A weak El Nino went away in July as sea-surface temperatures in the Pacific Ocean along the equator cooled to within a normal range, the National Oceanic and Atmospheric Administration reported Thursday.
NOAA's Climate Prediction Center estimated the chances of neutral conditions sticking through the winter at about 55%. An El Nino has a 30% percent chance of returning, while La Nina has a 15% chance of forming, according to the center.
Neutral conditions deprive climatologists of their primary clue to what the upcoming winter will be like. El Nino conditions tend to warm up the Northwest and lead to low snowpacks. La Nina conditions cool the region.
"For the winter ahead, there's just not a lot to go on," Washington State Climatologist Nick Bond said.
There is still a clue. Waters off the West Coast are warmer than average, which could tip the odds in favor of a mild winter, Bond said.
NOAA's report Thursday was the first this year that made neutral conditions the odds-on favorite to prevail through the winter.
An El Nino formed in February. Federal forecasters in the spring rated the chances of it staying throughout the year as good. The El Nino, however, never progressed from weak to moderate.
"It was never much of one," Bond said. "The weather patterns we got didn't resemble previous El Ninos."
Also Thursday, the U.S. Drought Monitor reported that 61% of Washington was in moderate or severe drought, unchanged from the week before.
Some 11% of Oregon and 5% of Idaho were in moderate drought, also unchanged from the prior week. California remained drought-free.