Hurricane season officially began June 1. Ten days later, NOAA declared an El Niño Advisory. As of the week centered June 17, the Niño 3.4 index stood at +1.7°C — up sharply from +1.1°C just weeks prior — and IRI model ensembles show it still climbing. The Atlantic, for its part, has been quiet.
That's not a surprise. It's a mechanism. And it's already running.
The Mechanism in Plain Terms
El Niño shifts the Pacific jet stream southward and strengthens upper-level winds across the tropical Atlantic. Those stronger upper-level winds create vertical wind shear — a difference in wind speed and direction between the lower and upper atmosphere. When wind shear is elevated, the tops of developing tropical storms get sheared off before they can organize into anything significant.
Think of it as a lid on the pot. The warm Atlantic water provides fuel. El Niño's wind shear keeps that fuel from igniting into a sustained storm.
What NOAA Said Before the Season Opened
NOAA's 2026 Atlantic hurricane season outlook, released May 21, called for a below-normal season with 55% probability. The forecast range: 8–14 named storms, 3–6 hurricanes, 1–3 major hurricanes. An average season produces 14 named storms, 7 hurricanes, and 3 majors.
The primary driver cited: El Niño, expected to develop and intensify through the peak months of August, September, and October. At the time of the outlook, El Niño hadn't yet been officially declared. Now it has — and it's strengthening faster than the baseline forecast assumed.
The Numbers Since Then
| Date | Development |
|---|---|
| May 21 | NOAA issues below-normal Atlantic hurricane outlook; 82% chance El Niño emerges by July |
| Jun 1 | Atlantic hurricane season officially begins |
| Jun 11 | NOAA issues El Niño Advisory; SST anomalies confirmed above threshold in central and eastern Pacific |
| Jun 17 (week centered) | Niño 3.4 weekly index reaches +1.7°C per IRI/NOAA OISSTv2 — up from +1.1°C |
| Jul 9 | Next NOAA CPC ENSO Diagnostic Discussion — next major data benchmark |
The jump from +1.1°C to +1.7°C in Niño 3.4 over just a few weeks is significant. IRI's mid-June model ensemble shows 13 of 24 dynamical models projecting the event reaching very strong territory (≥+2.0°C) during September–November 2026 — right when the Atlantic hurricane season historically peaks. (Source: IRI June 2026 ENSO Quick Look.)
The Competing Factor Nobody Should Ignore
El Niño is not the only variable in play. Near-term, Saharan dust settling over the tropical Atlantic has also contributed to the quiet opening weeks — dust suppresses convection and lowers sea surface temperatures beneath the storm development zone. That's a separate mechanism from El Niño, and it won't last all season. Atlantic sea surface temperatures are also running slightly warmer than normal — not at the extreme record levels of 2023–24, but elevated enough to provide fuel if El Niño's wind shear relaxes.
In 2023, that fuel won. Record Atlantic temperatures allowed storms to organize and intensify despite El Niño wind shear, producing an active and damaging season. NOAA's Ken Graham said it plainly when the 2026 outlook was released: "It only takes one storm to make for a very bad season."
The suppression signal is real and it's active. But a below-normal forecast is a probability statement about the overall count — not a guarantee of any individual storm's behavior.
The 2015 Analog: What Happened Last Time
The last time NOAA forecast a below-normal Atlantic hurricane season was 2015 — also an El Niño year. That season produced 11 named storms, 4 hurricanes, and 2 majors, well below the 14/7/3 average. The El Niño that year peaked at roughly +2.6°C in Niño 3.4 during November–December, making it one of the strongest on record by that metric.
The 2015 season is a useful but imperfect analog. The key similarity: a rapidly intensifying El Niño that was already elevating wind shear during the June–August ramp-up phase, exactly what's occurring now. The key difference: Atlantic temperatures in 2015 were not as anomalously warm as they are entering 2026, which gives the warm-Atlantic wildcard slightly more weight this cycle.
If 2026 tracks toward the strong-to-very-strong El Niño that IRI models currently favor, the suppression signal through August and September — the months that historically produce the majority of major hurricanes — should be meaningful. The 2015 season offers a reasonable comparison point for what a suppressed Atlantic season can look like during a strong El Niño.
What to Watch Through August
The next scheduled data benchmark is the July 9 NOAA CPC ENSO Diagnostic Discussion, which will include updated RONI values and the monthly model ensemble assessment. If Niño 3.4 continues its current trajectory and the atmospheric coupling strengthens — the Southern Oscillation Index moving more negative, lower-level easterlies weakening — the suppression signal becomes more robust heading into August and September.
NOAA has indicated it will update the hurricane season outlook in early August, ahead of the historical peak. By then, the El Niño trajectory should be substantially clearer. If the event is tracking toward strong-to-very-strong as models currently suggest, that August update is likely to reaffirm or deepen the below-normal call.