Monsoon 2018: a report
The report discusses the operational monitoring and forecasting aspects of the 2018 southwest monsoon. Various observed global and regional climate patterns associated with the 2018 monsoon have been highlighted. The report also presents monitoring of semi-permanent and transient weather systems, onset and progress of the monsoon during the season, rainfall distribution etc. using various tools such as automatic weather stations (AWSs) and satellite data, analysis of the extreme weather events occurred over various parts of the country such as heavy rainfall, floods, heat waves, etc. and meteorological explanation for the events, action taken by the local met. Offices, etc. During the Southwest Monsoon season rainfall over the country as a whole during 2018 was 91% of Long Period Average (LPA) and rainfall was well distributed across the country except Northeast India. During the season, the direct impact of the large-scale SST forcings from Pacific and Indian Oceans were absent and MJO was also weak. However, the large rainfall deficiency over Northeast India during the entire season and that over large parts of the country during second half of the monsoon season (particularly in September) was caused by the above normal convective activity over tropical northwest Pacific due to the SSTs over most parts of the region associated with evolving El Niño. Potential regional and global climate anomaly patterns responsible for the observed rainfall features have been discussed. The operational forecasts at various time scales issued by IMD and their verification have and performance of Various Numerical Weather Prediction Models is also emphasized.