In India, El Niño has the effect of suppressing rainfall. This year, the monsoon is expected to be well below normal, mainly on account of the El Niño. (File Photo)El Niño, a climate pattern of unusually warm Pacific waters that disrupts global weather, has strengthened and may intensify in the coming months to become one of the strongest on record, the US National Oceanic and Atmospheric Administration (NOAA) said on Thursday.“There is an 81 per cent chance of a very strong El Niño during October-December that would rank among the largest El Niño events in the historical record going back to 1950,” NOAA said in its monthly bulletin issued on Thursday night.El Niño and La Niña are the two phases of the El Niño Southern Oscillation (ENSO), a naturally occurring ocean-atmosphere interaction. These events influence global weather patterns and can trigger extreme weather, droughts, and heatwaves across the globe.El Niño has a general warming impact on the planet. Over the Indian region, it has the effect of suppressing rainfall. This year, the monsoon in India is expected to be well below normal, mainly on account of the developing El Niño.Also Read | Power ministry mulls advisory amid El Niño uncertaintyThe ENSO phase and the intensity of the El Niño and La Niña events are decided by the sea surface temperatures measured in a specific region of the Pacific Ocean, called the Niño 3.4 region. An El Niño is declared when the average sea surface temperature anomaly in this region surpasses 0.50°C.What it means for IndiaWith El Niño conditions strengthening, India could soon feel its negative effects. In its weekly update on July 9, the India Meteorological Department (IMD) forecast slightly below-normal rainfall over the country till July 22.Normal rainfall is forecast in Rajasthan, which is not a high rainfall-receiving state, as well as parts of Telangana, Andhra Pradesh, Maharashtra, and north interior Karnataka. Met experts have said that the subdued rainfall in July, which accounts for India’s highest seasonal rainfall, could be the first signs of El Niño’s impact. The IMD has forecast rainfall at below 94 per cent of the long period average this July.Story continues below this adFor the rest of the season, the IMD said the Indian Ocean Dipole (IOD)—the ENSO counterpart in the Indian Ocean—is likely to remain neutral. Only a positive IOD phase can counter the El Niño, which seems highly unlikely now.Also Read | Why is Mumbai seeing record rain in an El Niño year?Current El Niño phase likely to continue till next springThe current El Niño event began in June and is predicted to intensify and continue into 2027.In its latest bulletin, the NOAA said the Niño 3.4 index had crossed 1.2°C. This is still in the moderate range. An El Niño is usually considered strong when the Niño 3.4 index goes beyond 1.5°C, and very strong when it crosses 2°C. The strength of an El Niño phase is also dependent on how long it persists.The NOAA bulletin said the current El Niño phase was almost certain to continue through the early part of next year. “El Niño continues and will strengthen through the end of the year, with a 97 per cent chance it will last through early spring 2027,” it said.Story continues below this adThe 2015-2016 El Niño is the strongest one in recent memory. Termed Godzilla, this persisted for almost two years, 2014 to 2016, and broke several climate records. The Niño 3.4 index had remained above 2°C Celsius for well over four months. In India, both 2014 and 2015 figure in the top four driest years this century, with the monsoon rains in both those years remaining well below 90 per cent of the normal.Other very strong El Niño phases occurred in 1991-92, 1997-98, and 1982-83.