The needs of airports may vary, depending on the types of operations typically conducted at the airport as well as the type of weather common to the airport. Synthesis 105 aims to provide the operators of general aviation (GA) airports a comprehensive source of information about airport-based weather observation options, so they may make informed decisions to support the operational needs of their airport. Weather observations at airports can come from either FAA-approved (certified) or advisory (non-certified) sources. Weather reporting at a GA airport, whether certified or not, typically comes from automated sources, because human observers are increasingly being phased out or stationed mainly at commercial service airports.