SALEM – Forecasters predict that there is a chance that La Nina will form next fall, a climate phenomenon associated with large blankets of snow and good irrigation times in most of the northwest basins.
The National Oceanic and Atmospheric Administration released a La Nina watch on Thursday, indicating that conditions are ripe for development over the next six months.
According to forecasters from NOAA’s Climate Prediction Center and Columbia University’s Climate Research Center, A La Nina has a 66% chance of prevailing in November, December, and January.
The prediction contradicts most climate models. On average, 25 forecast models only predict a 34 percent chance of a La Nina next winter.
However, forecasters use their human judgment. Last winter, a La Nina ruled and historically one La Nina has followed the other, according to a statement by NOAA.
The La Nina watch is also supported by a group of climate models developed in the United States and Canada.
“I trust the people who know about the models,” said Nick Bond, Washington State climate researcher.
La Nina Generally Brings Cool and Humid Winters to the Northern Region of the US La Nina winters are generally warm and dry in the southern region of the US
“We like La Ninas up here for the snow,” said Bond. “When there are La Ninas in a row, the second is usually weaker than the first.”
Washington’s snowpack was 131% of the average on April 1 after a weak to moderate La Nina, according to the Natural Resources Conservation Service. Melting snow has helped the irrigation systems survive an exceptionally dry spring and early summer.
In Oregon, snow cover was up to 152% of normal in the northern basins, but only 77% of normal in the southern basins. Snowpacks in northern California were generally lower than in southern Oregon.
There have been two consecutive La Nina winters since 2010/11. Every year, Washington snowpack on April 1 was at least 113% of the average.
Sea surface temperatures, measured along the equator in the Central Pacific, are expected to remain normal throughout the summer.
If the models are correct, unaffected by human judgments, the ocean is likely to remain neutral through the winter, which robs the predictions of their best indication of seasonal prospects.
The models and forecasters see a small chance of an El Nino, combined with low snow cover in the northwest.
“The chances of getting an El Nino are slim, so at least we won’t have that,” said Bond.