The Hydrological Ensemble Prediction Experiment (HEPEX) is an international project to advance technologies for hydrological forecasting. Its goal is “to bring the international hydrological and meteorological communities together to demonstrate how to produce and utilize reliable hydrological ensemble forecasts to make decisions for the benefit of public health and safety, the economy, and the environment.” HEPEX is an open group composed primarily of researchers, forecasters, water managers, and users. HEPEX welcomes new members.

In the first workshop, held in the spring of2004, HEPEX participants formulated scientific questions that, once addressed, should help produce valuable hydrological ensemble prediction to serve users' needs. During the second HEPEX workshop, held in the summer of 2005, a series of coordinated test-bed demonstration projects was set up as a method for answering these questions. The test beds are collections of data and models for specific hydrological basins or subbasins, where relevant meteorological and hydrological data have been archived. The test beds will facilitate the intercomparison of various hydrological prediction methods and linkages to users. The next steps for HEPEX are to complete the work planned for each test bed and to use the results to engineer more valuable automated hydrological prediction systems.

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Consultant, N O A A National Weather Service, Office of Hydrologic Development, Silver Spring, Maryland

NOAA Earth System Research Laboratory, Physical Sciences Division, Boulder, Colorado

European Centre for Medium Range Weather Forecasts, Reading, England

National Institute for Water and Atmospheric Research, Christchurch, New Zealand