Mumbai witnessed one of the wettest monsoon season for the 2nd consecutive year. Month of August was a bit dampener but it got compensated with swampy June and July. During the season, there was even a hattrick of 3 digit rainfall in 24hr in June and otherwise on 7 occasions, the mark was breached, except in August.
Month of October has started on a dry note with just a sprinkle in some parts. But retreating monsoon showers till middle of October are, more often than not, become a parting gift. Mumbai nearly goes dry for the next 6 months between November and April, unless some freak cyclonic storm invades Konkan coast during the post monsoon season.
Normal date for withdrawal of monsoon from Mumbai is 06thOctober, which invariably gets surpassed. Year 2020 recorded the most delayed withdrawal from the city on 26thOctober. Sometimes, it gets linked with commencement of withdrawal from North India. Withdrawal of monsoon has been delayed repeatedly and is starting only after 27thSeptember, since 2016.
Earlier, the normal date to begin withdrawal was 01stSeptember which has now been revised to 17 Sep, since 2019. This year, the withdrawal process is likely to commence anytime soon from West Rajasthan and is expected to vacate rapidly from entire north and central parts with in 10days. The financial capital may see the signs of withdrawal as early as 12thOctober but is likely to make a final exit around 15thOctober.
While the monsoon retreat begins shortly, weather activity has picked over South Peninsula on either side of the coastline. Presence of a cyclonic circulation each in the Bay of Bengal, off Tamil Nadu coast and over Southeast Arabian Sea, aligned with coastal Karnataka and Goa, is going to enhance the intense weather activity across the region.
Presence of a shear line joining the two circulations and also a trough along the Konkan coast will bring moderate showers for Mumbai and suburbs between 05th and 09thOctober. These ‘hit and miss’ showers may become very light subsequently, before the announcement of withdrawal around 15th October.