TAG: GS 1: GEOGRAPHY
THE CONTEXT: A low-pressure area has formed over the southwest and adjoining west-central Bay of Bengal, just off the Tamil Nadu coast, as of the early morning hours of May 22, 2024.
EXPLANATION:
- This information has been confirmed by the India Meteorological Department (IMD).
- The IMD predicts that this storm system is likely to move northeast and intensify into a depression by the morning of May 24.
- Subsequently, the depression is expected to continue moving in the same direction, potentially intensifying further and reaching the northeast and adjoining northwest Bay of Bengal by the evening of May 25.
Potential Cyclone Development
- The IMD has not yet confirmed the system’s development into the season’s first cyclone, which would be named Remal.
- But the Joint Typhoon Warning Centre (JTWC) of the United States Navy has issued an alert for a depression in the Bay of Bengal.
- The JTWC highlighted favorable environmental conditions for the system’s intensification, such as warm sea-surface temperatures of 28-29 degrees Celsius and low vertical wind shear.
- These conditions are conducive to the growth of the storm system, providing the necessary heat and moisture while low vertical wind shear prevents the disruption of the cyclone’s structure.
Forecasts and Predictions of systems
- The weather analysis and visualization platform Windy.com also indicates the formation of a low-pressure area off the Tamil Nadu coast.
- According to Windy.com’s forecast, which uses data from the US Global Forecasting System (GFS), cyclone Remal could form on the morning of May 26 in the northwest Bay of Bengal.
- This forecast suggests that the cyclone may move close to the coasts of West Bengal and Bangladesh.
- The Weather Channel (TWC) has also issued an alert regarding the potential cyclone.
- TWC’s meteorological team suggests that while a cyclonic storm is likely, the chances of it intensifying into a severe or very severe cyclonic storm are slim.
- This caution is due to the increasing unpredictability in sea-surface temperatures and the behavior of winds around cyclones in recent years.
Expected Weather Conditions and Impact
- According to the IMD, the potential cyclone would bring light to moderate rainfall to many areas, with isolated heavy rainfall expected in North and South 24 Parganas and Purba Medinipur districts of West Bengal and Balasore district of Odisha on May 25 and 26.
- Similar weather conditions are predicted for Mizoram, Tripura, and south Manipur for the same dates.
- TWC forecasts significant rainfall totals of 200 millimeters or higher for Assam, Meghalaya, Manipur, Mizoram, and Tripura from May 26-28.
Environmental Conditions Favoring Cyclone Formation
- Warm sea-surface temperatures and low vertical wind shear are critical factors in the potential development of cyclone Remal.
- Warm sea-surface temperatures provide the necessary heat and moisture to fuel the storm, while low vertical wind shear ensures that the cyclone’s top structure is not disrupted, which could lead to dissipation.
- These conditions, highlighted by both IMD and JTWC, are crucial for the intensification of the storm system.
Challenges in Cyclone Forecasting
- Forecasting cyclones has become increasingly challenging due to the growing unpredictability in environmental conditions.
- Variations in sea-surface temperatures, especially below the surface, and the complex behavior of winds around cyclones contribute to this difficulty.
- These factors can lead to significant changes in the intensity and path of the storm, making precise predictions more complex.
Cyclone
- A cyclone is a large-scale system of air that rotates around the center of a low-pressure area.
- It is usually accompanied by violent storms and bad weather.
- According to the National Disaster Management Authority (NDMA), a cyclone is characterized by inward spiralling winds that rotate anticlockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.
- Types of Cyclones
- The NDMA classifies cyclones broadly into two categories:
- Extratropical cyclones
- Tropical cyclones
- Extratropical Cyclones
- Also known as mid-latitude cyclones, extratropical cyclones occur outside the tropics and have cold air at their core.
- They derive their energy from the release of potential energy when cold and warm air masses interact.
- These cyclones always have one or more fronts connected to them, which are the boundary between two kinds of air masses.
- Tropical Cyclones
- Tropical cyclones are the most devastating storms on earth and develop in the regions between the Tropics of Capricorn and Cancer.
- They develop when thunderstorm activity starts building close to the center of circulation, and the strongest winds and rain are no longer in a band far from the center.
- Tropical cyclones have different names depending on their location and strength.
- For instance, they are known as hurricanes in the Caribbean Sea, the Gulf of Mexico, the North Atlantic Ocean, and the eastern and central North Pacific Ocean. In the western North Pacific, they are called typhoons.
- The NDMA classifies cyclones broadly into two categories:
How the cyclones are named and what are the guidelines on adopting their names?
- In 2000, a group of nations called WMO/ESCAP (World Meteorological Organisation/United Nations Economic and Social Commission for Asia and the Pacific), which comprised Bangladesh, India, the Maldives, Myanmar, Oman, Pakistan, Sri Lanka and Thailand, decided to start naming cyclones in the region.
- After each country sent in suggestions, the WMO/ESCAP Panel on Tropical Cyclones (PTC) finalised the list.
- The WMO/ESCAP expanded to include five more countries in 2018 — Iran, Qatar, Saudi Arabia, United Arab Emirates and Yemen.
- The list of 169 cyclone names released by IMD in April 2020 were provided by these countries — 13 suggestions from each of the 13 countries.
What are the guidelines to adopt names of cyclones?
- While picking names for cyclones, countries need to follow some rules.
- The proposed name should be neutral to (a) politics and political figures (b) religious believes, (c) cultures and (d) gender
- Name should be chosen in such a way that it does not hurt the sentiments of any group of population over the globe
- It should not be very rude and cruel in nature
- It should be short, easy to pronounce and should not be offensive to any member
- The maximum length of the name will be eight letters
- The proposed name should be provided with its pronunciation and voice over
- The names of tropical cyclones over the north Indian Ocean will not be repeated. Once used, it will cease to be used again.
