Weather experts says IMD alerts and monsoon onset prediction were both faulty

Hindustan Times

27-05-2025

MUMBAI: On Monday, the city woke up to a heavy downpour that caught it completely off guard as the India Meteorological Department (IMD) had issued a yellow alert, the second mildest in its colour code, for the day. The weather bureau on Sunday had also stated that the onset of the monsoon in Mumbai was expected by Wednesday.
IMD maintained the yellow alert for May 26 till 8.30 am when the weather station updates the forecasts. It upgraded it to an orange alert at 9.39 am. Less than three hours later, at 12.30pm, it further upgraded the warning to a red alert, indicating extreme rains.
Shubhangi Bhute, director of IMD Mumbai was unavailable for comment.
On Monday, the weather alerts also coincided with IMD's Regional Meteorological Centre in Mumbai declaring an early onset of the monsoon, the earliest in the last 35 years in Maharashtra and the last 75 years in Mumbai. 'The rainy season approaches Mumbai from Kerala, as the southwest monsoon progresses on the west coast. Usually it takes at least 10-15 days for the southwest winds to reach Mumbai—however, this year they have come early,' said Sushma Nair, scientist at IMD Mumbai.
However, weather experts argued that the doppler radar of IMD showed different synoptic conditions. The scientist added that while there were favourable conditions for the monsoon onset, it was not possible for the winds to travel the west coast in two days. Rajesh Kapadia, author of 'Vagaries of Weather', agreed. 'The current rainfall activity does not meet IMD's criteria for announcing the monsoon,' he said. 'There are several technical criteria, which the current patterns do not fulfil. We are currently experiencing winds from the northwest so the rains will pass in two to three days.'
Deoras highlighted that IMD would have waited to declare the monsoon, had the current rainfall activity not occurred. 'For a layperson, the monsoon is generally about the rains, not wind patterns,' he said. 'However, to avoid criticism from people, IMD declares the monsoon onset closest to a rainfall activity.' Added Kapadia, 'Because the city has already received rainfall of over 200 mm, people think it is the monsoon already so the weather station has declared it as such.' Both weather experts said the current rain spell would subside over the next two days, leading to dry weather once again.
IMD has maintained a yellow alert till Thursday.