The pattern of El Niño has changed dramatically in recent years, according to the first seasonal record distinguishing different types of El Niño events over the last 400 years.
A new category of El Niño has become far more prevalent in the last few decades than at any time in the past four centuries. Over the same period, traditional El Niño events have become more intense.
This new finding will arguably alter our understanding of the El Niño phenomenon. Changes to El Niño will influence patterns of precipitation and temperature extremes in Australia, Southeast Asia and the Americas.
Some climate model studies suggest this recent change in El Niño “flavours” could be due to climate change, but until now, long-term observations were limited.
IRI ENSO Forecast
CPC/IRI ENSO Update
Published: May 9, 2019
El Niño/Southern Oscillation (ENSO) Diagnostic Discussion issued jointly by the Climate Prediction Center/NCEP/NWS and the International Research Institute for Climate and Society
ENSO Alert System Status: El Niño Advisory
Synopsis: El Niño is likely to continue through the Northern Hemisphere summer 2019 (70% chance) and fall (55-60% chance).
During April, above-average sea surface temperatures (SSTs) persisted across most of the equatorial Pacific Ocean (Fig. 1), reflecting the ongoing El Niño. All of the latest weekly Niño indices were near +0.8°C, except for Niño-1+2 index, which was at +0.3°C (Fig. 2). While surface indicators were relatively unchanged during the month, the anomalous upper-ocean subsurface temperatures (averaged across 180°-100°W) decreased through April (Fig. 3). Subsurface temperature anomalies remained positive close to the surface across the equatorial Pacific Ocean, but were increasingly negative at depth (Fig. 4). Suppressed tropical convection was evident near Indonesia and enhanced convection continued near the Date Line, though weaker compared to the last two months (Fig. 5). Low-level wind anomalies were weak over the tropical Pacific Ocean, with easterly anomalies evident over the western Pacific. Upper-level wind anomalies were easterly over the western Pacific and westerly over most of the eastern Pacific. Overall, oceanic and atmospheric conditions were consistent with El Niño.
The majority of models in the IRI/CPC plume predict El Niño to continue through 2019, with SST anomalies in the Niño-3.4 region clustering between +0.5°C and +1.0°C (Fig. 6). However, model predictions made during the spring tend to be less accurate relative to the rest of the year, so uncertainty remains whether this outcome will occur. In the shorter term, a recent increase in westerly wind anomalies over the west-central Pacific Ocean portends the possible development of another downwelling oceanic Kelvin wave, which could build up the above-average subsurface temperatures needed for El Niño to persist. In summary,El Niño is likely to continue through the Northern Hemisphere summer 2019 (70% chance) and fall (55-60% chance; click the CPC/IRI consensus forecast for the chance of each outcome for each 3-month period).
This discussion is a consolidated effort of the National Oceanic and Atmospheric Administration (NOAA), NOAA’s National Weather Service, and their funded institutions. Oceanic and atmospheric conditions are updated weekly on the Climate Prediction Center web site (El Niño/La Niña Current Conditions and Expert Discussions). Forecasts are also updated monthly in the Forecast Forum section of CPC’s Climate Diagnostics Bulletin. Additional perspectives and analysis are also available in an ENSO blog.
The next ENSO Diagnostics Discussion is scheduled for 13 Jun 2019. To receive an e-mail notification when the monthly ENSO Diagnostic Discussions are released, please send an e-mail message to: email@example.com.
CLICK ON THE “EL NINO” PICTURE ABOVE FOR THE WHOLE STORY.