Astronomical Dawn
The time at which the sun is 18 degrees below the horizon in the morning. Astronomical dawn is that point in time at which the sun starts lightening the sky. Prior to this time during the morning, the sky is completely dark.
Astronomical Dusk
This is the time at which the sun is 18 degrees below the horizon in the evening. At this time the sun no longer illuminates the sky.
Astronomical Unit
(abbrev. AU)- The mean earth-sun distance, equal to 1.496x1013 cm, or 214.94 solar radii.
Cosmic Ray
An extremely energetic (relativistic) charged particle.
Dry Microburst
A microburst with little or no precipitation reaching the ground; most common in semi-arid regions. They may or may not produce lightning. Dry microbursts may develop in an otherwise fair-weather pattern; visible signs may include a cumulus cloud or small Cb with a high base and high-level virga, or perhaps only an orphan anvil from a dying rain shower. At the ground, the only visible sign might be a dust plume or a ring of blowing dust beneath a local area of virga.
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.
First Law of Thermodynamics
The law of physics that states that the heat absorbed by a system either raises the internal energy of the system or does work on the environment.
MIC
Meteorologist In Charge
Microbarograph
A instrument designed to continuously record a barometer's reading of very small changes in atmospheric pressure.
Microburst
A convective downdraft with an affected outflow area of less than 2½ miles wide and peak winds lasting less than 5 minutes. Microbursts may induce dangerous horizontal/vertical wind shears, which can adversely affect aircraft performance and cause property damage.
Microclimate
The climate of a small area such as a cave, house, city or valley that may be different from that in the general region.
Micron
Unit of length equal to one thousandth (1/1000) of a millimeter; one millionth (1/1000000) of a meter (1x10-6 m).
Microscale
Pertaining to meteorological phenomena, such as wind circulations or cloud patterns, that are less than 2 km in horizontal extent.
Microwave
A type of electromagnetic radiation with wavelengths between those of infrared radiation and radio waves.
Microwave Burst
In solar-terrestrial terms, a radiowave signal associated with optical and/or X-ray flares
Photochemical Smog
Air pollution containing ozone and other reactive chemical compounds formed by the reaction of nitrogen oxides and hydrocarbons in the presence of sunlight.
Thermodynamic Chart
A chart containing contours of pressure, temperature, moisture, and potential temperature, all drawn relative to each other such that basic thermodynamic laws are satisfied. Such a chart typically is used to plot atmospheric soundings, and to estimate potential changes in temperature, moisture, etc. if air were displaced vertically from a given level. A thermodynamic chart thus is a useful tool in diagnosing atmospheric instability.
Thermodynamic Diagram
Used interchangably with Thermodynamic Chart; a chart containing contours of pressure, temperature, moisture, and potential temperature, all drawn relative to each other such that basic thermodynamic laws are satisfied. Such a chart typically is used to plot atmospheric soundings, and to estimate potential changes in temperature, moisture, etc. if air were displaced vertically from a given level. A thermodynamic chart thus is a useful tool in diagnosing atmospheric instability.
Thermodynamics
In general, the relationships between heat and other properties (such as temperature, pressure, density, etc.) In forecast discussions, thermodynamics usually refers to the distribution of temperature and moisture (both vertical and horizontal) as related to the diagnosis of atmospheric instability.
Wet Microburst
A microburst accompanied by heavy precipitation at the surface. A rain foot may be a visible sign of a wet microburst.

You can either type in the word you are looking for in the box below or browse by letter.

Search:

Browse by letter:

#  A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z