After heavy rain for nine hours, Mumbai achieves 44% of June’s average rainfall in one day

On Wednesday morning, the India Meteorological Department (IMD) declared the onset of monsoon over Mumbai. The Met department has said Mumbai will continue to receive extremely heavy rain spells (more than 200 mm in 24 hours) till June 13 and continue to remain under ‘orange’ alert (be prepared) during the next four days.

An ‘orange’ alert will continue over Palghar, Thane, Mumbai, Sindhudurg and Ratnagiri districts till June 13. In nine hours, Thane recorded 162.6 mm and Colaba recorded 45.6 mm rain. In the Konkan region, heavy rain was reported to include Matheran (104 mm), Dahanu (40.8 mm) and Alibaug (37.6 mm).

According to the IMD district forecast and warning, adjoining areas of Madhya Maharashtra, too, will experience similar heavy intensity rainfall till the end of this week owing to the strengthening of westerly winds and the formation of a low-pressure system along North Bay of Bengal on June 11. “Due to the strengthening of westerly winds along the West coast, along with these circulations in Arabian Sea and Bay of Bengal, dense moisture-laden clouds are kept spinning over Mumbai resulting in heavy to very heavy showers,” said K S Hosalikar, senior scientist with the IMD in Pune.

In the first nine days of June, the city has already achieved 84 per cent of June’s monthly average. Mumbai has, so far, recorded 416.2 mm rain this month (until 5.30 pm on June 9) against a monthly average of 493.1 mm. Last year, Mumbai received only 344.4 mm rain in June, its lowest monthly average in five years.

Two significant weather systems are driving torrential showers, including an upper air cyclonic circulation over Arabian Sea and a low-pressure zone forming over Bay of Bengal. Experts said these simultaneous circulations were having a “push and pull” effect on the monsoon trough, which entered most parts of interior Maharashtra, some parts of South Gujarat, parts of Telangana and Andhra Pradesh, most parts of central Bay of Bengal and some more parts of North Bay of Bengal on Wednesday.