Monsoon 2017: a report
The report discusses the operational monitoring and forecasting aspects of the 2017 southwest monsoon. Various observed global and regional climate patterns associated with the 2017 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. The Southwest Monsoon season rainfall over the country as a whole during 2017 was normal (95% of Long Period Average (LPA)). During the season, ENSO neutral conditions were observed over the Pacific and Positive IOD condition over the Indian Ocean. The large deficiency of monsoon rainfall during the second half of the season was mainly due to intra-seasonal variations associated with Northwest Pacific typhoon activity and formation of less number of monsoon low pressure systems. Potential regional and global climate anomaly patterns responsible for the observed rainfall features have been discussed vividly. The operational forecasts at various time scales issued by IMD and their verification have also been discussed. Performance of Various Numerical Weather Prediction Models is also emphasized.