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
April shower April shower In the United Kingdom and Ireland, an April shower is rain during the month of April. One of the major causes of the often heavy downpours is the position of the jet stream. In early spring, the jet stream starts to move northwards, allowing large depressions to bring strong winds and rain in from the Atlantic. In one day the weather can change from springtime sunshine to winter sleet and snow. The track of these depressions can often be across Ireland and Scotland bringing bands of rain followed by heavy showers (often of hail or snow) and strong