The National Oceanic and Atmospheric Administration (NOAA) released a La Niña warning this week, so it’s possible that the cold-weather phenomenon could be returning to the Pacific Northwest this winter.
Before you get too excited or panic—depending on how you feel about cold winters—there’s no guarantee it’ll even happen. Chances are at about a 55 to 60 percent right now, “which isn't huge,” Tom DiLiberto, a scientist with the El Niño Southern Oscillation (ENSO) team at NOAA's Climate Prediction Center, told us over email. “But is certainly a forecast that leans towards La Niña.”
What is La Niña?
La Niña refers to a weather event that causes cooler-than-normal temperatures on the east-central Pacific Ocean’s surface—like El Niño, which causes warmer-than-normal temperatures.
The event tends to cause cooler-than-normal temperatures in the Northwest and warmer-than-normal temperatures in the Southeast, says the National Oceanic and Atmospheric Administration (NOAA).
What does La Niña mean for Seattle?
It could mean any number of things. It increases the chances of cold weather and snow, both in the mountains and the lowlands, says KOMO’s Scott Stisek. But there are no guarantees.
“They maybe favor a certain solution but they’re certainly not promising anything,” NOAA Climate Prediction Center deputy director Mike Halpert told Curbed Seattle.
Last winter we also experienced a La Niña event, and while it was exceptionally cold, we weren’t hit by any major snow events—just a few light ones.
La Niña generally means a wet winter in the Pacific Northwest, said Halpert, “we’ll see how that pans out.”
Halpert said they’re putting out new outlooks next week, which may be a better indicator of what this winter will look like.
So we might be getting two La Niñas in a row? Does that mean anything?
In short: nothing special.
“There is nothing inherently special about two in a row,” said DiLiberto. “It doesn't necessarily increase the chances for an exaggerated La Nina. It's best to think of this as it's own event.”
We’ll keep this article updated as we learn more.