Warming across Pacific Ocean continues for the past many days, with minor fluctuations. However, past few days saw significant increase in the sea surface temperatures (SST), particularly Nino 3.4 that is a deciding factor for declaring El Niño.
Here’s a look at the recent Nino Index (in °C):
The Oceanic Nino Index (ONI), which is three months running mean of SST anomaly in the Nino 3.4 region, has further cemented the possibility of El Niño making a comeback.
El Niño is declared when ONI is higher than or equal to 0.5°C for overlapping 3 months for five consecutive episodes. The most recent ONI value MJJ (May – July 2018) is 0.1°C, which was in negative range in last episode.
With the increasing trend, there is 60% chance of El Niño making an appearance by the fall of the year, while this percentage will increase further to 70% by the winter of 2018-19.
As reiterated before, presence of El Niño has great bearing on Indian Monsoon. Not only this, evolving El Niño alone has the power to corrupt the Monsoon rains.
We can already see mild impact of the evolving El Niño on the Monsoon rains, which is getting visible now. So far, all the three Monsoon months have seen below normal rains. June ended at 95%, followed by July at 94%. August is also most likely to end below normal at 94% or 95%. According to weathermen, probably September is also likely to follow the same track.
Although we are on the verge of entering the last month of Monsoon 2018 but it has potential of affecting the rains. There has been significant rise in the SST, therefore impact on Monsoon rains would be now stronger in September.
However, silver lining to the cloud is that we can look forward to a good Northeast Monsoon.
Image Credit:en.wikipedia.org
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