May Climate Briefing: Models Say El Niño Stays, but it’s an Uncertain Time of Year

Authored by Elisabeth Gawthrop on May 31, 2019

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

Tony Barnston provides his last overview of the briefing:

What’s New

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.

Some recent weakening of Nino3.4 sea-surface temps, as well as the subsurface temperature anomalies. Is this a death sentence for #ElNino? pic.twitter.com/zHUyzI2m0E
— IRI (@climatesociety) May 16, 2019

SSTs remain weakly positive in the Niño 3.4 region. Enhanced convection continues at / west of the date line. It has essentially persisted there since the beginning of the year. Similar to the early 90s El Niño events that developed into a series of weak central-Pacific El Niños. pic.twitter.com/5vhYAN7lFK
— Weston Anderson (@AgroClim) May 16, 2019

A recent burst of westerly winds could resuscitate #ElNino, if it leads to a Kelvin wave, although we haven’t seen evidence of one in the thermocline yet. #IRIforecast pic.twitter.com/jLnqIys06N
— IRI (@climatesociety) May 16, 2019

Without looking at models, we would say that this event is over.

But models are split. CFSv2 indicates a continuation of the event while NASA indicates a transition to neutral conditions. MME (statistical and dynamic) indicates that warm SSTs will persist through the next season
— Weston Anderson (@AgroClim) May 16, 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.

Despite some signs in the current observations of a wavering #ElNino event, models continue to predict a weak El Niño will persist.

But, Tony Barnston warns, there have been some false alarms, and they have been at this time of year, during the spring predictability barrier. pic.twitter.com/Vt0ISeSOrU
— IRI (@climatesociety) May 20, 2019

Here are the probabilities of ENSO state based on the model outputs. The odds are fairly similar to the probabilities issued earlier in the month that include human judgement from @NWSCPC and IRI (available here: https://t.co/SFNAMcfXil). pic.twitter.com/g4FcxnaT6i
— IRI (@climatesociety) May 20, 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 May than in this mid-month CPC/IRI forecast. This early-May 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.

Here’s the #IRIforecast for seasonal rainfall the next three months. Some #ElNiño signatures – particularly in Indonesia. Other signals, such as a wet NW United States, are not as typical for El Niño. pic.twitter.com/t5rYusjU21
— IRI (@climatesociety) May 16, 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.

There's rain projected for the East African highlands, but closer to the coast serious drought persists. And Guatemala, Ethiopia and Somalia all are already in IPC Phase 3 (crisis), which means that this seasonal forecast for the persistence or development of drought is worrying pic.twitter.com/xLmRMy97Rl
— Weston Anderson (@AgroClim) May 16, 2019

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.