A delayed start to the withdrawal of the southwest monsoon does not bode well for the Durga Puja weather in Kolkata, though Met officials said it is too early to predict the weather on the festive days.
The India Meteorological Department said in a Thursday bulletin that the process of the withdrawal of the southwest monsoon is likely to start from Rajasthan on October 6.
The usual date of the start of the process is September 17. The usual date of the withdrawal of the monsoon from Kolkata is October 10.
This year, if the withdrawal is not unusually prompt, the monsoon will not be gone from Kolkata by October 10.
Puja starts on October 11.
Meteorologists said the withdrawal of the monsoon was not a uniform process and happened in phases.
“It is an extremely non-linear process. Two plus two does not mean four in this case,” said a Met official in Alipore.
The southwest monsoon saw delayed withdrawals in 2017, 2018, 2019 and 2020. A lookback at the withdrawal in the past three years validates the official’s point.
Last year, the monsoon’s withdrawal started on September 28 and it withdrew from Kolkata on October 28.
In 2019, the withdrawal had started on October 9, one of the most delayed in the recent past. But the rains left Kolkata on October 14.
In 2018, the withdrawal had started on September 29 and Kolkata bid adieu to the rains on October 6.
According to the IMD, the southwest monsoon starts receding from northwest India if there is a cessation of rainfall activity in the area for five continuous days.
An anticyclonic wind has to form over the lower troposphere, and there should also be considerable reduction in moisture content.
“From west to east, weather systems are still active. A low-pressure area is causing heavy rain in Jharkhand. It is likely to trigger heavy rain in north Bengal. There are no immediate signs of monsoon withdrawal,” said Das.