Cyclone Amphan may intensify by May 18: US forecast body

Cylcone Amphan can intensify quickly into an extremely severe cyclone by May 18, with wind speeds as high as 172 kilometre/hour, and move towards the Bangladesh coast, data from the National Centers for Environmental Prediction and Global Forecasting System of the United States showed.

Extremely severe cyclones have wind speeds between 166 and 221 km/hr. The development may bring heavy rainfall to the coastal regions of Odisha and West Bengal.  

The India Meteorological Department on may 14 said that Amphan may intensify from a depression in the Bay of Bengal
on May 16 and will be the first cyclone to form in the Indian Ocean Region in 2020. Apart from that, it did not give any other information on the development. It had on May 13 said a depression in Bay of Bengal could intensify into a cyclone by May 15.

It had further said the cyclone could move in the north-western direction and then curve towards the north-east in the Bay of Bengal.

Lessons from past

Cyclone Fani, which devastated the Odisha coast before moving into Bengal and as far as North East India in May 2019, was a severe category cyclone with a wind speed of 200 km/hr.

It was the longest-lived cyclone (nine days just at sea) to have ever formed in the Bay of Bengal. It kept the IMD on its toes throughout its life cycle, even though the former deployed doppler weather radars and weather monitoring satellites to keep a tab on it.

After forming a low pressure area on April 25, 2019 and intensifying into a depression, Fani moved towards Sri Lanka and threatened to make landfall on the Tamil Nadu coast. But it changed direction and decreased its pace to stay in the Bay of Bengal, all the while becoming more intense.

Such cyclones sniff out warm waters on the sea surface and progressively become more intense. Towards the end of its journey through the Bay of Bengal, Fani changed character again.

At first, the IMD predicted that Fani would make landfall in Odisha on the morning of May 4, 2019. Then it revised its estimate to the evening of May 3. On May 2, it again revised it to May 3 afternoon. The cyclone finally made landfall at 8.30 am on May 3 in Odisha’s Puri district.

The slow progress and intensification of cyclone Fani was a result of localised winds that steered the cyclones towards warmer ocean waters where it could gather more moisture and energy.

Such localised winds are difficult to record or predict, which makes them one of the missing scientific links in understanding cyclones and other wind-based weather phenomena.

But clear disruptions in wind patterns, especially slowing down of winds, are evident across the globe, according to scientists. These disruptions make natural phenomena like cyclones, cold waves and monsoon currents more erratic and unpredictable. The progress and tracking of Amphan will provide more clues to how winds are behaving in the Bay of Bengal and influencing cyclones.