Southwest monsoon 2021 is likely to start its 4 month-long journeys from June to September shortly. As a prelude to its entry over mainland India, the onset of monsoon is expected over the South Andaman Sea and the adjoining southeast Bay of Bengal anytime soon. The normal date of arrival over this area is 22nd May and this time may reach today itself, a day prior. Last year, the monsoon current had reached 5 days early on 17th May. However, the onset date over the Andaman Sea does not find any strong correlation with its arrival over Kerala.
The equatorial region in the proximity of the South and Southeast Bay of Bengal has been showing a fair amount of cross-equatorial flow, an essential component for bringing monsoon current. The complete chain of islands from South to North including Nancowry, Carnicobar, Hut Bay, Port Blair, Long Islands, and Maya Bandar has rained for the last 4-5 days. Satellite imagery is also indicative of monsoon clouds over the region.
The next stop of Southwest Monsoon will be over North Andaman Sea and Sri Lanka. The likely formation of a low-pressure area over Northeast Bay of Bengal and neighborhood, subsequently intensifying to a tropical storm next week, will facilitate the timely advance of the monsoon over those parts. Mainland Kerala awaits monsoon sometime around 30th May.
