New Delhi: “IMD has predicted a normal monsoon during the current season (2018 southwest monsoon season). The summary of the forecast issued on 30th May, 2018 is given below and detailed forecast is attached as Annexure-I.
- Rainfall over the country, as a whole, for the 2018 southwest monsoon season (June to September) is most likely to be NORMAL (96% to 104% of Long Period Average) (LPA).
- Quantitatively, monsoon season (June to September) rainfall for the country as a whole is likely to be 97% of the LPA with a model error of ±4%.
- Region wise, the season rainfall is likely to be 100% of LPA over North-West India, 99% of LPA over Central India, 95% of LPA over South Peninsula and 93% of LPA over North-East India all with a model error of ± 8 %.
- The monthly rainfall over the country, as whole, is likely to be 101% of its LPA during July and 94% of LPA during August, both with a model error of ± 9 %.
Government is aware that several foreign climate prediction agencies, including Japan Meteorological Agency (JMA), prepare and issue forecasts of seasonal rainfall and IMD has access to these forecasts. However, it may be mentioned that in the month of May, when IMD issued the Long Range Forecast, most of the model forecasts including that from JMA were indicating normal rainfall during the 2018 southwest monsoon season and not below normal rainfall. The details of the forecasts issued by other agencies are given in the Annexure-II:
The absolute error of the IMD’s monsoon forecasts for the seasonal rainfall over the country has shown significant decrease after the implementation of the new statistical ensemble forecasting system in 2007, compared to previous years. The average absolute error (difference between forecast and actual rainfall) of the new statistical forecasting system used for forecasting all India rainfall during the last 11 years (2007-2017) was 5.9% of Long Period Average (LPA), compared to the average absolute error of 8.5% of LPA during the previous 11 years (1996 -2006). This clearly indicates improvement made in the operational forecast system in the recent period compared to the earlier period. It may be mentioned that IMD was able to correctly predict the deficient monsoon rainfall experienced during 2014 & 2015.
Government has taken several measures to upgrade the IMD forecast system to further improve prediction accuracy. Systematic efforts are being made to further improve statistical forecasting system, which was introduced by IMD in 2007. Under the Monsoon Mission, a new dynamical prediction system for long range forecasting of Indian monsoon was implemented by IMD. IMD is working to improve the skill of this dynamical prediction system in collaboration with Indian and foreign academic institutions”.
This information was given by Union Minister of Earth Sciences, Dr. Harsh Vardhan, in a written reply to a question in Lok Sabha today.
