Seasonal Streamflow Forecast Assessments

Seasonal Streamflow Forecast Assessments
NWS, NRCS, UW, ...

Objectives
The NWS, NRCS and UW are performing a retrospective comparison of ensemble & statistical forecasts of seasonal streamflow using models and statistical methods developed separately in each organization. The primary goal of the comparison is to examine the influence of different approaches on the skill and accuracy of seasonal hydrologic predictions. A limited number of sites has been chosen for the initial comparison, but these may be expanded later. The range of forecasts methods may also be expanded, and other forecasting groups are invited to participate. The sites and a few comparison details are given below.

People Involved
Kevin Werner (NWS), Chad Kahler (NWS), Andy Wood (UW), Tom Pagano (NRCS), ...

Domain & Forecast Period

River              Stations                         ID              Forecast Period
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Feather River      Inflow to Lake Oroville          OROC1           April - July
Yakima River       Yakima near Parker               PARW1           April - September
Salmon             Salmon at Whitebird              WHBI1           April - July
Klamath            Inflow to Klamath Lake           KLAO3           March - September
Gunnison           Blue Mesa / Grand Junction       BMDC2 / GJNC2   April - July
Snake River        Jackson Lake Inflow (WY)         JLKW4           April - September
Owyhee River       Owyhee Reservoir Inflow (OR)     OWYO3           March - July
Blackfoot River    near Bonner (MT)                 BONM8           April - September
Salt River         near Roosevelt (AZ)                              April - July
American River     Inflow to Folsom Reservoir                       April - July
Weber River        near Oakley (UT)                                 April - July
Green River        Inflow to Fontanelle Res. (WY)                   April - July

Forecast Start dates:
first of month from Jan 1 - June 1

Forecast met ensemble traces: 1975-2004

Evaluation period: 1995-2005

Performance metrics:
MAE, RMSE, CRPS, and skill scores based on each

Data & Results
Various datasets are available in the table below:

Site	Dr. Area	Obs Data	NWS Fcst	NRCS Fcst	UW Fcst	Comments
Feather	3,624 mi2	tser(CDEC)	uw_esp_reforecast (PDF) mae_1995-2005 (PDF) mae_2000-2002 (PDF) rmse_byMonth (PDF) rmse_byYear (PDF)	--	calib flow plot calib stats ESP data, 50-05, KAF ESP results plot ESP results plot (95-05)	A longer 56 year hindcast dataset was generated for basin, although the NWS reforecast comparison focuses just on an 11 year period.
Yakima	--	tser	--	--	--	--
Salmon	--	tbl	--	--	calib flow plot calib stats ESP data, KAF ESP results plot ESP data, 35 yrs, KAF ESP results plot, 35 yrs	--
Klamath	3,800 mi2	tser (NRCS) tser (CNRFC)	--	--	--	indirectly estimated flow record
Gunnison (BMDC2)	--	tser	UW ESP results plot RFC ESP results plot MAE Skill RMSE Monthly RMSE Annual	--	calib flow plot calib stats UW ESP data (KAF) UW ESP results plot ESP data, 35 yrs, KAF ESP results plot, 35 yrs	The UW forecasts have been regenerated since the NWS verification was run.
Gunnison (GJNC2)	--	tser	--	--	calib flow plot calib stats ESP data, KAF ESP results plot ESP data, KAF ESP results plot	--
Snake	--	tbl	--	--	calib flow plot calib stats ESP data, KAF ESP results plot ESP data, 35 yrs, KAF ESP results plot, 35 yrs	--
Owyhee	--	tbl	--	--	calib flow plot calib stats ESP data, KAF ESP results plot ESP data, 35 yrs, KAF ESP results plot, 35 yrs	--
Blackfoot	--	tbl	--	--	--	--
Salt River	--	tbl unadjusted USGS	--	--	calib flow plot calib stats	--
American River	--	tser	--	--	--	--
Green River	--	tbl unadjusted USBR	--	--	calib flow plot calib stats	--
Weber River	--	tbl	--	--	calib flow plot calib stats	--

Questions? Comments? Please email Andy Wood, aww@hydro.washington.edu.

Seasonal Streamflow Forecast Assessments NWS, NRCS, UW, ...

Seasonal Streamflow Forecast Assessments
NWS, NRCS, UW, ...