Historic El Niño Could Rank Among Strongest Ever by Fall

Unprecedented El Niño Intensification Reshapes Atlantic Hurricane Outlook

El Niño strengthened dramatically over the past month. A massive expanse of sea surface temperature anomalies exceeding +1.0°C spread across the central and eastern equatorial Pacific. The latest weekly Niño-3.4 index value reached +1.2°C, while the westernmost Niño-4 region registered +0.5°C and the easternmost Niño-1+2 area hit +2.7°C. These ocean temperature patterns signal a strengthening climate phenomenon that meteorologists now believe could become one of the most powerful El Niño events in recorded history.

The National Oceanic and Atmospheric Administration released a significant forecast update Thursday, increasing the probability of a historically strong El Niño developing by fall. NOAA now projects an 81% chance that this El Niño will rank among the strongest on record this fall, up from a 63% chance in its June outlook. The agency maintains very high confidence that El Niño will continue through early 2027, with a 97% chance it will last through early spring of that year.

The equatorial subsurface temperature index, averaged from 180°-100°W, increased as a recent downwelling Kelvin wave deepened the thermocline and raised temperatures in the eastern Pacific. Low-level westerly wind anomalies and upper-level easterly wind anomalies appeared over the western and central equatorial Pacific. Convection enhanced over the central and east-central equatorial Pacific and became suppressed over Indonesia. The traditional and equatorial Southern Oscillation indices registered significantly negative, confirming the coupled ocean-atmosphere system reflected a strengthening El Niño.

Computer Models Predict Intensification Through Year’s End

The North American Multi-Model Ensemble average, including the NCEP CFSv2, forecasts El Niño to intensify through 2026. Model forecasts, combined with strong coupling of atmospheric and oceanic circulation across the Pacific, support forecasters’ confidence in continued strengthening. The projected ranking of this event among the largest El Niño episodes in records going back to 1950 underscores its potential to reshape weather patterns globally. Meteorologists emphasize that even the strongest El Niño events do not lead to typical impacts everywhere, but stronger events can more significantly tilt the odds in favor of expected outcomes.

El Niño describes one of three phases of a climate cycle called the El Niño-Southern Oscillation, or ENSO. It represents natural temperature changes in the central Pacific Ocean that alter atmospheric circulation and can greatly influence global weather. El Niño describes warmer than average water across the equatorial Pacific, while La Niña describes colder than average water conditions, and ENSO neutral refers to a state where temperatures remain close to average.

Atlantic Hurricane Season Faces Historic Suppression

The 2026 Atlantic hurricane season could become one of the least active in over a decade, due in part to this strengthening El Niño. Colorado State University’s tropical meteorology project team released its latest forecast update Wednesday, now projecting only nine storms, four of which will become hurricanes and only one of which will reach Category 3 status or stronger. That represents five fewer storms and three fewer hurricanes than an average season. The forecast would mark the fewest storms in any Atlantic season since 2014, the fewest hurricanes since 2015, and the fewest Category 3 or stronger hurricanes since 2013 failed to produce a single major hurricane.

A mid-June outlook from Atmospheric G2 and The Weather Company also forecast a below-average hurricane season. Colorado State University, which pioneered seasonal hurricane forecasts, lowered its Atlantic hurricane season forecast again Wednesday, citing the high likelihood that El Niño will strengthen to very strong levels during the climatological peak of the season, from mid-August to mid-October.

Why El Niño Suppresses Atlantic Hurricane Development

During El Niño, above-average water temperatures in the central and eastern Pacific Ocean alter the position and strength of the subtropical jet stream. The subtropical jet stream becomes more robust. It extends deep into the Caribbean and Atlantic Ocean, creating hostile conditions for tropical cyclone formation and intensification. Meteorologists describe the subtropical jet stream as a belt of very fast winds high in the atmosphere, and these strong winds hinder tropical development in the Atlantic during an El Niño because hurricanes prefer very calm conditions.

El Niño’s influence already appears evident in current atmospheric conditions. Wind shear over the Caribbean Sea reached notably high levels for early July, according to WPLG-TV hurricane expert Michael Lowry. Computer model forecasts through the heart of hurricane season hint at a classic signal of high wind shear in a strong El Niño across the “main development region,” that area stretching from Africa to Mexico’s Yucatan Peninsula. El Niño can produce higher wind shear and sinking, dry air over the Caribbean Sea and other parts of the Atlantic, which create hostile conditions for hurricanes and tropical storms to develop.

Pacific Basin Faces Opposite Scenario

While the Atlantic hurricane season faces suppression, the Pacific basin experiences completely different conditions. El Niño’s concentration of warm water and low wind shear in the central and eastern Pacific creates ideal conditions for major hurricanes and typhoons to form. The deepest pool of warm water and lowest wind shear across the central and eastern Pacific transforms that basin into a hyper-fueled engine for major hurricanes and monster typhoons. The stronger the El Niño, the more certain forecasters become about its strong influence on regional weather patterns.

Hurricane Season Still Poses Dangers Despite Lower Numbers

A less active hurricane season does not guarantee a no-impact season, as residents already witnessed last month. Tropical Storm Arthur wasn’t well organized, but its flooding rain smashed Louisiana’s all-time 24-hour rainfall record and produced the wettest June day on record in New Orleans. Arthur demonstrated that meteorologists don’t need a hurricane to produce impacts such as flash flooding. Even during suppressed seasons, individual storms can still cause devastating local impacts, particularly from heavy rainfall and flooding.

Monitoring and Updates Continue Through Fall

The National Oceanic and Atmospheric Administration, working with NOAA’s National Weather Service and their funded institutions, continues to monitor oceanic and atmospheric conditions. Officials update conditions weekly on the Climate Prediction Center web site through El Niño/La Niña Current Conditions and Expert Discussions. A probabilistic strength forecast remains available for public access. The next ENSO Diagnostics Discussion is scheduled for August 13, 2026. Forecasters emphasize that moderate El Niño conditions are already present in the central Pacific, with strengthening expected to continue through the remainder of the year.