“Monsoon 2020 should help the Indian economy. We have had a very good monsoon this year which has helped agriculture,” said M. Rajeevan Nair, secretary, Ministry of Earth Sciences, at a special briefing on the progress of the Indian monsoon. The accumulated rainfall so far this season has notched 107 per cent of the Long Period Average (LPA), which is considered Above Normal. However, with two weeks in September predicted as having lesser rainfall, the Indian Metereological Department (IMD) predicts that overall, this season, the monsoon will be in the “normal'' category. A normal monsoon is between 96 and 104 per cent of the LPA.
Giving details on the performance of the monsoon so far, IMD chief M. Mohapatra said that the monsoon arrived on June 1 on the Kerala coast, as per schedule and covered the entire country by June 26, two weeks ahead of the normal date of July 8. Significantly, there was no hiatus in the advance of the monsoon—the entire country was covered in one spell. This does not happen always—many times there is a break in the advance of the monsoon.
The distribution over time and space, however, has not been uniform, with the rainfall being in excess in the central (17 per cent) and southern (20 per cent) parts of the country, and near normal in the east and northeast. However, the northwest region, especially west UP, Jammu, Kashmir and Ladakh have received 10 per cent below normal rains.
Month-wise, June saw a 17 per cent overall excess, with floods in Assam, Bihar, Saurashtra, and Kutch. July saw a 10 per cent overall deficiency, and August recorded a 27 per cent excess, with floods in Maharashtra, Kerala, Karnataka, Telangana, Chhattisgarh and Odisha. The department predicts less rain for two weeks in September over the country as a whole, and therefore, the seven per cent excess should reduce to a near normal performance of the monsoon overall. The south west monsoon months in India are from June to September. By September 17, the rains should start withdrawing from the Rajasthan region, though it is too early to predict how the withdrawal will progress. Last year, the rains lasted well into October.
Currently, there is a neutral El Nino Southern Oscillation, and there is the possibility of a weak La Nina developing over the next few days. La Nina brings more rain to the Indian mainland while a positive El Nino is bad news. The Indian Ocean Dipole (IOD), too, is neutral right now, with chances of a negative IOD developing over the coming months. Therefore, balancing these two big influences, the prediction is for an overall near normal monsoon by the end of the season. While the El Nino is a warm current, the IOD is the difference of the surface temperatures at two ends of the Indian Ocean, Somalia coast and Indonesia. If the Somalian coast is warmer, the IOD is positive.
Nair said that urban flooding was increasing in India as the pattern of rainfall in changing, with more instances of very heavy rainy days occurring. Existing sewage systems are not able to deal with the excess rain.