February Climate Briefing: “Warm-Neutral” and Slowly Cooling

Authored by Jacquelyn Turner on February 24, 2020

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

As of mid-February, the sea-surface temperatures were at warm-neutral levels, while atmospheric indicators showed mainly warm-neutral conditions. A new set of model runs predicts neutral conditions are most likely through summer, with a 61% probability for ENSO-neutral (39% chance for El Niño) for the February-April season, rising to 75% for the April-June season. These model probabilities are fairly similar to those of the official ENSO forecast issued February 13, which used both models and human judgement.

Weston Anderson provides the briefing summary:

What’s New

See below for tweets summarizing the current El Niño situation.

The latest weekly Nino3.4 SST anomaly is 0.1ºC, which is within the neutral ENSO range. This map and more in our data library: https://t.co/sxpdQ5lhvl. + More about ENSO: https://t.co/GldQNBgs3D. pic.twitter.com/JLvKEdtsYe
— IRI (@climatesociety) February 18, 2020

Warm-neutral SST conditions in the tropical Pacific are persisting through February. SSTs have dropped to near neutral in many regions, but remain warm near the date line. Ocean heat content continues to be elevated throughout the tropical Pacific#IRIforecast pic.twitter.com/q0gozeRMMv
— IRI (@climatesociety) February 20, 2020

The atmosphere is not clearly coupled to the ocean at large scales. The warm SSTs near the dateline have resulted in increased convection near the dateline, but the Southern Oscillation Index is neutral#IRIforecast pic.twitter.com/wCYy8dTaoh
— IRI (@climatesociety) February 20, 2020

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.

ENSO if forecast to return to neutral by next season and remain neutral for the coming seasons#IRIforecast pic.twitter.com/zPyPgP8qXH
— IRI (@climatesociety) February 20, 2020

The probability for El Niño conditions to continue has dropped to around 40% for the remainder of the year. The El Niño odds are lower in the official probabilistic forecast issued by CPC and IRI in early January than in the mid-month IRI/CPC forecast. The earlier 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.

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.