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

Forecast Archive

Forecasts shown here were produced in real time in June preceeding the water year since 1998. Observed streamflow was added (red dashed line) after the fact to produce these figures. Note that different hydrologic model versions were used to produce forecasts in different years.

To display a retrospective forecast click on the links below, which are identified by water year. Red line in the 2002 forecast is simply the long term simulated mean, not the actual observed streamflow.

1998 1999 2000 2001 2002 2003 2004

Archive of Retrospective Forecasts

Forecasts shown here were produced retrospectively using the latest 1/4 degree hydrologic model and are based on driving data for the hydrology model from 1950-2000. There is no overlap of the driving data and the forecast for each year. The forecasts assume perfect foreknowledge of the ENSO state (and soil moisture in September preceding the water year) based on the observed December-February Nino3.4 index (+-0.5 standard deviations from the mean). The PDO state is assumed to persist from the previous year unless an April-September average streamflow event greater than or less than 1.5 standard deviations from the long-term mean in opposition to the dominant phase of the PDO occurs, in which case the phase of the PDO is assumed to change. In the retrospective forecasts below, the PDO is assumed to shift from warm phase following the high flow event in water year 1997. Water year 1997 is assumed to be warm phase PDO, since this is the information available in June of 1996. Note that the forecast ensembles contain different numbers of ensemble members for different climate categories since these climate states have different frequencies in the period from 1950-2000.

The figures are keyed as follows:

  • grey lines: forecast ensemble members
  • black lines: maximimum and minimum simulated streamflows
  • blue lines: observed naturalized streamflow
  • red lines: simulated observed streamflow.
  • Units are cfs.

Note that errors in the PDO forecast are reproduced in these forecasts.

For more information on the retrospective forecasts see: Retrospective Forecast Poster

1951 1952 1953 1954 1955 1956 1957 1958 1959

1960 1961 1962 1963 1964 1965 1966 1967 1968 1969

1970 1971 1972 1973 1974 1975 1976 1977 1978 1979

1980 1981 1982 1983 1984 1985 1986 1987 1988 1989

1990 1991 1992 1993 1994 1995 1996 1997 1998 1999