(abbrev. F) Fog is water droplets suspended in the air at the Earth’s surface. Fog is often hazardous when the visibility is reduced to about ¼ mile or less.
A fog the droplets of which freeze upon contact with exposed objects and form a coating of rime (a thin clear coating of ice) and/or glaze.
Precipitation in the form of ice crystals, mainly of intricately branched, hexagonal form and often agglomerated into snowflakes, formed directly from the freezing [deposition] of the water vapor in the air.
This product is issued by the National Weather Service when a low pressure system produces snow that may cause significant inconveniences, but do not meet warning criteria and if caution is not exercised could lead to life threatening situations. The advisory criteria varies from area to area. If the forecaster feels that it is warranted, he or she can issued it for amounts less than the minimum criteria. For example, it may be issued for the first snow of the season or when snow has not fallen in long while.
Snow flurries are an intermittent light snowfall of short duration (generally light snow showers) with no measurable accumulation (trace category).
A snow shower is a short duration of moderate snowfall. Some accumulation is possible.