A wind that is created by air flowing downhill. When this air is warm, it may be called a foehn wind, and regionally it may be known as a Chinook or Santa Ana. When this air is cold or cool, it is called a drainage wind, and regionally it may be known as a mountain breeze or glacier wind. The opposite of an anabatic wind.

A front where the warm air descends the frontal surface (except in the low layers of the atmosphere).

A temperature scale with the freezing point of -273 degrees K (Kelvin) and the boiling point of +273 degrees K. It is used primarily for scientific purposes. Also known as the Absolute Temperature Scale. Proposed in 1848 by William T. Kelvin, 1st Baron of Largs (1824-1907), Irish-born Scottish physicist and mathematician.

The measure of thunderstorm potential based on the vertical temperature lapse rate, the moisture content of the lower atmosphere and the vertical extent of the moist layer.

A nautical unit of speed equal to the velocity at which one nautical mile is traveled in one hour. Used primarily by marine interests and in weather observations. A knot is equivalent to 1.151 statute miles per hour or 1.852 kilometers per hour.