Context:

• The Indian Meteorological Department (IMD) declared about the development of Cyclone Midhili in the northwest Bay of Bengal.

Latest update on Cyclone Midhili

• Under the influence of Cyclone Midhili, heavy rainfall is forecasted in the coastal regions of Odisha, West Bengal, Tripura, and Mizoram with wind speed blowing in the range between 40 kmph and 70 kmph.

What are Cyclones?

• A Cyclone is a rapid inward air circulation around a low-pressure(LP) area. 
• They are confined to the area lying between 30° N and 30° S latitudes in the atmosphere.
• Cyclones in India:  Tropical cyclones in the North Indian Ocean region develop during the pre-monsoon (April to June) and post-monsoon (October to December) periods.

Conditions for the formation of a tropical cyclone:

• Large and continuous supply of warm and moist air.
• Strong Coriolis force that can prevent the filling of low pressure at the centre.
• Unstable condition that creates local disturbances.
• Absence of strong vertical wind wedge which disturbs the vertical transport of latent heat.

Formation of cyclones:

• Formation and Initial Development Stage:  A warm sea with abundant and turbulent transfer of water vapor.
• Mature Phase: Air rises and tends to spread out at the tropopause level. The air warms up by compression and a warm ‘Eye’ is generated.
• Modification and Decay: Cyclone begins to weaken as its source of warm moist air begins to ebb, or is abruptly cut off.

• Naming of cyclones: Countries affected by the Arabian Sea and Bay of Bengal cyclones rotationally give names of cyclones in a sequence.
  • The name ‘Midhili’ was given by the Maldives. 

News Source: Live mint