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 (NRC, 2006), "… 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 Enterprise to generate and communicate more forecast uncertainty information, there has been 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.

While the Completing the Forecast Report was commissioned by the National Weather Service (NWS), it recommended that the entire Enterprise should take responsibility for providing products that effectively communicate forecast uncertainty information and that product (and service) development should be collaborative with Enterprise partners and users from the outset. It is therefore fitting that the American Meteorological Society (AMS) Commission on the Weather and Climate Enterprise (CWCE) Board on Enterprise Communication (BEC) formed an Ad Hoc Committee on Uncertainty in Forecasts (ACUF) to engage the Enterprise in identifying an Enterprise-wide vision of forecast uncertainty characterization and communication.

The purpose of this presentation is to present the status of the ACUF's ongoing work and stimulate thought and discussion as it moves into the final year of completing its deliverables. This committee has a great opportunity to propose a Weather and Climate Enterprise-wide foundation for developing, producing, and providing new forecast uncertainty products and services that will benefit the Nation. The committee's work also has the ability to create a way forward for forecast uncertainty, as an opportunity to establish a paradigm of mutually-beneficial roles and responsibilities for enterprise partners to plan and execute other initiatives and endeavors as recommended in the report, Fair Weather: Effective Partnerships in Weather and Climate Forecasts (NRC, 2003).