Hydrologic Ensemble Forecast Service (HEFS) :
A Forecaster’s Initial Impressions
ALERT Users Group May 8, 2014
Pete Fickenscher
Senior Hydrologist NOAA / National Weather Service
California-Nevada River Forecast Center Sacramento, CA
Outline • What is HEFS?
• Goals • Current Status • Overview
• Case Study of HEFS • Event description • Current CNRFC HEFS products • Prototypes of potential new products • Elicit some feedback
HEFS – Goals • Deliver system capable of producing “operational” short,
medium and long range hydrologic ensemble products.
• Produce ensembles of hydrologic elements that contribute to effective risk based decision support. • Develop reliable members and products
• Unbiased • Appropriate Spread
• Make available when and where needed • Provide tools that facilitate application
HEFS – Current Status
HEFS: Hydrologic Ensemble Forecast Service (WY 2014 - )
xEFS: eXperimental Ensemble Forecast System (WY 2010 - 2013)
ESP: Ensemble Streamflow Prediction (1980’s - )
Deterministic: Single Trace Forecast
HEFS Complexity
MEFP PE “Raw”
Post- processed
Climatology – Historical precip and temp
(6-hr time step) – Water years 1950-2008 – Start at current time with
current basin conditions and go out 365 days
Weather Forecast
– Use precip and temp from weather prediction models
– Short term forecasts only (within first 15 days)
– CNRFC (HAS), GEFS, CFSv2 (future addition …)
days
16 to 365 4 -15 1 - 3
HAS GEFS Climatology / CFSv2
HEFS – Forcings
T0
- Build relationships between observed and forecast for all forecast models – HAS, GEFS
- Calibration period: - HAS: 2001-2010 - GEFS: 1985-2010
- For different lead times and aggregation periods (canonical
events)
- For different “seasons” (moving two month window)
HEFS – Forcings Calibration
HEFS in CNRFC Operations Water Year Accumulated Volume Plot
Dry Ck at Warm Springs Dam 4/20/2014 forecast
HEFS in CNRFC Operations
• Water Supply Forecasting (medium to long range forecasts) • Flood Forecasting (0 – 10 day forecasts)
• “Experimental” – producing products, but still evaluating its usefulness
“Essentially, all models are wrong, but some are useful.” - George E.P. Box
Case Study – Feb. 14, 2014
• 48-hour Precipitation
(2/12 – 2/14 4 am)
Smith River Jed Smith Fort Dick
Case Study – Feb. 14, 2014 CHPS – Modeled Soil States
Case Study – Feb. 14, 2014
TPW Satellite Feb 14th 10:00 am 1-1.5” TPW plume
Case Study – Feb. 14, 2014
Radar Reflectivity
(2/14/2014 5:30 am)
Case Study – Feb. 14, 2014
Case Study – Feb. 14, 2014
Case Study – Current Products HEFS Traces – Feb 14th
Case Study – Current Products 5-day Peaks – Feb 14th
Case Study – Current Products 10-day Histogram of Daily Maximum – Feb 14th
Case Study – Current Products Raw Ensembles – CSV Format
Case Study – Prototype Products Traces with Deterministic – Feb 14th
Case Study – Prototype Products Hourly Peaks Histogram – Feb 14th
Case Study – Prototype Products Daily Peaks Histogram – Feb 14th
Case Study – Prototype Products 5-day Peaks Histogram – Feb 14th
Case Study – Prototype Products Box & Whisker Plot – Feb 14th
Feedback
A. B. C.
D. E. F. Suggestions ??
Case Study Verification
Observed Flow 2/14 Forecast Flow
HEFS – Still a work in progress Feb. 28 - March 1, 2014 Southern Cal. Storm
Santa Clara River at Victoria Ave. (VCAC1)
Summary
• HEFS aims to produce short-term ensembles that are reliable and skillful for flood forecasting
• Communication and display of probabilistic
forecasts is new – how do we do it?
• Appreciate any and all feedback concerning what elements of HEFS are most useful.
Questions ?