Weathercatch: So long, La Nina. Hello El Nino and the warm, wacky weather you’ll bring
A disruption is simmering in the tropical Pacific Ocean that could impact weather patterns worldwide, including here in the Pacific Northwest.
“El Niño is here,” and it arrived early, the National Oceanic and Atmospheric Administration declared last month.
El Niño is a naturally-occurring climate phenomenon of warmer-than-normal Pacific seawater that straddles the equator. Even though El Niño forms in a remote part of the ocean, it can shape weather systems from Spokane to Singapore.
After a 4-year hiatus, the current pattern fully emerged a month or two earlier than most El Niños, “giving it more time to grow” in the coming months, NOAA meteorologist Michelle L’Heureux has said.
Should it grow into a strong El Niño, its effect is likely to vary by region. In the United States, robust El Niños often bring warmer and drier winters to the Pacific Northwest and Alaska, and cooler and wetter conditions to the southern-tier states. Meanwhile, it’s been known to bring less rainfall, higher temperatures and drought to Southeast Asia and Australia.
In Washington state, El Niño tends to cause warmer temperatures, less snowfall and less snowpack in winter. The last strong El Niño occurred during 2015-2016, when our state experienced an abnormally mild winter and low mountain snowpack that contributed to severe drought conditions the following summer.
It’s too soon to know for certain whether the new El Niño will develop into a mouse or a monster, but the pattern’s early appearance amid anomalously high ocean temperatures suggests the latter. Also, from a statistical and historical perspective, it’s coming hot on the heels of an unusual three-year La Niña phase – the opposite pattern of El Niño – indicating the climate pendulum is likely to make a hard swing toward El Niño conditions. (La Niña is characterized by cooler-than-average ocean temperatures, whereas El Niño is characterized by warm water temperatures.)
Even so, keep in mind that El Niño is only one factor in a complex global weather machine. A strong one doesn’t guarantee that our region will be warmer and drier, but it definitely tilts the odds.
Is the early-bird arrival of El Niño contributing to our region’s warmer than normal summer so far? Perhaps, but not in a big way. According to NOAA, “The effects of El Niño are mostly weak or insignificant in the U.S. during summer.”
Meanwhile, El Niño continues to intensify. Should it turn brutish during the next few months, expect its biggest impact to be felt in December and after the New Year.
Nic Loyd is a meteorologist in Washington state. Linda Weiford is a writer in Moscow, Idaho, who’s also a weather geek.