The India Meteorological Department (IMD) has forecasted normal southwest monsoon seasonal rainfall over the country in its Summary of the Forecast for the 2022 Southwest Monsoon Rainfall, which has been issued today by the official met department.
“The monsoon seasonal rainfall is likely to be 99 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 for the period 1971-2020 is 87 centimetre (cm),” the press release read.
The monsoon forecast that was released on April 14 is the first stage forecast which is issued in April followed by the updated forecast by the end of May.
IMD releases Long Range Forecast for Rainfall during Southwest Monsoon Season, 2022. For details visit https://t.co/2wn4JWttNx
Southwest monsoon seasonal (June to September) rainfall over country as a whole is most likely to be normal (96 to 104 % of Long Period Average (LPA)). pic.twitter.com/RKv0IiNp4t— India Meteorological Department (@Indiametdept) April 14, 2022
As per the IMD, La Niña conditions – a weather phenomenon which causes colder temperatures – are prevailing over the equatorial Pacific region and are likely to continue. La Niña is associated with good rainfall in the country whereas El conditions (when a band of warm ocean water that develops in the central and east-central equatorial Pacific, including the area off the Pacific coast of South America) often trigger droughts in India.
“At present, neutral IOD [Indian Ocean Dipole] conditions are present over the Indian Ocean and the latest MMCFS [Monsoon Mission Climate Forecasting System] forecast indicates that the neutral IOD conditions are likely to continue until the beginning of southwest monsoon season. Thereafter, enhanced probability for negative IOD condition is predicted,” the press release was quoted as saying.
It outlined that as the sea surface temperature conditions over the Pacific and Indian Oceans are known to have a strong influence on Indian monsoon, the Met department is carefully monitoring the evolution of sea surface conditions over these Ocean basins.
Last year, IMD had 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 a newly developed Multi-Model Ensemble (MME) forecasting system based on coupled global climate models (CGCMs) from different global climate prediction and research centers including IMD’s Monsoon Mission Climate Forecast System (MMCFS) along with the existing statistical forecasting system to generate these forecasts,” the press release stated.
The IMD also stated that the New All India rainfall normal computed based on data of 1971-2020 for the southwest monsoon season, which stretches from June to September, is 868.6 mm. It will replace the normal of 880.6 mm based on data of 1961-2010, the press release stated.
“The New All-India annual rainfall normal based on data of 1971-2020 is 1160.1 mm as compared to earlier normal of 1176.9 mm based on data of 1961-2020. There is a decrease of 12 mm in mean rainfall during the southwest monsoon season and 16.8 mm in annual rainfall for the country as a whole from 1961-2020 to 1971-2020,” it further added.