Evolution of Monitoring and Forecasting of Southwest Monsoon

In this review article, we discuss how monsoon monitoring and forecasting has evolved over the last 150 years. Since there are several other articles in this issue on short-range and operational forecasts of the IMD, we focus only on the details of monsoon monitoring, extended range forecasts (10-30 days) and seasonal forecasts (up to one season). IMD now has a system to monitor the monsoon performance at the district level on a daily basis. Under the monsoon mission, IMD has been able to set up an extended range forecasting system which now has a capability of skilful prediction up to 2 weeks. In some special cases, the skill is extended to three weeks. IMD is the first country to begin systematic research into seasonal monsoon forecasting. Statistical models formed the backbone of the IMD’s seasonal forecasting system. Since 2017, the IMD has also been using dynamic models for seasonal forecasts. Opportunities to further improve monsoon monitoring and forecasting systems are also identified and discussed.