La Niña Watch: Cooler, wetter weather expected in Oregon for late fall, early winter
PORTLAND, Ore. (KOIN) — The Pacific Northwest could see a cooler and wetter fall and winter, and even a chance of snow, according to the latest forecast from meteorologists.
The National Weather Service’s Climate Prediction Center issued a La Niña Watch on Thursday. La Niña brings cooler temperatures to the Pacific Ocean, therefore impacting the weather in Oregon and Washington.
NWS, a division of the National Oceanic and Atmospheric Administration, expects conditions to reach La Niña thresholds in three overlapping, three-month periods: September to November, October to December and November to January.
“ENSO-neutral is most likely through the late Northern Hemisphere summer 2025 (56% chance in August-October),” the Climate Prediction Center reported. “Thereafter, a brief period of La Niña conditions is favored in the fall and early winter 2025-26 before reverting to ENSO-neutral.”
KOIN 6 Chief Meteorologist Josh Cozart explained that these forecast models are indicating a weak La Niña period that will cause slightly cooler-than-average conditions in the late fall and early winter. “ENSO-neutral” conditions, which mean the ocean surface will neither be above nor below average, are expected to come later in the year — along with the Pacific Northwest’s typical wet and cool winter.
Cozart noted there is snow potential amid an ENSO-neutral winter, and even a weak La Niña period could increase the snow forecast in western Oregon and southwest Washington.
“However, last year a weak La Niña was in place and Portland saw a relatively mild and snow-free winter,” Cozart said. “So, this is not a black and white way of forecasting winter weather months in advance, but it does help to give guidance.”
According to the meteorologist, an El Niño year would bring warmer conditions to the sea surface waters and cause a warmer, drier winter for the region.
NWS is expected to issue an update on upcoming weather conditions later in September.