USA National Weather Service Community Hydrologic Prediction System Rob Hartman Hydrologist in Charge NOAA / National Weather Service California-Nevada River Forecast Center Sacramento, CA
Background Outline NWS Mission and organization Relationship with other agencies Methods, products and services Use of FEWS in CHPS Migration Strategy Interactive Forecast Display (IFD) Runtime Modifications (MODS) Multiple Screens WFO use (authorization schemes) Ensembles (current and future)
Mission of USA NWS Hydrologic Services Program Provide river and flood forecasts and warnings for the protection of lives and property. Provide basic hydrologic forecast information for the nation s s environmental and economic well being.
USA NWS Field Offices 9 National Centers for Environmental Prediction (NCEP) 13 RFCs River Forecast Centers 122 WFOs Weather Forecast Offices
CNRFC Staffing NWS/CNRFC Hydrologist in Charge Development and Operations Hydrologist (DOH) Service Coordination Hydrologist (SCH) California DWR/DFM Hydrology Branch Chief 7 Engineers/Forecasters 3 Senior Hydrologists 2 Hydrologists 2 Senior HAS Forecasters 2 HAS Forecasters 1 Information Tech. Officer Administrative Assistant
CNRFC Customers RFC WFOs Public Warning Water and Flood Management Agencies, Utilities
Available CNRFC Forecasts
Operational River Forecasting Hydrologist hydrologic expertise & judgment model guidance H A S forecast precip / temp River Forecast System bulletins graphics Flood Forecast Guidance data parameters Observing Systems Calibration
Operational HAS Function 10 NWFOs NCEP - HPC Local collaboration as required 3-Day Forecasts Updated every 6 hours Atmospheric Models Local Models Surface Observations Remotely Sensed Data H A S 5-Day Forecasts (6 hour interval ) - Precipitation - Temperature - Snow Level
~220 flood, non-flood, and reservoir locations Updated w/each model run 2x / day winter weekdays 1x / day summer weekdays and weekends 4x / day during flood events River Guidance Graphics (www.cnrfc.noaa.gov)
River Guidance - Graphics Issued with each model run -/+ 5 days Obs + Forecast + Guidance Available CNRFC Website CDEC Website Interpretation Online help 1 page flier (www.cnrfc.noaa.gov)
River Guidance - Text Issued with each model run + 5 days Summary table and SHEF encoded data Available CNRFC Website CDEC Website Basis of WFO issued flood warnings Issued for 10 areas Same frequency as graphics (www.cnrfc.noaa.gov)
River Guidance - Verification Flood locations only -/+ 5 days Observed and Forecast precipitation streamflow Select by date next/previous looping Available All flood forecast locations CNRFC Website Interpretation Online help All since Fall 2003
20-Day Spring Snowmelt Forecasts (www.cnrfc.noaa.gov/products/snowmelt/snowmelt.pdf)
CNRFC Monthly Water Supply Outlooks www.cnrfc.noaa.gov/products/water_supply
Statistical Models Statistical Models vs. Ensemble Techniques Low data requirement Easy to calibrate and maintain Perform better for seasonal volume forecasts Inflexible (use/output) May have difficulty in extreme years Difficult to integrate weather and climate forecasts Dominate model in the past ESP Techniques High data requirement More difficult to calibrate and maintain ($$) Perform better for partial season forecasts Flexible (use/output) Should work reasonably well in extreme years Easier to integrate weather and climate forecasts Dominate model in the future
April Equation (Millerton, Apr-Jul) Standard Error = 155 KAF Dec-Mar Precipitation Auberry North Fork Ranger Station Apr 1 SWE Gem Pass Mono Pass Piute Pass Cora Lakes Lake Thomas Edison Rock Creek 2 Mammoth Pass
Monthly Coefficient of Variation (Standard Error / Average) CV
Ensemble Streamflow Prediction Use same forecasting infrastructure as Flood/Routine forecasts (CHPS) Same models, observed data, model states Modeling system run with multiple scenarios of future precipitation and temperature Scenarios are Spatially and temporally coherent Equally likely Resulting streamflow scenarios form a set that can be statistically sampled and analysed
Ensemble Streamflow Prediction Climate Forecast Adjustments Daily RFC Forecasting Data Ingest Data QC Model Updating Current Conditions Soil Reservoir Levels Streamflow April-July Historical Time Series All Years of Record Mean Areal Time Series Precipitation Temperature CHPS Hydrologic Models Streamflow Forecast Time Series Time
ESP Product Generation Significant flexibility User selectable time aggregation 6 hrs to 1 year User selectable window Days, weeks, months or multiples there of Information on Peaks Number of days to critical thresholds (e.g. Flood Stage)
Sample ESP Products
CNRFC Ensemble User Interface Create Your Own Ensembles run nightly Assumes knowledgeable user Online help and interpretive tools available (www.cnrfc.noaa.gov)
CHPS and FEWS FEWS Models Models from Federal, State, Local, University and international researchers Other Models FEWS FC USACE Models NWS Models
CHPS Migration Strategy Hydrologist hydrologic expertise & judgment model guidance H A S forecast precip / temp NWSRFS CHPS bulletins graphics Flood Forecast Guidance data parameters Observing Systems Calibration
Migration Strategy Prototype and test at 4 of 13 RFCs Remaining 9 follow by 12 months Migrate existing functionality only No incremental requirements Leave pre-processing, processing, post-processing, processing, and calibration requirements for later
Migration Strategy (continued) Provide for all operationally required functionality Adapted or integrated NWSRFS models Adapters for NWS models supported by NWS/OHD Identified FEWS analogs Develop migration scripts to create CHPS xml configurations from NWSRFS definitions Improved and refined over time Develop Interactive Forecaster Display (IFD) that meets operational forecaster needs
CHPS Implementation CAT-I RFCs Today Pilots/Demonstrations BOC Migration Parallel Ops Operational 2006 2007 2008 2009 2010 2011 Parallel Ops Operational CAT-II RFCs BOC-II Migration Retire NWSRFS 30
CHPS Implementation Status Fully Operational August 2010 50% Operational October 2010, Fully Operational December 2010 Fully Operational January 2011 Remaining 9 RFCs operational April December 2011
What s s Different about CHPS? Significant investment in user interface (IFD) Common use of runtime modifications (MODs) Potential use by WFOs Limited authorization scheme
CHPS Interactive Forecast Display (IFD)
Span Display
Modification Interface Unit Hydrograph Adjustment Sacramento SMA States Adjustment
Major Efforts for CNRFC Identify/develop and validate replacements for NWSRFS meteorological inputs (forcings) precipitation air temperature freezing level suitable Validate migrated functionality Improve NWSRFS configuration in order to simplify CHPS configuration
Validation Most are ~perfect like this one
Some showed differences that were resolved by correcting the xml configuration
Areas of Potential Collaboration Model calibration interface(s) and diagnostics Based on FEWS Stand Alone (FEWS SA) Data quality control Procedures Algorithms User interfaces Ensemble applications HEPEX HEFS Hydrologic Ensemble Forecasting System
HEFS - Hydrologic Ensemble Forecasting System Relies on flexibility of CHPS Short, medium, and long range RELIABLE ensemble- based probabilistic forecasts Components Preprocessing, Generation, Post processing, Product generation, Verification Active area of emphasis Collaboration through HEPEX
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