We began HEPEX almost 10 years ago in March, 2004 at a workshop co-sponsored by ECMWF and NOAA. Lots of progress has been made since then in many aspects of weather, water, and climate ensemble prediction and the practical use of these predictions especially in the water and energy sectors. But there are lots of questions that HEPEX might help to answer. Examples include:
· What can HEPEX do to advance the use of hydrologic ensemble prediction?
·What needs to be done to make the best possible use in hydrology of weather and climate forecasts ?
·How can hydrologic ensemble forecasts be used in decision support systems to help make better decisions?
· Why are hindcasts important? Weather? Climate? Streamflow?
· How important is post-processing for applications of hydrologic ensemble forecasts in decision support systems?
· How important is hydrologic model calibrations? Can postprocessing help?
· What drives the predictive uncertainty of hydrologic