SYNOPSIS Whereas in current practice in the United States, select is that form of precipitation which is not snow, rain, or hail, an attempt to make a detailed descriptive and genetic definition seems advisable, and 30 cases of sleet are analyzed as a basis: Select, a rattling type of ice precipitation formed in the free air, has the following characteristics: Size, smallest dimensions of largest pieces less than 6 mm. (¼ inch); form, angular, irregular, or nearly spherical; structure, nonregular ice part or all of which is cloudy or bubbly (except in extremely small drops), not more than one clear layer. A select particle may be (1) a snowflake partly melted and refrozen. (2) a frozen raindrop, or (3) a frozen combination of snowflake, and raindrop or liquid (not undercooled) cloud droplets. A generalized vertical section of sleet weather shows select as occurring usually with a cloud from which snow is falling through a stratum of air having a temperature above freezing and into air with a temperature below freezing.
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