Subj : Wx Terms (D)(5) To : All From : Daryl Stout Date : Sat Aug 05 2017 12:08 am Duration of Sunshine The amount of time sunlight was detected at a given point. DURG During DURN Duration Dusk Same as Civil Dusk; the time at which the sun is 6 degrees below the horizon in the evening. At this time objects are distinguishable but there is no longer enough light to perform any outdoor activities. Dust Devil A small, rapidly rotating wind that is made visible by the dust, dirt or debris it picks up. Also called a whirlwind, it develops best on clear, dry, hot afternoons. Dust Plume A non-rotating "cloud" of dust raised by straight-line winds. Often seen in a microburst or behind a gust front. Dust Storm A severe weather condition characterized by strong winds and dust-filled air over an extensive area. Dust Whirl A rotating column of air rendered visible by dust. DVLP Develop DVV Downward Vertical Velocity (sinking air) DWNDFT Downdraft - A small-scale column of air that rapidly sinks toward the ground, usually accompanied by precipitation as in a shower or thunderstorm. A downburst is the result of a strong downdraft. DWNSLP Downslope DWPT Dew Point - A measure of atmospheric moisture. It is the temperature to which air must be cooled in order to reach saturation (assuming air pressure and moisture content are constant). Dynamic Ice In hydrologic terms, pressure due to a moving ice cover or drifting ice. Pressure occuring at movement of first contact termed Ice Impact Pressure. Dynamic Lifting The forced uplifting of air from various atmospheric processes, such as weather fronts, and cyclones. Dynamic Wave Routing Model (DWOPER) A computerized hydraulic routing program whose algorithms incorporate the complete one-dimensional equations of unsteady flow. Dynamics Generally, any forces that produce motion or effect change. In operational meteorology, dynamics usually refer specifically to those forces that produce vertical motion in the atmosphere. DZ Drizzle --- þ Synchronet þ The Thunderbolt BBS - wx1der.dyndns.org .