E-Paper
As El Nino shadow looms, IMD forecasts below-normal monsoon at 92% LPA
According to the monsoon’s spatial distribution, some areas over northeast, northwest and south Peninsular India may receive normal to above-normal rainfall
India is likely to see a “below normal” monsoon this year, the India Meteorological Department (IMD) announced on Monday in its first stage long range forecast for monsoon season. Rainfall is expected to be 92% of the Long Period Average (LPA), with an error margin of +/-5%, a projection that could signal challenges for the country’s rain-fed agriculture and the broader rural economy.
The LPA of the seasonal rainfall over the country as a whole during 1971-2020 is 87 cm.
The spatial distribution released by IMD suggests that the below-normal seasonal rainfall is most likely over many parts of the country except some areas over northeast, northwest and south Peninsular India, where normal to above-normal rainfall is likely.
The forecast carries significant economic implications. Monsoon is the lifeblood of India’s economy. According to the agriculture ministry, 51% of India’s farmed area, accounting for 40% of production, is rain-fed. With 47% of the country’s population dependent on agriculture for their livelihood, a below-par monsoon can dampen rural consumption and push up food prices in a year when the conflict in West Asia threatens to pose a larger threat to energy availability and fertilisers – a critical farm input.
The last time India received “below normal” rain was in 2023, also an El Nino year, when rainfall over the country as a whole during monsoon season was 94% of its LPA.
El Nino conditions are likely to be established during the monsoon season especially during July, August and September, according to the Monsoon Mission Climate Forecast System (MMCFS).
At present, weak La Niña–like conditions are transitioning to ENSO-neutral conditions over the equatorial Pacific. Atmospheric circulation features across the tropical Pacific remain consistent with weak La Niña–like conditions. Further, at present, neutral Indian Ocean Dipole (IOD) conditions are present over the Indian Ocean and the latest climate models forecast indicate that positive IOD conditions are likely to develop only towards the end of the southwest monsoon season.
Winter and spring snow cover extent over Northern Hemisphere and Eurasia, which generally has an inverse relationship with the subsequent southwest monsoon seasonal rainfall over the country, is marginally favourable, IMD scientists said.
“Overall, we can say that both El Nino onset during monsoon and neutral IOD conditions are likely to impact the monsoon. Hence we are expecting below normal rainfall during the season,” said M Ravichandran, secretary, ministry of earth sciences.
“But, we expect the impact to be more pronounced during the second half of monsoon. We are not expecting much of an impact of El Nino during June and July,” he added.
El Nino and La Nina are opposite phases of a natural climate cycle — called ENSO, or El Nino Southern Oscillation — driven by sea-surface temperature changes in the equatorial Pacific. El Nino, the warmer phase, typically suppresses India’s monsoon and brings weaker rainfall; La Nina, its cooler counterpart, tends to strengthen it.
IMD has made its LRF for monsoon both based on statistical models and dynamic models that considers both oceanic and atmospheric conditions.
The statistical models suggest that there is a 35% probability of a “deficient” monsoon (< 90%); 31% probability of a “below normal” monsoon (90 to 95%); 27% probability of a “normal” monsoon (96 -104%); 6% probability of an “above normal” monsoon (105-110%) and only 1% probability of “excess” rainfall (> 110%).
“The MME (Multi-Model Ensemble) forecast for the 2026 southwest monsoon seasonal rainfall was prepared based on the April initial conditions and using a group of coupled climate models that have the highest prediction skill over the Indian monsoon region,” IMD said.
In the second stage forecast issued around end of May consist of an update for the seasonal rainfall forecast issued in April along with the probabilistic forecasts for the seasonal rainfall over the four homogenous regions of India (northwest India, central India, south Peninsula and northeast India) and monsoon core zone (MCZ).
In addition, IMD will issue quantitative and probabilistic forecasts for the country as a whole, and the spatial distribution of probabilistic forecasts for June rainfall over the country.
As reported by HT, private weather forecaster Skymet Weather has also said that India’s monsoon rainfall this year is likely to be below normal at around 94% of the long-period average (LPA), with an error margin of ±5%.
There is a 40% probability of below-normal rainfall — between 90% and 95% of the LPA — and a 30% chance of drought conditions, with rainfall falling below 90% of the LPA, according to Skymet’s projections.
