IMD predicts ‘normal’ rainfall during the southwest monsoon in India, from June to September.
By Jagriti Parakh
India Meteorological Department (IMD) announced that India is most likely to have a normal monsoon this year. Quantitatively, they have predicted the monsoon rainfall to be 100 percent of the long period average (LPA), with a model error of ± five percent. They have also revised the onset and withdrawal dates of monsoon, based on recent data.
During its first stage Long Range Forecast (LRF) for Southwest monsoons, Dr. Madhavan Nair Rajeevan, Secretary, Ministry of Earth Sciences, said, “Seasonal rainfall during southwest monsoon (June to September) over the country as a whole is likely to be normal (96 to 104 percent of LPA). ”
The statistical model of IMD suggests that there is a high probability (41 percent) for 2020 monsoon rainfall to be normal. They have based this forecast on the LPA of the seasonal rainfall over the country as a whole for the period 1961-2010, which is 88 centimeters. The IMD representatives said that they have estimated deficient monsoon at around nine percent, which is again a piece of good news for the agriculture sector.
The present normal monsoon onset and withdrawal dates were based on records of only a few stations (149 stations) during the period 1901-1940. IMD has now revised the normal onset and withdrawal dates based on recent data.
Monsoon onset over Kerala remains the same, i.e. June 1. However, new monsoon advance dates over the states like Maharashtra, Gujarat, Madhya Pradesh, Chhattisgarh, Telangana, Andhra Pradesh, Odisha, Jharkhand, Bihar, and parts of Uttar Pradesh are delayed by three to seven days compared to existing normal dates. However, over extreme northwest India, the monsoon is now expected to arrive a little earlier, on July 8 instead of July 15.
There are however appreciable changes in the monsoon withdrawal dates, especially over Northwest and Central India. Monsoon is expected to withdraw from NW India almost 7 to 14 days later from the existing dates. There is no change in the final withdrawal date over south India, i.e., October 15.
Dr. M. Rajeevan also pointed out that the delayed onset of the crucial southwest monsoon, followed by its slow progress, usually aggravates the agrarian distress in India, however, these new dates come as a relief for many applications like agriculture, water and power management, among others.
Dr. Mrutyunjay Mohapatra, Director General of Meteorology, IMD, said, “Sea surface temperature (SST) conditions over the Pacific and Indian Oceans are known to have a strong influence on Indian monsoon. 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.
“Our in-house Statistical Ensemble Forecast system indicates these conditions are likely to persist during the ensuing monsoon season. However, a few other global climate models indicate the possibility of development of weak La Nina conditions, over the Pacific Ocean during the second half of the season, around late July.”
Experts say that both these conditions are favorable for the agricultural sector.
Dr. Suresh Pal, an agricultural economist, said, “The La Niña effect is the colder counterpart of El Nino. The predicted conditions imply that there is an increased likelihood of above-average rainfall which could improve pasture and crop yield. Farmers can now plan the agricultural activities normally.”
IMD also clarified that there has not been any significant impact of the nationwide lockdown on its activities. Dr. M. Rajeevan said that since IMD comes under essential services, their operations have remained unaffected during this period as they receive their data from satellites and other such means.
Dr. Suresh Pal also pointed out that the government will soon come up with guidelines about how to carry out essential agricultural operations despite the lockdown so that the primary sector of our economy is not crippled. “Now that we have secure and encouraging weather forecast, we should focus on making other arrangements in the rural areas. We can ensure that all operations in the agricultural sector are expected to be unaffected by the lockdown and function normally, except market arrival.”
IMD will issue updated forecasts in the last week of May or the first week of June as a part of the second stage forecast. Along with the updated forecast, separate forecasts for the monthly (July and August) rainfall over the country as a whole and seasonal (June-September) rainfall over the four broad geographical regions of India will also be issued.
Watch the full press conference here:
— IMD Weather (@IMDWeather) April 15, 2020
