India last witnessed a larger monsoon surplus in August 1976, when 28.4% above normal rainfall was recorded, according to Department of Meteorology of India data. Met officials said active monsoon conditions are expected on the remaining three days of the month, meaning that the 25% surplus rain might not change much.
Across the country, an average of 296.2 mm of rain has been recorded so far this month, compared to an average of 237.1 mm. In absolute terms, rainfall for the entire month could be the highest in August since 1988, when 329.6mm was recorded.
The monsoon was most active in central India, which received incessant rains during the month, adding a huge surplus of 57% in August. South India has also had 42% excess rainfall, in addition to the 16% surplus it received in July.
Between the two months, July and August, what made the difference in monsoon conditions was the number of low-pressure systems that formed in the Bay of Bengal. While there were none in July, August has had five so far against an average of three to four in each of the two months.
“In July, a low-pressure system formed in the first week, but it quickly dissipated. Therefore, it would not be considered a suitable system. In August, we had a series of low-pressure circulations that had long life spans, which brought heavy rains, particularly over central India. The region had a rainfall deficit of 22% in July, while in August it had a surplus of 57%, ”said D Sivananda Pai, IMD’s lead monsoon forecaster.
The abundance of rainfall in August has led to an overall monsoon surplus of 9% for the season (June 1 to August 28) so far. If September turns out to be even a little wetter than normal, the 2020 monsoon season could end with excess rain (more than 10% above normal).
However, IMD officials said September could see slightly below normal rains, although La Niña conditions are developing in the Pacific Ocean favoring good monsoon rains over India.
“We expect Northwest India to rain over the next week. After that, around September 5, the monsoon activity is likely to shift to northeast India, which has not had good rains in August. The risk of flooding could increase in that region after this rainy period, ”said Mrutyunjay Mohapatra, Director of IMD.
While northwestern India received normal rains in August, various parts of the region, particularly the western subdivision of Uttar Pradesh, have had poor rainfall. For the season as a whole, Northwest India has a rainfall deficit of 11%.
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