The National Oceanic and Atmospheric Administration is calling for a warm, dry winter this year—but add that this year’s outlook is less certain than in the past.
Forecasters with NOAA’s Climate Prediction Center said in a press release this week that El Niño, the weather pattern expected to dominate this year’s winter weather, simply failed to appear.
El Niño is a weather pattern in which warmer ocean water in the equatorial Pacific shifts patterns of tropical rainfall, in turn affecting the jetstream and storms over the Pacific Ocean and the U.S.
That pattern was expected to have developed by now, said Mike Halpert, deputy director of the Climate Prediction Center.
“This is one of the most challenging outlooks we’ve produced in recent years, because El Niño decided not to show up as expected,” he said. “In fact, it stalled out last month, leaving neutral conditions in place.”
However, the center is still planning on an El Niño year, Halper said, because there is still a window for it to emerge.
National Weather Service meteorologist Greg Kaiser with the service’s branch in Pocatello said that residents of the region should count on an El Niño year—but predicting the weather this far in advance is not always accurate.
“That far out, it’s hard to be completely accurate,” he said. “Historically, when we have an El Niño pattern, that’s what the trend is—warmer and drier.”
The last strong El Niño pattern was in 2009-10, Kaiser said.
According to the Natural Resources Conservation Service archives, a snowpack and precipitation summary for Christmas week 2009 showed that the Big Wood River basin snow water equivalent was at 52 to 69 percent of average.
The region was also warmer than normal, up 3 to 6 degrees.
By March 25, 2010, snow water equivalents were still at 58 to 62 percent of normal, with temperatures at about average for Blaine County. Precipitation for the Wood River Valley was at 66 to 70 percent of normal between Oct. 1, 2009, and March 25, 2010.
Kaiser said that even when weather patterns show up—unlike the currently undeveloped El Niño—their effects can be hard to predict. For example, he pointed out that last year was the second year in a La Niña pattern, which usually means cold, wet weather.
“That didn’t pan out,” he said.
Last year’s data as of March 22 showed year-to-date precipitation for the Wood River Valley as normal. Storms in January boosted snowpacks to 81 percent of normal in early February, nearly causing skiers to forget about the dry December.
As of Dec. 18, 2011, it had been one month without significant snowfall, causing many to worry about the prospect of a white Christmas. A similar dry spell occurred in January and early February of 2011—also a La Niña year.
NOAA’s winter outlook also stated that areas ravaged by drought last year were not likely to see relief this year.
As for this year’s Oct. 22 snowfall, Kaiser said last weekend is likely not the last time this season that Wood River Valley residents will see grass.
“We’re still going to have some pretty good warm-ups through late October and early November,” he said. “It’s not the complete onset of the winter season.”
Kate Wutz: firstname.lastname@example.org