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 ?