Weak and short La Niña coming: How it will impact Oregon's winter
AUSTIN (KXAN) -- La Niña is on the way for this winter, the Climate Prediction Center said in an updated outlook Thursday, but it may not be such a powerful force to reckon with after all.
La Niña happens when the waters in the eastern equatorial Pacific cool at least 0.5 degrees Celsius below average. It's the opposite of El Niño, when those same ocean waters are warmer than average.
This year, La Niña is expected officially from between now and November. The odds of La Niña continuing through winter (December-February) are at 77%, but La Niña is not expected to last long into 2025.
The Climate Prediction Center described the outlook for this upcoming La Niña as "weak and short," which would have implications for the upcoming winter forecast.
What a weak La Niña means for winter
La Niña usually provides a relatively predictable pattern for winters in North America, but the strength of La Niña impacts that predictability.
Remember, a typical La Niña means drier and warmer weather for most of the southern states, while being wetter and colder for many of the northern tier states as the Pacific Jet Stream is usually farther north.
But, according to the updated outlook, a weaker La Niña is "less likely to result in conventional winter impacts, though predictable signals could still influence the forecast guidance."
That would mean a winter outlook that only loosely resembles the map above. The Southern states may still see drier and warmer conditions, but it may not be so dramatic to be a noticeable deviation from the average. Similarly, the Pacific Northwest and Ohio Valley could still get more rain than they otherwise would, but the forecast is murkier.
A weaker La Niña essentially means that the accuracy of a winter outlook may be harder to nail down without the usual influences of a strong El Niño or strong La Niña at play.
When will La Niña end?
This "short duration" La Niña is expected to begin at some point between September and November, then strengthen into winter.
However, by early next year, it's already favored to fade away. The Climate Prediction Center thinks it may be over by spring of 2025.
Beyond that, it's too early to say. Odds of an El Niño appearing creep up as we head through late spring 2025, but remain slim overall.