Abstract
Vapor fluxes are calculated across a mountain barrier during two wintertime storms using a passive microwave radiometer and a Doppler radar. The vapor flux fields are shown to have complicated structures that are not detectable by conventional rawinsonde techniques. The vapor-flux fields show several major pulses which are compared to episodes of supercooled liquid water, riming, precipitation and synoptic weather patterns. It appears from this data that the presence of an enhanced vapor in the flux field is a necessary condition for precipitation, but not a sufficient condition. It is suggested that detailed measurements of the vapor flux field are imperative to the improved local forecasting of precipitation.
