WindNinja is a numerical model that simulates near-surface winds in complex terrain. It is developed and maintained by researchers at the Missoula Fire Sciences Laboratory. WindNinja is widely used by operational wildland fire managers in the US and abroad for fire modeling, planning, accident investigations, and situational awareness. It is embedded in a number of operational systems including FlamMap, WFDSS, and IFTDSS. It is also used for snow modeling research, wind erosion research, avalanche forecasting, and wind energy applications. Key features of the model include the user-friendly interface and fast simulation times. Ongoing work is focused on further reducing computational times and extending model capabilities. Recently, a new solver has been incorporated into WindNinja. This new solver uses Semi-Lagrangian techniques with origins in meteorology and, more recently, in computer graphics research. This solver should reduce model runtimes and also allow for treatment of transient flow effects, such as vortex shedding, and explicit handling of thermally-driven flows. In this talk I outline the current status of WindNinja, describe the new Semi-Lagrangian solver, show some examples of the current prototype, and discuss ongoing work and plans for the future.