Monsoon may finally start withdrawing in next three days, says IMD

The southwest monsoon might finally start withdrawing from parts of North-West India over the next three days, signaling the end of its four-month journey over the country that started in June, the India Meteorological Department (IMD) said.

However, though the retreat might begin from next week, the rains might not descend quickly, as the met department predicted fresh spells of rains in Vidarbha, Chhattisgarh and east MP on September 21-22 and over Odisha, Coastal areas north Andhra Pradesh and Gangetic West Bengal on September 19-21.

“Due to anti-cyclonic flows over northwest India at lower tropospheric levels, dry weather is very likely over west Rajasthan, Punjab, Haryana, Chandigarh and Delhi during the next five days.

"Hence conditions are becoming favourable for the withdrawal of Southwest Monsoon from parts of northwest India during next three days,” the IMD said.

Till a few years back, the usual date for the start of the southwest monsoon's retreat was September 1.

This was later changed to September 17 according to the new onset and withdrawal dates released by IMD a few years back.

A few weeks back, the met department had said the southwest monsoon will start withdrawing from parts of Rajasthan from September 1, which it later updated as development of fresh weather systems meant the rains were not expected to go in hurry.

For the whole of September, the IMD in its last forecast had said that monsoon for the country as a whole was expected to be 109 of the Long Period Average (LPA). The LPA for September is 167.9 millimeters.

“As per the revised onset and withdrawal dates, the monsoon should start retreating from far western Rajasthan from September 17 as against the earlier withdrawal date of September 1.

"This date is within a range of plus and minus 7 days, so even if the withdrawal starts a few days after September 17, it will be within the range,” IMD director general Mrutyunjay Mohapatra told Business Standard.

He said rainfall has been above normal over most parts of the country in the first fortnight of September, which was in accordance with the predictions made by the IMD.

Mahesh Palawat, Vice-President, Meteorology and Climate Change at private weather forecasting agency Skymet said that anti-cyclone conditions are expected to develop over West Rajasthan over the next 2-3 days which could signal the withdrawal of southwest monsoon.

And, even the fresh weather systems developing over Bay of Bengal, will start recurving from North Madhya Pradesh and not reach Rajasthan as was the case of the recent low pressure area.

“Withdrawal is expected to start within the next 2-3 days and as per the latest patterns it isn’t delayed,” Palawat told Business Standard.

A delayed withdrawal of monsoon might help in leaving good soil moisture for the preceding rabi crops, but could make the standing kharif crops prone to damage and pests due to prolonged exposure to rains at the pre-harvesting stage.

IMD considers monsoon to have withdrawn from a particular area if there is cessation of rainfall activity over the area for continuous five days, establishment of anticyclone in the lower troposphere and considerable reduction in moisture content as inferred from satellite water vapour imageries and tephigrams.

“As per the new onset and withdrawal dates issued a few years back, the monsoon might reach Central India with a delay of 10 days while leave North-West India after 10-15 days from its earlier dates.

"This should help in getting a good rabi harvest particularly in the North,” Mohapatra said.