IMD: Southwest monsoon withdraws from country
The southwest monsoon withdrew from the entire country on Monday, making it the seventh-most delayed retreat since 1975, and with the setting in of north-easterly winds, northeast monsoon commenced over south peninsular India, according to the India Meteorological Department (IMD).
“In view of significant reduction in rainfall activity over most parts of the country, the southwest monsoon has withdrawn from the entire country today (Monday). Simultaneously, with the setting in of north-easterly winds in the lower tropospheric levels, the northeast monsoon rain has commenced over extreme south peninsular India today,” IMD said.
“The withdrawal of the southwest monsoon 2021 from the entire country is the seventh-most delayed withdrawal (on or after October 25) during 1975-2021,” it said.
The southwest monsoon had completely withdrawn from the country on October 28 last year; October 25 in 2017; October 28 in 2016; October 29 in 2010; October 25 in 2000 and October 27 in 1975. Interestingly, the southwest monsoon retreated on or after October 25 five times between 2010 and 2021 — in 2017, 2010, 2016, 2020 and 2021, the IMD data showed.
DS Pai, scientist and head of climate research and services at IMD Pune, said the past 10 years have shown delayed withdrawal of monsoon from the country. “Southwest monsoon should withdraw from the country around October 15 and northeast monsoon should commence over peninsular India by October 20. But there is some delay. This may be linked to a prolonged summer in the northern hemisphere. It is also linked to climate change, which the intergovernmental panel on climate change (IPCC) has also recognised in its latest report,” Pai said.
Unseasonal rain in October triggered by western disturbances caused flooding and landslides in different parts of northwest India earlier this month. Uttarakhand in particular was badly impacted. “…Delayed monsoon withdrawal from the country (has) provided adequate moisture for intensification of rainfall episodes,” Pai added.
In October so far (till October 25), the country has witnessed 42% excess rainfall, with 212% excess rain over northwest India; 22% excess over east and northeast India; 19% excess over central India and 28% excess over south peninsula. Against a normal of 21.4 mm rainfall, northwest India has recorded 66.8 mm rain. Uttarakhand and Delhi, for example, have recorded 525% and 444% excess rain, respectively.
Meanwhile, Met department said that a cyclonic circulation is likely to develop over southeast Bay of Bengal and neighbourhood by Tuesday. It is likely to move westwards and under its influence, a low-pressure area is likely to form over central parts of South Bay of Bengal during subsequent 48 hours.
Isolated heavy rainfall is likely over Tamil Nadu and Puducherry till October 29, over Kerala till October 27; over south interior Karnataka till October 26; over coastal Andhra Pradesh and Rayalaseema on October 28 and 29, IMD said.