OREGON STATE UNIVERSITY

OSU researcher predicts end to dry weather

02/08/2001

CORVALLIS - Studying data in his Oregon State University lab, state climatologist George Taylor ventures to predict a wet spring for the Pacific Northwest.

That's good news for a region that has been woefully short on rainfall this winter.

Since November, successive high pressure ridges have stood guard over the region, sending wet Pacific storms northward into Alaska and Canada and leaving much of the Northwest dry.

"What seems to happen with these winters with a ridge of high pressure is that sooner or later the jet stream breaks through and opens the door to those Pacific storms. The chances are good that we will have a normal or wetter than normal spring," said Taylor, who is a faculty member with OSU's College of Oceanic and Atmospheric Sciences.

"Even getting a normal spring would help out quite a bit." The region normally gets about one-third of it's annual total of rain between February and the end of June, he said.

Taylor is making his prediction based on historical patterns and cautions that while history often repeats itself, there is a chance that spring rains could bypass the region, leaving the state in a moderate drought. "Right now, we're drier than normal or pre-drought," he said.

For example, from October through January, Klamath Falls has received only 31 percent of normal rainfall. The picture isn't much brighter in other regions: Medford has 46 percent of normal; Grants Pass 36 percent; the Portland Airport, 55 percent; Salem 48 percent and Roseburg 52 percent. But some regions in the eastern half of the state are actually at or above normal for the period. Pendleton's rate of precipitation is at 100 percent; Enterprise and Joseph are both at 109; and portions of Malheur County are touching 120 percent.

"So far, February looks promising," Taylor said, "with the snow pack in the Central Cascades jumping from 65 percent of normal to 69 percent, and indications that storms will continue to bring rain and snow to the area.

"If those conditions continue," he added, "our summer water situation will be much better."

The dry Pacific Northwest winter caught forecasters across the country by surprise, Taylor said. "No one predicted this dry winter. It was really wet in October." Rainfall dropped below normal in November, but "it really looked as if it would break in December."

The region's last sustained drought was 1985 to 1994 when nine out of 10 years were drier than normal. That period included severe statewide droughts in 1992 and 1994.