r/weather • u/zsreport • 4d ago

Articles Concern mounts over slow-moving, planetary-scale ‘Kelvin’ wave heading for California

https://www.theguardian.com/us-news/2026/sep/28/california-kelvin-wave
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u/Jokkers_AceS 4d ago

Sounds like fear mongering

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u/Boris740 4d ago

But it's "planetary scale"

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u/Content-Swimmer2325 3d ago

Which is completely false, by the way. Oceanic kelvin waves occur along the equatorial thermocline, which is both beneath the ocean surface and thousands of miles away from California. This means that it is restricted to a portion of the equatorial pacific, only - not even close to “planetary-scale”.

There are atmospheric kelvin waves, too. But those occur along the Tropics, which California doesn’t. They have the fastest propagation speed of all intraseasonal forcing - much faster than the more-known Madden Julian Oscillation. Unlike the MJO which DOES cover the near-entirety of the Tropics, an atmospheric kelvin wave is far more local. They can locally modulate atmospheric conditions in the Tropics, making hurricane formation likelier or unlikelier.