Month of March delivered more than its share and churned 2 weather systems, both over Bay of Bengal (BoB). The 1st one made it to a weak cyclonic storm (01B) and the 2nd missed the grade by a whisker to make landfall over Myanmar as deep depression. Pre monsoon storms in the Indian Seas are not favorite in April for the coastline. Frequency of formation as such is low and in case of any eventuality, Arakan coast of Myanmar and Bangladesh mostly face the brunt.
Since 2010, no tropical storm has formed over Arabian Sea, in the month of April. Bay of Bengal has hosted 2 storms, ‘Fani’ and ‘Marutha’. These storms also came up towards the 3rd week of April or even later. Cyclone Fani appeared as a depression on26th April 2019 over central parts of BoB strengthened to a cyclonic storm on 27thApril. It struggled to grow further meeting strong resistance of wind shear but survived and intensified to a severe cyclonic storm on 29thApril. Thereafter, rapid intensification upgraded the storm to ‘Extremely Severe’, equivalent to a Cat-IV hurricane on 30thApril. Later, based on 1 minute sustained wind speed of 280kmh, it was upgraded to the topmost category of Cat-V. It made landfall on 03rdMay 2019, near Puri (Odisha) and weakened to Cat-I rapidly.
The only other tropical storm of the recent decade was ‘Marutha’. The cyclone came up over the Andaman Sea and lasted for merely 24hours. The storm formed late on 15thApril 2017 and crossed Myanmar coast near Sandoway early on 17thApril. No storm formed over the Indian Seas from 2010 to 2016, 2018, 2020 and 2021.
The tropical storms in the month of April generally come up over BoB between 8°N and 13°N and east of 85°E. These systems initially track north and northwest and later recurve northeast, to head for Myanmar and Bangladesh. Similar track is seen over the Arabian Sea, where after recurving, the storms head for Gujarat – Sind and Mekran coast.
Preliminary model guidance suggest a low pressure area, likely in the 1st week of April 2022 (05-06 Apr). It is too early to comment on its prospects and only speculations can be made for further consolidation. As it is, this weather system will enter the Andaman Sea while travelling across Gulf Of Thailand, Range of Tenasserim hills and Gulf of Martaban. The low pressure area will encounter land and water bodies before entering Andaman Sea. Resultant fragmentation will need time to get stabilized over the oceanic surface of BoB. A watch period of 3-4 days, between 02nd and 05thApril will have to be observed .
