What's Next for the Pacific Northwest?
Neutral ENSO Conditions
Neutral El Niño-Southern Oscillation (ENSO) conditions are still present in the equatorial Pacific Ocean, but the Climate Prediction Center issued "El Niño" Watch is still in effect. ENSO forecast models favor weak El Niño conditions for the upcoming winter. Over the last 4 weeks, sea-surface temperatures (SSTs) have warmed across the equatorial Pacific. Probabilities of El Niño development are at 70% for both the November through January and December through February periods.
What does this mean for Washington in the coming months?
The expectation of El Niño development is evident in the seasonal forecasts from the Climate Prediction Center (CPC). The CPC November temperature outlook has higher chances of above normal temperatures for all of WA. The November precipitation forecast indicates increased chances of below normal precipitation for the entire state, with higher chances of below normal precipitation in eastern WA.
The CPC November-December-January (NDJ) outlook has increased chances of above normal temperatures statewide, with chances exceeding 50% on the three-tier system. For precipitation, there are increased chances of below normal precipitation mainly east of the Cascade crest. The rest of WA (western WA and the north central Cascades) has equal chances of below, equal to, or above normal precipitation.
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: 10/18/2018
Climate Prediction Resources
NWS Local 3-Month Temperature Outlook
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