There is a 70 percent chance of another El Nino event developing over the next three months, according to the World Meteorological Organisation (WMO) which has issued its latest update the latest update to the ENSO (El Nino Southern Oscillation) prediction.
This irregular phenomenon dominated international news in 2016 as the cause of extreme weather worldwide.
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“WMO does not expect the anticipated El Nino to be as powerful as the 2015-2016 event, but it will still have considerable impacts,” said WMO Secretary-General Petteri Taalas.
In short, ENSO is the swishing to-and-fro of the warmest water in the equatorial Pacific. In what is known as the neutral phase, the Philippines Sea hosts the warmest water. As an El Nino event develops, this water swishes, slowly, towards the coast of Ecuador.
Warm water evaporates into the atmosphere, so this has the effect of moving the biggest steam kettle on the planet an astonishing 15,000km east.
Weather patterns are determined by many factors, but evaporation from the ocean surface is what eventually makes rain. If the biggest source of that evaporation is moved, so will the patterns of rainfall.
The general effects of a significant El Nino event are known: Below-normal rainfall is expected in Central America and the Caribbean, parts of southern Asia, eastern Asia and the Pacific. Above-normal rainfall is favoured in part of the southern United States, southeast equatorial Africa, the Gulf of Guinea region in Africa, the Near East and small portions of the interior of South America.
The likelihood of higher-than-average temperatures in many places may just be seen as a continuation, after another warmer-than-average northern hemisphere summer. In North America, El Nino is associated with milder winters in north-western Canada and Alaska because of fewer cold air surges from the Arctic
These effects are a general, not specific forecast and memories of 2016 will remind one that on the ground this means flood for some and drought for others.