Seasonal to Interannual Forecasts
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The Climate Impacts Group (CIG) translates global-scale climate forecasts and conditions into regional-scale climate forecasts for Pacific Northwest (PNW) resource managers and the general public. The El Niño/Southern Oscillation (ENSO) is the most important factor for seasonal forecasting, changing the odds for different types of winter and spring weather (e.g. warmer/drier, cooler/wetter) in the PNW. Another important climate variable for Pacific Northwest climate is the Pacific Decadal Oscillation (PDO). The climate outlook also provides the basis for natural resource forecasts, including the CIG's annual streamflow forecasts.
What's Next for the Pacific Northwest?
Updated January 10, 2006 (interim update: 2.2.06)
The climate outlook is reviewed monthly and updated as needed.
Current indicators for Pacific climate:
El Niño/Southern Oscillation (ENSO). Cooler than average ocean temperatures in the tropical Pacific, along with stronger than average easterly trade winds, persistently wet conditions over southeast Asia, and dry weather over the central equatorial Pacific, all indicate a continuation of weak La Niña-like conditions. However, based on NOAA's criteria for ENSO events, recent measures reflect ENSO-neutral conditions that are very near the La Niña threshold. Most forecast models suggest that tropical climate will continue to have ENSO-neutral to weak La Niña characteristics for the rest of winter and spring.
Interim update: NOAA announced the official return of La Niña in the tropical Pacific on February 2, 2006. The development of a La Niña increases the odds for continued above normal precipitation in the Pacific Northwest. The development has also led to modification of the NOAA Climate Prediction Center's seasonal outlook for temperature. Previous CPC outlooks called for slightly above average winter temperatures, reflecting a +10 year trend in above average temperatures for the region. The current 90 day (Feb-Mar-April) outlook now calls for near-average temperatures.
A full update to the monthly climate outlook for the PNW will be posted on or around February 10. For more information on the La Niña announcement, see the NOAA press release.
Pacific Decadal Oscillation (PDO). North Pacific sea surface temperature (SST) anomalies trended towards the negative PDO pattern in September, October, and November, but changed to a near-neutral PDO state in December. These relatively large changes in North Pacific SSTs were directly related to a persistently positive Pacific North America pattern of atmospheric circulation in the month of December (view the PNA index). Given the state of the tropics and the expected continuation of ENSO-neutral to weak La Niña characteristics, it is likely that the PDO will remain neutral or slightly negative for winter and spring 2006 (see note on PDO forecasting).
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What will it mean for the PNW in coming months?
The wet weather pattern for the PNW that began in mid-December is predicted to persist for at least the next week, and if it does it may threaten the record of 33 consecutive days of precipitation in Seattle that was set in 1953 - stay tuned! For the next two seasons, NOAA's Climate Prediction Center forecasts climatological odds for precipitation (meaning the chance for below average, near average, or above average precipitation is 33.3% for each category) and a slight tilt in favor of warmer than average winter, spring, and summer temperatures for most of the PNW region.
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Pacific Northwest Resource Outlooks
- Water Resources Forecasts (streamflow and other hydrologic conditions)
- Salmon survival forecast
- Forecast of extreme weather events
Climate Prediction Resources
The links below provide access to the latest information on the current state of global and regional climate, as well as links to global and regional climate predictions.
The Current State of the Tropical Pacific
- Real-time data from moored ocean buoys (from NOAA’s TAO array)
- ENSO diagnostic discussion (from NOAA’s Climate Prediction Center)
- Weekly ENSO update (from NOAA’s Climate Prediction Center)
- ENSO Quick Look (from the International Research Institute for Climate Prediction)
- Monitoring El Niño/La Niña (from NOAA’s Climate Prediction Center)
Predictions of Tropical Pacific Conditions
- Seasonal Niño3 sea surface temperature anomaly plume forecasts (from the European Center for Medium-Range Weather Forecasts)
- ENSO forecast forum (from NOAA’s Climate Prediction Center)
- Statistical Probabilistic ENSO Predictions (from the International Research Institute for Climate Prediction)
- Sea surface temperature forecasts (from the International Research Institute for Climate Prediction)
The Current State of the Globe
- Climate diagnostics bulletin (from NOAA’s Climate Prediction Center)
- Monitoring climate in the Extratropics and Tropics (from NOAA’s Climate Prediction Center)
- The North Atlantic Oscillation (NAO) (from NOAA’s Climate Prediction Center)
- Monthly climate information digest (from the International Research Institute for Climate Prediction)
- Accumulated daily precipitation time series graphs (from NOAA’s Climate Prediction Center)
- Daily global and regional precipitation analysis (from NOAA’s Climate Prediction Center)
- Index of Climate Prediction Center’s climate monitoring activities and data
Current and Predicted U.S. Conditions
- Monthly to seasonal climate outlooks (from NOAA’s Climate Prediction Center)
- Northern Hemisphere snow report (updated monthly by NOAA/NCEP)
- Spring and summer streamflow forecasts (from the USDA Natural Resources Conservation Service)
- Drought in the US
- Water supply forecasts and snowpack conditions for the Western U.S.
- Experimental seasonal fire risk forecasts (from the U.S. Forest Service)
- Western U.S. climate conditions and forecasts (from the Western Regional Climate Center)
Pacific Northwest Conditions
- Western Washington water and snowpack (from Seattle City Light)
- Seattle water supply conditions and outlook (from Seattle Public Utilities)
- Coastal conditions (from NOAA’s CoastWatch)
- Data on PNW snowpack (from the Western Regional Climate Center)