Accretion (meteorology) Accretion (meteorology) Accretion is defined as the gradual collection of something over time. In meteorology or atmospheric science it is the process of accumulation of frozen water as precipitation over time as it descends through the atmosphere, in particular when an ice crystal or snowflake hits a supercooled liquid droplet, which then freeze together, increasing the size of the water particle. The collection of these particles eventually forms snow or hail in clouds and depending on lower atmosphere temperatures may become rain, sleet, or graupel. Accretion is the basis for cloud formation and can also be seen as water accumulates
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,