NCAR’s real-time convection-allowing ensemble project

Beginning 7 April 2015, scientists at the U.S. National Center for Atmospheric Research (NCAR) began producing daily, real-time, experimental, 10-member ensemble forecasts with 3-km horizontal grid spacing across the entire conterminous United States. Graphical forecast products were posted in real time to the Internet, where they attracted a large following from both forecasters and researchers across government, academia, and the private sector. Although these forecasts were initially planned to terminate after one year, the project was extended through 30 December 2017 because of the enthusiastic community response. This article details the motivation for the NCAR ensemble project and describes the project's impacts throughout the meteorological community. Classroom and operational use of the NCAR ensemble are discussed in addition to the diverse application of NCAR ensemble output for research purposes. Furthermore, some performance statistics are provided, and the NCAR ensemble website and data visualization approach are described. We hope the NCAR ensemble's success will motivate additional experimental forecast demonstrations that transcend current operational capabilities, as forward-looking forecast systems are needed to accelerate operational development and provide students, young scientists, and forecasters with glimpses of what future modeling systems may look like. Additionally, the NCAR ensemble dataset is publicly available and can be used for meaningful research endeavors concerning many meteorological topics.