Despite the driest August in a century, India has dodged a drought this year, thanks to unexpectedly heavy rains in September.
As of September 30 – officially the last day that counts for monsoon rainfall – India received 94% of the expected rain from June to September. This is below the forecast of 96%, but still within the error margin of the forecast models of the India Meteorological Department (IMD). Rainfall which reaches 96% to 104% of the long term average is considered ‘normal.’
The IMD on Saturday also forecast a ‘normal’ north-east monsoon from October to December, and ‘normal to above-normal rainfall’ over large parts of north-west India and the southern peninsula.
Wild variations
The near normal southwest monsoon rainfall however conceals variations over both time and geographies, with north-west India getting its expected quota of 58.7 cm, while the north-east and eastern parts of India posted an 18% deficit. Southern India saw an 8% deficit, while central India got close to its expected quota. Overall, about 9% of the country received ‘excess’ rainfall, with 18% seeing ‘deficient’ rainfall. The monsoon was ‘normal’ in the rest of the country.
The four monsoon months also reported wild swings, with June getting 9% less than its normal rainfall, July getting 13% more than normal, August reporting a 36% deficit, and September a 13% surplus. July and August are the most important monsoon months and contribute 60% of the total monsoon rainfall of 89 cm. THis meant that until September 1, India was staring at a 10% deficit, an indicator of drought-like conditions.
Little El Nino impact
Early in the monsoon season, the IMD and several global agencies had expected rainfall to be below normal on the back of an El Nino, a cyclical warming of the eastern and central Pacific that generally corresponds to depressed rainfall over India. For most of the monsoon season, the El Nino was ‘weak’ and expected to significantly influence rainfall in August and September. However, excess rains in September were due to favourable conditions in the Indian Ocean, scientists said.
Also read | North India more affected by El Nino
“A positive Indian Ocean Dipole helped counteract the El Nino effect,” said D.S. Pai, senior meteorologist with the IMD. “Historically, El Nino means weak rainfall in September. This has been a bonus for us,” he added.
More active monsoons
For the fifth year in row, September – usually the weakest of the four monsoon months-- has reported more rain than its usual quota of 17 cm. This, meteorological records suggest, is unprecedented in over a century. “ Every 20 to 30 years, monsoon rainfall goes through a shift, with rainier monsoons more likely some years than others. We have now entered a period of more active monsoons. September is more active now, but we can’t assume it will last,” Dr. Pai added.
The monsoon began to withdraw from western Rajasthan last week, but is expected to persist until mid-October when it fully withdraws from the Indian mainland. However, this is not officially counted as “monsoon rainfall”. The north-east monsoon is expected to set in around October 20.
Published - September 30, 2023 04:58 pm IST
