PORTLAND, Ore. (KOIN) — The National Oceanic and Atmospheric Administration’s Climate Prediction Center is warning that heavy rain and above-average snowfall could hit the Pacific Northwest on the week of Thanksgiving. 

Global weather calculations show that chances are favorable for above-normal precipitation across the region between Nov. 19 and Nov 24.

“Just a heads up, but the Climate Prediction Center has issued a slight risk for heavy precipitation across much of Oregon and Washington,” Portland’s National Weather Service Office reports. “This includes the risk for heavy snow across the Cascades in that period. It’s usually wise to pay attention to the forecast if you plan to travel across mountain passes this time of the year, but this could be particularly important leading up to and during Thanksgiving.”

Heavy snow in the Cascades and ample rainfall in valleys could be possible on the week of Thanksgiving. | NWS

KOIN 6 Meteorologist Kelley Bayern reports that, although extended-weather forecasts can be accurate, they’re not always reliable.

“It’s important to note that this is an extended weather outlook based on hints in the long-range forecast,” Bayern said. “It’s not certain. We tend to use these long-range outlooks for temperature or rainfall.”

Based on the current weather information, Bayern predicts that mountain snow and rainy conditions in the Willamette Valley will be possible during the days when many people will be traveling for the Thanksgiving holiday.

“Global weather models are showing a trend for heavier precipitation in the two-week forecast with cold conditions seeping back into the Pacific Northwest,” she said. “This could lead to heavy snowfall in the higher elevations, and likely a rainier pattern returning to the valley. These impacts could cause travel issues over the mountains. We will keep our eyes on these trends and get a much better idea of what may arrive next week.”