical. Extratropical cyclones, sometimes called mid-latitude cyclones or wave cyclones, are a group of Cyclones defined as synoptic scale low ^[32]

Formation

Main article: Tropical cyclogenesis

Times

Worldwide, tropical cyclone activity peaks in late summer, when the difference between temperatures aloft and sea surface temperatures is the greatest. Tropical cyclogenesis is the technical term describing the development and strengthening of a Tropical cyclone in the Atmosphere. However, each particular basin has its own seasonal patterns. On a worldwide scale, May is the least active month, while September is the most active. ^[33]

In the Northern Atlantic Ocean, a distinct hurricane season occurs from June 1 to November 30, sharply peaking from late August through September. Events 193 - Roman Emperor Didius Julianus is Assassinated 987 - Hugh Capet is elected Events 1700 - Battle of Narva — A Swedish army of 8500 men under Charles XII defeats ^[33] The statistical peak of the Atlantic hurricane season is September 10. The following is list of Atlantic hurricane seasons. The Atlantic hurricane season is the period in a year when hurricanes usually form in the Atlantic Ocean Events 506 - The Bishops of Visigothic Gaul meet in the Council of Agde. The Northeast Pacific Ocean has a broader period of activity, but in a similar time frame to the Atlantic. The Pacific Ocean is the largest of the Earth 's Oceanic divisions ^[34] The Northwest Pacific sees tropical cyclones year-round, with a minimum in February and March 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. ^[33]

In the Southern Hemisphere, tropical cyclone activity begins in late October and ends in May. Southern Hemisphere is the half of a Planet that is South of the Equator —the word hemisphere literally means 'half ball' Southern Hemisphere activity peaks in mid-February to early March. ^[33]

Factors

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. ^[36] While six factors appear to be generally necessary, tropical cyclones may occasionally form without meeting all of the following conditions. In most situations, water temperatures of at least 26. Sea surface temperature (SST is the water Temperature close to the surface 5 °C (79. 7 °F) are needed down to a depth of at least 50 metres (160 ft);^[37] waters of this temperature cause the overlying atmosphere to be unstable enough to sustain convection and thunderstorms. ^[38] Another factor is rapid cooling with height, which allows the release of the heat of condensation that powers a tropical cyclone. The enthalpy of vaporization, (symbol \Delta{}_{v}H also known as the heat of vaporization or heat of evaporation, is the Energy required ^[37] High humidity is needed, especially in the lower-to-mid troposphere; when there is a great deal of moisture in the atmosphere, conditions are more favorable for disturbances to develop. The troposphere is the lowest portion of Earth's atmosphere. It contains approximately 75% of the atmosphere's mass and almost all of its Water vapor and ^[37] Low amounts of wind shear are needed, as high shear is disruptive to the storm's circulation. Wind shear, sometimes referred to as windshear or Wind gradient, is a difference in Wind speed and direction over a relatively ^[37] Tropical cyclones generally need to form more than 555 kilometres (345 mi) or 5 degrees of latitude away from the equator, allowing the Coriolis effect to deflect winds blowing towards the low pressure center and creating a circulation. Latitude, usually denoted symbolically by the Greek letter phi ( Φ) gives the location of a place on Earth (or other planetary body north or south of the The equator (sometimes referred to colloquially as "the Line") is the intersection of the Earth 's surface with the plane perpendicular to the In physics the Coriolis effect is an apparent deflection of moving objects when they are viewed from a Rotating frame of reference. ^[37] Lastly, a formative tropical cyclone needs a pre-existing system of disturbed weather, although without a circulation no cyclonic development will take place. ^[37]

Locations

Most tropical cyclones form in a worldwide band of thunderstorm activity called by several names: the Intertropical Front (ITF),^[39] the Intertropical Convergence Zone (ITCZ),^[40] or the monsoon trough. The Intertropical Convergence Zone (ITCZ, also known as the Intertropical Front, Monsoon trough, Doldrums or the Equatorial The monsoon trough, also known as the Intertropical Convergence Zone ( ITCZ) is depicted by a line on a Weather map showing the locations of minimum sea ^[41] Another important source of atmospheric instability is found in tropical waves, which cause about 85% of intense tropical cyclones in the Atlantic ocean,^[42] and become most of the tropical cyclones in the Eastern Pacific basin. Tropical waves, or easterly waves, also known as African easterly waves in the Atlantic region are a type of Atmospheric trough, ^[43][44]

Tropical cyclones move westward equatorward of the subtropical ridge, intensifying as they move. Most of these systems form between 10 and 30 degrees away of the equator,^[45] and 87% form no farther away than 20 degrees of latitude, north or south. The equator (sometimes referred to colloquially as "the Line") is the intersection of the Earth 's surface with the plane perpendicular to the ^[46] Because the Coriolis effect initiates and maintains tropical cyclone rotation, tropical cyclones rarely form or move within about 5 degrees of the equator, where the Coriolis effect is weakest. In physics the Coriolis effect is an apparent deflection of moving objects when they are viewed from a Rotating frame of reference. ^[45] However, it is possible for tropical cyclones to form within this boundary as Tropical Storm Vamei did in 2001 and Cyclone Agni in 2004. Tropical Storm Vamei (international designation 0126, JTWC designation 32W, sometimes called Typhoon Vamei; formerly had the alternate Cyclone Agni (also referred to as Tropical Cyclone 05A) was a Tropical cyclone of the 2004 North Indian Ocean cyclone season. ^[47][48]

Movement and track

Steering winds

Although tropical cyclones are large systems generating enormous energy, their movements over the Earth's surface are controlled by large-scale winds—the streams in the Earth's atmosphere. The path of motion is referred to as a tropical cyclone's track and has been analogized by Dr. Neil Frank, former director of the National Hurricane Center, to "leaves carried along by a stream". The US National Hurricane Center, located at Florida International University in Miami Florida, is the division of National Weather Service ^[49]

Tropical systems, while generally located equatorward of the 20th parallel, are steered primarily westward by the east-to-west winds on the equatorward side of the subtropical ridge—a persistent high pressure area over the world's oceans. The equator (sometimes referred to colloquially as "the Line") is the intersection of the Earth 's surface with the plane perpendicular to the The subtropical ridge is a large belt of high pressure situated around 30°N in the Northern Hemisphere and 30°S in the Southern Hemisphere. ^[49] In the tropical North Atlantic and Northeast Pacific oceans, trade winds—another name for the westward-moving wind currents—steer tropical waves westward from the African coast and towards the Caribbean Sea, North America, and ultimately into the central Pacific ocean before the waves dampen out. The trade winds (also called trades) are the prevailing pattern of easterly winds found in the Tropics near the Earth's Equator. Tropical waves, or easterly waves, also known as African easterly waves in the Atlantic region are a type of Atmospheric trough, ^[43] These waves are the precursors to many tropical cyclones within this region. ^[42] In the Indian Ocean and Western Pacific (both north and south of the equator), tropical cyclogenesis is strongly influenced by the seasonal movement of the Intertropical Convergence Zone and the monsoon trough, rather than by easterly waves. The Intertropical Convergence Zone (ITCZ, also known as the Intertropical Front, Monsoon trough, Doldrums or the Equatorial The monsoon trough, also known as the Intertropical Convergence Zone ( ITCZ) is depicted by a line on a Weather map showing the locations of minimum sea ^[41]

Coriolis effect

Infrared image of Cyclone Monica near peak intensity, showing clockwise rotation due to the Coriolis effect

The Earth's rotation imparts an acceleration known as the Coriolis effect, Coriolis acceleration, or colloquially, Coriolis force. Severe Tropical Cyclone Monica (JTWC designation 23P, also known as simply Cyclone Monica) was a Tropical cyclone that affected northern A clockwise motion is one that proceeds 'like the Clock 's hands' from the top to the right then down and then to the left and back to the top In physics the Coriolis effect is an apparent deflection of moving objects when they are viewed from a Rotating frame of reference. In physics the Coriolis effect is an apparent deflection of moving objects when they are viewed from a Rotating frame of reference. This acceleration causes cyclonic systems to turn towards the poles in the absence of strong steering currents. ^[50] The poleward portion of a tropical cyclone contains easterly winds, and the Coriolis effect pulls them slightly more poleward. The westerly winds on the equatorward portion of the cyclone pull slightly towards the equator, but, because the Coriolis effect weakens toward the equator, the net drag on the cyclone is poleward. Thus, tropical cyclones in the Northern Hemisphere usually turn north (before being blown east), and tropical cyclones in the Southern Hemisphere usually turn south (before being blown east) when no other effects counteract the Coriolis effect. Northern Hemisphere is the half of a Planet that is North of the Equator —the word hemisphere literally means 'half ball' Southern Hemisphere is the half of a Planet that is South of the Equator —the word hemisphere literally means 'half ball' ^[21]

The Coriolis effect also initiates cyclonic rotation, but it is not the driving force that brings this rotation to high speeds – that force is the heat of condensation. The enthalpy of vaporization, (symbol \Delta{}_{v}H also known as the heat of vaporization or heat of evaporation, is the Energy required ^[19]

Interaction with the mid-latitude westerlies

Storm track of Typhoon Ioke, showing recurvature off the Japanese coast in 2006

When a tropical cyclone crosses the subtropical ridge axis, its general track around the high-pressure area is deflected significantly by winds moving towards the general low-pressure area to its north. Hurricane Ioke (was also Typhoon Ioke, international designation 0612, JTWC designation 01C, and sometimes called Super For a topic outline on this subject see List of basic Japan topics. The subtropical ridge is a large belt of high pressure situated around 30°N in the Northern Hemisphere and 30°S in the Southern Hemisphere. When the cyclone track becomes strongly poleward with an easterly component, the cyclone has begun recurvature. ^[51] A typhoon moving through the Pacific Ocean towards Asia, for example, will recurve offshore of Japan to the north, and then to the northeast, if the typhoon encounters southwesterly winds (blowing northeastward) around a low-pressure system passing over China or Siberia. For a topic outline on this subject see List of basic Japan topics. China ( Wade-Giles ( Mandarin) Chung¹kuo² is a cultural region, an ancient Civilization, and depending on perspective a National Siberia (Сиби́рь Sibir) is the name given to the vast region constituting almost all of Northern Asia and for the most part currently serving Many tropical cyclones are eventually forced toward the northeast by extratropical cyclones in this manner, which move from west to east to the north of the subtropical ridge. Extratropical cyclones, sometimes called mid-latitude cyclones or wave cyclones, are a group of Cyclones defined as synoptic scale low An example of a tropical cyclone in recurvature was Typhoon Ioke in 2006, which took a similar trajectory. Hurricane Ioke (was also Typhoon Ioke, international designation 0612, JTWC designation 01C, and sometimes called Super ^[52]

Landfall

See also: List of notable tropical cyclones and Unusual areas of tropical cyclone formation

Officially, landfall is when a storm's center (the center of its circulation, not its edge) crosses the coastline. This is a list of notable Tropical cyclones, subdivided by basin and reason for notability Tropical cyclogenesis is the technical term describing the development and strengthening of a Tropical cyclone in the Atmosphere. Landfall is the event of a Tropical cyclone (also known as a hurricane or a Waterspout coming onto Land after being over water ^[53] Storm conditions may be experienced on the coast and inland hours before landfall; in fact, a tropical cyclone can launch its weakest winds over land, yet not make landfall; if this occurs, then it is said that the storm made a direct hit on the coast. ^[53] Due to this definition, the landfall area experiences half of a land-bound storm by the time the actual landfall occurs. For emergency preparedness, actions should be timed from when a certain wind speed or intensity of rainfall will reach land, not from when landfall will occur. ^[53]

Multiple storm interaction

Main article: Fujiwhara effect

When two cyclones approach one another, their centers will begin orbiting cyclonically about a point between the two systems. The Fujiwhara effect or Fujiwara interaction is a type of interaction between two nearby cyclonic vortices, causing them to appear to "orbit" The two vortices will be attracted to each other, and eventually spiral into the center point and merge. When the two vortices are of unequal size, the larger vortex will tend to dominate the interaction, and the smaller vortex will orbit around it. This phenomenon is called the Fujiwhara effect, after Dr. Sakuhei Fujiwhara. ^[54]

Dissipation

Factors

Tropical Storm Franklin, an example of a strongly sheared tropical cyclone in the Atlantic Basin during 2005

A tropical cyclone can cease to have tropical characteristics through several different ways. Tropical Storm Franklin was a Tropical storm over the western Atlantic Ocean during July of the 2005 Atlantic hurricane season. Wind shear, sometimes referred to as windshear or Wind gradient, is a difference in Wind speed and direction over a relatively One such way is if it moves over land, thus depriving it of the warm water it needs to power itself, quickly losing strength. ^[55] Most strong storms lose their strength very rapidly after landfall and become disorganized areas of low pressure within a day or two, or evolve into extratropical cyclones. Extratropical cyclones, sometimes called mid-latitude cyclones or wave cyclones, are a group of Cyclones defined as synoptic scale low While there is a chance a tropical cyclone could regenerate if it managed to get back over open warm water, if it remains over mountains for even a short time, weakening will accelerate. ^[56] Many storm fatalities occur in mountainous terrain, as the dying storm unleashes torrential rainfall,^[57] leading to deadly floods and mudslides, similar to those that happened with Hurricane Mitch in 1998. A flood is an overflow of an expanse of water that submerges land a deluge Mudslide redirects here it is also the name of a cocktail. A mudflow or mudslide is the most rapid (up to 80 km/h / 50 mph Hurricane Mitch was one of the deadliest and most powerful Hurricanes on record in the Atlantic basin with maximum sustained winds of 180 mph (285 km/h ^[58] Additionally, dissipation can occur if a storm remains in the same area of ocean for too long, mixing the upper 60 metres (200 ft) of water, dropping sea surface temperatures more than 5 °C (41 °F). ^[59] Without warm surface water, the storm cannot survive. ^[60]

A tropical cyclone can dissipate when it moves over waters significantly below 26. 5 °C (79. 7 °F). This will cause the storm to lose its tropical characteristics (i. e. thunderstorms near the center and warm core) and become a remnant low pressure area, which can persist for several days. This is the main dissipation mechanism in the Northeast Pacific ocean. ^[61] Weakening or dissipation can occur if it experiences vertical wind shear, causing the convection and heat engine to move away from the center; this normally ceases development of a tropical cyclone. Wind shear, sometimes referred to as windshear or Wind gradient, is a difference in Wind speed and direction over a relatively ^[62] Additionally, its interaction with the main belt of the Westerlies, by means of merging with a nearby frontal zone, can cause tropical cyclones to evolve into extratropical cyclones. Extratropical cyclones, sometimes called mid-latitude cyclones or wave cyclones, are a group of Cyclones defined as synoptic scale low This transition can take 1–3 days. ^[63] Even after a tropical cyclone is said to be extratropical or dissipated, it can still have tropical storm force (or occasionally hurricane/typhoon force) winds and drop several inches of rainfall. In the Pacific ocean and Atlantic ocean, such tropical-derived cyclones of higher latitudes can be violent and may occasionally remain at hurricane or typhoon-force wind speeds when they reach the west coast of North America. The Pacific Ocean is the largest of the Earth 's Oceanic divisions These phenomena can also affect Europe, where they are known as European windstorms; Hurricane Iris's extratropical remnants are an example of such a windstorm from 1995. A European windstorm is a severe cyclonic storm that tracks across the North Atlantic towards northwestern Europe in the winter months Hurricane Iris was the ninth named Tropical cyclone and fifth hurricane of an active 1995 Atlantic hurricane season. ^[64] Additionally, a cyclone can merge with another area of low pressure, becoming a larger area of low pressure. This can strengthen the resultant system, although it may no longer be a tropical cyclone. ^[62]

Artificial dissipation

In the 1960s and 1970s, the United States government attempted to weaken hurricanes through Project Stormfury by seeding selected storms with silver iodide. The federal government of the United States is the central United States Governmental body established by the United States Constitution. Project Stormfury was an attempt to weaken Tropical cyclones by flying aircraft into them and seeding with Silver iodide. Cloud seeding, a form of weather modification, is the attempt to change the amount or type of precipitation that falls from Clouds by dispersing substances Silver iodide ( Ag[[Iodine I]] is a Chemical compound used in Photography and as an Antiseptic in medicine It was thought that the seeding would cause supercooled water in the outer rainbands to freeze, causing the inner eyewall to collapse and thus reducing the winds. ^[65] The winds of Hurricane Debbie—a hurricane seeded in Project Stormfury—dropped as much as 31%, but Debby regained its strength after each of two seeding forays. TemplateHurricane season single. -->The 1969 Atlantic hurricane season officially began on June 1, 1969, and lasted until ^[66] In an earlier episode in 1947, disaster struck when a hurricane east of Jacksonville, Florida promptly changed its course after being seeded, and smashed into Savannah, Georgia. Savannah is a city located in the state of Georgia, United States. ^[67] 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% chance of making landfall within 48 hours, greatly reducing the number of possible test storms. The project was dropped after it was discovered that eyewall replacement cycles occur naturally in strong hurricanes, casting doubt on the result of the earlier attempts. The eye is a region of mostly calm Weather found at the center of strong Tropical cyclones The eye of a Storm is a roughly circular area and typically 30–65 km Today, it is known that silver iodide seeding is not likely to have an effect because the amount of supercooled water in the rainbands of a tropical cyclone is too low. ^[68]

Other approaches have been suggested over time, including cooling the water under a tropical cyclone by towing icebergs into the tropical oceans. An iceberg is a large piece of freshwater Ice that has broken off from a snow-formed Glacier or Ice shelf and is floating in open water ^[69] Other ideas range from covering the ocean in a substance that inhibits evaporation,^[70] dropping large quantities of ice into the eye at very early stages of development (so that the latent heat is absorbed by the ice, instead of being converted to kinetic energy that would feed the positive feedback loop),^[69] or blasting the cyclone apart with nuclear weapons. The enthalpy of vaporization, (symbol \Delta{}_{v}H also known as the heat of vaporization or heat of evaporation, is the Energy required ^[18] Project Cirrus even involved throwing dry ice on a cyclone. ^[71] These approaches all suffer from one flaw above many others: tropical cyclones are simply too large for any of the weakening techniques to be practical. ^[72]

Effects

The aftermath of Hurricane Katrina in Gulfport, Mississippi. Hurricane Katrina of the 2005 Atlantic hurricane season was the costliest hurricane, as well as one of the five deadliest in the history of the United States Gulfport is the second largest city in Mississippi after the state capital Jackson. Katrina was the costliest tropical cyclone in United States history.

Main article: Effects of tropical cyclones

Tropical cyclones out at sea cause large waves, heavy rain, and high winds, disrupting international shipping and, at times, causing shipwrecks. The effects of tropical cyclones are the impacts that Tropical cyclones have on the areas they move through ^[73] Tropical cyclones stir up water, leaving a cool wake behind them,^[24] which causes the region to be less favourable for subsequent tropical cyclones. On land, strong winds can damage or destroy vehicles, buildings, bridges, and other outside objects, turning loose debris into deadly flying projectiles. Wind is the flow of Air or other Gases that compose an Atmosphere (including but not limited to the Earth's) The storm surge, or the increase in sea level due to the cyclone, is typically the worst effect from landfalling tropical cyclones, historically resulting in 90% of tropical cyclone deaths. Storm surge or tidal surge is an offshore rise of water associated with a low pressure weather system typically a Tropical cyclone. ^[74] The broad rotation of a landfalling tropical cyclone, and vertical wind shear at its periphery, spawns tornadoes. Intense Tropical cyclones usually produce Tornadoes the majority of them weak upon landfall Tornadoes can also be spawned as a result of eyewall mesovortices, which persist until landfall. The eye is a region of mostly calm Weather found at the center of strong Tropical cyclones The eye of a Storm is a roughly circular area and typically 30–65 km ^[75]

Over the past two centuries, tropical cyclones have been responsible for the deaths of about 1. 9 million persons worldwide. Large areas of standing water caused by flooding lead to infection, as well as contributing to mosquito-borne illnesses. Crowded evacuees in shelters increase the risk of disease propagation. ^[76] Tropical cyclones significantly interrupt infrastructure, leading to power outages, bridge destruction, and the hampering of reconstruction efforts. ^[76][77]

Although cyclones take an enormous toll in lives and personal property, they may be important factors in the precipitation regimes of places they impact, as they may bring much-needed precipitation to otherwise dry regions. In Meteorology, precipitation (also known as one class of hydrometeors, which are atmospheric water phenomena is any product of the condensation of atmospheric ^[78] Tropical cyclones also help maintain the global heat balance by moving warm, moist tropical air to the middle latitudes and polar regions. The middle latitudes are between 33 degrees 33' 33" North and 66 degrees 33' 33" and 64 degrees 33' 33" South and 33 degrees 33' 33" South Latitude, or ^[79] The storm surge and winds of hurricanes may be destructive to human-made structures, but they also stir up the waters of coastal estuaries, which are typically important fish breeding locales. An estuary is a semi-enclosed Coastal body of Water with one or more Rivers or Streams flowing into it and with a free connection to the open Tropical cyclone destruction spurs redevelopment, greatly increasing local property values. ^[80]

Observation and forecasting

Observation

Main article: Tropical cyclone observation

Sunset view of Hurricane Isidore's rainbands photographed at 7,000 feet (2,100 m)

Intense tropical cyclones pose a particular observation challenge, as they are a dangerous oceanic phenomenon, and weather stations, being relatively sparse, are rarely available on the site of the storm itself. Tropical cyclone observation has been carried out over the past couple of centuries in various ways Hurricane Isidore was the ninth named storm and the second hurricane in the 2002 Atlantic hurricane season. A weather station is a facility with instruments and equipment to make observations of atmospheric conditions in order to provide information to make weather forecasts Surface observations are generally available only if the storm is passing over an island or a coastal area, or if there is a nearby ship. Usually, real-time measurements are taken in the periphery of the cyclone, where conditions are less catastrophic and its true strength cannot be evaluated. For this reason, there are teams of meteorologists that move into the path of tropical cyclones to help evaluate their strength at the point of landfall. ^[81]

Tropical cyclones far from land are tracked by weather satellites capturing visible and infrared images from space, usually at half-hour to quarter-hour intervals. A weather satellite is a type of Satellite that is primarily used to monitor the Weather and Climate of the Earth. Infrared ( IR) radiation is Electromagnetic radiation whose Wavelength is longer than that of Visible light, but shorter than that of As a storm approaches land, it can be observed by land-based Doppler radar. Pulse-Doppler is a Radar system capable of not only detecting target location (bearing range and altitude but also measuring its radial velocity (range-rate A weather radar is a type of Radar used to locate precipitation, calculate its motion estimate its type ( Rain Radar plays a crucial role around landfall by showing a storm's location and intensity every several minutes. ^[82]

In-situ measurements, in real-time, can be taken by sending specially equipped reconnaissance flights into the cyclone. In situ (ɪn siːˈtuː is a Latin phrase meaning in the place. In the Atlantic basin, these flights are regularly flown by United States government hurricane hunters. Hurricane Hunters are aircraft that fly into Tropical cyclones in the North Atlantic Ocean and Northeastern Pacific Ocean for the specific purpose of ^[83] The aircraft used are WC-130 Hercules and WP-3D Orions, both four-engine turboprop cargo aircraft. WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout A turboprop engine is a type of aircraft powerplant that uses a Gas turbine engine to drive a Propeller. These aircraft fly directly into the cyclone and take direct and remote-sensing measurements. The aircraft also launch GPS dropsondes inside the cyclone. Dropsonde is also an album by ambient musician Biosphere. A dropsonde is a Weather reconnaissance device created by the These sondes measure temperature, humidity, pressure, and especially winds between flight level and the ocean's surface. 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. The Aerosonde is a small Unmanned aerial vehicle (UAV designed to fly over oceans in order to collect weather data including Temperature, Atmospheric pressure A similar mission was also completed successfully in the western Pacific ocean. This demonstrated a new way to probe the storms at low altitudes that human pilots seldom dare. ^[84]

A general decrease in error trends in tropical cyclone path prediction is evident since the 1970s

Forecasting

See also: Tropical cyclone track forecasting, Tropical cyclone prediction model, and Tropical cyclone rainfall forecasting

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. Tropical cyclone track forecasting involves predicting where a Tropical cyclone is going to track over the next five days every 6 to 12 hours A tropical cyclone forecast model is a computer program that uses meteorological data to forecast the motion Tropical cyclone rainfall forecasting involves using scientific models and other tools to predict the precipitation expected in Tropical cyclones such as hurricanes and typhoons The deep layer mean flow, or average wind through the depth of the troposphere, is considered the best tool in determining track direction and speed. The troposphere is the lowest portion of Earth's atmosphere. It contains approximately 75% of the atmosphere's mass and almost all of its Water vapor and If storms are significantly sheared, use of wind speed measurements at a lower altitude, such as at the 700 hPa pressure surface (3,000 metres (9,800 ft) above sea level) will produce better predictions. The bar (symbol bar) decibar (symbol dbar) and the millibar (symbol mbar, also mb are units of Pressure. Tropical forecasters also consider smoothing out short-term wobbles of the storm as it allows them to determine a more accurate long-term trajectory. ^[85] High-speed computers and sophisticated simulation software allow forecasters to produce computer models that predict tropical cyclone tracks based on the future position and strength of high- and low-pressure systems. A tropical cyclone forecast model is a computer program that uses meteorological data to forecast the motion Combining forecast models with increased understanding of the forces that act on tropical cyclones, as well as with a wealth of data from Earth-orbiting satellites and other sensors, scientists have increased the accuracy of track forecasts over recent decades. ^[86] However, scientists are less skillful at predicting the intensity of tropical cyclones. ^[87] The lack of improvement in intensity forecasting is attributed to the complexity of tropical systems and an incomplete understanding of factors that affect their development.

Classifications, terminology, and naming

Intensity classifications

Main article: Tropical cyclone scales

Three tropical cyclones at different stages of development. Tropical cyclones are ranked according to their maximum winds using several scales The weakest (left), demonstrates only the most basic circular shape. A stronger storm (top right) demonstrates spiral banding and increased centralization, while the strongest (lower right) has developed an eye. A squall is a sudden sharp increase in wind speed which is usually associated with active weather such as rain showers thunderstorms or heavy snow The eye is a region of mostly calm Weather found at the center of strong Tropical cyclones The eye of a Storm is a roughly circular area and typically 30–65 km

Tropical cyclones are classified into three main groups, based on intensity: tropical depressions, tropical storms, and a third group of more intense storms, whose name depends on the region. For example, if a tropical storm in the Northwestern Pacific reaches hurricane-strength winds on the Beaufort scale, it is referred to as a typhoon; if a tropical storm passes the same benchmark in the Northeast Pacific Basin, or in the Atlantic, it is called a hurricane. The Beaufort scale (ˈboʊfət is an Empirical measure for describing Wind speed based mainly on observed sea conditions A Pacific hurricane or tropical storm is a Tropical cyclone that develops in the northeastern part of the Pacific Ocean. ^[53] Neither "hurricane" nor "typhoon" are used in either the Southern Hemisphere or the Indian Ocean. In these basins, storms of tropical nature are referred as simply "cyclones". Northwestern Pacific Ocean See also Pacific typhoon The Northwest Pacific Ocean is the most active basin on the planet

Additionally, as indicated in the table below, each basin uses a separate system of terminology, making comparisons between different basins difficult. Tropical cyclones are ranked according to their maximum winds using several scales In the Pacific Ocean, hurricanes from the Central North Pacific sometimes cross the International Date Line into the Northwest Pacific, becoming typhoons (such as Hurricane/Typhoon Ioke in 2006); on rare occasions, the reverse will occur. Hurricane Ioke (was also Typhoon Ioke, international designation 0612, JTWC designation 01C, and sometimes called Super ^[88] It should also be noted that typhoons with sustained winds greater than 67 metres per second (130 kn) or 150 miles per hour (240 km/h) are called Super Typhoons by the Joint Typhoon Warning Center. ^[89]

A tropical depression is an organized system of clouds and thunderstorms with a defined, closed surface circulation and maximum sustained winds of less than 17 metres per second (33 kn) or 39 miles per hour (63 km/h). The maximum sustained winds associated with a Tropical cyclone are a common indicator of the intensity of the storm It has no eye and does not typically have the organization or the spiral shape of more powerful storms. The eye is a region of mostly calm Weather found at the center of strong Tropical cyclones The eye of a Storm is a roughly circular area and typically 30–65 km However, it is already a low-pressure system, hence the name "depression". ^[17] The practice of the Philippines is to name tropical depressions from their own naming convention when the depressions are within the Philippines' area of responsibility. The Philippines ( Filipino: Pilipinas, officially known as the Republic of the Philippines (fil ''Republika ng Pilipinas'' RP ^[90]

A tropical storm is an organized system of strong thunderstorms with a defined surface circulation and maximum sustained winds between 17 metres per second (33 kn) (39 miles per hour (63 km/h)) and 32 metres per second (62 kn) (73 miles per hour (117 km/h)). At this point, the distinctive cyclonic shape starts to develop, although an eye is not usually present. Government weather services, other than the Philippines, first assign names to systems that reach this intensity (thus the term named storm). ^[17]

A hurricane or typhoon (sometimes simply referred to as a tropical cyclone, as opposed to a depression or storm) is a system with sustained winds of at least 33 metres per second (64 kn) or 74 miles per hour (119 km/h). ^[17] A cyclone of this intensity tends to develop an eye, an area of relative calm (and lowest atmospheric pressure) at the center of 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 16 kilometres (9. The eye is a region of mostly calm Weather found at the center of strong Tropical cyclones The eye of a Storm is a roughly circular area and typically 30–65 km 9 mi) to 80 kilometres (50 mi) wide in which the strongest thunderstorms and winds circulate around the storm's center. Maximum sustained winds in the strongest tropical cyclones have been estimated at about 85 metres per second (165 kn) or 195 miles per hour (314 km/h). ^[91]

Origin of storm terms

Taipei 101 endures a typhoon in 2005

The word hurricane, used in the North Atlantic and Northeast Pacific, is derived from the name of a native Caribbean Amerindian storm god, Huracan, via Spanish huracán. The Caribbean (ˌkærəˡbiən kæ'rəbiən Cariben|Caraïben or Caraïben; Caraïbe or more commonly Antilles; Caribe is a Region consisting For indigenous peoples in the United States other than Hawaii and Alaska see also Native Americans in the United States. God is the principal or sole Deity in Religions and other belief systems that worship one deity. See also Huracán (disambiguation Huracan (also Hurakan, from Mayan Jun Raqan "one legged" was a ^[96] (Huracan is also the source of the word Orcan, another word for the European windstorm. A European windstorm is a severe cyclonic storm that tracks across the North Atlantic towards northwestern Europe in the winter months These events should not be confused. ) Huracan became the Spanish term for hurricanes.

Naming

Main articles: Tropical cyclone naming and Lists of tropical cyclone names

Storms reaching tropical storm strength were initially given names to eliminate confusion when there are multiple systems in any individual basin at the same time, which assists in warning people of the coming storm. Presently most Tropical cyclones are given a name using one of several Lists of tropical cyclone names. Due to their long-term persistence and the need for a unique identifier in issuing forecasts and warnings Tropical cyclones and Subtropical cyclones are given names according ^[97] In most cases, a tropical cyclone retains its name throughout its life; however, under special circumstances, tropical cyclones may be renamed while active. Presently most Tropical cyclones are given a name using one of several Lists of tropical cyclone names. These names are taken from lists that vary from region to region and are drafted a few years ahead of time. The lists are decided on, depending on the regions, either by committees of the World Meteorological Organization (called primarily to discuss many other issues), or by national weather offices involved in the forecasting of the storms. Each year, the names of particularly destructive storms (if there are any) are "retired" and new names are chosen to take their place.

Notable tropical cyclones

Main articles: List of notable tropical cyclones, List of Atlantic hurricanes, and List of Pacific hurricanes

Tropical cyclones that cause extreme destruction are rare, although when they occur, they can cause great amounts of damage or thousands of fatalities. This is a list of notable Tropical cyclones, subdivided by basin and reason for notability This is a list of notable Pacific hurricanes, subdivided by reason for notability

The 1970 Bhola cyclone is the deadliest tropical cyclone on record, killing more than 300,000 people^[98] and potentially as many as 1 million^[99] after striking the densely populated Ganges Delta region of Bangladesh on November 13, 1970. The 1970 Bhola cyclone was a devastating Tropical cyclone that struck East Pakistan (now Bangladesh) and India 's West Bengal on The Ganges Delta (also Sunderban Delta or the Bengal Delta) is a River delta in the South Asia region of Bengal, consisting of Bangladesh ( Bengali: বাংলাদেশ inc-Latn Bangladesh) officially Events 1002 - English king Ethelred orders the killing of all Danes in England, known today as the St Year 1970 ( MCMLXX) was a Common year starting on Thursday (link shows full calendar of the Gregorian calendar. Its powerful storm surge was responsible for the high death toll. ^[98] The North Indian cyclone basin has historically been the deadliest basin, with several cyclones since 1900 killing more than 100,000 people, all in Bangladesh. The following is a list of North Indian Ocean cyclone seasons. ^[76][100] Elsewhere, Typhoon Nina killed nearly 100,000 in China due to a 2000-year flood that caused 62 dams including the Banqiao Dam to fail. Super Typhoon Nina (international designation 7503, JTWC designation 04W) was a short-lived but intense 1975 China ( Wade-Giles ( Mandarin) Chung¹kuo² is a cultural region, an ancient Civilization, and depending on perspective a National The Banqiao Reservoir Dam ( and Shimantan Reservoir Dam ( are among 62 Dams in Zhumadian Prefecture of China 's Henan Province that ^[101] The Great Hurricane of 1780 is the deadliest Atlantic hurricane on record, killing about 22,000 people in the Lesser Antilles. The Great Hurricane of 1780, also known as the Hurricane San Calixto II, is the deadliest Atlantic hurricane on record The Lesser Antilles, also known as the Caribbees, are part of the Antilles, which together with the Bahamas and Greater Antilles form the ^[102] A tropical cyclone does need not be particularly strong to cause memorable damage, primarily if the deaths are from rainfall or mudslides. Tropical Storm Thelma in November 1991 killed thousands in the Philippines,^[103] while in 1982, the unnamed tropical depression that eventually became Hurricane Paul killed around 1,000 people in Central America. Tropical Storm Thelma (international designation 9125, JTWC designation 27W, Philippine name Uring) was the The Philippines ( Filipino: Pilipinas, officially known as the Republic of the Philippines (fil ''Republika ng Pilipinas'' RP Hurricane Paul was the sixteenth tropical storm and tenth hurricane in the 1982 Pacific hurricane season. ^[104]

Hurricane Katrina is estimated as the costliest tropical cyclone worldwide,^[105] causing $81. Hurricane Katrina of the 2005 Atlantic hurricane season was the costliest hurricane, as well as one of the five deadliest in the history of the United States 2 billion in property damage (2005 USD)^[106] with overall damage estimates exceeding $100 billion (2005 USD). ^[105] Katrina killed at least 1,836 people after striking Louisiana and Mississippi as a major hurricane in August 2005. The State of Louisiana ( or, État de Louisiane, pronounced) is a state located in the southern region of the United States of America Mississippi ( is a state located in the Deep South of the United States Tropical cyclones are ranked according to their maximum winds using several scales ^[106] The Galveston Hurricane of 1900 is the deadliest natural disaster in the United States, killing an estimated 6,000 to 12,000 people in Galveston, Texas. "Galveston" redirects here For the town in the US state of Indiana see Galveston Indiana. ^[107] Hurricane Iniki in 1992 was the most powerful storm to strike Hawaii in recorded history, hitting Kauai as a Category 4 hurricane, killing six people, and causing U. Hurricane Iniki (, Hawaiian for strong and piercing wind was the most powerful Hurricane to strike the U The State of Hawaii ( or həˈwaɪʔiː Hawaiian: Mokuāina o Hawaii) is a state in the United States located on an Archipelago in the Kauai (in standard Hawaiian kauˈaʔi in Kauai- Ni{{okina}}ihau dialect; usually spelled Kauai outside the Hawaiian Islands and ˈkaʊɑɪ or /kaʊˈɑɪ/ S. $3 billion in damage. ^[108] Other destructive Eastern Pacific hurricanes include Pauline and Kenna, both causing severe damage after striking Mexico as major hurricanes. A Pacific hurricane or tropical storm is a Tropical cyclone that develops in the northeastern part of the Pacific Ocean. Hurricane Pauline was one of the strongest and deadliest Pacific hurricanes to make landfall on Mexico. Hurricane Kenna was the third-most intense Pacific hurricane to strike the west coast of Mexico in recorded history The United Mexican States ( or commonly Mexico (ˈmɛksɪkoʊ () is a federal constitutional Republic in North America. ^[109][110] In March 2004, Cyclone Gafilo struck northeastern Madagascar as a powerful cyclone, killing 74, affecting more than 200,000, and becoming the worst cyclone to affect the nation for more than 20 years. Cyclone Gafilo was a powerful Tropical cyclone which struck Madagascar in March 2004 causing devastating damage Madagascar, or Republic of Madagascar (older name Malagasy Republic) is an Island nation in the Indian Ocean off the southeastern ^[111]

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

The most intense storm on record was Typhoon Tip in the northwestern Pacific Ocean in 1979, which reached a minimum pressure of 870 mbar (25. Super Typhoon Tip (international designation None JTWC designation 23W) was the largest and most intense Tropical cyclone on record Cyclone Tracy was a Tropical cyclone that devastated the city of Darwin, Northern Territory, Australia, from Christmas Eve Super Typhoon Tip (international designation None JTWC designation 23W) was the largest and most intense Tropical cyclone on record The bar (symbol bar) decibar (symbol dbar) and the millibar (symbol mbar, also mb are units of Pressure. 69 inHg) and maximum sustained wind speeds of 165 knots (85 m/s) or 190 miles per hour (310 km/h). Inches of mercury, inHg or "Hg is a measuring unit for Pressure. ^[112] Tip, however, does not solely hold the record for fastest sustained winds in a cyclone. Typhoon Keith in the Pacific and Hurricanes Camille and Allen in the North Atlantic currently share this record with Tip. The 1997 Pacific typhoon season has no official bounds it ran year-round in 1997 but most Tropical cyclones tend to form in the northwestern Pacific Ocean between Hurricane Camille was the third and strongest tropical cyclone and second hurricane of the 1969 Atlantic hurricane season Hurricane Allen was the strongest Hurricane of the 1980 Atlantic hurricane season. ^[113] Camille was the only storm to actually strike land while at that intensity, making it, with 165 knots (85 m/s) or 190 miles per hour (310 km/h) sustained winds and 183 knots (94 m/s) or 210 miles per hour (340 km/h) gusts, the strongest tropical cyclone on record at landfall. ^[114] Typhoon Nancy in 1961 had recorded wind speeds of 185 knots (95 m/s) or 215 miles per hour (346 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 storm with the highest wind speeds on record. Super Typhoon Nancy (international designation 6118) was a powerful Tropical cyclone of the 1961 Pacific typhoon season. ^[91] Similarly, a surface-level gust caused by Typhoon Paka on Guam was recorded at 205 knots (105 m/s) or 235 miles per hour (378 km/h). Typhoon Paka (international designation 9728, JTWC designation 05C, PAGASA designation Rubing, also known as Super Typhoon Paka Guam ( Chamorro: cha Guåhån) officially the Territory of Guam, is an island in the western Pacific Ocean and is an organized unincorporated Had it been confirmed, it would be the strongest non-tornadic wind ever recorded on the Earth's surface, but the reading had to be discarded since the anemometer was damaged by the storm. A tornado is a violent rotating column of air which is in contact with both the surface of the earth and a Cumulonimbus cloud or in rare cases the base of a Cumulus An anemometer is a device for measuring wind speed and is one instrument used in a Weather station. ^[115]

In addition to being the most intense tropical cyclone on record, Tip was the largest cyclone on record, with tropical storm-force winds 2,170 kilometres (1,350 mi) in diameter. The smallest storm on record, Cyclone Tracy, was roughly 100 kilometres (62 mi) wide before striking Darwin, Australia in 1974. Cyclone Tracy was a Tropical cyclone that devastated the city of Darwin, Northern Territory, Australia, from Christmas Eve For a topic outline on this subject see List of basic Australia topics. ^[116]

Hurricane John is the longest-lasting tropical cyclone on record, lasting 31 days in 1994. Hurricane John (also Typhoon John) formed during the 1994 Pacific hurricane season and became both the longest-lasting and second-farthest-traveling Tropical The 1994 Pacific hurricane season officially started on May 15 1994 in the eastern Pacific and on June 1 1994 in the central Pacific and lasted until November 30 1994 Before the advent of satellite imagery in 1961, however, many tropical cyclones were underestimated in their durations. ^[117] John is the second longest-tracked tropical cyclone in the Northern Hemisphere on record, behind Typhoon Ophelia of 1960, which had a path of 8,500 miles (12,500 km). The 1960 Pacific typhoon season had no official bounds it ran year-round in 1960 but most tropical cyclones tend to form in the northwestern Pacific Ocean between June Reliable data for Southern Hemisphere cyclones is unavailable. ^[118]

Long-term activity trends

Atlantic Multidecadal Cycle since 1950, using accumulated cyclone energy (ACE)

See also: Atlantic hurricane reanalysis

While the number of storms in the Atlantic has increased since 1995, there is no obvious global trend; the annual number of tropical cyclones worldwide remains about 87 ± 10. Atlantic hurricane reanalysis is an ongoing project within the National Oceanic and Atmospheric Administration which seeks to correct and add new information about past However, the ability of climatologists to make long-term data analysis in certain basins is limited by the lack of reliable historical data in some basins, primarily in the Southern Hemisphere. ^[119] In spite of that, there is some evidence that the intensity of hurricanes is increasing. Kerry Emanuel stated, "Records of hurricane activity worldwide show an upswing of both the maximum wind speed in and the duration of hurricanes. Kerry Emanuel is an American professor of Meteorology currently working at the Massachusetts Institute of Technology in Boston The energy released by the average hurricane (again considering all hurricanes worldwide) seems to have increased by around 70% in the past 30 years or so, corresponding to about a 15% increase in the maximum wind speed and a 60% increase in storm lifetime. "^[120]

Atlantic storms are becoming more destructive financially, since five of the ten most expensive storms in United States history have occurred since 1990. This can be attributed to the increased intensity and duration of hurricanes striking North America,^[120] and to a greater degree, the number of people living in susceptible coastal areas, following increased development in the region since the last surge in Atlantic hurricane activity in the 1960s.

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 may have gone unmeasured in some instances. 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. ^[121]

The number and strength of Atlantic hurricanes may undergo a 50–70 year cycle, also known as the Atlantic Multidecadal Oscillation. The Atlantic multidecadal oscillation (AMO is a mode of natural variability occurring in the North Atlantic Ocean and which has its principle expression in the Sea surface Although more common since 1995, few above-normal hurricane seasons occurred during 1970–94. ^[122] Destructive hurricanes struck frequently from 1926–60, including many major New England hurricanes. Twenty-one Atlantic tropical storms formed in 1933, a record only recently exceeded in 2005, which saw 28 storms. The 1933 Atlantic hurricane season was the second most active Atlantic hurricane season on record with 21 storms forming during that year in the northwest Atlantic Ocean. Tropical hurricanes occurred infrequently during the seasons of 1900–25; however, many intense storms formed during 1870–99. During the 1887 season, 19 tropical storms formed, of which a record 4 occurred after 1 November and 11 strengthened into hurricanes. Events 996 - Emperor Otto III issues a deed to Gottschalk Bishop of Freising which is the oldest known document using the name Ostarrîchi Few hurricanes occurred in the 1840s to 1860s; however, many struck in the early 19th century, including an 1821 storm that made a direct hit on New York City. The City of New York Some historical weather experts say these storms may have been as high as Category 4 in strength. The Saffir-Simpson Hurricane Scale is a classification used for most Western Hemisphere Tropical cyclones that exceed the intensities of Tropical depressions ^[123]

These active hurricane seasons predated satellite coverage of the Atlantic basin. Before the satellite era began in 1960, tropical storms or hurricanes went undetected unless a reconnaissance aircraft encountered one, a ship reported a voyage through the storm, or a storm hit land in a populated area. ^[121] The official record, therefore, could miss 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

See also: Global warming

The U. Global warming is the increase in the average measured temperature of the S. National Oceanic and Atmospheric Administration Geophysical Fluid Dynamics Laboratory performed a simulation to determine if there is a statistical trend in the frequency or strength of tropical cyclones over time. The National Oceanic and Atmospheric Administration ( NOAA) is a scientific agency within the United States Department of Commerce focused on the conditions of the The Geophysical Fluid Dynamics Laboratory (GFDL is a laboratory in the National Oceanic and Atmospheric Administration (NOAA/ Office of Oceanic and Atmospheric Research Statistics is a mathematical science pertaining to the collection analysis interpretation or explanation and presentation of Data. In Chemistry, periodic trends are the tendencies of certain elemental characteristics to increase or decrease as one progresses from one corner of the Periodic table The simulation concluded "the strongest hurricanes in the present climate may be upstaged by even more intense hurricanes over the next century as the earth's climate is warmed by increasing levels of greenhouse gases in the atmosphere". ^[124]

In an article in Nature, Kerry Emanuel stated that potential hurricane destructiveness, a measure combining hurricane strength, duration, and frequency, "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". Nature is a prominent Scientific journal, first published on 4 November 1869 Kerry Emanuel is an American professor of Meteorology currently working at the Massachusetts Institute of Technology in Boston Emanuel predicted "a substantial increase in hurricane-related losses in the twenty-first century". ^[125] Similarly, P. J. Webster and others published an article in Science examining the "changes in tropical cyclone number, duration, and intensity" over the past 35 years, the period when satellite data has been available. Science is the Academic journal of the American Association for the Advancement of Science and is considered one of the world's most prestigious Scientific Their main finding was although the number of cyclones decreased throughout the planet excluding the north Atlantic Ocean, there was a great increase in the number and proportion of very strong cyclones. ^[126]

The strength of the reported effect is surprising in light of modeling studies^[127] that predict only a one half category increase in storm intensity as a result of a ~2 °C (3. 6 °F) global warming. Such a response would have predicted only a ~10% increase in Emanuel's potential destructiveness index during the 20th century rather than the ~75–120% increase he reported. ^[125] Secondly, after adjusting for changes in population and inflation, and despite a more than 100% increase in Emanuel's potential destructiveness index, no statistically significant increase in the monetary damages resulting from Atlantic hurricanes has been found. ^[128]

Sufficiently warm sea surface temperatures are considered vital to the development of tropical cyclones. Sea surface temperature (SST is the water Temperature close to the surface ^[37] Although neither study can directly link hurricanes with global warming, the increase in sea surface temperatures is believed to be due to both global warming and nature variability, e. g. the hypothesized Atlantic Multidecadal Oscillation (AMO), although an exact attribution has not been defined. The Atlantic multidecadal oscillation (AMO is a mode of natural variability occurring in the North Atlantic Ocean and which has its principle expression in the Sea surface ^[129] However, recent temperatures are the warmest ever observed for many ocean basins. ^[125]

In February 2007, the United Nations Intergovernmental Panel on Climate Change released its fourth assessment report on climate change. The United Nations ( UN) is an International organization whose stated aims are to facilitate cooperation in International law, International security Climate Change 2007, the Fourth Assessment Report (AR4 of the United Nations Intergovernmental Panel on Climate Change ( IPCC) is the fourth Climate change is any long-term significant change in the “average weather” that a given region experiences The report noted many observed changes in the climate, including atmospheric composition, global average temperatures, ocean conditions, among others. The report concluded the observed increase in tropical cyclone intensity is larger than climate models predict. Additionally, the report considered that it is likely that storm intensity will continue to increase through the 21st century, and declared it more likely than not that there has been some human contribution to the increases in tropical cyclone intensity. ^[130] However, there is no universal agreement about the magnitude of the effects anthropogenic global warming has on tropical cyclone formation, track, and intensity. For example, critics such as Chris Landsea assert that man-made effects would be "quite tiny compared to the observed large natural hurricane variability". Christopher Landsea, formerly a research Meteorologist with Hurricane Research Division of Atlantic Oceanographic & Meteorological Laboratory at NOAA, is now the Science ^[131] A statement by the American Meteorological Society on February 1, 2007 stated that trends in tropical cyclone records offer "evidence both for and against the existence of a detectable anthropogenic signal" in tropical cyclogenesis. The American Meteorological Society ( AMS) promotes the development and dissemination of information and education on the atmospheric and related oceanic Events 1327 - Teenaged Edward III is crowned King of England, but the country is ruled by his mother Queen Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Tropical cyclogenesis is the technical term describing the development and strengthening of a Tropical cyclone in the Atmosphere. ^[132] Although many aspects of a link between tropical cyclones and global warming are still being "hotly debated",^[133] a point of agreement is that no individual tropical cyclone or season can be attributed to global warming. ^[133][129]

Related cyclone types

Subtropical Storm Gustav in 2002

See also: Cyclone, Extratropical cyclone, and Subtropical cyclone

In addition to tropical cyclones, there are two other classes of cyclones within the spectrum of cyclone types. Hurricane Gustav was a Category 2 hurricane that paralleled the East Coast of the United States in September during the 2002 Atlantic hurricane season The 2002 Atlantic hurricane season was an average Atlantic hurricane season, officially starting on June 1 2002 and ending on November 30 dates which conventionally In Meteorology, a cyclone refers to an area of closed circular fluid motion rotating in the same direction as the Earth. Extratropical cyclones, sometimes called mid-latitude cyclones or wave cyclones, are a group of Cyclones defined as synoptic scale low A subtropical cyclone is a Weather system that has some characteristics of a Tropical cyclone and some characteristics of an Extratropical cyclone. These kinds of cyclones, known as extratropical cyclones and subtropical cyclones, can be stages a tropical cyclone passes through during its formation or dissipation. Extratropical cyclones, sometimes called mid-latitude cyclones or wave cyclones, are a group of Cyclones defined as synoptic scale low A subtropical cyclone is a Weather system that has some characteristics of a Tropical cyclone and some characteristics of an Extratropical cyclone. Tropical cyclogenesis is the technical term describing the development and strengthening of a Tropical cyclone in the Atmosphere. ^[134]

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;^[2] additionally, although not as frequently, an extratropical cyclone can transform into a subtropical storm, and from there into a tropical cyclone. From space, extratropical storms have a characteristic "comma-shaped" cloud pattern. A comma ( ,   is a Punctuation mark It has the same shape as an Apostrophe or single closing Quotation mark in many typefaces but it differs ^[135] Extratropical cyclones can also be dangerous when their low-pressure centers cause powerful winds and high seas. ^[136]

A subtropical cyclone is a weather system that has some characteristics of a tropical cyclone and some characteristics of an extratropical cyclone. The weather is a set of all the phenomena occurring in a given Atmosphere at a given Time. They can form in a wide band of latitudes, from the equator to 50°. Latitude, usually denoted symbolically by the Greek letter phi ( Φ) gives the location of a place on Earth (or other planetary body north or south of the The equator (sometimes referred to colloquially as "the Line") is the intersection of the Earth 's surface with the plane perpendicular to the Although subtropical storms rarely have hurricane-force winds, they may become tropical in nature as their cores warm. ^[137] From an operational standpoint, a tropical cyclone is usually not considered to become subtropical during its extratropical transition. ^[138]

Tropical cyclones in popular culture

Main article: Tropical cyclones in popular culture

In popular culture, tropical cyclones have made appearances in different types of media, including films, books, television, music, and electronic games. The appearances of tropical cyclones in popular culture spans many genres of media Popular culture (or pop culture) is the Culture — patterns of human activity and the symbolic structures that give such activities significance and importance — A Book is a set or collection of written printed illustrated or blank sheets made of Paper, Parchment, or other material usually fastened together Television ( TV) is a widely used Telecommunication medium for sending ( Broadcasting) and receiving moving Images, either monochromatic Music is an Art form in which the medium is Sound organized in Time. A video game is a Game that involves interaction with a User interface to generate visual feedback on a video device. The media can have tropical cyclones that are entirely fictional, or can be based on real events. Fiction is the telling of stories which are not real More specifically fiction is an imaginative form of Narrative, one of the four basic Rhetorical modes. ^[139] For example, George Rippey Stewart's Storm, a best-seller published in 1941, is thought to have influenced meteorologists into giving female names to Pacific tropical cyclones. George Rippey Stewart ( May 31, 1895 – August 22, 1980) was an American Toponymist, a novelist and a professor of English Storm is a novel written by George Rippey Stewart and published in 1941 A bestseller is a Book that is identified as extremely popular by its inclusion on lists of currently top selling titles that are based on publishing industry and book trade ^[140] Another example is the hurricane in The Perfect Storm, which describes the sinking of the Andrea Gail by the 1991 Halloween Nor'easter. The Perfect Storm is a 2000 Film adapted from the book of the same title by Sebastian Junger. Events Andrea Gail began her final voyage departing from Gloucester on September 20, 1991 bound for the Grand Banks. The 1991 Halloween Nor'easter, also known as the Perfect Storm, was an unusual nor’easter which was Extratropical, absorbed one Hurricane ^[141] Also, hypothetical hurricanes have been featured in parts of the plots of series such as The Simpsons,^[142] Invasion,^[143] Family Guy, ^[144] Seinfeld,^[145] CSI Miami,^[146] and Dawson's Creek. The appearances of tropical cyclones in popular culture spans many genres of media Invasion is an American Science fiction television series that aired on ABC for only one season beginning Family Guy is an animated American television sitcom created by Seth MacFarlane that airs on Fox and regularly on other Seinfeld is an American Situation comedy, or sitcom that originally aired on NBC from July 5 1989 to May 14 1998 lasting nine seasons CSI Miami is a spin-off of the CBS network series. CSI Miami airs new episodes Mondays at 10 PM ET/PT on CBS. Dawson's Creek was an American Primetime Television Drama which initially aired from January 20, 1998 ^[147] The 2004 film The Day After Tomorrow includes several mentions of actual tropical cyclones as well as featuring fantastical "hurricane-like" non-tropical Arctic storms. The Day After Tomorrow is a 2004 apocalyptic science-fiction film that depicts the catastrophic effects of both Global warming and Global cooling ^[148][149]

See also

• Hypercane
• List of wettest tropical cyclones by country
• Secondary flow in tropical cyclones

References

External links

Learning resources

• Surviving a hurricane – A guide for children and youth
• WMO guide on cyclone terminology
• Summary of cyclone terminology from NOAA FAQ
• NOVA science now: Hurricanes
• Mariner's Guide for Hurricane AwarenessPDF (1. 23 MiB)
• World Meteorological Organization Severe Weather Information Center – Shows all current tropical systems worldwide and their tracks
• Tropical Storms Worldwide – by Hawaii University
• FEMA for Kids: Hurricanes
• Is Global Climate Change Affecting Hurricanes?
• Anti hurricane technology
• Economic Costs of Hurricanes and associated Economic Benefits from Improved Forecasting

Regional specialised meteorological centers

• US National Hurricane Center – North Atlantic, Eastern Pacific
• Canadian Hurricane Centre - Canadian Maritimes
• Caribbean Hurricane Network - Caribbean region
• Caribbean Disaster Emergency Response Agency - Caribbean region
• Central Pacific Hurricane Center – Central Pacific
• Japan Meteorological Agency – NW Pacific
• India Meteorological Department – Bay of Bengal and the Arabian Sea
• Météo-France – La Reunion – South Indian Ocean from Africa to 90° E
• Fiji Meteorological Service – South Pacific east of 160°, north of 25° S

Past storms

• Global climatology of tropical cyclones
• Unisys historical and contemporary hurricane track data
• United States Tropical Cyclone Rainfall Climatology – Nearly 30 years of tropical cyclone histories with an emphasis on storm total rainfall, in color, up to present. A mebibyte (a contraction of me ga bi nary byte) is a unit of Information or Computer storage, abbreviated MiB. The Bay of Bengal is a bay that forms the northeastern part of the Indian Ocean. The Arabian Sea ( Arabic: بحر العرب transliterated: Baḥr al-'Arab Sanskrit: सिन्धु सागर transliterated: Broken up by year, region, by point of landfall, and North American countries impacted
• Global ISCCP B1 Browse System Satellite Archive
• Digital Typhoon: Typhoon Images and Information