The transition zone where a colder air mass overtakes and replaces a warmer air mass. An upper level low pressure system that is no longer in the normal west to east air flow. Usually a cut-off low will lie to the South of the established upper air flow. An area of low pressure. Winds blow in a counter clockwise direction in the Northern Hemisphere and in a Clockwise direction in the Southern Hemisphere.
Inclimate weather is associated with a cyclone.
A measure of departure from the mean daily temperature. A strong downward rush of air which produces a blast of damaging wind on or close to the surface. Air that descends an elevated plain and consequently warms and dries. Occurs when prevailing wind direction is from the same direction as the elevated terrain and often produces fair weather conditions. A cloud, with its base on the surface, reducing visibility.