What forecasters have confirmed
In its April 2026 ENSO Diagnostic Discussion, the CPC stated that neutral conditions are present and favored through the April-to-June window, with an 80% probability. The same bulletin placed El Nino odds at 61% for the May-to-July period and projected the event to persist through at least the end of the year. Those two numbers, 80% for near-term neutrality and 61% for a mid-year transition, form the backbone of the current official outlook. “The CPC’s probabilistic language is designed to convey a range, not a single outcome,” said a paraphrased summary drawn from the agency’s diagnostic discussion, which frames the forecast as spanning continued neutral conditions through a very strong El Nino. The CPC’s companion product, its ENSO Strength Probabilities table, breaks the forecast into intensity bins using the Relative Oceanic Nino Index, or RONI. Unlike the older Oceanic Nino Index, RONI adjusts for the long-term warming trend in ocean temperatures, giving forecasters a clearer read on how intense a given event truly is relative to the shifting baseline. NOAA adopted RONI alongside the older index in a March 2026 National Weather Service advisory that tied the new metric directly to drought early-warning efforts. (The specific advisory has not been independently archived with a permanent URL; readers seeking the original document should check the NWS advisory archive or contact NWS public affairs.) Columbia University’s International Research Institute for Climate and Society independently reinforced the CPC’s direction. Its March 2026 ENSO Quick Look tied observed ocean and atmosphere data, including subsurface warmth, the Southern Oscillation Index, and outgoing longwave radiation patterns, to a multi-model plume showing rapidly increasing El Nino odds later in the year. The convergence between the IRI’s models and the CPC’s own systems adds confidence that the warming signal is real, even if its ultimate strength remains an open question.Why “super” is on the table but far from certain
The most important caveat comes from the CPC itself. The agency’s discussion explicitly states that outcomes range from continued neutral conditions to a very strong El Nino. That spread is not diplomatic hedging. It reflects genuine physical uncertainty about whether the pool of warm water building below the Pacific surface will lock in with atmospheric circulation patterns strongly enough to sustain a major event. Timing compounds the uncertainty. The 80% neutral figure for April through June and the 61% El Nino figure for May through July share a two-month overlap. These are not contradictory statements. They describe a system in transition: neutral conditions can dominate early spring while warming gathers momentum by late spring. But the overlap means the precise month of onset, if it happens, remains poorly pinned down, and that matters for industries where a few weeks of lead time can mean the difference between a managed response and a scramble. Forecasters also face what climatologists call the spring predictability barrier. Models initialized in March or April tend to lose accuracy for targets in May and June before regaining skill for later seasons. The IRI’s Quick Look addresses this directly, noting that the 61% figure for the May-to-July window carries wider uncertainty than a comparable number issued in summer for a winter target. In practical terms, the headline probability looks precise, but the confidence interval around it is broader than usual. As of May 2026, no named NOAA or IRI scientist appears to have publicly characterized the current setup as a likely super El Nino, based on a review of publicly available CPC and IRI statements. The CPC strength table includes the 2.0-degree-Celsius-or-greater bin and assigns it a small but nonzero probability, though the exact percentage for that bin is best confirmed by consulting the CPC’s published table directly, as the figure is low enough that paraphrasing it without the precise number could overstate the likelihood. The “super” framing rests on the existence of the category and its nonzero odds, not on any forecaster’s public statement that such an outcome is probable or even more likely than a moderate event.Why this cycle is harder to compare to past events
The adoption of RONI introduces a wrinkle for anyone trying to measure this potential El Nino against history. The blockbuster events of 1997-98 and 2015-16 were classified using the Oceanic Nino Index alone. Because RONI accounts for the ocean’s long-term warming trend, a 2.0-degree reading on the new index is not directly equivalent to the same number on the older one. NOAA’s drought-outreach materials have flagged this distinction, cautioning that direct comparisons to historical thresholds require adjusting for the methodological shift. The broader climate system has also changed since the last very strong El Nino. Global sea-surface temperatures have run at or near record levels for much of the past two years, altering the baseline on which any new El Nino would be superimposed. That evolution complicates the use of simple historical analogs. A 2026-27 El Nino, even one that reaches similar index values, would unfold in a warmer atmosphere with more moisture available, potentially amplifying some impacts while muting others in ways that past events cannot fully predict.What is at stake beyond the United States
El Nino’s reach extends well beyond North America. Strong events have historically brought severe drought to eastern Australia, Indonesia, and parts of southern Africa while triggering heavy rainfall and flooding along the western coast of South America. The 2015-16 episode contributed to crop failures, water shortages, and coral bleaching across the tropics. Global commodity markets, particularly for wheat, rice, and sugar, tend to react to El Nino forecasts months before physical impacts arrive, meaning the current probability shift is already a factor in trading decisions. Atlantic hurricane forecasters will also be watching closely. A robust El Nino increases vertical wind shear over the Atlantic basin, which tends to suppress tropical cyclone development. After several hyperactive Atlantic hurricane seasons, any shift toward suppression would be significant for coastal communities and insurers, though the effect depends heavily on how strong the El Nino becomes and when it peaks relative to the June-to-November hurricane season.How to use the forecast window
Risk communication specialists at NWS public affairs offices stress scenario planning over single-number forecasts. In the current context, that means preparing conditional strategies: what to do if El Nino strengthens rapidly, what to do if it emerges but stays weak, and what to do if the system stalls in neutral. The CPC’s explicit range of outcomes supports that approach. For water managers in California and the Colorado River basin, a strong El Nino could mean above-average winter precipitation, a welcome prospect after years of drought stress. For agricultural planners in the Midwest, it could shift temperature and rainfall patterns during the growing season. For Gulf Coast emergency managers, it could alter the hurricane calculus. None of those outcomes is locked in, but all are plausible enough to justify preparation. The responsible read of the evidence as of May 2026 is neither complacent nor alarmist. The tropical Pacific is neutral, but multiple independent lines of analysis point toward warming later this year, with a real if uncertain chance of a very strong event. The CPC and IRI will update their outlooks monthly as new ocean observations arrive and models push past the spring predictability barrier. Until the picture sharpens, the smartest move for decision-makers is to treat El Nino as a high-impact possibility on the horizon and use the current window of relative calm to stress-test plans before the atmosphere forces the issue. More from Morning Overview*This article was researched with the help of AI, with human editors creating the final content.
