The rainfall during the southwest monsoon season, which ended on Monday, has been termed as “above normal” as the country experienced its wettest monsoon in 25 years, according to the India Meteorological Department (IMD).
Rainfall during September this year was the second heaviest in 102 years, according to the IMD’s 2019 Southwest Monsoon Rainfall report, issued on Monday.
The rainfall across India during June to September this year was recorded at 968 mm, taking the total rainfall to 110 per cent of the Long Period Average (LPA), which was last seen in 1994, according to the agency.
Meteorologists attributed this excess rain to the continuous low-pressure systems that formed over the Bay of Bengal and traversed along the monsoon trough, bringing good spells of rainfall, mainly over central Indian regions. “The larger states like Madhya Pradesh, Maharashtra, Odisha, Rajasthan, along with Chhattisgarh, benefitted due to these systems, some of these that lasted for as long as even 10 days,” D Sivanand Pai, head of the IMD’s Climate Research and Services at Pune, told The Indian Express.
Most states have received normal or above normal and some even recorded excess rainfall this season.
However, some states remained rainfall deficient, including Manipur (-56 per cent), Haryana (- 42 per cent), Delhi (-35 per cent) and Jammu and Kashmir (- 21 per cent).
States that recorded excess rain were Madhya Pradesh (44 per cent), Gujarat (43 per cent), Maharashtra (23 per cent), Karnataka (32 per cent) and Sikkim (22 per cent).
The weakening of El Nino in early July helped the monsoon regain strength after a delayed onset and rainfall in June being 33 per cent short of normal.
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It was also for the first time since 1931 that the seasonal rainfall remained more than the LPA (88 cm), despite an over 30 per cent rainfall deficiency in June, the statement said.
Monsoon activity, which picked up during July and August, wiped off all existing deficiencies in most regions barring the Northeast. The cumulative rainfall recorded during August and September (130 per cent) this year was second highest after 1983 (142 per cent) for these two months.
While the Met department had in June forecast normal rainfall for this season, the total reaching the above normal category was due to large-scale intra-seasonal variability. “The positive phase of Indian Ocean Dipole (IOD) during the second-half of the season coupled with the many low pressure systems formed in the Bay of Bengal brought this excess rainfall that took the total rainfall to above normal category,” Pai said.
The monsoon trough, this season, largely remained to the south of its normal position, that enhanced the rainfall activity over central, west and the south peninsular regions during the months of July and August. IMD officials also observed that the north-western regions remained on the warmer side in comparison to the southern region. “This difference in temperatures acted favourably in pulling monsoon winds landwards, keeping the monsoon active for most time of the season,” said AK Srivastava, head of the Climate Research Division at IMD.