Monsoon delayed, Mumbai records its longest wait for rains in a decade
Even though the weather bureau on Thursday declared the onset of monsoon in south Konkan and parts of south central Maharashtra, it said the arrival of the rains in the city and the north Konkan region is not expected for another four to five days.Updated: Jun 21, 2019 08:47 IST
Mumbai’s wait for the monsoon this year is its longest in a decade, with the rains delayed by 10 days. Even though the weather bureau on Thursday declared the onset of monsoon in south Konkan and parts of south central Maharashtra, it said the arrival of the rains in the city and the north Konkan region is not expected for another four to five days.
According to the India Meteorological Department (IMD), monsoon usually arrives in the city by June 10. In 2009, the onset of monsoon was on June 27. The delay was due to El Niño — a phenomenon caused when warm water from the western Pacific Ocean flows towards the east. Last year, the monsoon’s onset in the city was on June 9. The second-longest delay since 2009 was in 2016, when monsoon arrived on June 20. The onset of the season in the city in 2012, 2014 and 2015 was also delayed by an El Niño-like situation or other factors. KS Hosalikar, deputy director general, western region, IMD, said this year monsoon was delayed in Mumbai owing to a late onset over Kerala and the impact of cyclone Vayu. “A similar situation occurred in June 2014 because of cyclone Nanauk. So, even though such events [delayed monsoon] are irregular, they are not ruled out,” Hosalikar said.
He added, “Delay or early arrival of monsoon has a different reason every year. The 10-year window is still a much shorter one…over a 100-year period, longer delays have been witnessed.”
Bishwambhar Singh, director, regional meteorological centre, IMD, Mumbai, said the northern limit of the monsoon over the west coast is currently over Ratnagiri and Kolhapur. “Gradual progress is expected over the next 72 hours to cover more parts of Maharashtra,” Singh said.
Independent meteorologists, however, are of the opinion that monsoon arrived in Mumbai and the Konkan region around mid-June itself (June 15). “The arrival was not robust due to the presence of tropical cyclone Vayu, but as the cyclone completely disintegrated, parts of the west coast of India, including south Konkan, began receiving good rainfall,” said Akshay Deoras, meteorologist and PhD researcher at the department of meteorology, University of Reading, UK.
Sridhar Balasubramanian, associate professor, department of mechanical engineering and associate faculty, IDP Climate Studies, Indian Institute of Technology-Bombay, said there were three indicators that confirmed the arrival of monsoon in Mumbai, around June 15-16. These are – more than 2mm rainfall recorded at all stations in Mumbai over two continuous days; westerly wind depth touching 3.1km/hour; and outgoing radiation going below 200 watts per square metre (cloud cover reduces sunlight, reducing outgoing longwave radiation). “IMD declares monsoon onset in a phased manner. As southwest monsoon did not cross most of the southern peninsula up till June 20, the weather bureau has not declared the onset. However, it needs to be decided by IMD whether the factors indicating monsoon are vital vis-à-vis the movement of monsoon currents in a phased manner,” he said.
Meanwhile, between 8.30am on June 1 and 8.30am on June 20, the suburbs recorded 165.3mm rainfall, deficient by 103mm or 38.3%. During the same time, south Mumbai recorded 127.2 mm rainfall, deficient by 145.4mm or 53.3%.
According to data tabled before the civic body’s standing committee on Wednesday, as of June 19, at 6.03%, the water stock across seven lakes that supply water to Mumbai has dipped to 87,251 million litres, the lowest in three years.