The Tropical Cyclone Information System (TCIS) is a tool that fuses hurricane models and observations within a web-based system to improve forecasting capabilities. TCIS provides scientists with the capability to overlay user-selected observational data on top of a variety of user-selected model predictions, and to perform online analysis of models and observations. TCIS required development of processing techniques to enable multi-source data fusion across hurricane forecast models, satellite data, and in situ sensors. The TCIS team also developed tools to manage the validation and assessment of model comparisons to more easily evaluate the performance of different numerical models. These online, interactive visualization techniques are ideal for analyzing highly complex systems like hurricanes.