The El Niño brewing in the Pacific Ocean has yet to exert much influence on the climate, but odds remain high that winter will be warmer than normal in Washington, Oregon, Idaho and California, the National Oceanic and Atmospheric Administration reported Nov. 15.
For the entire U.S., the odds of a warm winter are highest in the Alaska Panhandle and Northwest, according to NOAA’s Climate Prediction Center
The chances are 50 to 60 percent that the four states will have a warm December through February. The odds of temperatures averaging below normal over the three-month period are 6 to 16 percent.
The odds slightly favor a wetter-than-normal winter for most of California and the eastern half of Idaho. The climate center sees no factor strongly influencing precipitation — wet or dry — for Washington, Oregon, western Idaho and the northern tip of California.
Sea-surface temperatures along the equator were 0.5 to 1 degree Celsius above normal in the past week, according to the center. The temperatures are in the range of a weak to borderline moderate El Niño, but the ocean conditions are still considered neutral, neither warm nor cool.
Warmer temperatures must persist to qualify as an El Niño. “The atmospheric conditions associated with a developing El Niño event remain modest at best,” according to NOAA’s written discussion on the three-month outlook.
The sea-surface temperature in the central Pacific is expected to peak in January at about 1 degree Celsius above normal, the threshold for a moderate El Niño. NOAA anticipated the ocean will slowly cool back to neutral conditions over the rest of the winter and spring.
In El Niño winters, temperatures typically are a few degrees warmer than normal. Less snow accumulates in the mountains to melt in the spring for irrigation.