PROBCAST: A Web-Based Portal to Mesoscale Probabilistic Forecasts

Abstract

This paper describes the University of Washington Probability Forecast (PROBCAST), a Web-based portal to probabilistic weather predictions over the Pacific Northwest. PROBCAST products are derived from the output of a mesoscale ensemble system run at the University of Washington, with the fields being postprocessed using Bayesian model averaging to produce sharp and reliable probabilistic predictions of temperature and precipitation. Based on research by University of Washington psychologists and human-interface specialists, a Web site has been constructed that allows for access to key elements of the probabilistic information produced by the system. The design approach of the PROBCAST system is explained in this paper as well as some of the challenges for future development. PROBCAST is intended to be a prototype for the kind of probabilistic forecast interface that could be used throughout the nation.