Tropical Cyclone Idai and how it originates

Tropical Cyclone Idai and how it originates
Cyclone

A cyclone is a large scale air mass that rotates around a strong center of low atmospheric pressure. Cyclones are characterized by inward spiraling winds that rotate about a zone of low pressure.

The largest low-pressure systems are polar vortices and extratropical cyclones of the largest scale (the synoptic scale). Warm-core cyclones such as tropical cyclones and subtropical cyclones also lie within the synoptic scale. Mesocyclones, tornadoes and dust devils lie within smaller mesoscale.

Structure
There are a number of structural characteristics common to all cyclones. A cyclone is a low-pressure area. A cyclone's center (often known in a mature tropical cyclone as the eye), is the area of lowest atmospheric pressure in the region. Near the center, the pressure gradient force (from the pressure in the center of the cyclone compared to the pressure outside the cyclone) and the force from the Coriolis effect must be in an approximate balance, or the cyclone would collapse on itself as a result of the difference in pressure.
Tropical Cyclone Idai and how it originates
Cyclone
Tropical Cyclone Idai and how it originates
Cyclone

Formation



Cyclogenesis is the development or strengthening of cyclonic circulation in the atmosphere. It can occur at various scales, from the microscale to the synoptic scale.

Extratropical cyclones begin as waves along weather fronts before occluding later in their life cycle as cold-core systems. However, some intense extratropical cyclones can become warm-core systems when a warm seclusion occurs.

Tropical cyclones form as a result of significant convective activity, and are warm core. Mesocyclones form as warm core cyclones over land, and can lead to tornado formation. Waterspouts can also form from mesocyclones, but more often develop from environments of high instability and low vertical wind shear.

Cyclone Idai
Intense Tropical Cyclone Idai is regarded as one of the worst tropical cyclones on record to affect Africa and the Southern Hemisphere as a whole. The long-lived storm caused catastrophic damage in multiple nations, leaving more than 700 people dead and hundreds more missing. its death toll is comparable to that of the 1892 Mauritius cyclone, the 1903 French Polynesia cyclone, the 1927 Madagascar cyclone, and Cyclone Leon–Eline in 2000.

Tropical Cyclone Idai and how it originates

Tropical Cyclone Idai and how it originates

Tropical Cyclone Idai and how it originates

Idai originated from a tropical depression that formed off the east coast of Mozambique on 4 March. The storm, Tropical Depression, made landfall in Mozambique later in the day and remained a tropical cyclone through its trek over land. On 9 March, the depression re-emerged into the Mozambique Channel and was upgraded into Moderate Tropical Storm Idai next day. Idai then began a stint of rapid intensification, reaching an initial peak intensity as an intense tropical cyclone with winds of 175 km/h (110 mph) on 11 March. Idai then began to weaken due to ongoing structural changes within its inner core, falling to tropical cyclone intensity. Idai's intensity remained stagnant for about a day or so before it began to re-intensify. On 14 March, Idai reached peak intensity with maximum sustained winds of 195 km/h (120 mph) and a minimum central pressure of 940 hPa (27.76 inHg). Idai then began to weaken as it approached the coast of Mozambique due to less favourable conditions. On 15 March, Idai made landfall near Beira, Mozambique, as an intense tropical cyclone, subsequently weakening into a remnant low on 16 March. On 19 March, Idai's remnants re-emerged into the Mozambique Channel, and dissipated on 21 March.

Idai brought strong winds and caused severe flooding in Madagascar, Mozambique, Malawi, and Zimbabwe, which killed 762 people – 446 in Mozambique, 259 in Zimbabwe, 56 in Malawi, and one in Madagascar – and affected more than 2.6 million others. Catastrophic damage occurred in and around Beira in southern Mozambique.

Tropical Cyclone Idai and how it originates

Tropical Cyclone Idai and how it originates

Reference: Wikipedia.
Images: clubofmozambique.com, public.wmo.int, http://tropic.ssec.wisc.edu.

By: James Henry

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