Equatorial sea surface temperatures (SSTs) continued to be positive across most of the Pacific Ocean. In fact, the most recent Oceanic Nino Index (ONI) figure i.e. for OND (October-November-December) stands at 0.9°C. El Niño conditions are declared when the ONI which is three months running mean of SSTs anomaly in the Nino 3.4 region, is more than or equal to 0.5°C for overlapping 3 months for five consecutive episodes.
The average value of oceanic Niño Index (ONI) taken over a period of three months for the last four consecutive episodes are as follows:
However, since December, equatorial SSTs have been witnessing weakening trend. This means the magnitude has decreased, which indicates that peak is over and El Niño probabilities should now decline. Here’s a look at the recent Nino Index (in °C):
With this, there are 60% probability of El Niño conditions to form and continue through the Northern Hemisphere spring 2019. By the time Southwest Monsoon 2019 arrives, El Niño probability would be less than 50% and ENSO neutral conditions would also increase.
The four-month long Southwest Monsoon seasons hold great relevance for India, as it caters to 75% of the annual rainfall of the country. El Niño has the power corrupt the Monsoon and is invariably related to below normal Monsoon rains.
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