April Climate Briefing: Models Say Weak El Niño Will Continue

Authored by Elisabeth Gawthrop on April 29, 2019

Read our ENSO Essentials & Impacts pages for more about El Niño and La Niña.

Tony Barnston provides an overview of the briefing:

What’s New

An abbreviated briefing update this month. See below for tweets summarizing the current El Niño situation, and our update from March for much more on how this ENSO event has evolved.

Atmosphere: the atmospheric coupling is weak, the event may still die

OLR is decreased (more precip) around the date line but the Southern Oscillation Index has weakened considerably from last month. Westerly winds have mostly decayed and aren't generating a new kelvin wave pic.twitter.com/aTQ5PMhJTO
— Weston Anderson (@HydroClim) April 18, 2019

Barnston says, #ElNino signals are a bit weaker than it was a month ago, but still present. As shown in the SST chart (bottom is the most recent time period) the reds/oranges area is shrinking – as noted in the 'funneling' of the orange signal. #IRIforecast pic.twitter.com/EIo5rDfY3B
— Andrew Kruczkiewicz (@wxpizza) April 18, 2019

Chiming in on today's @climatesociety #IRIforecast briefing with my favorite graphic. Signature of El Niño, says Barnston, is the convection around the dateline. This is the atmospheric variable that's holding up this #ElNiño the most. pic.twitter.com/xwlz4oHdws
— Elisabeth Gawthrop (@egawthrop) April 18, 2019

ENSO Forecasts

To predict ENSO conditions, computers model the SSTs in the Niño3.4 region over the next several months. The plume graph below shows the outputs of these models, some of which use equations based on our physical understanding of the system (called dynamical models), and some of which use statistics, based on the long record of historical observations.

The latest #ElNiño predictions. Despite recent signs pointing to weakening El Niño, majority of models still predicting at least a weak event through remainder of the year. #IRIforecast pic.twitter.com/GZbKwbtQ4t
— IRI (@climatesociety) April 23, 2019

In terms of probability of at least a weak #ElNiño event, odds remain high the next few months. Models-only (mid-month) forecast is 5-10 points higher for El Niño each season than early-month forecast. Produced with @NWSCPC. pic.twitter.com/eEDXl4xmDA
— IRI (@climatesociety) April 23, 2019

The probability for El Niño conditions to continue is high in the coming months. El Niño conditions are the most likely outcome through the end of the forecast period. The El Niño odds are somewhat lower in the official probabilistic forecast issued by CPC and IRI in early April than in this mid-month CPC/IRI forecast. This early-April forecast uses human judgement in addition to model output, while the mid-month forecast relies solely on model output. More on the difference between these forecasts in this IRI Medium post.

ENSO in context: Resource page on climate variability

IRI’s Global Seasonal Forecasts

Each month, IRI issues seasonal climate forecasts for the entire globe. These forecasts take into account the latest model outputs and indicate which areas are more likely to see above- or below-normal temperatures and precipitation.

The seasonal rainfall forecasts show signs of a weak #ElNiño hanging around. Here are the probabilities for the coming season. Strongest wet signal is in northeastern Brazil, strongest dry signal is in the Philippines and parts of Indonesia. #IRIforecast pic.twitter.com/T0mBTISprN
— IRI (@climatesociety) April 18, 2019

All forecast maps, including temperature in addition to precipitation, and also including a description of the methodologies, are available on our seasonal forecast page. Additional forecast formats, such as our flexible forecast maproom, are available in the IRI Data Library.

Learn more about El Niño and La Niña on our ENSO resources page, and sign up here to get notified when the next forecast is issued. In the meantime, check out #IRIforecast.