NWS Hydrology Mission:
- Provide river and flood forecasts and warnings for the protection of
lives and property.
- Provide basic hydrologic forecast
information for the nation’s environmental and economic well
River Forecast Center Functions:
- Continuous hydrometeorological data assimilation, river basin modeling, and
Technical support and interaction with supported and supporting NWS
Technical support and interaction with outside water management agencies
research, development, and technological implementation to facilitate
and support the above
Water Supply Forecasts
Historical Synopsis of Climate In
Water Resources Forecasting
(credit: Dave Brandon)
1917–Church,J.E. The first documented application to
forecasting using correlation of snowpack to water level in
1943-USWB. Created bi-monthly 30-day weather Internal outlooks,
and went public in 1953.
1947-USWB/SCS. Started publishing seasonal water supply
1955-CBIAC Report. Evaluated use of 30-day outlooks in
forecasting Columbia Streamflow…potential could be great but
there was little/no skill.
1958-USWB. Created seasonal 90-day internal outlooks and went
public in 1974 (temp) and 1978 (precip).
1964-CBIAC. Follow-up Report Forecast skill improving but hard
to apply broad forecasts to specific basins.
1974-NWS. Seasonal 90-day temperature forecasts release to the
public followed by precipitation forecasts in 1978.
1976-Marron(NRCS). Began using SOI in forecasts for Lake Tahoe
1977-Schaake, J. (NWS). Used 30-day precipitation outlook to
remove a series of anti-analogs in ESP.
1987-Croley/Hartmann. Used climate outlooks subjectively to
alter ESP traces in forecasting Great Lake Levels.
1995-Rundquist, L. Developed ESP post weighting scheme.
1988-Perkins, T.(NRCS). Began using SOI as predictor in lower
1989-Cayan/Peterson. Investigated El Nino and western
1994-Hartman, (NWS) Investigated using SOIs at CBRFC
1995-CPC. Begins issuing new climate format, with tercile
probability anomalies for 13 overlapping months.
1997-Mantua et al. Development of PDO
1997/1998-El Nino spurred variety of research
1998-Brandon, D. (NWS). Began using SOIs in preliminary
Outlooks issued in the fall.
2000-Perica, S. (NWS). Developed CPC pre-adjustment technique
to be used in NWSRFC ESP.
Increased skill in medium to long range precipitation forecasts
- Castuccio et al (1981) estimated that a 6 percent improvement
in forecasting accuracy would produce $36.5 million in annual
benefits to agriculture and hydropower in the west
New methods for incorporating climate forecasts
- Must be based on data that is available when forecasts are made
New methods for incorporating and assimilating data into hydrologic forecasts.
Improving forecast verification to validate impact of climate forecasts
Expanding and improving use of water supply forecasts (including ensemble based decision support systems)
Longer term forecasts
(e.g. 2 year and beyond) – RFCs are increasingly being asked to
produce water supply outlooks for 2 years, sometimes even
Data – High quality,
long duration, high frequency records of precipitation,
streamflow, and temperature are necessary for calibration and
A (partially) Successful Collaboration
partnership to improve medium range forecasts
Incorporated probabilistic meteorological model output into ESP
Documented improvements in medium range streamflow forecasts (Werner et al, 2005)
Implemented in CBRFC operations
No direct national
implementation although concepts have helped drive national
Elements of Successful Collaboration:
Focus on mutually
- Directly address operational requirement(s).
- Also address relevant research question(s).
Early and active NWS
involvement: Must include both RFC or WFO and OHD as active
must be possible in real-time NWS forecasting environment.