The forecast is based on both dynamical and statistical models, and it suggests above normal rainfall is likely over most part of the country except some areas of Northwest, East and Northeast India.
The Indian Meteorological Department on Tuesday released the long range forecast of rainfall for the 2024 South West monsoon season.
Secretary, Ministry of Earth Sciences, Dr M. Ravichandran told the media that the country as a whole is likely to receive above normal rainfall during the south west monsoon from June to September 2024.
Briefing the media about the summary of the 2024 Southwest Monsoon Season Rainfall during a press conference in New Delhi, he said there will be 106 per cent of the Long Period Average (LPA) with a model error of ± 5 per cent. The LPA of the season rainfall over the country as a whole is 87 cm based on data of 1971-2020.
Dr. Ravichandran said, the forecast is based on both dynamical and statistical models, and it suggests above normal rainfall is likely over most part of the country except some areas of Northwest, East and Northeast India, where below normal rainfall is likely.
Giving a detailed presentation DG, IMD, Dr Mrutyunjay Mohapatra said that currently, moderate El Niño conditions are prevailing over the equatorial Pacific region and the climate model forecasts indicate neutral condition by the beginning of monsoon season and La Niña conditions during second half of monsoon season.
Carefully monitoring
Dr Mrutyunjay Mohapatra also informed the media that at present neutral Indian Ocean Dipole (IOD) conditions are prevailing and climate model forecast indicate positive IOD conditions likely to develop during the monsoon season.
He added that since Sea Surface temperature conditions over the pacific and the Indian Ocean are known to have a strong influence on the Indian Monsoon, IMD is carefully monitoring the evolution of sea surface conditions over these ocean basins.
Dr Mohapatra further said that Northern hemisphere snow cover extent during the last three months (January to March 2024) was below normal which indicates above rainfall this monsoon season. Winter and spring snow cover extent over Northern Hemisphere as well as Eurasia has a generally inverse relationship with the subsequent monsoon season rainfall. He said, IMD will issue the updated forecasts for monsoon season rainfall in the last week of May 2024.
Since 2003, India Meteorological Department (IMD) has been issuing the operational long-range forecast (LRF) for the southwest monsoon seasonal (June-September) rainfall averaged over the country as a whole in two stages. The first stage forecast is issued in April and the second stage or update forecast is issued by the end of May. Since 2021, IMD has implemented a new strategy for issuing monthly and seasonal operational forecasts for the southwest monsoon rainfall over the country by modifying the existing two stage forecasting strategy. The new strategy uses both dynamical and statistical forecasting system. Multi-Model Ensemble (MME) forecasting system based on coupled global climate models (CGCMs) from different global climate prediction centres, including IMD’s Monsoon Mission Climate Forecast System (MMCFS) is used in dynamical forecast system.
In continuation to the above forecasts, monthly rainfall forecast is issued around the end of June, July and August respectively for the subsequent one month. In addition, quantitative and probabilistic forecasts for the country as a whole and spatial distribution of probabilistic forecasts of rainfall for second half (August-September) of the season is issued around end of July along with forecast for August.
Image: License to use Creative Commons Zero – CC0.
