NOAA’s Climate Prediction Center released its latest ENSO Diagnostic Discussion on March 12, noting a transition from La Niña conditions and increasing odds that El Niño will develop later this year. The signal is being reinforced by warmer subsurface temperatures across the Pacific Ocean, and a European climate forecasting model has separately pushed El Niño likelihoods even higher. But the timing of these forecasts, issued during a well-documented window of reduced prediction accuracy, means the rising probabilities carry a significant asterisk.
What the March Forecast Actually Says
The CPC’s March 12 discussion describes a Pacific Ocean in transition. La Niña conditions are fading, and for longer forecast horizons, the center sees growing chances that El Niño will take hold. That language tracks closely with what CPC forecasters wrote in their January 2026 discussion, which stated that “for longer forecast horizons, there are growing chances of El Niño.” The consistency across two months of official assessments suggests forecasters are watching for a developing signal, though confidence is still limited by the time of year.
The official probabilistic forecast is a consensus product between CPC and the International Research Institute for Climate and Society, updated monthly alongside each ENSO Diagnostic Discussion. That consensus structure is intended to reduce reliance on any single model by blending dynamical and statistical approaches into a single probability table. When that table starts tilting toward El Niño across multiple overlapping three-month seasons, it carries more weight than any individual model run.
NOAA has also been updating the tools it uses to track ENSO’s evolution. A new version of the El Niño–Southern Oscillation index, described by the drought-focused portal at Drought.gov, is intended to better link ocean–atmosphere conditions with early warning for dry spells. That kind of index does not replace the CPC–IRI outlooks, but it gives forecasters another way to monitor whether the atmosphere is responding to Pacific warming in a way that would amplify drought or heavy rain risks.
Defining “Strong” and Why the Threshold Matters
Not all El Niño events produce the same consequences. CPC tracks the probability that the Niño‑3.4 index, a measure of sea surface temperature anomalies in the central‑eastern Pacific, will exceed specific intensity thresholds. A “strong” El Niño is defined as the Niño‑3.4 index reaching or exceeding 1.5 degrees Celsius above the long‑term average. That threshold matters because strong events are often associated with outsized effects, including shifts in rainfall and drought patterns in different regions around the world.
The methodology behind these strength outlooks was formalized in a peer‑reviewed study published in the American Meteorological Society journal Weather and Forecasting. That work established the threshold‑based framework CPC now uses to convert raw model output into probability estimates for weak, moderate, and strong events. CPC’s operational implementation appears on its ENSO strengths outlook, where monthly updates show how likely it is that Niño‑3.4 will cross each intensity category in the seasons ahead.
For decision‑makers, these categories are not academic. A modest El Niño might nudge seasonal rainfall statistics without fundamentally changing risk profiles. A strong event, by contrast, can shift the odds of extreme outcomes in ways that matter for infrastructure planning, reservoir operations, crop selection, and disaster preparedness. Knowing whether models are merely hinting at a weak warming or converging on a strong event helps determine how aggressively to lean on the forecast.
The Spring Predictability Problem
Here is the tension at the center of this story: the same models showing rising El Niño odds are operating during the least reliable forecasting window of the year. The CPC’s own March discussion acknowledges that model forecasts are relatively less accurate this time of year. The January discussion carried the same caveat, emphasizing reduced forecast skill through spring.
Climate scientists call this the spring predictability barrier, or SPB. Predictions for El Niño made before and through the February‑to‑May transition period have historically shown lower accuracy, a pattern documented in research published in Computers and Geosciences and traced back to earlier work by Duan and Wei in 2013. The barrier exists because the tropical Pacific undergoes its own seasonal reset in spring, making it harder for models to distinguish between noise and a genuine warming trend that will persist into fall and winter.
A study highlighted by NOAA’s Climate Program Office and published in npj Climate and Atmospheric Science sharpened this concern further. That research found that models often issue high‑confidence El Niño projections in spring that do not always verify, highlighting overconfidence as a persistent blind spot. In plain terms, models can look certain about El Niño arriving while the ocean has not yet committed to that path.
This does not mean spring forecasts are useless, but it does mean they should be interpreted probabilistically rather than as a lock. Forecasters emphasize that the probabilities themselves can shift quickly as new observations come in, especially once the Pacific moves past its seasonal transition and model skill typically improves.
Why Multiple Forecasting Centers Agree This Time
Despite the spring barrier, the current signal is drawing attention because it is not coming from a single source. A European modeling system cited by The New York Times has also pointed toward El Niño, and other international centers have warned of a potential shift toward warmer‑than‑normal Pacific waters later this year. The New York Times report notes that these outlooks are “notoriously difficult to trust” in spring, but the fact that independent systems are leaning in the same direction suggests the emerging pattern is not an artifact of one model family.
Agreement across centers matters because each system has its own physics, data assimilation schemes, and historical biases. When they converge, forecasters gain confidence that they are seeing a real ocean‑atmosphere signal rather than model‑specific noise. In this case, CPC has pointed to signs of a transition away from La Niña, while some reporting has also highlighted subsurface warmth and atmospheric changes that could support warming later in the year.
Still, experts caution that “agreement” does not mean certainty. The European model’s aggressive warming scenario could easily moderate in future runs if the subsurface heat fails to surface or if atmospheric feedbacks stall. Likewise, CPC’s consensus probabilities are designed to be updated as new data arrive; a few weeks of cooler‑than‑expected sea surface temperatures or a resurgence of easterly winds could nudge the odds back down.
How to Read the Odds in the Months Ahead
For now, the practical message is one of conditional preparedness. Water managers, agricultural planners, and emergency officials can begin stress‑testing their plans against an elevated chance of El Niño, especially a moderate or strong event, while recognizing that the forecast is passing through its least reliable phase. Using tools like the updated ENSO index and the CPC strength outlooks, they can track not just whether El Niño is favored, but how intense it might become if it materializes.
For the public, the key is to avoid treating any single spring forecast as destiny. Instead, the focus should be on how the probabilities evolve into late spring and early summer, when the spring predictability barrier weakens and models have a clearer view of the Pacific’s trajectory. If the current multi‑model consensus holds or strengthens by then, concerns about a consequential El Niño later this year will carry far more weight than they do today.
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*This article was researched with the help of AI, with human editors creating the final content.
