PORTLAND, Ore. (KOIN) – The National Oceanic and Atmospheric Administration has issued a 90-day forecast for anticipated winter weather around the Pacific Northwest between December of 2022 and March 2023. In the long-term seasonal outlook, the NOAA’s Climate Prediction Center reports that much of the Pacific Northwest is forecast to see above-average amounts of rain and snow, and colder-than-average winter temperatures.
“Precipitation outlook favors above normal precipitation over the Pacific Northwest, through parts of the Northern Plains, as well as over the Great Lakes and Ohio and Tennessee Valley regions,” the NOAA report reads. “Elevated odds of below-normal precipitation are favored over the southern third of the U.S., with the highest probabilities over parts of southeastern New Mexico and southern Texas, as well as parts of the Gulf Coast States.”
Washington and most of Oregon have an increased chance of seeing more substantial levels of rain and snow. Drought-stricken areas of Southern Oregon, meanwhile, have an equal chance at a wet or dry winter.
Currently, almost all of Oregon, Washington and California are in some form of drought. Crook County in Central Oregon is experiencing the harshest drought conditions. According to the U.S. Drought Monitor, much of the area is in a state of “exceptional drought.” Other parts of Central and Southern Oregon are in various stages of moderate, severe and extreme drought.
Although areas of Southern Oregon are not forecast to see above-normal precipitation, almost all regions of Oregon and Washington are expected to see colder than normal temperatures between January and April of 2023. The southeastern corner of Malheur County is the only area that has an equal chance of seeing warmer temperatures during this time.
According to the report, the predicted increase in precipitation and drop in temperatures is tied to the La Niña weather pattern, which has a 76% chance of persisting through February. Odds of La Niña weather dissipate as the region nears the spring of 2023.
A La Niña is a weather pattern change in the Northern hemisphere that occurs every two to seven years. The shift is caused by strong westerly trade winds that pull frigid, deep ocean waters to the surface in the eastern Pacific. The cold, ascending water pushes the polar jet stream north, bringing cooler temperatures, heavy rains and occasional flooding to the Pacific Northwest.
“A La Niña advisory remains in effect and the tropical Pacific atmosphere is consistent with La Niña,” the NOAA report reads.
In the extended long-term forecast, NOAA predicts that the Portland area will have an increased chance of seeing warmer-than average weather between May and November of 2023.