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Facts About Cyclones For Kids


Cyclones are usually characterized by inward spiraling winds that rotate counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere of the Earth. The largest low-pressure systems are cold-core polar cyclones and extratropical cyclones which lie on the synoptic scale.

  • According to NHC glossary, warm-core cyclones such as tropical cyclones and subtropical cyclones also lies within synoptic scale.
  • Upper level cyclones can exist without the presence of a surface low, and can pinch off from the base of the Tropical Upper Tropospheric Trough during the summer months in the Northern Hemisphere.
  • Extratropical cyclones form as waves in large regions of enhanced mid-latitude temperature contrasts called baroclinic zones.
  • These zones contract to form weather fronts as the cyclonic circulation closes and intensifies.
  • Weather fronts separate two masses of air of different densities and are associated with the most prominent meteorological phenomena.
  • Strong cold fronts typically feature narrow bands of thunderstorms and severe weather, and may on occasion be preceded by squall lines or dry lines.
  • Warm fronts form east of the cyclone center and are usually preceded by stratiform precipitation and fog.
  • Tropical cyclogenesis describes the process of development of tropical cyclones.
  • Tropical cyclones form due to latent heat driven by significant thunderstorm activity, and are warm core.
  • Mesocyclones form as warm core cyclones over land, and can lead to tornado formation.
  • There are a number of structural characteristics common to all cyclones.
  • The cyclones have high pressure outside and low pressure inside.
  • Because of the Coriolis effect, the wind flow around a large cyclone is counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.
  • This rotational flow will push polar air equatorward west of the low via its trailing cold front, and warmer air with push poleward low via the warm front.
  • Tropical cyclogenesis is the technical term describing the development and strengthening of a tropical cyclone in the atmosphere.
  • There are six main requirements for tropical cyclogenesis: sufficiently warm sea surface temperatures, atmospheric instability, high humidity in the lower to middle levels of the troposphere, enough Coriolis force to develop a low pressure center, a preexisting low level focus or disturbance, and low vertical wind shear.
  • An average of 86 tropical cyclones of tropical storm intensity form annually worldwide, with 47 reaching hurricane/typhoon strength, and 20 becoming intense tropical cyclones (at least Category 3 intensity on the Saffir–Simpson Hurricane Scale).
  • The descriptor “extratropical” refers to the fact that this type of cyclone generally occurs outside of the tropics, in the middle latitudes of the planet.
  • Upper cyclones and upper troughs which trail tropical cyclones can cause additional outflow channels and aid in their intensification process.