Oregon and Washington’s flash droughts are receding, and La Nina is shaping up in the Pacific Ocean, causing long-range forecasts for the Northwest to turn wetter and cooler, federal climatologists reported Thursday.
Some 64 percent of Washington is in a drought, down from 78 percent the week before, according to the U.S. Drought Monitor. Oregon’s drought retreated to 28 percent of the state, down from 43 percent.
An abrupt change in weather patterns stemmed droughts that had been spreading over both states in September. For example, Spokane, which remains in a “moderate drought,” went a record-setting 80 days without rain. The streak ended Sept. 17, with nearly an inch of rain falling over three days.
Looking ahead, the National Oceanic and Atmospheric Administration’s Climate Prediction Center issued a new seasonal forecast that puts the chances of a La Nina taking shape between November and January at 62 percent, up from 26 percent a month ago.
La Nina, a cooling of sea-surface temperatures, tilts the odds toward wetter and colder winters in the northern U.S., and drier and warmer winters in the southern U.S.
The odds still favor a warmer than usual fall and early winter in Oregon, Washington, Idaho and Northern California, but not as strongly as a month ago, according to the Climate Prediction Center.
A large reservoir of unusually cold water on the equator off the coast of South America contributed to the reassessment that La Nina conditions likely will emerge.
Washington received more snow than usual last winter during a weak La Nina, building up a snowpack that helped farmers get through a summer notable for record heat and dry spells, but not water shortages.
Here is a state-by-state look at drought conditions and the October through December forecast:
• Oregon: The northern half of Eastern Oregon remains in a “moderate drought.” Storms washed the drought away from northwest Oregon. Odds favor slightly above-average precipitation for the next three months, except in the southwest corner of the state, where precipitation is expected to be normal.
Washington: Rain rolled back drought conditions in southwest Washington and part of the Olympic Peninsula. Precipitation is forecast to be above-average, except in northwest Washington, where chances are equal for above- or below-average rainfall.
• Idaho: Drought conditions were unchanged, with 23 percent of the state in moderate or severe drought. Odds favor above-average precipitation throughout Idaho.
• California: Drought conditions also were unchanged in California, where 8 percent of Southern California is still in moderate drought. Northern California has equal chances for above- or below-average precipitation.