Hydrologic Forecasting & Drought Assessment Tools From

the California Nevada River Forecast Center

US Drought Monitor Forum

April 14-16, 2015

Reno, NV

Alan Haynes

Service Coordination Hydrologist

NOAA/NWS – California Nevada River Forecast Center

Overview

• Characteristics of CNRFC hydrologic modeling &

type of information provided by the CNRFC

• Highlight some features of the CNRFC webpage

• Water resources

• Climate/Drought

• Observed precipitation

• Ensemble forecasts

CNRFC Operations

• 245,000 sq. miles

• ~270 Basins modeled

• 94 Forecast Points

• ~60 Reservoir Inflows

Hydrologic Modeling

Modeling Components

•Rain-Snow Elevation

•Snow-17

•Soil Model (SAC-SMA)

•Unit Hydrograph

• River Routing Models

• Reservoir Models

Model Characteristics

• Spatially Lumped Basins

• semi-lumped mountainous basins:

lower, middle & upper zones

• Six Hour Time-Step

Deterministic (single-trace)

Streamflow Prediction

Daily RFC

Forecasting

•Data Ingest

•Data QC

•Model Updating

Current States

•Soil

•Snow water

•Reservoir Levels

•Streamflow

Forecast

Meteorology

Mean Areal

Time Series

Precipitation

Temperature

Hydrologic

Models

Ensemble (multi-trace) Streamflow

PredictionDaily RFC

Forecasting

•Data Ingest

•Data QC

•Model Updating

Current States

•Soil

•Snow water

•Reservoir Levels

•Streamflow

Forecast

Meteorology

Mean Areal

Time Series

Precipitation

Temperature

Hydrologic

Models

Historical

Time Series

MAPs/MATs

All Years of

Record

He

Ensemble River Forecasts

Timeline

Model R

un T

ime

Observed Weather

Streamflow

Model States

Short Term Weather

Models

Days 1-15

Climatology

Days 16-365

Streamflow Forecasts

Ensemble Forecasts

• Start with current model states

• Feed hydrology model with multiple meteorological possibilities

• Result is 60+ hydrographs

World Wide Web

Summary – Water Resources

• Water Resources Page

• WY observed flow to date

• Observed flow for previous year

• Seasonal and WY volume forecasts

• Date of peak flow

Summary – Drought & Precipitation

• Climate/Drought Page

• Drought Monitor

• Seasonal Outlooks

• Observed precipitation

• Recent precipitation

• WY to date precipitation

Summary – Ensemble Forecasts

• Ensemble Forecasts

• Raw ensembles – 10 Day Traces

• Apr-Jul & WY Volume Forecasts

• Trend Plots

• Sacramento Valley WRI

Planned Tools

Droughts reflect multi-year precipitation shortages,

so…

The CNRFC plans to produce water resources products

that look back over the past three years.