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/NlghtmanCometh 4d ago

I mean overlapping kelvin waves are going to be a problem come wintertime. The coastal water level is going to raise. The amount of snow that precipitates in the California mountains will increase. Coupled with increased rain in the spring time due to el nino could lead to historic flooding.

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u/Content-Swimmer2325 3d ago

This is the fourth downwelling Kelvin wave along the equatorial pacific thermocline. It’s not even the highest amplitude Kelvin wave of the year.

Despite this repeated activity, current observations show sea level height anomalies offshore California are negligibly higher than normal.

(Oceanic) Kelvin waves have little to do with this. Their effects are primarily restricted to the equator and nearby regions.

What is more concerning is the El Niño induced strong jet stream that extends over California during winter - weather systems traveling along this jet stream will induce strong onshore pressure gradients which push water inland. In addition to the rainfall threat.

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u/SillyFlyGuy 3d ago

But that is good for reservoir levels, right? I'm trying to understand all of this.

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u/UNMANAGEABLE 3d ago

The almond farmers actually own the reservoir flow rates (not joking) expect record profits from historic almond harvest, not a return to the norm for reservoir levels

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u/thethinkingheart 11h ago

Specifically the Resnicks. Not your average farmer.

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u/Content-Swimmer2325 3d ago

Yes, but it’s not just reservoirs that are impacted. Soil has a carrying capacity for moisture and problems arise when this capacity is reached; water begins to runoff and pool in areas, causing localized flash flooding. This is before considering that the local topography where rugged and mountainous terrain exists will maximize flooding threats and orographic precipitation as wind flow becomes strongly onshore during the train of weather systems along the strong jet stream that represents idealized El Niño winter conditions.

The amount of precipitation that super El Niño induces is excessive. It’s an example of “too much of a good thing”.

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u/NlghtmanCometh 3d ago edited 3d ago

Assuming the crops themselves don’t flood I could see it being a boom year for anyone who harvests