Western Water Supply Kevin Werner, Andrew Murray, WR/SSD Jay Breidenbach, WFO Boise Cass Goodman, Steve Shumate, CBRFC Alan Takamoto, Scott Staggs, CNRFC Don Laurine, NWRFC Chad Kahler, WFO Tuscon

Outline Western Water Supply –History Project overview –Westwide map –Forecast evolution –Verification –Ensemble services Future enhancements –Climate variability and change –Short range ensembles services

Western Water Supply Forecasts Forecasts for spring runoff amounts from snow melt dominated basins in western US Routinely produced at 6 RFCs and coordinated with other agencies (NRCS and California DWR) NWS forecast program began in 1940s Primary forecast tools: –Ensemble Streamflow Prediction –Multivariate Linear Regression Legacy Water Supply Forecast Product (Credit: NRCS / NOAA)

Project in a Nutshell Map: Single map for all western WS forecasts from 6 RFCs Forecast evolution: Plotting capability to show evolution of current year forecast and observed river flow Verification: Forecast evaluation from past forecasts and forecast tools Ensemble services: Interaction capability with ensemble streamflow predication Data Access: Access data from database

Milestones Milestones (past): –April 2005: Working group formed, planning meeting held –January 2006: Initial website launched –September 2006: Included AB, WG, and MB RFCs in development –January 2007: Common database developed –March 2007: Launched outreach effort and included SHs –September 2007: Move software to NWRFC web farm Milestones (future): –December 2007: Launch verification 1.0 capabilities Launch forecast evolution 2.0 Launch ensemble services 1.0 –January 2008: Integrate WGRFC data –2008?: Integrate climate change capabilities

Map “One Stop Shop” for NWS water supply forecasts Flexible and consistent map presence across western USA Zoomable to basin scale Mouse over capability for forecast values

Forecast Evolution Time evolution of forecast and observed streamflow Plot options include: -Observed monthly or seasonal streamflow -Historical monthly or seasonal streamflow -Forecast seasonal streamflow -Accumulation options

Forecast Evolution Version 2.0 coming December 2007 Additions include: -ESP seasonal forecasts for easy comparison to official forecasts -Multi-year plots

Ensemble Services December 2007 RFC Ensemble Forecasts -Initially offered at NWS water supply points -Display probability function for monthly volumes -Tools included to query historical data and forecast ensemble members -User customizable plots

Ensemble Services December 2007 Median Historical Runoff & 1983 ensemble member November – May Seasonal Runoff

Forecast Verification December 2007 Data VisualizationError MAE, RMSE, etc Conditional on Lead time, year Skill Skill relative to Climatology Conditional Categorical Traditional (NWS) verification including FAR and POD Category definitions tied to climatology values (e.g. mean flow, terciles, etc.) or user definable Easy to understand Meaningful Accessible from forecasts Dynamically generated plots from database Plot credit: Chad Kahler

Data Access December 2007 Access to forecast and observed data from database

Future Directions Climate Change Hydrologic Scenarios Short Range Hydrologic Scenarios Climate Variability and Hydrologic Response Relationships

Figure TS.5 (IPCC AR4, WG2). Illustrative map of future climate change impacts on freshwater which are a threat to the sustainable development of the affected regions. Climate Change: Fresh Water Projections

Extend NWS Product Suite? Current product suite covers hours to seasons; Should we consider climate change scenarios and build multi-year products for run-off, temperature, precipitation? User requirements from power companies, BoR, etc for climate change scenarios Climate Change run off scenarios? Years

Climate Change Scenarios Example: Lake Granby inflows on the Colorado River Two temperature scenarios: Historical Temperatures +0.2 deg F increase per year based on historical temperatures

Climate Change Scenarios (Con’t) Corresponding simulations of Lake Granby inflows: Warmed simulation has earlier runoffs late in the simulation

Climate Change Scenarios (con’t) Hungry Horse Dam inflows on Flathead River Simulations with 1% less precipitation per year

Climate Change Scenarios (con’t) Ultimately include climate change scenarios in the ensemble services application for easy comparison with other datasets.

Summary New stuff coming in December We like feedback: