The U.S. air transportation system faces a continuously growing gap between the demand for air transportation and the capacity to meet that demand. Two key obstacles to bridging this gap are traffic delays due to en route severe-weather conditions and airport weather conditions. Lincoln Laboratory has been addressing these traffic delays and related safety problems under the Federal Aviation Administration's (FAA) Aviation Weather Research Program. Our research efforts involve real-time prototype forecast systems that provide immediate benefits to the FAA by allowing traffic managers to safely reduce delay. The prototypes also show the way toward bringing innovative applied meteorological research to future FAA operational capabilities. This article describes the recent major accomplishments of the Convective Weather and the Terminal Ceiling and Visibility Product Development Teams, both of which are led by scientists at Lincoln Laboratory.