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Geneva, 26 February 2019 - There is a 50-60% chance of El Niño developing by May 2019, although it is not expected to be a strong event, according to the latest update from the World Meteorological Organization (WMO). Sea surface temperatures in the tropical Pacific were at or slightly below El Niño thresholds in January and early February 2019. Some El Niño-like atmospheric patterns also emerged around late January.

Model predictions and expert opinion indicate a 50–60% chance that the ocean and atmosphere will couple, and a weak El Niño event will become established during the March–May 2019 season. A strong event (sea surface temperatures in the east-central tropical Pacific rising to at least 1.5 degrees Celsius above average) is unlikely. Through the first three quarters of 2019, the development of La Niña is highly unlikely and can be practically ruled out.

“WMO recently confirmed 2015, 2016, 2017 and 2018 as the four warmest years on record. But even a weak El Niño is likely to make 2019 warmer than 2018,” said Maxx Dilley, Director of WMO’s Climate Prediction and Adaptation branch.

The El Niño/Southern Oscillation (ENSO) is a naturally occurring phenomenon involving fluctuations of ocean surface temperatures in the equatorial Pacific, coupled with changes in the overlying atmospheric circulation. It has a major influence on weather and climate patterns over many parts of the world.

Scientific progress on the understanding and modelling of ENSO, underpinned by major observational programmes, has improved monitoring and prediction capabilities, helping society to prepare for the associated hazards such as heavy rains, floods and drought. ENSO also affects global temperature.

WMO’s update is based on forecast models and expert interpretation from around the world. It is used by planners within the United Nations system, and complements information issued by National Meteorological and Hydrological Services and WMO Regional Climate Centres as a source of information for country-level decision-making by disaster managers, for planning in climate-sensitive sectors, and by governments.

Notes to Editors

El Niño is often associated with warm and dry conditions in southern and eastern inland areas of Australia, as well as Indonesia, the Philippines, Malaysia and central Pacific islands such as Fiji, Tonga and Papua New Guinea.
In northern hemisphere winter, drier than normal conditions are typically observed over south-eastern Africa and northern Brazil. Wetter than normal conditions are typically observed along the Gulf Coast of the United States, the west coast of tropical South America (Colombia, Ecuador and Peru) and from southern Brazil to central Argentina. Parts of eastern Africa and southernmost parts of South Asia also usually receive above-normal rainfall.
El Niño is associated with milder winters in north-western Canada and Alaska due to fewer cold air surges from the Arctic – a result of a large-scale region of lower pressure centred on the Gulf of Alaska/ North Pacific Ocean.
It is important to stress that these are typical effects – not specific forecasts – and that actual conditions vary according to the strength and timing of the El Niño event. Other factors (such as the Indian Ocean Dipole or the North Atlantic Oscillation/Arctic Oscillation) can also have an important influence on seasonal climate.
Global-scale seasonal forecasts, including those of precipitation and surface temperature, are routinely produced by WMO accredited centres using sophisticated atmosphere-ocean coupled models, which take into account ENSO as well as other climate drivers.  There are now 13 WMO Global Producing Centres of Long Range Forecasts, whose products are consolidated by a Lead Centre of Long Range Forecast Multi Model Ensemble (https://www.wmolc.org/).
Web links of the National Meteorological Hydrological Services
Information and web links to WMO Regional Climate Centres
Archive of all WMO El Niño/La Niña Updates issued so far, including this one

For further information contact: Clare Nullis, media officer. Email cnullis@wmo.int. Cell +41 79 709 13 97