Short-term forecasting of airport surface visibility using radar and ASOS

Surface visibility is important for airport operations, since it affects the VFR/IFR status and category. This study demonstrates a method of making short-term visibility forecasts using an approach similar to that employed in the Weather Support to Deicing Decision Making (WSDDM) snow rate forecast. The ASOS installations at each major airport include sensors which measure visibility. This study uses those visibility measurements, along with radar observations and other ASOS data, to determine a relationship between radar reflectivity and visibility during snow conditions. This relationship is used together with an extrapolation forecast of radar reflectivity to determine forecast visibility during snow conditions out to one hour. The paper will present an evaluation of the technique at New York, Minneapolis, and Denver airports.