Precipitation Precipitation In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravity. The main forms of precipitation include drizzle, rain, sleet, snow, graupel and hail. Precipitation occurs when a portion of the atmosphere becomes saturated with water vapor, so that the water condenses and "precipitates". Thus, fog and mist are not precipitation but suspensions, because the water vapor does not condense sufficiently to precipitate. Two processes, possibly acting together, can lead to air becoming saturated: cooling the air or adding water vapor to the air. Precipitation forms as smaller droplets coalesce via collision with
Winter weather advisory Snow Advisory, specific for when snow and blowing snow were the only hazards expected in the advised area. The Winter Weather Advisories for Snow, for Sleet, for Blowing Snow, and for Snow and Blowing Snow, respectively, have since replaced them. Because of the changes with the 2008-09 winter storm season, several varieties have been noted throughout the US. Also to be noted: Winter weather advisory A Winter Weather Advisory is issued by the National Weather Service of the United States when a low pressure system produces a combination of winter weather (snow, freezing rain, or sleet) that presents a hazard,