The NWS Hydrologic Ensemble Forecast System

 

Launch Module
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Published on: 2009-09-29
Estimated time to complete: .75 - 1.00 h
Includes audio: yes

Topic Area(s):

Hydrology/Flooding

Description:

In this webcast, Dr. Richard Koehler, the National Hydrologic Sciences Training Coordinator for NOAA’s NWS provides an introduction to the elements of the NWS Hydrologic Ensemble Forecast System (HEFS). The module starts with a background on Ensemble Streamflow Prediction (ESP), along with an historical perspective on its development. Details are then provided on the need for and characteristics of hydrologic ensemble forecasts. A comparison is made to show how hydrologic and meteorological ensembles differ. Dr. Koehler then looks at the relationship between probability, risk and uncertainty as well as the probabilistic information within hydrologic ensemble products. Also discussed is how errors and uncertainty arise from both meteorological and hydrologic data input as well as the uncertainty within the model itself.

Objectives:

Understand the general characteristics and need for hydrologic ensembles
- Recognize the difference between meteorological and hydrologic ensembles
- Understand the relationship between probability, risk and uncertainty
- Recognize and identify sources of hydrologic uncertainty within ensembles
- Understand the goals of Hydrologic Ensemble Forecast System processes
- Comprehend probability information within hydrologic ensemble products

Keywords

National Weather Service Hydrologic Ensemble Forecast System, Hydrologic Ensemble Forecast System, NWS Hydrologic Ensemble Forecast System , HEFS, NWS HEFS, Hydrology, Hydrologic Ensembles, hydrologic ensemble, hydrologic ensembles, Hydrologic Ensemble Process, ESP, Ensemble Streamflow Prediction, , hydrologic uncertainty, Ensemble spread, Streamflow simulation, Streamflow forecast, hydrologic forecast lead time, uncertainty of hydrologic and water resource forecasts, hydrologic forecast lead time, hydrologic forecast accuracy, Extended Streamflow Prediction, Weibull formula, Community Hydrologic Prediction System, CHPS, Experimental Ensemble Forecast System, XEFS, Hydrologic Uncertainty, Meteorological Ensembles, Hydrologic Ensemble Pre-Processor, Hydrologic Ensemble Data Assimilation, Hydrologic Processor, Hydrologic Model Output Statistics Processor, HMOS, Hydrologic Model Output Statistics, HMOS Processor, streamflow simulations, single value operational forecast, Hydrologic Ensemble Post-Processor, hydrologic bias and uncertainty, Statistical post processing, residual hydrological uncertainty, Ensemble Forecast Verification, forecast verification processor, Hydrologic Ensemble Product Information, ESP probabilities, spaghetti plots, hydrologic ensemble product, streamflow volumes, streamflow, Exceedance Probability, probability distributions, probabilistic streamflow values