The following outline is provided as an overview of and topical guide to tropical cyclones:

Tropical cyclone – storm characterized by a large low-pressure center and numerous thunderstorms that produces strong winds and heavy rain. Tropical cyclones develop or strengthen when water evaporated from the ocean is released as the saturated air rises, resulting in condensation of water vapor contained in the moist air. They are fueled by a different heat mechanism than other cyclonic windstorms such as nor'easters, European windstorms, and polar lows. The characteristic that separates tropical cyclones from other cyclonic systems is that at any height in the atmosphere, the center of a tropical cyclone will be warmer than its surroundings; a phenomenon called "warm core" storm systems.

Nature of tropical cyclones

Tropical cyclones can be described as all of the following:

  • Storm – disturbed state of an environment or astronomical body's atmosphere especially affecting its surface, and strongly implying severe weather. It may be marked by significant disruptions to normal conditions such as strong wind, hail, thunder and lightning (a thunderstorm), heavy precipitation (snowstorm, rainstorm), heavy freezing rain (ice storm), strong winds (tropical cyclone, windstorm), or wind transporting some substance through the atmosphere such as sand or debris.
  • Natural disaster – major adverse event resulting from natural processes of the Earth; examples include floods, volcanic eruptions, earthquakes, tsunamis, and other geologic processes. A natural disaster can cause loss of life or property damage, and typically leaves some economic damage in its wake, the severity of which depends on the affected population's resilience, or ability to recover.

Types of tropical cyclones

Cumulative graph of tropical cyclones in the eastern Pacific
  • Tropical cyclone – a rapidly rotating low-pressure system consisting of a spiral band of thunderstorms, strong winds, and atmospheric circulation that can produce heavy rain and squalls. Depending on the location, they are given different names such as hurricanes, cyclones, or typhoons.
  • Annular tropical cyclone – a tropical cyclone that possesses annular characteristics. Annular characteristics are often seen in major cyclones, where they possess a symmetrical eye and a thick ring of convection.
  • Subtropical cyclone – a low-pressure system that gains both tropical and extratropical-like quantities.
  • Extratropical cyclone – a low-pressure system that is capable of producing weather conditions such as tornadoes, thunderstorms, gales, etc.
  • Post-tropical cyclone – a former tropical cyclone that no longer has enough tropical quantities to be considered a tropical cyclone. Post-tropical cyclones, such as remnant lows, no longer possess tropical quantities through either unfavorable conditions (e.g. increased wind shear) or land interaction.
  • Pacific hurricane – a tropical cyclone that forms west of 100°W to the International Date Line in the Northern Hemisphere. The National Hurricane Center is responsible for the region east of 140°W, while the Central Pacific Hurricane Center is responsible for storms forming west of 140°W to the International Date Line.
  • Atlantic hurricane – a tropical cyclone that forms in the Atlantic Ocean. The National Hurricane Center is responsible for the region.
  • Typhoon – a tropical cyclone that forms between the International Date Line and 100°E in the Northern Hemisphere. The main RSMC for this region is the Japan Meteorological Agency.
  • Mediterranean tropical-like cyclone – a tropical cyclone that forms in the Mediterranean Sea.
  • Cape Verde hurricane – a tropical cyclone that forms from a tropical wave over or near the Cape Verde islands. Cape Verde hurricanes occur between August and October and contain some of the most destructive hurricanes to strike land in the Atlantic. Examples include Hurricane Ivan, Hurricane Isabel, Hurricane Dorian, etc.
  • Tropical wave – an atmospheric trough or low-pressure area that forms along the subtropical ridge or supported from an area of high pressure, which lies either north or south of the Intertropical Convergence Zone.

Tropical cyclone observations

Saffir–Simpson scale, 1-minute maximum sustained winds
Category m/s knots mph km/h
5 ≥ 70 ≥ 137 ≥ 157 ≥ 252
4 58–70 113–136 130–156 209–251
3 50–58 96–112 111–129 178–208
2 43–49 83–95 96–110 154–177
1 33–42 64–82 74–95 119–153
TS 18–32 34–63 39–73 63–118
TD ≤ 17 ≤ 33 ≤ 38 ≤ 62
  • Tropical cyclone scales – used to determine a cyclone's intensity, longetivity, and strength throughout its lifetime.
    • Saffir-Simpson Hurricane Scale – a scale widely used by the National Hurricane Center, Central Pacific Hurricane Center, and the Joint Typhoon Warning Center to determine a storm's strength using maximum sustained winds.
    • Accumulated cyclone energy – a metric used by several agencies to measure the longetivity of a tropical cyclone.
    • Hurricane Severity Index – a metric that measures the strength and destructive capability of a tropical cyclone based on wind and intensity.
    • Chicago Mercantile Exchange Hurricane Index – an index used to measure the damage of an Atlantic hurricane at landfall in the United States.
    • Dvorak technique – a technique created by late meteorologist Vernon Dvorak to describe the cyclone's intensity through satellite imagery.
  • Tropical cyclone naming – once a tropical cyclone reaches winds of 34 kt (39 mph), a name would be given to that specific cyclone. Names are usually given by their respective RSMCs when the cyclone reaches tropical storm status.

Forecasting

Tropical cyclone history

Tropical cyclone seasons

Specific tropical cyclones

Hurricane Isabel viewed from the International Space Station in September 2003

See also

References

    Regional Specialized Meteorological Centres
    Tropical Cyclone Warning Centers
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