The National Oceanic and Atmospheric Administration’s updated forecast for precipitation and temperatures in the winter months of 2019 may portend bad news for skiers and snowboarders in central Idaho.
NOAA issued its most recent forecast last week, and it predicts a strong chance of above-normal temperatures in the Pacific Northwest in January, February and March, and lower-than-normal precipitation. The strongest chances are in western Washington and western Oregon, but elevated chances extend into central Idaho as well.
The forecasts are probabilistic and do not preclude the possibility of large storms moving through the northern Rocky Mountains and dropping a significant amount of snow.
NOAA estimated that El Niño has a 90 percent chance of forming in the Pacific Ocean this winter, and has a 60 percent chance of remaining in the spring. El Niño refers to “a warming of the ocean surface, or above-average sea surface temperatures in the central and eastern tropical Pacific Ocean,” according to NOAA.
This winter’s El Niño is likely to be a mild or moderate one; sea surface temperatures in the Pacific Ocean have been above average for the past several weeks, according to NOAA.
El Niño is a significant influence on the jet stream, which directs the track of precipitation-laden storms over the American West. The historic pattern is for areas of Southern California and the Southwest to receive above-average precipitation during El Niño winters, while the Pacific Northwest is drier than normal.
The snowpack in the Big Wood River basin has been below normal to start the winter. On Dec. 22, its snow-water equivalent was 69 percent of the 1981-2010 median, though that was an increase from the week prior, thanks to two snowstorms that blew through last week.
Drought has gripped Oregon and parts of Idaho and Washington in 2018. The U.S. Drought Monitor reported that 98 percent of Oregon was experiencing some classification of drought, from moderate, severe or extreme. In Washington, 33 percent of the state was experiencing drought, while about 35 percent of Idaho was experiencing drought.
Locally, 59 percent of Blaine County was considered “abnormally dry” on Dec. 18, but no portion was experiencing drought. That’s an improvement from mid-October, when 100 percent of the county was considered abnormally dry.
Looking at global temperatures, November was tied for the fifth-warmest on record with 2004 and 2016, said Deke Arndt, chief of the monitoring branch for the National Centers for Environmental Information, on a conference call with journalists last week.
“This was largely driven by warm oceans,” Arndt said. “We’ve completed 11 laps of a 12-lap race. It is virtually certain that 2018 will go down as our fourth-warmest year. It was quite dry in the Pacific Northwest where drought intensified.”