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Climate Outlook What's Next for the Pacific Northwest? La Niña or not? Since mid-February, the cold sea-surface temperature (SST) anomalies in the Equatorial Pacific have been decreasing in magnitude. The 3-month average SST anomaly in the Niño 3.4 region for February-March-April was -1.1°C and currently as of this week (May 5) is 0.6°C below average, a weak La Niña. The majority of current model forecasts indicate the continuation of a weak La Niņa through Spring and early summer. Thereafter, the models remain somewhat split between a weak La Niña and neutral ENSO conditions through the second half of the year. What does this mean for Washington in the coming months? The Climate Prediction Center's outlook through the month of May, suggests an increased probability of below normal temperatures and below normal precipitation for Washington. The outlook for early summer, May-June-July, continues to suggest temperatures will likely remain below normal for western Washington with equal chances of above, normal, or below temperatures for eastern Washington. For the same period, odds are precipitation will remain below normal for the entire state. U.S. Temperature and Precipitation Impacts based on historical La Niña episodes Another factor is the Pacific Decadal Oscillation, which has been negative since September 2007 and is expected to remain negative through 2008 (PDO index value). Last Updated: 5/6/2008 Climate Prediction Resources NWS Local 3-Month Temperature Outlook 
The links below provide access to global and regional climate predictions.
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