However, the season as a whole is expected to see “normal” monsoon as expected in June; rainfall in August of this year were the highest since 1926 at 32.7cm, about 27% more than normal for the month, according to data from the Indian Meteorological Department (IMD) on Monday.
- In August 1926, precipitation recorded was 34.8 cm, above normal by 33%.
- IMD officials said that although the August rains were excessive, this year's monsoon figure as a whole would likely be within the department's June forecast for normal precipitation (96-104% of the long-term average.
“There has been a decrease in rainfall across India since the start of September. However, we expect a new recovery around September 17th, ”Mrutunjay Mahapatra, IMD director general, said at a press conference on Monday.
- From June to September 6, India recorded 7% more precipitation than normal for this period.
- In the normal course, the monsoon begins to withdraw from September 15th and this can last almost a month.
Low pressure systems
The heavy rains in August were due to several long lasting low pressure systems, or rainy winds, which formed in the Bay of Bengal and were vigorous enough to move from the southeast coast in northwest India.
“In a typical monsoon season, there are 12-13 LPA. There were fewer this year, but there were six in August and they lasted for several days. Together this led to several days of rain in August, ”Mrutunjay Mahapatra, IMD director general,
- The excess rains mainly occurred in Rajasthan, Gujarat, Maharashtra, Karnataka, Kerala, Telangana, Chhattisgarh and Odisha.
- Prolonged periods of heavy rains followed by prolonged periods of drought are a hallmark of climate change and part of a global shift in monsoon patterns in India, IMD previously said.
- Mahapatra admitted that the agency's monthly forecast for July and August was grossly misplaced, but said this was due to “intra-seasonal” variations and that IMD's short-term forecast models had anticipated periods of heavy rains and suitably warned to the authorities.
- This year, IMD launched urban flood forecasting services for Mumbai and Chennai and will extend them to Bengaluru and Kolkata.
- “We can provide these forecasts for other cities as well, but we need detailed city maps. The [four cities] we served were extremely cooperative and communicative with this data, ”said Madhavan Rajeevan, secretary of the Ministry of Earth Sciences.
- Northwestern India saw 10% less rain than normal; Central India had a surplus of 17%; South India has a 20% surplus and North East India has received exactly what it normally gets.
- Cooler than normal conditions in the central equatorial Pacific have contributed to the increase in precipitation.