In this SBIR project, Daniel H. Wagner Associates, Inc., will design and demonstrate the feasibility of a system for integrating environmental data into flight planning and execution for Unmanned Air Systems (UAS) in the National Airspace System (NAS). The Weather Aware Route Planning (WARP) system will provide weather-based Indicators and Warnings (I&W) and navigational recommendations for UAS in order to improve their autonomy, safety, and energy efficiency. Using all available environmental and navigational data, WARP will assess environmental impacts to planned/executing flight plans and generate alerts and recommendations for those plans based on expected environmental impacts. Operating within a ground-based control center, WARP will incorporate position and environmental data from existing and emerging Next Generation Air Transportation System (NextGen) sources. Using a combination of rules-based/heuristic and computationally-intensive approaches, WARP will assess environmental impacts to individual UAS flight plans and provide I&W and recommendations for each UAS to avoid negative environmental impacts and take advantage of positive environmental impacts. WARP will assist ground-based pilots, and eventually UAS autonomous controllers, in performing safer and more efficient flight.