Delayed monsoon in Delhi: early warning for farmers

“Predicting the monsoon onset is difficult due to a couple of reasons,” explains PIK expert Elena Surovyatkina who was in charge for the new forecast method for Delhi. "Firstly, the monsoon does not start at fixed dates, it begins at different dates in different parts of the country. Also, the time of the monsoon onset varies within a month from year to year. Nevertheless, we overcame these obstacles in Central India. The next step is to go North where the challenges still exist."

According to Surovyatkina's forecast, the Southwest Monsoon is likely to reach Delhi between July 11 and July 19, that is two weeks later than the normal date. However, pre-monsoon isolated rainfalls are likely to happen two weeks before the monsoon arrival, between June 28 and July 5, with a succeeding dry spell. After July 19, continuous monsoon rainfall is expected over the region. The PIK scientist also continues to forecast the monsoon over Central India and Telangana and predicts a delayed monsoon arrival in both regions. 

Why is the monsoon delayed?

During April 2021, the anticyclones over western Siberia were dominant, resulting in higher temperatures than the average one for the period 1991-2020. Outbreaks of polar air westward from this high-pressure area caused the negative temperature anomaly in the large area from Iceland to the Mediterranean and Black Seas. Air temperatures were below average over Eastern Siberia, China, and most of the tropical and sub-tropical Eastern Pacific Ocean. Specifically, in northern Pakistan, northern and central India the temperatures were about 3- 4°C lower than average. "I expect that this temperature tendency will remain during the beginning of the monsoon. If so, it disorganizes the onset of monsoon, alternating premature rainfall and dry spells leading to the transition to monsoon longer and delayed monsoon onset over Telangana, Central India, and Delhi," said Surovyatkina.

Why is the long-term monsoon forecast so important? 

The Monsoon variability strongly affects different aspects of life in India such as agricultural productivity and food security, economic growth, and political stability. To plan the agricultural cycle, farmers need to know one month in advance when the monsoon starts, whether or not a dry spell appears after the initial rainfalls, and when the continuous monsoon begins. Depending on their location on the Indian subcontinent, for the seeding period, they have only one to three weeks time after the monsoon onset. A dry spell week could result in seeding succumb which leads to loss of their investment in seeds.  Farmers who live just above the poverty line could possibly fall below it due to drought-induced income loss. "For the first time, I was able to provide forecasts in such a detailed way as an early warning for farmers. I hope this helps them to better plan their seeding," Surovyatkina concludes.