Water vapor imagery is now available routinely from weather satellites for use in meteorological operations. Research during the past 5 years has provided insight concerning the physical interpretation of this data under varying atmospheric moisture and temperature distributions. Investigations have also identified new applications for use in operational weather analysis and forecasting. The water vapor patterns and the changes of these patterns with time, relate to upper tropospheric flow, the jet stream, tropopause breaks, the intensification of thunderstorms, and tropical storm motion. Animated hourly water vapor imagery will become available next year for use by National Weather Service (NWS) field forecasters. It will provide them with a new diagnostic tool for short range forecasts.