Uncertainty is a fundamental characteristic of fluid system prediction including weather, climate, and hydrological forecasts. According to the National Research Council (NRC) Report: Completing the Forecast. Characterizing and Communicating Uncertainty for Better Decisions Using Weather and Climate Forecasts, "… effective communication of uncertainty information in hydrometeorological forecasts benefits users' decisions." Although there are notable exceptions, most current forecast products are based on a single deterministic prediction with no accompanying forecast uncertainty information. Consequently, decisions by users at all levels are generated largely without the benefit of knowing and accounting for the inherent uncertainties of the forecast upon which they rely. Furthermore, while there are increasing numbers of individual development and prototyping efforts within the weather, water, and climate enterprise (Enterprise) to generate and communicate more forecast uncertainty information, there is no comprehensive approach to identify and validate user needs and science opportunities, and to develop and implement responsive products and services that cost-effectively leverage partner capabilities.

The purpose of this presentation is to provide an overview and status of the American Meteorological Society (AMS) Commission on the Weather and Climate Enterprise Ad Hoc Committee on Uncertainty in Forecasts (ACUF). The charge of the ACUF is to engage the weather and climate enterprise in identifying a vision of forecast uncertainty characterization and communication as motivated by the 2006 NRC Report. Specifically, the ACUF (composed of representatives from government, the private sector, academia, and the user community) will serve to identify future paths for more thoroughly addressing forecast uncertainty products, services, and information needs of the Nation. In so doing the ACUF will propose roles and responsibilities of enterprise partners in developing, generating, and providing uncertainty information to the user community.