Tropical cyclone

A tropical cyclone is a rapidly rotating storm system with a low-pressure area, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain and squalls.

Tropical cyclones are very rare in the South Atlantic (although occasional examples do occur) due to consistently strong wind shear and a weak Intertropical Convergence Zone.

[6] Within this broad area of low-pressure, air is heated over the warm tropical ocean and rises in discrete parcels, which causes thundery showers to form.

[1] These warning centers issue advisories which provide basic information and cover a systems present, forecast position, movement and intensity, in their designated areas of responsibility.

[29] During La Niña years, the formation of tropical cyclones, along with the subtropical ridge position, shifts westward across the western Pacific Ocean, which increases the landfall threat to China and much greater intensity in the Philippines.

[45][46] It is plausible that extreme wind waves see an increase as a consequence of changes in tropical cyclones, further exacerbating storm surge dangers to coastal communities.

[47] A 2021 study review article concluded that the geographic range of tropical cyclones will probably expand poleward in response to climate warming of the Hadley circulation.

[53] According to World Weather Attribution the influence of climate change on the rainfall of some latest hurricanes can be described as follows:[54] Tropical cyclone intensity is based on wind speeds and pressure.

[56][57] The most intense storm on record is Typhoon Tip in the northwestern Pacific Ocean in 1979, which reached a minimum pressure of 870 hPa (26 inHg) and maximum sustained wind speeds of 165 kn (85 m/s; 305 km/h; 190 mph).

[71][72] Dry air entraining into a tropical cyclone's core has a negative effect on its development and intensity by diminishing atmospheric convection and introducing asymmetries in the storm's structure.

[84] The Brown ocean effect can allow a tropical cyclone to maintain or increase its intensity following landfall, in cases where there has been copious rainfall, through the release of latent heat from the saturated soil.

[85] Orographic lift can cause a significant increase in the intensity of the convection of a tropical cyclone when its eye moves over a mountain, breaking the capped boundary layer that had been restraining it.

[1] The SMAP uses an L-band radiometer channel to determine the wind speeds of tropical cyclones at the ocean surface, and has been shown to be reliable at higher intensities and under heavy rainfall conditions, unlike scatterometer-based and other radiometer-based instruments.

The ADT, used by a large number of forecasting centers, uses infrared geostationary satellite imagery and an algorithm based upon the Dvorak technique to assess the intensity of tropical cyclones.

[114][115] Formal naming schemes have subsequently been introduced for the North and South Atlantic, Eastern, Central, Western and Southern Pacific basins as well as the Australian region and Indian Ocean.

[19][20][23] Tropical cyclones that develop around the world are assigned an identification code consisting of a two-digit number and suffix letter by the warning centers that monitor them.

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.

[122] In a weaker storm, the eye may be obscured by the central dense overcast, which is the upper-level cirrus shield that is associated with a concentrated area of strong thunderstorm activity near the center of a tropical cyclone.

[141] When wind shear and latent heat release is present, tropical cyclones tend to move towards regions where potential vorticity is increasing most quickly.

[67] On land, strong winds can damage or destroy vehicles, buildings, bridges, and other outside objects, turning loose debris into deadly flying projectiles.

[187] In October 2019, Typhoon Hagibis struck the Japanese island of Honshu and inflicted US$15 billion in damage, making it the costliest storm on record in Japan.

[195] The Caribbean islands are regularly hit by hurricanes, which have caused multiple humanitarian crises in Haiti since 2004 due in part to the lack of infrastructure and high population density in urban areas.

[214][215] 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.

[244] Major tropical cyclones leave traces in overwash records and shell layers in some coastal areas, which have been used to gain insight into hurricane activity over the past thousands of years.

[244] Proxy records based on paleotempestological research have revealed that major hurricane activity along the Gulf of Mexico coast varies on timescales of centuries to millennia.

[1] It took several years for some of the warning centers to take advantage of this new viewing platform and develop the expertise to associate satellite signatures with storm position and intensity.

[1] 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.

[273][274][275] When a tropical cyclone develops and is forecast to impact land, each member nation of the World Meteorological Organization issues various watches and warnings to cover the expected effects.

[286][288] Common injuries arise from falls from heights, such as from a ladder or from level surfaces; from electrocution in flooded areas, including from backfeed from portable generators; or from motor vehicle accidents.

[285][288][289] Long and irregular shifts may lead to sleep deprivation and fatigue, increasing the risk of injuries, and workers may experience mental stress associated with a traumatic incident.

View of a tropical cyclone from space
Hurricane Florence viewed from International Space Station in 2018. The eye , eyewall, and surrounding rainbands are characteristics of tropical cyclones.
A schematic diagram of a tropical cyclone
A diagram of a tropical cyclone in the Northern Hemisphere
The 20-year average of the number of annual Category 4 and 5 hurricanes in the Atlantic region has approximately doubled since the year 2000. [ 36 ]
Climate change's increase of water temperatures intensified peak wind speeds in all eleven 2024 Atlantic hurricanes. [ 37 ]
Perceptions in the United States differ along political lines, on whether climate change was a "major factor" contributing to various extreme weather events experienced by respondents in 2023. [ 38 ] "Severe storms" includes hurricanes.
Satellite image of a cyclone where the thickest clouds are displaced from the central vortex
Hurricane Paulette , in 2020 , is an example of a sheared tropical cyclone, with deep convection slightly removed from the center of the system.
Satellite image of three simultaneous tropical cyclones
Three tropical cyclones of the 2006 Pacific typhoon season at different stages of development. 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 .
The eye and surrounding clouds of 2018 Hurricane Florence as seen from the International Space Station
Though large hurricane size does not imply strength —which is based on sustained wind measurements—it can mean that more people are exposed to its hazards. [ 128 ]
Path of a tropical cyclone
Storm track of Typhoon Ioke , showing recurvature off the Japanese coast in 2006
total collapse of houses, cars and facilities
Aftermath of Hurricane Ike in Bolivar Peninsula, Texas
The number of $1 billion Atlantic hurricanes almost doubled from the 1980s to the 2010s, and inflation-adjusted costs have increased more than elevenfold. [ 169 ] The increases have been attributed to climate change and to greater numbers of people moving to coastal areas. [ 169 ]
Aerial view of storm clouds
A sunset view of Hurricane Isidore 's rainbands photographed at 2,100 m (7,000 ft)
Head-on view of an airplane
" Hurricane Hunter " – WP-3D Orion is used to go into the eye of a hurricane for data collection and measurements purposes.
A graph shows five colored curves (actually, jagged point-to-point data sets) measuring average forecast errors in nautical miles (0 to 700, the y-axis on the left) for each year (from 1970 to 2022, the x-axis at the bottom). The red curve indicates forecast errors 24 hours in advance, and is the lowest of the five curves; its points and the resultant trend line are below that of the other curves. The 24-hour forecast trends from approximately 140 nm in 1970 to about 45 nm in 2022. The green line shows forecast errors 48 hours in advance, with a trend line from about 290 nm in 1970 to 45 nm in 2022. The yellow curve indicates errors from 72-hour forecasts, and jags dramatically up and down in the first 10 years shown. Its trend line runs from approx. 445 nm (1970) to about 50 nm (2022). The two remaining lines stretch only from 2001. The brown curve shows a 96-hour forecast (trending from about 240 nm in 2001 to 100 nm in 2022), and the blue line for forecasts 120 hours in advance trends from about 310 nm (2001) to 150 nm (2022). With remarkable consistency, the farther in advance the forecast is, the greater the error visible here, and the trend line for each set of plotted points is clearly downward, generally with increasing steepness for the wider-ranging forecasts.
A general decrease in error trends in tropical cyclone path prediction is evident since the 1970s.
Evacuation route sign on Tulane Avenue in New Orleans shows lines from long standing floodwaters after Hurricane Katrina .
View of tropical cyclone damage from a helicopter
Relief efforts for Hurricane Dorian in the Bahamas