The India Meteorological Department (IMD) on Saturday announced the commencement of the southwest monsoon’s withdrawal from parts of west Rajasthan, two days later than the normal date, signalling the beginning of the end of the four-month June-September rainy season.
“Conditions are also favourable for further withdrawal from some more parts of Rajasthan and some parts of Punjab, Saurashtra and Kutch during the next 3-4 days,” the Met Department said in a statement.
The complete withdrawal of the monsoon from the country is expected by October 15, a few days ahead of the onset of the winter or northeast monsoon in peninsular India.
Typically, after its onset over the Kerala coast, the southwest monsoon covers the country over the subsequent four months before beginning its withdrawal from the western parts of Rajasthan.
This year, the monsoon arrived over Kerala on June 4, but its progress subsequently lost momentum. It regained pace in July and covered the entire country by July 9.
According to the IMD, rainfall during the monsoon season from June 1 to September 19 was 14.9% below the long-period average (LPA), placing it in the “deficient” category. Overall rainfall during the season is likely to be the lowest since 2009.
Monsoon rainfall was previously in the “deficient” range in 2002 (-20.9%), 2009 (-18.3%), 2015 (-12.7%) and 2014 (-10.15%).
The Met department has also indicated a continued strengthening of El Niño conditions through the remaining period of the southwest monsoon season. Regionally, central India received rainfall in the normal range so far this season, while northwest India (-9.2%), east and northeast India (-25.7%) and south peninsular India (-28.5%) recorded below-normal rainfall.
After scanty rainfall in June, when precipitation was 36% below the LPA, monsoon rains revived in July, with rainfall 1% above the LPA. This was within the “normal” range and helped accelerate kharif crop sowing.
However, rainfall in August was unevenly distributed, with precipitation 16.3% below the LPA. All regions, except the monsoon core zone of central India, recorded “deficient” rainfall. For September, the Met department has forecast rainfall to be “below normal”, or less than 91% of the benchmark.
Kharif crop sowing, which had been lagging until the end of June, also picked up pace in July and August. The total acreage so far is around 1.45% lower than last year and 0.72% below normal acreage, defined as the average area covered over the past five years.
In May, the IMD revised its June-September rainfall projection to 90% of the LPA from 92% in its April forecast, placing the season in the “below-normal” category. The Met Office also said there was an 84% probability that rainfall during the season would remain in the “deficient to below-normal” range.
The IMD classifies rainfall between 96% and 104% of the LPA as ‘normal’. Rainfall between 90% and 95% is considered ‘below normal’, while precipitation below 90% of the LPA is termed ‘deficient’. Rainfall in the range of 105% to 110% is classified as ‘above normal’.