A wind that blows down a slope which is strongly cooled after sunset. Given the right topography and surface composition, surprisingly high speeds can be achieved in otherwise light-wind situations.
When the warm air associated with a frontal surface descends relative to the cold air, the front is a kata-front. Such fronts are usually weak/ill-defined, but often mask more complex mechanisms, including upper frontal structures, and mesoscale processes.
(abbr. kt or kn) One nautical mile per hour (for speed of wind, ship movement, depression movement etc.) [ 1 knot = 0.515 m/s = 1.85 km/hr = 1.151 mph. As a working approximation, to obtain m/s, halve the reported wind in knots. ]
Knots (nautical miles per hour, as used in METAR/TAF reports etc.)