Monsoon to be normal in Aug-Sept: IMD, La Nina threat to crops in Oct, analysts

The normal monsoon withdrawal date is October 15. Coincidentally, both 2010 and 2020 had Lal Nina.

India Meteorological Department (IMD) on Monday predicted that the monsoon would be ‘normal’ during August-September. However, a possible emergence of La Nina in the Pacific Ocean from October may prolong the monsoon season and bring in more rains during the harvesting period, potentially damaging some kharif crops, analysts warned.

“The 2021 August-September rainfall over the country as a whole is likely to be normal and quantitatively 100% of the Long Period Average (LPA),” IMD director general Mrutyunjay Mohapatra said at an online briefing. Rainfall between 95% and 105% of LPA is considered ‘normal’ for the two months. The LPA (1961-2010) during the August-September period is 428.3 mm. During August, monsoon rainfall is likely to be 99% of LPA, Mohapatra added.

‘Below normal’ to ‘normal’ rainfall has been predicted over many areas of the north-west, east and north-east India, the key paddy and sugarcane growing regions. ‘Normal’ to ‘above normal’ precipitation is seen over most parts of peninsular India, home to plantation crops like rubber and coffee, and soybean, cotton and pulses growing central region during August-September.

Pan-India precipitation was 1% below the benchmark (LPA) during June-July, even though there was a 7% deficit in July, the wettest of the four-month season that is crucial for summer crop sowing. The precipitation was 10% above LPA in June. Normally, 65% of the sowing takes place in July while the remaining 35% of 107-million-hectare normal kharif acreage gets covered in June and August-September.

As most of the global models forecast the emergence of the La Nina condition from October-November (currently ENSO neutral), there could be more rains in India during that period, which might adversely impact crops ready for harvesting.

Last year, the monsoon retreated from the country on October 28, the second-most delayed exit since 1975, and as a result, soybean crops got damaged by heavy rains in Madhya Pradesh during September-October. In 2010, the southwest monsoon withdrawal got completed on October 29. The normal monsoon withdrawal date is October 15. Coincidentally, both 2010 and 2020 had Lal Nina.

Since 2016-17, the country’s foodgrains output (comprising rice, pulses and coarse cereals) during kharif season has been hitting new records every year. During the 2020-21 kharif season, the production was 148.4 million tonne, 3.2% higher than a year ago.

El Niño, which is associated with warmer-than-average sea surface temperatures in the central and eastern tropical Pacific Ocean, normally brings lower monsoon rainfall. It develops when the surface temperatures of the Pacific rise above normal. La Nina is opposite of El Nino and occurs when sea surface temperatures in the Pacific Ocean drops below average.

Though the stalling of the monsoon for the three weeks till July 11 adversely impacted sowing, there has been a pick-up of the activities over the past week, especially in major crop-producing regions. So, sown areas reached 79% of the season’s normal acreage of 107.3 million hectares as on Friday as against 67% a week before; of course, the area under crops was still 5% below the year-ago level.