Weak La Nina may help ease drought
Federal climatologists predict that dry conditions will generally recede over the winter in Oregon, Idaho, Washington and parts of Northern California, providing an early and upbeat outlook on next year’s water supply.
The Climate Prediction Center forecast a 70 percent chance of a weak La Nina, a cooling of the ocean around the equator.
La Nina generally tilts the odds in favor of wetter and cooler winters in the northern U.S., according to the center.
It’s not a sure bet, though. La Nina’s influence will vary by region. The odds it stays through the winter are 55 percent.
Washington State Climatologist Nick Bond said he expects the La Nina to be too feeble to dictate the weather.
Higher ocean temperatures in the northeast Pacific Ocean and a trend toward warmer winters also may influence the weather, he said.
Still, even a normal winter would seem cold after the past several years, Bond said.
“There’s no indication that we’ll have a snowpack like the disaster we had two years ago,” he said. “There’s no reason to be pessimistic about next summer’s water supply.”
Idaho State Climatologist Russell Qualls also said La Nina’s influence may be blunted by unusually high inland temperatures. Still, most of the state is expected to have above-average precipitation, and snow may accumulate at high elevations, he said.
“The signals are a bit confusing in terms of the water supply outlook,” he said. “From what it looks like, the drought at least is likely not going to be getting any worse.”
The center issued the forecast for November, December and January.
It also projected that drought conditions likely will be erased by the end of January in Oregon and parts Northern California. About one-third of Oregon is in drought, while 81 percent of California remains in drought.
A year ago, 100 percent of Washington was classified as being in a drought. Now only 8 percent of the state is even “abnormally dry.”
In Idaho, 19 percent of the state is abnormally dry and 1 percent is in drought.
Bond, the Washington climatologist, said that even without a strong La Nina or El Nino, the state could have an eventful winter. He said current climatic conditions resemble the months before massive flooding in February 1996. “I’d be surprised if we didn’t have some major flooding,” he said.
The seasonal outlook rates the chances that an area will have above-average or below-average precipitation and temperatures.
Here’s a state-by-state look at the seasonal outlook:
• Washington: The odds favor above-average precipitation in most of the state, though the chances are no better than even in the South Cascades, south Puget Sound, and southwestern and south-central Washington. The chances are even that temperatures will be above or below normal for most of the state. The odds favor above-average temperatures in southeastern Washington.
• Idaho: Southwest Idaho has equal chances for above- or below-average precipitation. The odds favor a wet winter elsewhere. The north end of the panhandle has equal chances of above- or below-normal temperatures. In the rest of the state, the odds favor a warm winter.
• Oregon: Equal chances of above- or below-average precipitation. Odds favor above-average temperatures.
• California: Chances for above- or below-average precipitation are equal in most of the state. Precipitation could change the status of parts of Northern California that are now in moderate drought. Odds favor a dry winter in the southern tip. The odds favor above-average temperatures throughout California. The drought could worsen in Southern California, according to the climate center.