According to the IMD’s long-range forecast (LRF), southwest monsoon seasonal (June to September) rainfall over the country as a whole is most likely to be normal (96 to 104 % of Long Period Average (LPA)).
- Quantitatively, the monsoon seasonal (June to September) rainfall is likely to be 98% 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.
- Since 2003, India Meteorological Department (IMD) has been issuing the operational long-range forecast (LRF) for the southwest monsoon season (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. These forecasts are prepared using the state-of-the-art Statistical Ensemble Forecasting system (SEFS) that was developed indigenously by IMD.
- Since 2017, IMD has been also using a high-resolution dynamical global Climate Forecasting System (CFS), which was developed under the Monsoon Mission of the Ministry of Earth Sciences (MoES).
