One year lead-time experimental streamflow forecasts for the Columbia River at The Dalles

What's New with Streamflow Forecasting?

1. Historical temperature and precipiation data are now available from 1915-2003. Having more data increases the sample size of ENSO based streamflow forecasts. For example, 27 warm ENSO events occurred between 1916-2003 as opposed to 18 warm ENSO events between 1950 and 2003. The new data set also includes a number of very dry years in the 1930s and 1940s that enhance the understanding of drought risks.



2. Streamflow forecasts are now bias corrected. This allows a direct comparison with observed naturalized streamflow values.



3. New methods have been developed to predict the year to year value of the PDO index with long lead times, creating a more objective forecast based on the relationship to the PDO index. The forecasts are now composited according to the interannual value of the PDO index as warm, neutral, or cool PDO. The longer temperature and precipitation record also provides more realizations in each of these categories, which improves estimates of uncertainty.



4. The UW experimental West-Wide streamflow forecasting system has been operating on a quasi operational basis through water year 2004 with forecast updates once a month. Review the forecast performance for 2004 at: UW West Wide Streamflow Forecasts



5. Temperature adjusted data sets for forecasting purposes are being produced and should be available by mid winter.

August 25, 2004