April 2026 was the fourth-warmest April globally on record, with an average ERA5 surface air temperature 1.43°C above the preindustrial 1850-1900 baseline, the Copernicus Climate Change Service reported in early May. [1] The Copernicus Marine Service ranked it the second-warmest April ever for the global ocean, with a mean sea surface temperature of 21.08°C — only 0.02°C cooler than April 2024. [2] Around 8% of the global ocean ranked as the warmest April ever recorded; more than half of the ocean was within the ten warmest. The Mediterranean ranked tenth-warmest. The North Atlantic ranked third-warmest. The equatorial Pacific hit a record April mean of 26.99°C, surpassing the previous 2017 mark.
These are background facts to the actual story this week, which is the preseason hurricane forecasts and the gap between them.
NOAA's Climate Prediction Center, in its April 9 ENSO Diagnostic Discussion, gave a 61% probability that El Niño emerges in May-July 2026, persisting through year-end. [3] The GFDL SPEAR model puts the odds of a moderate-to-strong El Niño by fall at unusually high, with a roughly 25% chance of a "very strong" event — Niño-3.4 anomalies of +2.0°C or higher.
That is where the preseason consensus ends.
Colorado State University's April outlook calls for a below-average season: 13 named storms, 6 hurricanes, 2 majors. North Carolina State predicts a near-normal season: 12-15, 6-9, 2-3. The University of Arizona's April 3 model produces an above-average season: 20 named, 9 hurricanes, 4 majors. [4] CSU at 2 majors. Arizona at 4 majors. The Arizona forecast is twice as active.
The dispersion is not a forecast disagreement. It is a window into what current preseason hurricane skill actually looks like when two physical processes pull in opposite directions. Atlantic sea surface temperatures are at near-record warmth — the fuel side of the equation. El Niño typically produces stronger upper-level wind shear over the Caribbean and tropical Atlantic, which tears storms apart before they intensify — the suppression side. CSU is betting the shear wins. Arizona is betting the heat does. NCSU is hedging. None of them know.
For the National Hurricane Center, which begins routine operational coordination this week ahead of the June 1 Atlantic season start, the dispersion is itself the planning signal. The 2026 season introduces a new operational change: NHC will issue inland tropical-storm and hurricane watches and warnings using cones that extend further inland than in prior years, in response to the freshwater-flooding deaths that dominated Helene's 2024 toll. The procedural change matters precisely because the seasonal forecast does not narrow the planning envelope.
The El Niño-versus-warm-ocean tension also has a temporal asymmetry. El Niño typically peaks in late autumn and winter — its shear-suppressive effect is strongest in October and November, when Atlantic activity is winding down. The early- and mid-season months — August, the historical peak — could see the warm-ocean signal dominate before the El Niño shear sets in. The preseason forecasts compress this seasonal evolution into a single number that may not survive contact with the actual hurricane calendar.
The 12-month period from April 2025 through March 2026 ran 1.43°C above the preindustrial average — the same number as April alone. The signal is the floor, not the ceiling. The ocean is the heat reservoir; the equatorial Pacific has set monthly SST records at the same time the central Pacific transitions toward El Niño conditions. The preseason hurricane forecasters disagree because they are forecasting against this combination for the first time in this configuration.
The 2025 Atlantic season produced 14 named storms, 7 hurricanes, 3 majors — squarely on the 1991-2020 climatological mean of 14/7/3. The 2026 forecasts cluster from below-average to nearly twice that. June 1 is 26 days away. The first forecast cone with the new inland-warning protocol will be drawn in real time, against an ocean that has spent the spring at near-record heat and an ENSO state still in transition.
The CSU outlook is a model output. The Arizona outlook is a model output. Both are products of physical reasoning. That they disagree by a factor of two on majors — at the same Brent crude headline that's been driving the hospitals and helium and demographic stories elsewhere in this paper — is what current preseason hurricane skill looks like in 2026. The forecast skill is not the story; it is part of the climate story.
-- DARA OSEI, London