Between 1891 and 2020, only eight cyclones have been formed in March, including two in the Arabian Sea and six in the Bay of Bengal, the India Meteorological Department (IMD) said on Thursday. Of the eight, six dissipated over sea and one crossed the Tamil Nadu coast as a cyclonic storm in 1926. Another crossed Sri Lanka in 1907.
Cyclones normally form during the pre-monsoon months over the north Indian Ocean between April and May. "Climatologically March is not cyclone season. It is April and May. The ocean is cooler in March and solar insolation is not very high. In March, westerly systems are predominant in the northern parts of the country and easterly waves are predominant over the Peninsular region," said an IMD official.
According to IMD's experimental pre-genesis intensity forecast and wind distribution track, the low-pressure area (LPA) over Southeast Bay of Bengal is likely to intensify into a depression on March 20 and cyclone Asani on March 21.
Initially, the LPA is likely to travel east-north-eastwards till March 19 morning. It will move northwards along and off the Andaman and Nicobar Islands till March 20, north-north-eastwards, and reach near Bangladesh and north Myanmar coasts around March 22 morning. The maximum impact of Asani is expected in Andaman and Nicobar Islands. "We are not issuing any forecast for landfall as of now. It is likely to move towards Myanmar/Bangladesh coasts but we have to watch," the official said.
The part of the Bay of Bengal, where the LPA has formed, is warmer than normal with a sea surface temperature of around 30 degrees Celsius, according to Cooperative Institute for Meteorological Satellite Studies.
On March 21, gale winds at 70-80 kmph gusting to 90 kmph are expected over Andaman and Nicobar Islands, east-central Bay of Bengal, and adjoining the south-east Bay of Bengal. Gale winds of 70-80 kmph gusting to 90 kmph are likely over the east-central Bay of Bengal and the north-east Bay of Bengal, and along and off south-east Bangladesh and North Myanmar coasts on March 22. Squally winds of 45-55 kmph gusting to 65 kmph are likely over the North Andaman Islands, the North Andaman Sea, and the south-east Bay of Bengal.
Heavy to very heavy rainfall is likely at a few places over Andaman and Nicobar Islands and isolated extremely heavy rainfall over the Nicobar Islands on March 19. Six to nine-meter waves are expected over the Andaman Sea, south-east and adjoining the east-central Bay of Bengal on March 21. Sea is likely to be high over the east-central and adjoining south-east and the north-east Bay of Bengal and the north Andaman Sea on March 22.
Fishermen have been advised not to venture into the sea between March 17 to 22. A suspension of offshore activities has been advised for March 20 and 22. Air traffic also needs to be regulated on March 20 and 21, IMD said.
"If the forecast materialises, Tropical #CycloneAsani will become the first-ever tropical cyclone to hit Andaman and Nicobar Islands in March. Not a single tropical cyclone has hit the region in March in at least 132 years," tweeted Akshay Deoras, a meteorologist at the University of Reading, UK.