The busiest long-haul airspace in the world sits between the United States and Europe, and this winter it may also be one of the rougher ones. Forecasters expect the El Niño now building in the tropical Pacific to strengthen through the 2026–27 Northern Hemisphere winter, and a growing body of research links strong El Niño events to more turbulence along the North Atlantic tracks that connect the two continents.
What El Niño does to the jet stream
El Niño is a periodic warming of the central and eastern equatorial Pacific that reorganises weather patterns far beyond the tropics. One of its most consistent effects is on the jet stream: during El Niño winters the Pacific jet tends to strengthen, extend eastward and shift its position, and those changes ripple downstream across North America and the Atlantic. A stronger, sharper jet means stronger wind shear, the abrupt change in wind speed or direction over a short distance, and wind shear is the raw ingredient of clear-air turbulence.
Clear-air turbulence, or CAT, is the type pilots dread most because it gives no warning. It forms at the boundaries of the jet stream at cruising altitude, roughly 9 to 12 kilometres up, where there are no clouds to see and nothing for onboard radar to detect. An aircraft can be flying through a clear sky one moment and hit a patch of churning air the next.
The research, and a historical marker
Studies of the relationship between El Niño and CAT have found that stronger events are associated with materially more moderate-or-greater turbulence over parts of the United States and the North Atlantic, with some analyses pointing to increases on the order of 50 percent in the worst-affected regions during strong episodes. The strongest signal shows up precisely along the transatlantic corridor, where the North Atlantic tracks funnel hundreds of flights a day through jet-stream airspace.
History offers a marker. The winter of 1997–98, one of the most powerful El Niño events on record, coincided with an unusually large spike in pilot reports of turbulence. The practical value of that predictability is not that any single patch of rough air can be seen coming months out as clear-air turbulence can't be prevented, and by its nature it stays hidden until an aircraft is in it. What a seasonal signal buys is preparation: airlines can plan a bumpier winter into their operations, carrying more contingency fuel to absorb altitude changes and reroutes, building extra buffer into schedules, and tightening seat-belt and cabin-service policy over jet-stream airspace to reduce the injuries that turbulence, not delay, makes its real cost.
Why this winter matters
According to NOAA's Climate Prediction Center, El Niño conditions are already present and are forecast to strengthen into the 2026–27 winter, with a real chance of reaching the strongest tier seen only a handful of times in the modern record. For airlines running the US–Europe schedule, that raises the odds of a rougher season on the tracks, with consequences that go beyond passenger comfort. Turbulence is a leading cause of in-flight injuries to crew and passengers, and while no forecast can pinpoint an individual patch of clear-air turbulence, turbulence-guidance products flag the regions and altitudes where it is most likely, so dispatchers and crews can favour cruise levels and tracks that stay clear of the sharpest jet-stream gradients and adjust altitude when a bumpy layer is reported ahead. A stronger, displaced jet reshapes the winds on the crossing itself, too: fuel is a large share of airline operating costs, and the swing between a strong headwind and a strong tailwind on a single transatlantic sector can mean tonnes of difference in burn.
Turning a seasonal signal into operational decisions
Knowing a season is likely to be turbulent is only useful if operations teams can act on it day to day. That is where high-resolution wind data and timely alerting come in. The OpenWeather Weather Dashboard gives operations and dispatch teams a single working environment for the forecasts, maps and alerts that shape route and altitude decisions during a bumpy season.
Its capabilities map directly onto the problem. Configurable alerts let teams set their own thresholds on wind speed and shear and route those warnings into automated workflows. Interactive maps provide location-specific forecasts across multiple sites, suited to coordinating airport operations and route planning. Detailed meteorological reports and direct consultations with OpenWeather's in-house team add expert interpretation when conditions are marginal. Underpinning all of it is the OWHL™ hyper-local model, which combines ECMWF, GFS and Met Office data with radar, satellite and station observations to deliver forecasts at 100 m resolution with 10-minute updates.
CAT will never be fully visible in advance, its defining trait is that it hides in clear air. But a season shaped by a strong El Niño is a season that can be prepared for, and the operators who pair the seasonal signal with granular, well-alerted weather data will be the ones best placed to keep the North Atlantic corridor smooth, safe and on schedule.