Monsoon withdrawal likely to be delayed
The monsoon is likely to take longer to complete its withdrawal this year because of the influence of two low-pressure areas that are likely to bring widespread and heavy rain to Odisha, Bihar, Jharkhand, Chhattisgarh and east Madhya Pradesh, weather scientists said.
“We don’t see any indication of rains stopping immediately in east and northeast India and even eastern parts of central India. Withdrawal cannot be announced before rain stops completely and, in any case, northeast monsoon will set in over peninsular India from October 15 onwards,” said K Sathi Devi, head of the India Meteorological Department’s national weather forecasting centre.
A low-pressure area is likely to form over the Andaman Sea around October 9 and is gradually likely to intensify into a depression over central Bay of Bengal during the next two days, moving towards the north Andhra Pradesh and Odisha coasts.
There is also a low-pressure area presently lying over northwest Bay of Bengal and the adjoining Odisha coast which is likely to persist until October 5 and become less marked, but the cyclonic circulation associated with it is likely to move to south Chhattisgarh on October 6.
Under the influence of current low-pressure area over northwest Bay of Bengal and adjoining Odisha coast, fairly widespread to widespread rain is likely over Odisha, Bihar, Jharkhand and Gangetic West Bengal during the next four days.
Isolated heavy rainfall is likely over Odisha during October 4 to 6, over Jharkhand on October 4, 6 and 7, over Bihar on October 6 and 7, over Chhattisgarh from October 4 to 7; the fresh low-pressure area is likely to trigger rainfall over Odisha and coastal Andhra Pradesh from October 11 to 13.
“Monsoon withdrawal from the eastern side will be delayed. It will withdraw from northwest India, including Gujarat but will not withdraw very quickly from east India. Another well-marked low pressure area is likely to move from Gulf of Thailand to Bay of Bengal around October 16,” said Mahesh Palawat, vice president, climate change and meteorology, Skymet Weather, a private forecaster.
“This is also the cyclone season because the north Bay of Bengal is warmer and there is less wind shear (a zone of change in wind direction and velocity) when the monsoon withdraws,” he added.
DS Pai, senior scientist at IMD-Pune, said that as of now the likely depression over Andaman Sea will not intensify into a cyclone but since October is typically the cyclone season, development of more such systems can be expected.
This year, the monsoon’s withdrawal started from west Rajasthan on September 29. Last year, the monsoon started withdrawing only on October 9 against the normal date of September 1 and prolonged rains brought a deluge to parts of Maharashtra, Kerala and Bihar in August when rains usually diminish. The monsoon withdrew completely only by October 17.
The monsoon season officially ended on September 30. This year’s monsoon season recorded total rainfall equal to 108.7% of the long-period average (LPA), the third highest since 1990, behind only 1994 and 2019 when rainfall equal to 112% and 110% of LPA was recorded.