Genesis of cyclones is a complex phenomenon which is initiated by a tropical depression which can grow into a tropical storm and a severe or very severe storm based on the available cyclone heat potential in the ocean. Sufficiently warm weather can result in a higher rate of evaporation and pumps moisture into the cyclone. It is the condensation of this massive amount of water vapour that makes storms so powerful and can lead to extreme amounts of rain when these storms hit land. This is also why cyclones fall apart when they hit land, since they have no more moisture and energy source.
The other factor that is critical for depressions to grow into tropical storms or cyclones is the change in wind strength or direction with height in the atmosphere. Strong changes in strength or direction can rip off the head of the cyclone and prevent it from gaining strength. This is what suppresses Genesis of cyclones during the monsoon season.
The moisture supply to the cyclone is also enhanced by the so-called Find later jet, the south-westerly winds trucking in boatloads of moisture across the equator in the western Indian Ocean over to the Arabian Sea and then into India over the Western Ghats. When a cyclone forms over the Bay of Bengal, the moisture demand is so strong that the Find later jet is dragged to become more eastward from its usual north-eastward tilt. All these factors complicate the cyclone development process as well as predictions of its track more than two to three days in advance.
History says that Bangladesh has a peak in cyclone strikes in May and November whereas Myanmar has a peak in May. Since cyclones usually head northeast after approaching the Indian coast, India may yet avoid a direct strike even though it’s too early to make this call with great confidence. IMD forecasts have already suggested that Tamil Nadu and Puducherry will get very hot but are unlikely to receive heavy rains from Fani.
In the Atlantic and Pacific Oceans, massive high pressure centers called subtropical highs play a role in steering hurricanes and typhoons as well. The Bay has no such strong high pressure centre, which makes the cyclones wander a bit more unpredictably. On the other hand, the expanse of the Bay is also much smaller compared to the Pacific and Atlantic Oceans, which keeps tropical storms from gaining the kind of strength observed for some of the super typhoons and massive hurricanes.
The Bay of Bengal also responds differently to global warming since its temperatures are already above the convective threshold. Any attempt to warm it will only drive more convection to get rid of the excess energy. The impact of these regional idiosyncrasies on the number and strength of cyclones is yet to be understood. The Arabian Sea is cooler and has room to warm and is showing an increase in the number of post-monsoon cyclones.
• Cyclone Fani is likely to intensify into an extremely severe cyclone
• Its name was selected from a list of 64 names given by eight countries
• The name Fani was suggested by Bangladesh and is pronounced as Foni
Tamil Nadu, Andhra Pradesh and other states with their coastlines hugging the Bay of Bengal are bracing up for Cyclone Fani to make a landfall. Cyclone Fani (pronounced as Foni) is gaining strength over southeast Bay of Bengal and will soon develop into an “extremely severe cyclonic” storm.
The name for this cyclone was suggested by Bangladesh. The World Meteorological Organization (WMO) has devised a mechanism where countries submit a list of names from time to time. Names of cyclones are chosen from this pool.
For tropical cyclones developing in the North Indian Ocean, countries like India, Sri Lanka, Bangladesh, Maldives, Myanmar, Oman, Pakistan and Thailand send their names to the regional tropical cyclone committee.
At present, all eight countries have submitted eight names each for naming future cyclones. The name Fani was chosen from this list containing 64 names.
The word Fani (pronounced as Foni) means snake.
Last year Cyclone Titli hit Andhra Pradesh and parts of Odisha. This cyclone was named by Pakistan. In 2017, Cyclone Ockhi caused severe damage in Kerala and parts of Tamil Nadu. Its name was given by Thailand.
The names given by India are: Agni, Akash, Bijli, Jal, Lehar, Megh, Sagar & Vayu.
How countries select names:
While selecting names for cyclones, countries have to take care that the word is easily understood by people in the region, hence the names are generally familiar words.
• The main purpose of naming a tropical cyclone is basically for people to easily understand and remember the tropical cyclone in a region, thus to facilitate tropical cyclone disaster risk awareness, preparedness, management and reduction.
• Another important reason why cyclones are named is to help authorities quickly identify storms and keep a track of them because it is easier to remember cyclones by their names than remembering them using technical information like longitude and latitude.
Where Cyclone Fani got its name
The name of the Cyclone ‘Fani’, pronounced as ‘Foni’ was suggested by Bangladesh. It means ‘Snake’ or ‘hood of snake’.
India, Sri Lanka, Bangladesh, Maldives, Myanmar, Oman, Pakistan and Thailand send names of tropical cyclones developing in the North Indian Ocean to the regional committee. Presently, each country has suggested eight names for cyclones occurring in future. The name ‘Fani’ was decided from a list containing 64 names.
What is a ‘yellow alert’
The India Meteorological Department late on Tuesday issued a “yellow warning” for the Odisha coast, predicting heavy to very heavy rainfall at some places ahead of the landfall of Cyclone Fani.
A yellow warning indicates severely bad weather, warning people who are at risk to take preventive action. Yellow also means that you should plan ahead thinking about possible travel delays, or the disruption of your day-to-day activities.