How and when El Niño could impact Seattle
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El Niño, the ocean and atmosphere cycle in the tropical Pacific that can supercharge global extreme weather events, is officially back after about a four-year hiatus, NOAA announced.
Why it matters: El Niño holds large sway over global weather patterns. It is likely to increase global average surface temperatures, potentially leading to an all-time record warm year this year or next, which could surpass the El Niño year of 2016.
- El Niño could contribute to heat waves, droughts, floods and other weather extremes, which already are worsening from human-caused climate change.
- It has also made for an especially uncertain outlook for the North Atlantic hurricane season.
Zoom in: Impacts to the Pacific Northwest won't emerge directly until the end of the year when it's predicted the region will experience a warmer than usual winter, National Weather Service Seattle meteorologist Dev McMillian told Axios.
- Milder temperatures could mean less mountain snowpack, arguably the most crucial climate-related variable for the Pacific Northwest, raising drought and water-supply fears, state climatologists Nicholas Bond and Karin Bumbaco have said.
Zoom out: El Niño events are characterized by unusually warm sea surface temperatures in the equatorial tropical Pacific, particularly across the central and eastern Pacific.
- During an El Niño, the ocean conditions in turn drive atmospheric responses. These include a reversal of the typical trade winds across the ocean basin and shifts, where heavy tropical downpours tend to develop near the equator.
The intrigue: The natural climate phenomenon now occurs against a backdrop of a rapidly warming planet being worsened by human emissions of fossil fuels. It makes the evolution and impacts more uncertain — and potentially more significant, experts told Axios.
- Since El Niño years tend to yield global temperature milestones, this year and next could provide a preview of what our typical climate will look like as warming continues, said Michelle L'Heureux, chief of Climate Prediction Center's El Niño-Southern Oscillation team.
- “The global oceans are very warm right now and I’m afraid that this is putting us into territory that we don’t have much experience with,” she said in an interview.
What they're saying: “It is a little bit nerve-wracking,” said L'Heureux.

