A system and method that downlinks weather data, generated by existing weather and data sensors, to a groundstation. The groundstation utilizes data from multiple aircraft to form refined weather information, and uplinks the refined weather information to the aircraft. The refined weather information is stored at the aircraft and picture generating equipment, such as an existing on-board ground proximity terrain picture and symbol generator, generates pictorial information depicting the weather information. The pictorial information is displayed, for example by an existing EFIS or weather radar display, in the form of polygons.