ENSO Conditions and Coral Bleaching

I) CPC Official Probabilistic Forecast
(based on a consensus of NOAA's CPC and Columbia University's IRI forecasters, using observational information and model output, along with human judgment):

March 13, 2025 (updated early-month)

Alert Status: La Niña Advisory
(definitions)

ENSO-neutral is favored to develop in the next month and persist through the Northern Hemisphere summer (62% chance in June-August 2025)

DIAGNOSTIC DISCUSSION:

During February 2025, below-average sea surface temperatures (SSTs) weakened in the central and east-central equatorial Pacific Ocean. All weekly Niño indices reflected this decline, with near-to-below average values lingering in the Niño-3.4 and Niño-4 regions. Significant coastal warming was evident near South America, with the latest Niño-1+2 value at 1.6°C. This warming, however, was shallow (in the upper 50m) and was associated with low-level westerly wind anomalies over the eastern Pacific. Below-average subsurface temperatures also weakened, but negative anomalies persisted at depth in the eastern Pacific and extended down to 200m in the central Pacific.

Tropical Pacific atmospheric anomalies continued to indicate La Niña conditions. Low-level wind anomalies remained easterly over the western and central Pacific, while upper-level wind anomalies were westerly over the east-central Pacific. Convection was suppressed around the Date Line and was enhanced near Indonesia. The traditional and equatorial Southern Oscillation indices were positive. Collectively, the coupled ocean-atmosphere system reflected weakening La Niña conditions and a trend toward ENSO-neutral.

Last month, the IRI multi-model average predicted a transition to ENSO-neutral in the coming season. The forecast team concurs and predicts ENSO-neutral, with chances greater than 50% through July-September 2025. As is typical for forecasts made in the spring, there is large forecast uncertainty at longer time horizons, with no outcome exceeding a 50% chance (chances of El Niño are the lowest).

... Read more at the NOAA's Diagnostic Discussion, CPC ENSO Update, and CPC's Official Probabilistic ENSO Forecast sites, all updated at the same time in the early-month.

** Note: IRI's Monthly Ouick Look updates twice per month and presents the latest update between the (I) early-month CPC official Probabilistic Forecast (shown in this section) and (II) mid-month IRI Model-Based Probabilistic Forecast (shown in the following two sections).

(The update of the CPC ENSO diagnostics discussion and forecast is scheduled for the second Thursday of each month.)

II) IRI Model-Based Probabilistic Forecast
(a purely objective ENSO probability forecast that uses as input the model predictions from IRI's ENSO Predictions Plume):

March 19, 2025 (updated mid-month)

In summary, a high probability (91%) for ENSO-neutral conditions from Mar-May 2025, and these condition are favored to continue through Sep-Nov 2025.

As of mid-March 2025, the equatorial Pacific is transitioning from weak La Niña conditions to a ENSO-neutral state. This shift is marked by sea surface temperatures in the Niño 3.4 region that are now closer to average, with anomalies at -0.35°C for Feb, 2025, well above the -0.5°C threshold required for La Niña conditions. The IRI ENSO plume forecast indicates a high probability (91%) for ENSO-neutral conditions from Mar-May 2025, and these condition are favored to continue through Sep-Nov 2025. For the later forecast seasons, Oct-Dec 2025 and Nov-Jan 2025/26, there is no strong preference for any category, although La Niña is slightly favored over ENSO-neutral. The probability of El Niño remains very low throughout the forecast period, increasing gradually from 1% in Apr-Jun to 20% in Nov-Jan 2025/26.

... Read more at the IRI Technical ENSO Update, IRI Model-Based Probabilistic ENSO Forecast, IRI ENSO Predictions Plume, and IRI Forecast Probability Distribution Based on the IRI ENSO Prediction Plume sites, all updated at the same time in the mid-month.

** Note: IRI's Monthly Ouick Look updates twice per month and presents the latest update between the (I) early-month CPC official Probabilistic Forecast (shown in this section) and (II) mid-month IRI Model-Based Probabilistic Forecast (shown in the following two sections).

(The update of the IRI ENSO forecast is scheduled for the 19th of each month. If the 19th falls on a weekend or holiday, it is released on the closest business day.)

III) IRI ENSO Predictions Plume
The following graph shows forecasts made by a set of dynamical and statistical models for SST in the Niño-3.4 region, for nine, overlapping, three-month periods.

March 19, 2025 (updated mid-month)

The IRI ENSO prediction plume indicates high chances for ENSO-neutral conditions during Mar-May 2025. The multimodel mean of statistical and dynamical models show ENSO-neutral conditions during the forecasts period (March to November).

... Read more here, where any specific model can be interactively examined, along with other detailed information.

(The update of the IRI ENSO forecast is scheduled for the 19th of each month. If the 19th falls on a weekend or holiday, it is released on the closest business day.)

Historically Speaking & More:

El Niño and La Niña events tend to develop during the period Apr-Jun and they

Tend to reach their maximum strength during October - February
Typically persist for 9-12 months, though occasionally persisting for up to 2 years
Typically recur every 2 to 7 years

The spring predictability barrier: Forecasts made at some times of the year generally have higher skill than forecasts made at other times of the year -- namely, they are better when made between June and December than when they are made between February and May. This is a well-known challenge for forecaster and it can impact statistical models more than dynamical models.

Disclaimer

The content posted on this web page solely represents the opinions of the authors and does not constitute a statement of policy, decision, or position on behalf of NOAA or the US Government.

The appearance of external links on this World Wide Web site does not constitute endorsement by the Department of Commerce/National Oceanic and Atmospheric Administration of external Web sites or the information, products or services contained therein. For other than authorized activities, the Department of Commerce/NOAA does not exercise any editorial control over the information you may find at these locations. These links are provided consistent with the stated purpose of this Department of Commerce/NOAA Web site.