What is the difference between a cold front and a warm front?

1 Cold fronts

A cold front is a boundary where a cold air mass pushes under a warm air mass, lifting it up and causing it to cool and condense. Cold fronts usually move from west to east, and are often associated with low pressure systems and strong winds. Cold fronts can produce showers, thunderstorms, hail, and sometimes snow, depending on the season and the temperature difference. Cold fronts are marked on weather maps by a blue line with triangles pointing in the direction of movement.

2 Warm fronts

A warm front is a boundary where a warm air mass slides over a cold air mass, creating a gradual slope. Warm fronts usually move from south to north, and are often associated with high pressure systems and gentle winds. Warm fronts can produce clouds, fog, drizzle, and rain, depending on the moisture content and the stability of the warm air. Warm fronts are marked on weather maps by a red line with semicircles pointing in the direction of movement.

3 Frontal zones

A frontal zone is an area where two air masses meet and interact, but do not mix completely. Frontal zones can be several hundred kilometers wide and can last for days or weeks. Frontal zones can produce variable and changing weather conditions, such as wind shifts, pressure changes, temperature changes, and precipitation. Frontal zones are marked on weather maps by a purple line with alternating triangles and semicircles pointing in the direction of movement.

4 Occluded fronts

An occluded front is a boundary where a cold front overtakes a warm front, lifting the warm air mass above the ground and cutting it off from its source of moisture. Occluded fronts usually occur near the end of the life cycle of a low pressure system, when the cold air mass has wrapped around the warm air mass. Occluded fronts can produce clouds, rain, snow, and sometimes thunderstorms, depending on the temperature and moisture of the air masses involved. Occluded fronts are marked on weather maps by a purple line with triangles and semicircles on the same side, pointing in the direction of movement.

6 Frontal passages

A frontal passage is the moment when a front crosses a specific location, causing a noticeable change in the weather. Frontal passages can be identified by observing the changes in temperature, pressure, wind direction, wind speed, cloud cover, and precipitation. Frontal passages can also affect the flight performance, visibility, and safety of an aircraft, so pilots need to be aware of the weather forecasts and the signs of an approaching front. Frontal passages can be challenging or rewarding, depending on the type of front and the preparedness of the pilot.