Super El Niño Set to Upend US Winter

Judah Cohen, a polar vortex expert at MIT, said the science on how the two patterns interact is still uncertain and the relationships are not particularly strong. If the vortex holds together this winter, he said, it will be a mild winter overall regardless of El Niño, except possibly along the West Coast. If it weakens and stratospheric warming follows, he said it could bring a repeat of the severe mid-Atlantic winter weather of 2019-2020.

Darryn Waugh, a professor of Earth and planetary sciences at Johns Hopkins University, cautioned against certainty. With the jet stream, the stratospheric polar vortex and El Niño, he said, "It's when this happens, there's an increased probability that something will happen."

Ben Kirtman, dean of the Rosenstiel School at the University of Miami, said the bigger unknown is the backdrop. "This is an El Niño superimposed on top of a pretty big climate change signal," he said. "We don't have a clear understanding how that changes the teleconnections, those relationships. That's an open science question."

The Fish Angle

NASA said its satellites have detected warmer sea surface temperatures, higher sea surface height and falling chlorophyll — the signature of weakened trade winds and deeper warm surface water shutting off the upwelling that feeds phytoplankton.

NOAA research oceanographer Andrew Leising told Newsweek that reduced phytoplankton "definitely can ripple through the ecosystem," because it "is the bottom of the food web and therefore supplies energy to basically everything else." Cold-water species may move north or deeper and grow and reproduce less, he said — while warm-water species such as tunas may show up closer to shore and farther north, which "can actually make for more fishing opportunities on these species than normal years."

Michael Jacox, an oceanographer at NOAA's Southwest Fisheries Science Center, said that along the US West Coast, "the tendency is for El Niño to limit productivity by reducing the availability of nutrients in the surface ocean."