This article was published on: 02/16/18 12:00 AM
While much of the Columbia River basin states had above-average precipitation in January, Oregon and southern Idaho were “abnormally dry” for the month, and those conditions are expected to continue in Oregon through May, according to the NOAA Climate Prediction Center.
“It was a dry month for many locations” across the country,” said NOAA Climate Scientist Jake Crouch during a monthly briefing Thursday. Temperatures across the Columbia River basin were above average during the month.
“Temperatures were really warm in the west, particularly from the West Coast to the Rockies,” Crouch added, in contrast to cooler-than-average weather that prevailed across much of the eastern U.S.
Crouch noted that about 36 percent of the contiguous states are in drought, and the U.S. Drought Monitor is projecting that nearly all of the Oregon will be “abnormally dry” over the next three months, with “likely” drought development over most of the state east of the Cascades.
By contrast, the northern tier of Washington, Idaho and Northwest Montana had above-average precipitation in January. The March forecast calls for cooler weather over the basin states, and above-average precipitation in the Rockies of Idaho and Montana.
“We expect the current La Nina conditions to decrease rapidly to “neutral” conditions that are expected to persist through the summer,” said Dan Collins, a seasonal forecaster with the Climate Prediction Center.
La Nina is driven by cooler sea-surface temperatures in the eastern equatorial Pacific Ocean that currently persist.
La Nina generally translates to cooler and wetter weather for the Pacific Northwest, but those conditions can take shape differently in more localized areas.
Last winter’s La Nina weather pattern, for instance, generated above-average precipitation in Oregon with below-average precipitation in the Northern Rockies, but the La Nina influence had the opposite effect this winter on those two parts of the Columbia Basin states.
The three-month outlook shows a sharp contrast between cool and wet conditions across most of the northern half of the U.S. and well above normal temperatures and dry conditions in the southern half of the country, particularly the Southwest.