The last cyclone in the Indian Seas was during the southwest monsoon 2021, otherwise supposed to be benign for such massive cyclonic disturbances. On 24th September 2021, a low pressure area from Gulf of Martaban (Myanmar) entered North Bay of Bengal. It was upgraded to a cyclonic storm named Gulab, on 25th Sep. It had a short sea travel and made landfall ,20km north of Kalingapatnam, on 26thSep (1800hr).
The weakened storm crossed entire stretch of southern parts and its remnants entered Arabian Sea as a well marked low pressure area on 29thSeptember. On 30thSep (0530hr), it was upgraded to a depression over Gulf of Kutch. Around midnight, it strengthened in to a cyclonic storm, renamed as ‘ Shaheen’ and kept heading westward. It made landfall over North Oman, making it one of the rare cyclones to strike that region since 1890.
The tropical cyclone season has no bounds in the North Indian Ocean. This includes Bay of Bengal and Arabian Sea. Precariously, it has 2 peaks of activity. The 1st peak when the sun traverse from equator to Tropic of Cancer (March-June) and 2nd one, when northeast monsoon regime accelerates over Bay of Bengal, between Oct-Dec. Typically, the strongest cyclones which impact Indian coastline are during fall peak.
However, exceptions are always there like storm ‘Fani’, an extremely severe cyclonic storm, struck in April and ‘Amphan’, a super cyclone dashed in May. While, the spring tropical cyclones often carry towards Myanmar and Bangladesh, the latter one threaten the entire eastern coastline. The relative silence in between the 2 peaks is because of Asian Monsoon.
Southwesterly monsoon winds sweep the moisture flux from late springe through summer, fueling heavy rainfall at times. During monsoon months, upper winds become too strong for any cyclone to develop. Weak vertical wind shear in the pre monsoon and post monsoon season are instrumental to raise level of cyclogenesis and trigger storms in the North Indian Ocean.
Since 1970, a total of 239 cyclonic storms have formed in the Indian Seas (Bay of Bengal & Arabian Sea). Out of this, 164 formed in Bay of Bengal and 75 over the Arabian Sea. However, in the last decade or so, the number of storms have also increased over Arabian Sea. Between 2010 and 2021(so far), total of 53 storms have formed and Bay of Bengal and Arabian Sea has a share of 30 & 23 respectively. Intensity of these storms over the Arabian Sea has also picked up.
Maximum of 9 storms in a single year have formed over the Indian Seas( 2019). Before this, 8 storms each had formed in 1975, 1987 and 1998. ‘Amphan’ was the severe most cyclone(super cyclone) in the recent past, striking last year during pre-monsoon.
As per statistical records, 2-3 cyclonic storms form in the post monsoon season over the Indian Seas. Exception being 2017, when only one storm ( Ockhi) formed, without making a landfall over the Indian coastline.
There are initial indicators for development of maiden cyclone of this post monsoon season over Bay Of Bengal around fag end of November or start of December. Cyclonic disturbance is expected to enter Andaman Sea from Gulf of Thailand and Myanmar region around 29thNovember. Andaman Sea and Southeast Bay of Bengal remains under scanner for any significant development over the next 72hr.
In case of a cyclone, it will be named ‘Jawad’ as proposed by Saudi Arabia. At this time of the year, such storms can threaten the entire eastern coastline, and more so of Odisha