Addressing a press conference through video link, Secretary of Ministry of Earth Sciences Dr. M. Rajeevan released the IMD’s Long Range Forecast for the 2020 Southwest Monsoon Season Rainfall. Director General of IMD, Dr. M. Mohapatra was also present.
The IMD also issued the ‘New Normal Dates of Onset/Progress and Withdrawal of Southwest Monsoon Over India’.
DR. Rajeevan said that quantitatively, the monsoon seasonal (June to September) rainfall is likely to be 100% of the Long Period Average (LPA) with a model error of 5%. The LPA of the season rainfall over the country as a whole for the period 1961-2010 is 88 cm.
“Good news is that it is estimated that the deficient rainfall will be 9 per cent. This forecast is based on the statistical model, it suggests that we will have a normal monsoon”, he said.
He said, IMD will issue the updated forecasts in the last week of May/first week of June 2020 as a part of the second stage forecast.
Dr. Rajeevan pointed out that “ Neutral El Nino Southern Oscillation (ENSO) conditions are prevailing over the Pacific Ocean and Neutral Indian Ocean Dipole (IOD) conditions are prevailing over the Indian Ocean. Some climate model forecasts indicate these conditions are likely to persist during the ensuing monsoon season”. “As sea surface temperature (SST) conditions over the Pacific and Indian Oceans are known to have strong influence on Indian monsoon, IMD is carefully monitoring the evolution of sea surface conditions over the Pacific and the Indian oceans,” he added.
Dr. Rajeevan said that La Nina, or cooler-than-usual sea surface temperatures in the east-central Pacific Ocean, is typically associated with better monsoon rains and colder winters in India while El Nino is associated with below-normal rainfall in the country.
The southwest monsoon season, that replenishes the country’s farm-dependent economy, first hits the southern tip of Kerala usually in the first week of June and retreats from Rajasthan by September.
Monsoons are expected to hit Kerala’s Thiruvananthapuram on June 1. In states like Maharashtra, Gujarat, Madhya Pradesh, Chattisgarh, Telegana, Andhra Pradesh, Odisha, Jharkhand, Bihar and parts of Uttar Pradesh, monsoon will be delayed by 3-7 days compared to the existing normal dates.
However, over extreme northwest India, the monsoon arrives now little earlier, on 8th July compared to the existing date of 15th July.
Monsoons are expected to withdraw in south India on October 15.