Newsroom

CORVALLIS - The recent pattern of comparatively warm fall and winter seasons will likely continue in Oregon this year, though the precipitation levels may be higher than average, according to Oregon State University atmospheric scientist George Taylor, who serves as the state climatologist.

That should be good news for Oregonians worried about late-season wildfires and drought conditions next summer.

However, it may not be a serene winter, Taylor cautions. Based on comparisons with previous "analog" years - which had similar ocean and atmospheric conditions leading into the fall - Oregon could see at least one severe weather event, most likely a wind storm or flood.

"It's hard to compare one year to another, but there are certain patterns in climate cycles, ocean currents, sea level pressure, water temperature, and other factors that give us a pretty good indication of what may happen," Taylor said. "And in those analog years - like 1964, 1995 and a few others - there was at least one severe weather event."

In fact, the fall and winter of 1964 and 1995 had two such events each year, Taylor pointed out. In December of 1964, the state experienced major flooding and shortly thereafter, in February, Oregonians were rocked by a major wind storm. Thirty-one years later, the situation was reversed. A strong wind storm hit the state in December of 1995, followed by a major flood in February.

In one analog year, 1988, the severe weather was a prolonged cold snap which paralyzed the state in February of 1989.

"The severe event is more likely to be a flood or wind storm, but cold temperatures, a blizzard, or an ice storm aren't out of the question, either," he said. Taylor issued his annual fall and winter forecast for the state on Thursday from his office, the Oregon Climate Service, on the OSU campus. The entire forecast - and other weather and climate information and links - is posted on the OCS website at: http://www.ocs.oregonstate.edu/.

Taylor said Oregonians can generally expect above-average temperatures in the first half of the season - from October through December - with normal or somewhat above-normal precipitation. The same pattern should fit east or west of the Cascades.

From January through March temperatures should be about average throughout the state, though the precipitation could be well above-average west of the Cascades, and may be somewhat higher than average in central and eastern Oregon.

That could lead to a late winter, early spring flood, he cautioned.

One of the factors Taylor looks at in making his forecasts involves the tropical Pacific - El Nino or La Nina conditions. The National Oceanic and Atmospheric Administration's Climate Prediction Center and other experts monitor such patterns and frequently disagree about the interpretation of equatorial conditions.

"One model suggests a weak El Nino will develop, while another says a La Nina is more likely," Taylor said with a laugh. "And there are other climatologists who say neither is prevalent. But most of the scientists agree that there will be no sweeping changes in the conditions this year, so this is a 'La Nada' year.

"Typical Oregon conditions during what looks to be a weak La Nina winter are slightly wetter than normal with near-normal temperatures," Taylor added, "and that matches pretty closely with other indicators."

Taylor said fall may arrive earlier this year. In Oregon, October historically is the biggest transition month of the year, beginning mild and dry, then ending cool and wet. That transition, often abrupt, may start a few weeks early this year - even by late September or early October. Last year's prediction was a qualified success, Taylor said. The first half began warm, as predicted, but the October transition brought record cold late in the month and into early November. Taylor's precipitation pattern was on the mark, with a wet second half that lasted through spring, but his call on cool January-March temperatures missed the mark, he admitted. It was surprisingly mild.

"Every year, our diagnostic ability and the amount of data we analyze increases greatly," Taylor said, "but we still have a ways to go. It could be that there was an analog year almost exactly like the one we will see, but it took place several hundred years ago - and we just don't know about it.

"Mother Nature is fickle," he added. "That's what makes this such a challenge."