Such an air mass may extend over hundreds or even thousands of kilometres. This term, as used in weather forecasts, refers to hot dry winds blowing from the interior plateau to the coast. The air becomes hot as a result of the decent. When the temperature falls below freezing point but when the air is too dry for visible frost. Front Front - The transition zone between two different air masses.
Fronts generally move from west to east and are associated with low pressure systems.
When cold air displaces warmer air the front is a cold front and, conversely, if the air in the rear of the front is warmer the front is a warm front. The passage of a front is characterised by fairly sharp changes in wind direction, temperature and humidity. The warm air is forced over the heavier colder air which wedges in under it and this causes the cloud and precipitation which is found at an active front. Fronts generally move from west to east and are associated with low pressure systems. When cold air displaces warmer air the front is a cold front and, conversely, if the air in the rear of the front is warmer the front is a warm front.