‘Below normal’ end for patchy monsoon: IMD

India's monsoon season this year brought only 94% of its usual rainfall, classifying it as a "below normal" season.

This year’s monsoon brought only 94% of the rain it usually brings across the country, the India Meteorological Department (IMD) said on Saturday, classifying it as a “below normal” season that officially draws to a close on September 30.

The monsoon has been inconsistent across the months and over the length and breadth of the country.

IMD officials said the effects of an El Nino weather phenomenon, which usually saps the monsoon in India, were countered by some positive effects, helping make some deficit up.

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“The 2023 monsoon ended with 94.4% cumulative rainfall. It is nearly normal, but if you go by our categorisation, it would be a ‘below normal’ monsoon season,” said IMD director general M Mohapatra in a press briefing on Saturday.

The weather agency chief also warned of a warmer than usual October in most parts of India.

The monsoon has been inconsistent across the months and over the length and breadth of the country, a trend that scientists said was a sign of things to come as the Earth warms up due to the climate crisis.

This year, the annual summers rains — crucial for the economy’s lifeblood agriculture sector — has been a story of wild swings: it started 9% deficient in June, turned to an excess of 13% in July, before logging a big deficiency of 36% in August and, finally, ending with 13% excess precipitation in September.

The patchiness is worse when the spread is considered. Rain volume was near normal over northwest India (101%) and over central India (100%), but deficient over the south peninsula (92%) and over the northeast region (82%). The monsoon core zone, consisting of most of the rainfed agriculture regions in the country, received 101% of the LPA, or long-period average volumes, which are calculated by taking the average rain recorded between 1971 and 2020, which comes to 87cm.

In contrast, the country recorded 82cm of rain this year.

On the ground, the on-again, off-again pattern manifested in some of the longest dry, as well as wet, spells in the country. In an analysis HT reported on September 26, a 13-day stretch ending on August 17 this year was among the top 3% in terms of the longest monsoon dry spells (assumed as consecutive days when nationwide rains have been over 20% deficient) India has ever recorded.

For people, this meant more hot and humid days. For farmers, it meant unpredictability for their sowing and harvesting. And for states where the rains recorded unusual intensity — such as those in the Himalayan regions – it meant large scale destruction of infrastructure, homes, lives and livelihoods.

“It is a below normal monsoon year with 94.4% rainfall. The rainfall in September is not helping the summer crops but it may be beneficial for Rabi crop because of the soil moisture restored this month,” said Mahesh Palawat, vice president (climate and meteorology) at Skymet Weather.

Roxy Mathew Koll, climate scientist, Indian Institute of Tropical Meteorology (IITM), said that the capacity of air to hold moisture for a longer time has increased due to constant rise in land and sea temperatures. This, in turn, has influenced the intensity of monsoon rains, he said.

“For instance, the Arabian Sea has warmed since January, infusing more moisture over northern and northwestern India. This continuous supply of moisture fed to the weather systems leads to increased rains, which also results in extreme weather events,” Koll said.

In its monsoon forecast, the IMD had predicted a ‘normal’ monsoon for India at 96% of the Long Period Average (LPA) with a model error of ± 4%, while warning that the impact of El Nino might impact the latter half of the season. El Nino refers to a warming of the ocean surface, or above-average sea surface temperatures, in the central and eastern tropical Pacific Ocean. In India, it results in weaker monsoon and drier spells.

In its forecast, IMD also said that in October, most parts of India are likely to receive below-normal rains. However, many areas in south peninsular India, northeast, parts of the northernmost region of the country are likely to experience above-normal rainfall.

“Monthly rainfall over the country during October 2023 is likely to be normal — 85-115 % of the LPA,” the forecast for October said.

October is also expected to record above-normal maximum and minimum temperatures over most of the country, according to the Met. While higher than normal minimum temperatures will persist in most parts, some areas in northeast India are likely to record normal minimum temperatures.