What's Next for the Pacific Northwest?
El Niño Conditions
El Niño conditions are still present in the tropical Pacific Ocean, though a transition to neutral conditions is expected by summer 2016. Averaged over the last four weeks, sea-surface temperature (SST) anomalies are above normal throughout the equatorial Pacific, but have weakened. At the time of this writing, the weekly SST anomalies are about 1 degree Celsius above normal in western and central tropical Pacific. The "El Niño Advisory" that was released on March 5, 2015 is still in effect. Model consensus is high that the El Niño will persist through the spring, with chances above 90%. By summer (May-July), models favor neutral conditions (55% chance), but there are already indications that a La Niña will develop in the fall. In fact, a "La Niña Watch" has also been issued, as La Niña conditions may develop in the next six months.
What does this mean for Washington in the coming months?
The CPC three-class May-June-July (MJJ) temperature outlook has increased chances of above normal temperatures for the entire state, with chances exceeding 50% on the three-tiered scale. There is not much indication of how precipitation will turn out for May-July. The CPC outlook has equal chances of below, equal to, or above normal precipitation for the entire state.
The outlook for summer (June-July-August; JJA) is very similar: there are increased chances of above normal temperatures statewide (and for the entire country, for that matter). Like May-July, the precipitation outlook for JJA has equal chances of below, equal to, or above normal precipitation. In other words, the precipitation outlook is split into equal probabilities that below, equal to, or above normal precipitation will occur.
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: 4/21/2016
Climate Prediction Resources
NWS Local 3-Month Temperature Outlook
The links below provide access to global and regional climate predictions.