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. 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. Heat Wave - A period of abnormally and uncomfortable hot weather lasting for several days or even weeks. In a high pressure system there is usually gradual subsidence of the air which is unfavourable for rain especially if the system extends fairly high up in the atmosphere.