What happened to Oregon's winter? Record warmth projected as dry spell continues

What happened to Oregon's winter?

That's the question meteorologists are contemplating as the state continues yet another stretch of historically dry weather culminating with near-record warm temperatures across Western Oregon Friday and Saturday.

Temperatures could reach 60 degrees in the Willamette Valley and 70 degrees in southern Oregon, which would be close to record levels for both regions.

"Whether we make a run at the record will depend on how long that morning fog sticks around," said Rebecca Muessle, meteorologist for the National Weather Service in Portland.

While few would complain about borderline t-shirt weather in February, the larger issue has been an unusually long period of dry weather caused by a strong high pressure ridge sitting off the West Coast that is currently diverting all the wet storms to the north.

"Think of it as a giant boulder in the middle of a river," Muessle said. "The water hits the boulder and goes up and around it. Right now we're right behind that boulder and all the water is missing us, mostly going up to British Columbia and Alaska."

High pressure ridges are not uncommon during Oregon winters, but this year's has lasted an unusually long time — almost four weeks. It has dashed hopes for a major rebound from the years-long drought the state has faced.

After a major influx of snow and rain in late December and early January, the water has almost completely turned off, leaving a decent situation in the northern half of the state but only deepening the drought in the south, central and eastern parts of the state.

"In terms of rainfall and snowpack, northern Oregon looks pretty good — we'll probably be OK," Oregon state climatologist Larry O'Neill said. "But it's pretty bad almost everywhere else. The most concerning thing is that southern and eastern Oregon, who now have multiple years of historically dry weather, are seeing even more."

The situation is particularly unfortunate in places like the Klamath Basin, which still sits under extreme drought and badly needs a good water year.

"Seven counties in Oregon had their lowest precipitation on record last year. Another five had top 5 lowest rainfall totals. And now, in the wettest time of the year, it's turning out to be very dry," O'Neill said.

Long-lasting high-pressure systems have been a plague for Oregon in recent years, fueling some of the state's worst droughts and setting the stage for drier and hotter summers by sapping the soil of its moisture and limiting snow in the mountains.

O'Neill said he suspects climate change plays a role in what "feels" like more frequent and longer-lasting high-pressure ridges, but there isn't any specific research pointing toward it at this time.

"These ridges are a big deal but right now the research is inconclusive," he said. "It does seem as though it has happened more often over the past 5 to 10 years but nobody has the numbers to say specifically that it's one way or the other."

The good news is that Oregon will still have the chance for more rain and snow throughout late February, March and April.

"There is a chance for some precipitation this coming Monday and Tuesday," NWS hydrologist Andy Bryant said. "But there's no sign of a complete pattern shift that would start letting in a lot of storms."

Long-term, O'Neill said, the weather appears to be a roll of the dice over whether Oregon will see significant precipitation, but after such a dry few weeks, it has suddenly become a more urgent issue.

"If we have another dry spring — on top of this dry stretch of winter — that just doesn't bode well for the summer," he said.

Zach Urness has been an outdoors reporter in Oregon for 15 years and is host of the Explore Oregon Podcast. To support his work, subscribe to the Statesman Journal.

Urness is the author of “Best Hikes with Kids: Oregon” and “Hiking Southern Oregon.” He can be reached at zurness@StatesmanJournal.com or (503) 399-6801. Find him on Twitter at @ZachsORoutdoors.

This article originally appeared on Salem Statesman Journal: Oregon temps approach record warmth as dry weather stays locked in