Experimental assessment of local weather forecasts for small unmanned aircraft flight

Control of small unmanned aircraft systems (sUAS) is heavily influenced by the local wind field characteristics. Small UAS missions are often contained within sub-grid regions of current numerical weather prediction (NWP) model outputs. For example, state-of-the-art forecasting tools, such as the High Resolution Rapid Refresh model, cannot resolve the local-scale wind field that can have an impact on sUAS missions. NCAR has been developing a coupled Weather Research and Forecasting-Large Eddy Simulation (WRF-LES) capability, a 100-meter resolution NWP model that has the potential to be used by sUAS applications. The present work compares sUAS measurements of temperature, humidity and wind speed to those obtained with a realtime implementation of WRF-LES. Initial results suggest both model and sUAS measurement biases and uncertainties need to be addressed more comprehensively before WRF-LES forecasts can be used in path planning applications for sUAS.