El Niño has arrived, and here’s what it means for Idaho’s summer heat, winter snow
“El Niño is here,” weather experts declared this month, potentially impacting Boise’s weather this summer and into the rest of 2023.
“El Niño conditions have developed, as the atmospheric response to the warmer-than-average tropical Pacific sea surface kicked in over the past month,” the National Oceanic and Atmospheric Administration stated in a June news release.
Those atmospheric changes can have a significant impact on daily weather. And, NOAA added, the odds of this El Niño “becoming a strong event at its peak are pretty good.”
Here’s what to know about the El Niño year and what it means for Idaho:
Is 2023 going to be an El Niño year?
NOAA declared in June that El Niño conditions had officially developed.
El Niño occurs when trade winds — the permanent east-to-west winds that blow near the Equator — weaken, allowing the Pacific Ocean’s warmer waters to push back east toward the United States’ West Coast.
This weakening allows the Pacific jet stream to dip further south, amplifying the storm track across the southern U.S. and Central America, but keeping stronger tropical moisture away from the north.
“El Niño — the warm phase of the El Niño-La Niña climate pattern — changes global atmospheric circulation in known ways, giving us an idea of potential upcoming weather and climate patterns,” the group said. “A stronger El Niño means global temperature, rain and other patterns are more likely to reflect the expected El Niño impacts.”
NOAA estimates a 56% chance this El Niño will become “a strong event at its peak” and about an 84% chance “of at least a moderate event.” A strong El Niño event means sea temperatures in the eastern Pacific Ocean are at least 1.5 degrees above normal.
What does El Niño mean for Idaho?
During an El Niño winter, the Pacific Northwest is usually drier and warmer, while the southern U.S. will experience wetter-than-usual conditions. El Niño doesn’t have as big of an impact on the Pacific Northwest in the spring and summer, National Weather Service meteorologist Joel Tannenholz previously told the Idaho Statesman.
“There are too many other factors in weather to say that El Niño is directly responsible this far north,” Tannenholz said.
Moderate to strong El Niño’s have also been associated with drier-than-average conditions in the Pacific Northwest and above-average temperatures. From December to February, Boise typically sees an average of 3.95 inches of precipitation and 14.2 inches of snow, meaning totals will likely be lower than those two figures for the upcoming winter.
This story was originally published June 23, 2023 at 4:00 AM.
