Mumbai: The southwest monsoon has arrived over the Andaman and Nicobar Islands, the India Meteorological Department (IMD) said on Friday, indicating that it would soon reach the mainland. The development also marks the beginning of the four-month rainy season.
“In association with the strengthening and deepening of the southwesterly winds, the southwest monsoon has advanced over the southwest and southeast Bay of Bengal, south Andaman Sea and Nicobar islands,” the IMD said in its special weather update, issued on Friday afternoon.
With the arrival of the monsoon, light to moderate rain is forecast till Sunday over the Andaman and Nicobar islands. Squally winds with the speed of around 50-60 kms/hour could blow along the southeast Bay of Bengal and south Andaman Sea from Friday onwards, IMD officials said.
However, Mumbaikars will have to wait a little longer for the onset of a proper monsoon, weathermen have hinted. “Though the southwest monsoon has advanced into the south Andaman sea, it is estimated to reach Kerala by around May 26. It will take 11 to 15 days to reach Mumbai and adjoining areas after that, depending on the strength of the current. As per our calculations, the actual monsoon will establish in the city by June 10, however, a week or so ahead of this, the city is likely to witness pre-monsoon showers,” said Rajesh Kapadia, Mumbai-based independent weatherman and founder of the popular private weather blog, ‘Vagaries of Weather’.
The IMD tracks the course of the monsoon every year, as it moves from the Andaman Sea towards Kerala by the end of May. Last week, the IMD had said that the monsoon was likely to arrive in Kerala on May 31st, a day ahead of its normal schedule. However, it seems that it might arrive a few days earlier.
The IMD had last month predicted that a normal monsoon this year. As part of its Long Range Forecast (LRF), released on April 16, the IMD predicted that the country would experience a normal monsoon (96 to 104 per cent of Long Period Average) this year.
This year will mark a hattrick year of normal monsoon for India, weathermen have said. In 2019, the country’s overall LPA was 110 per cent, in 2020, the LPA was 109 per cent, while this year, the weathermen have predicted an LPA between 98-104 per cent.
“The quantitative rainfall during the upcoming June to September season this year would be around 103 per cent of the LPA, which falls under the normal rainfall category,” predicted Skymet, a private weather forecast agency.
Cyclone ‘Yaas’ forming in the Bay of Bengal
Meanwhile, a low-pressure area is expected to develop over the central and adjoining southeast Bay of Bengal and this system is most likely to intensify into a cyclonic storm by May 26.
“The low-pressure system will help the southwest monsoon, as it will strengthen the cross-equatorial flow. This will help the monsoon, which is in its advancing phase,” said IMD Director General Mrutyunjay Mohapatra.
The cyclone, once formed, is expected to travel towards either coasts of Odisha or West Bengal, where the Met department was warned of heavy rainfall from May 25.
Cyclone Tauktae effect: Mumbai lake levels rise
Cyclone Tauktae, which lashed Mumbai earlier this week, causing tree falls, house/wall collapses and waterlogging in the financial capital, has left behind a residual benefit. The rainfall between May 17 and May 20 because of the cyclone storming through and in its wake has resulted in Vihar and Tulsi lakes receiving 210 and 178mm of rainfall respectively, the highest among the seven lakes that supply drinking water to Mumbai, civic officials said on Friday. This caused a marginal rise in the lake levels. The seven lakes provide Mumbai with 3,850 million litres of water per day (MLD).
According to the Brihanmumbai Municipal Corporation, Modak Sagar received 102mm rain, followed by Middle Vaitarna (62mm), Tansa (59mm) and Bhatsa (29mm) rain during the same period. However, the Upper Vaitarna did not receive any rain, BMC officials said.