The 2026 southwest monsoon seasonal (June to September) rainfall over the country is most likely to be below normal or around 95-90 per cent of the Long Period Average (LPA), the India Meteorological Department (IMD) said on Monday.
Releasing its Long Range Forecast for the 2026 Southwest Monsoon season rainfall, the IMD said that the seasonal rainfall over the country as a whole is likely to be 92 per cent of the LPA with a model error of plus-minus 5 per cent.
The LPA of the seasonal rainfall over the country as a whole, based on the period of 1971-2020, is 87 cm.
The IMD said that it will issue the updated forecasts for monsoon season rainfall in the last week of May.
On Sea Surface Temperature (SST) conditions, the IMD said that, at present, weak La Nina–like conditions are transitioning to ENSO-neutral conditions over the equatorial Pacific. "Atmospheric circulation features across the tropical Pacific remain consistent with weak La Nina–like conditions. The Monsoon Mission Climate Forecast System (MMCFS) suggests the development of El Nino conditions during the SW Monsoon season," it said.
El Nino and La Nina are opposite phases of the El Nino-Southern Oscillation (ENSO) cycle, representing periodic fluctuations in sea surface temperatures and trade winds in the tropical Pacific Ocean that alter global weather.
El Nino (warm phase) features weakening trade winds and warmer waters, causing wetter conditions in the US and droughts in Asia, while La Nina (cool phase) brings stronger winds and cooler waters.
The IMD said, at present, neutral Indian Ocean Dipole (IOD) conditions are present over the Indian Ocean, and the latest climate models forecast indicates that the positive IOD conditions are likely to develop towards the end of the southwest monsoon season.
As sea surface temperature (SST) conditions over the Pacific and the Indian Oceans are known to have a strong influence on the Indian monsoon, IMD is carefully monitoring the evolution of sea surface conditions over these Ocean basins, said the statement.
--IANS