What's Next for the Pacific Northwest?
La Niña Conditions
La Niña is still alive and well in the tropical Pacific Ocean. Both the atmospheric and oceanic conditions over the last month have reflected La Niña, and the "La Niña Advisory" is still in effect from the Climate Prediction Center. ENSO forecast models do show a weakening of La Niña conditions during spring 2018 with the chances of La Niña persisting through the March-May (43%) period less than the chances of neutral conditions (54%).
What does this mean for Washington in the coming months?
The Climate Prediction Center (CPC) March temperature outlook shows increased chances of below normal temperatures for WA. The likelihood of below normal temperatures is relatively high for the state - with chances exceeding 50% on the three-tiered system (chances of above normal temperatures decrease to only 10% while chances of near-normal temperatures is 33%). On the other hand, there are equal chances of below, equal to, or above normal March precipitation (about a 33% chance of each of the three outcomes) for most of the state. The eastern-most area of the state has slightly elevated chances of above normal precipitation for March.
The CPC outlook for spring (March-April-May; MAM) is similar to the monthly March forecast. There are higher chances of below normal temperatures for the entire state, and the eastern third of the state has higher chances of above normal precipitation. The rest of the state has equal chances of below, equal to, or above normal precipitation for spring.
Remember that these outlook percentages are based on a tercile system, and therefore the chances of below, equal to, or above normal temperatures or precipitation are split into equal probabilities of 33%. When there is a greater than a 33% chance of an occurrence, it should be looked at as a slight tilting of the odds in favor of that outcome.
Last Updated: 2/15/2018
Climate Prediction Resources
NWS Local 3-Month Temperature Outlook
The links below provide access to global and regional climate predictions.