Friday will feel like a weather shock for many Oregonians.
In place of the daily sunshine, hot temperatures and smog, the cold rain and mountain snow that usually defines Oregon in late October returns.
What meteorologists describe as a “pattern change” will begin Friday, bringing several inches of rain to the Willamette Valley and 2 to 4 inches of snow in the passes of the Cascade Range through Saturday and Sunday.
The reason for this change is simple – the ridge of high pressure that has been pushing the Pacific storms north and south is breaking down as the jet stream of moisture moves through it, bringing wet conditions over the next few weeks.
“It’s a wholesale change, and while no single storm produces a ton of rain or snow, it’s something that tends to increase over time,” National Weather Service meteorologist Colby Neumann said.
The rain is reducing and clearing the air two wildfires that have been producing smoke and poor air quality – the Cedar Creek Fire and the Nakia Creek Fire.
Rain will begin Friday and continue Friday evening. A half inch to an inch and a half will fall in the Willamette Valley over the weekend, and 1 to 3 inches in the Cascade foothills and Coast Range.
Snow is expected over the weekend
Snow may affect travel Saturday morning and evening, with several inches expected to stick on both Santiam Pass (highway 20) and Willamette Pass (highway 58).
High mountains will be covered in even deeper snow, and previously explored areas in the Cascade Mountains, such as the Mount Jefferson or Three Sisters wilderness areas, will receive a white coat, making access more difficult. In other words, if you’re planning on sneaking one last backpacking trip this weekend, you’re going to need snowshoes.
A cooler, wetter pattern is expected to persist for the next couple of weeks.
“Maybe we’ll have a dry day here or there, but overall, folks, it’s going to be pretty wet and at least a little bit of rain most days,” Neumann said. “The sunny days are over every afternoon, and probably will be by next spring.”
Another summer record for heat
The shift will be interesting in part because it’s been another record year of heat and dryness in Oregon and the Willamette Valley.
The period from July 1 to October 18 was the hottest in Salem and Eugene, averaging 69.7 degrees in Salem and 68.2 in Eugene. In Salem, the five warmest late summer and fall periods on record dating back to the 1890s have all occurred since 2014, according to the NWS. Four of the five warmest periods in Eugene have occurred since 2014.
It was also very dry in both cities. During the same period – July 1 to October 18 – Eugene recorded its driest year on record at 0.42 inches, the second driest since 2018. Other years in the top five for dryness in Eugene include 1952, 1942 and 2006.
In Salem, it was the second driest period on record at 0.54 inches. The driest year was 1952, which saw 0.2 inches. Rounding out the top five years for drought are 2018, 1991 and 2006.
Zach Urness has been an outdoor reporter in Oregon for 15 years and is the host of the Explore Oregon Podcast. To support his work, subscribe to “Statesman” magazine. Urnes is the author of “Best hikes with kids: Oregon” and “Southern Oregon Tourism.” He can be contacted zurness[email protected] or 503-399-6801. Find him on Twitter at @ZachsORoutdoors.