Dart Leader: An electrical charged ionized channel which dart from the thunderstorm cloud to the
ground after the Stepped Leader has estabilished contact with the ground.
Deepening:When the central pressure of a cyclone drops.

"Dimensional Space" 1. Engineer of a train on a railroad track. Is a One Dimensional Space Continuum. You can describe the position of a train on track any time by a single co-ordinate point such as a station. 2. A Captian of a ship at sea"......Is a Two-Dimensional Space Continuum. Using the Latitude and Longitude to idendify it's location. 3. Pilot of an airfcaft........... Is a Three-Dimensional Space Continuum. Using the Latitude and Longitude plus its height above the ground to identify it's location. 4. People of the world: (Space)..... The Space of our world as we perceive it is the same as the Aircraft's Pilot, Three-Dimensional. 5. Time............... Time is another Dimension. When added to the railraod train gives it a Two-Dimensional Continuum. 6. Time............... Time when added to the ship at sea gives it a Three-Dimensional Continuum. 7. Time............... Time when added to the aircraft flying above the earth gives it a Four Dimensional Continuum. 8. Dimension.......... A Measurement. In Physics, a Quantity such as Mass, Length, Time. 9. Continuum.......... Continous Time. Back To Top OF Page

Dendrology:The study of trees.
Deposition: When vapor goes to the solid stage without entering the liquid stage.
Depression: An area of low pressure.
Derecho: Derecho: Spanish meaning "Straight". In meteorology a wide spread fast moving cluster of thunderstorms associated with
"Extratropical Mesoscale Convective Systems" (MCS) which produce strong dounbursts in clusters creating straight line wind damage of
hundreds of miles. Mostly occur in the spring and summer, however, may occur anytime.

Designated (RVR) Runway: A designated runway by the FAA for reporting RVR (Runway Visual Range.)
Dissemination: To send a weather report.
Dew:Vapor which has condensed into water. Dew adds about 2+ inches of water throughout the year.
Dew deposits about 1/50 inch to 3/100 of and inch overnight. Dew may stimulate the growth of harmful fungi to plants.

Dew Point:The temperature at which condensation forms.

Distance: 1 Mile: = 5,280 feet.
Distance: 3/4 Mile: = 3,960 feet.
Distance: 1/2 Mile: = 2,640 feet.
Distance: 1/4 Mile: = 1,320 feet.
Distance: 1/8 Mile: = 660 feet.
Distance: 3/16 Mile: = 330 feet.

Disturbance: A small area of low pressure.
Diurnal:Daily.
Divergence:In the atmosphere when air diverges it sinks, moves clock wise and outward creating
"High Pressure" Centrifugal Force. Compressional Warming. Anti-Cyclonic conditions.

Doppler Effect: To detect if and object is moving towards or away from you.
Doppler Effect: First name after the Austrian Physiciest "Johann Christian Doppler" in 1842.
Doppler Weather Radar: A "Weather Radar" which can determine the speed and direction precipitation is moving
towards or away from the radar.
Downdraft: A small downward movement of air.
Downpour: A sudden fall of heavy rain.
Downwind: When walking the wind will be from your back moving away from you.
Drifting snow: Snow lifted by the wind and carried to a height of less than 6 feet.
Drizzle: Precipitation composed of fine drops with diameters of less than 0.02 inch (0.5mm).
Dropsonde: A radiosonde dropped from amd aircraft to obtain readings of the atmosphere.
Temperature/Pressure/Humidity/Wind Speed & Direction.
Drought: An extended period with below normal or no precipitation.
Dry Adiabatic Lapse Rate: When air rises at 5.0 Deg F., 3.0 Deg. C. per 1,000 feet.
Dry Bulb Temperature: The temperature of the air.
Dust: Very minute particles of dust or sand in the air which produce a tan or gray color to the atmosphere.
The Sun appears yellow when looking through dust.
Dust Devil: A small whirlwind of air of short duration which moves along the ground picking up dust, sand, dirt, leaves, debris.
Dust Storm: A large area of dust blown in the air by strong winds over a wide area.
Dyne: A unit of force.