El Nino conditions have been observed for the first time in seven years.  The tropical Pacific atmospheric anomalies are consistent with weak El Nino conditions, the US Climate Prediction Center (CPC) has said.

During the past four weeks, above average sea surface temperatures (SSTs) persisted over the eastern and east-central Pacific Ocean. “SSTs near Ecuador and Peru remain strongly above average,” the CPC said in its monthly update on Thursday. 

The observations are in line with the India Meteorological Department’s prediction that El Nino, which causes drought and deficient rainfall in Asia, will set in this month. 

‘Peaking in winter’

El Nino, which has been responsible for 10 of the 15 droughts that India faced over the last 75 years, will likely persist through the Northern Hemisphere Winter (December 2023-February 2024) with chances of the likelihood being 90 per cent, it said. 

“Nearly all models indicate El Nino will persist into the Northern Hemisphere winter 2023-24. A strong El Nino (ONI values at or greater than 1.5ºC) is indicated by the dynamical model average through December 2023-February 2024,” the CPC said. 

Forecasters, too, favour continued growth of El Nino through the fall, peaking this winter with moderate-to-strong intensity. However, chances of a “historically strong” El Nino that will rival winters of 1997-98 and 2015-16 are only one in five, the US climate agency said.  

SSTs exceeding thresholds

An update from the World Meteorological Organization, which combines forecasts and expert guidance from across the world, has also forecast  a 90 per cent probability of the El Nino event continuing during the second half of 2023.  

Earlier this month, the Australian Bureau of Meteorology said central and eastern Pacific SSTs  were exceeding El Nino thresholds. “Models indicate a high likelihood of further warming, with SSTs exceeding El Nino thresholds until at least the beginning of the southern hemisphere summer,” it said. 

However, the values of the Southern Oscillation Index (SOI) are just shy of El Nino levels. “Sustained changes in wind, cloud and broad-scale pressure patterns towards El Nino-like patterns have not yet been observed. This means the Pacific Ocean and atmosphere have yet to become fully coupled, as occurs during El Nino events,” the Australian weather agency said. 

On the other hand, it said the Indian Ocean Dipole (IOD) is currently neutral. “All models suggest a positive IOD is likely to develop in the coming months,” it said. If a positive IOD coincides with El Niño, it can exacerbate El Nino’s drying effect, the Australian agency cautioned.