Warm front produces what kind of weather

Pilots can expect the weather in the area to persist for several days, and the surface winds will blow parallel to the frontal zone. An occluded front occurs when a fast-moving cold front catches up with a slower warm front. It may benefit you to think of an occluded front as three sections — a cold front, a warm front, and an area of cool air ahead of the warm front.

A cold front occlusion occurs when the fast-moving cold front is colder than the air ahead of the slow-moving warm front, resulting in the warm front being lifted aloft into the atmosphere. This collision of different air masses produces a mixture of weather found in both warm and cold fronts.

Conversely, a warm front occlusion occurs when the air ahead of the slow-moving warm front is colder than air from the cold front. When this happens, the cold front will be lifted above the area of cool air ahead of the warm front, causing severe weather with a relatively unstable lapse rate.

In such situations, embedded thunderstorms, rain, and fog are likely to occur. By understanding the different characteristics of fronts, you can make more informed flight planning decisions. For example, we understand that cold fronts are fast approaching with little warning, and they bring about a complete weather change in just a few hours.

With this knowledge, analyzing a surface analysis chart may favor delaying an intended flight until the front completely passes. If the weather is caused by a stationary or occluded front, it may be best to delay your departure, since those fronts could take several days before the weather becomes conducive to completing your flight. Always obtain a weather briefing before each flight. If you are unsure of the characteristics or effects of an approaching front, a weather briefer can help you understand the impending weather phenomena and associated hazards.

To learn more about fronts and weather systems, reference the Gleim Aviation Weather and Weather Services book! News: To better serve our users and the aviation safety community, SKYbrary is transitioning to a new, more flexible platform mid-November , providing users with a better service and easier access to the wealth of safety knowledge it offers. If you wish to access the latest content from the SKYbrary team, please visit and bookmark www.

When large masses of warm air and cold air meet, they do not mix because of density differences. Instead, they form a front, usually hundreds of miles long.

A Warm Front forms when a relatively moist, warm air mass slides up and over a cold air mass. As the warm air mass rises, it often condenses into a broad area of clouds. The warm air at the surface, behind the warm front, advances slowly, replacing the cold air at the surface. Depending on the amount of moisture available and the intensity of lifting being produced, light to heavy amounts of rain or snow can occur ahead of the surface warm front.

The weather may be cold and clear or only partly cloudy. Winds may continue to blow into the low pressure zone at the front. The weather at a cold front varies with the season. Along a warm front , a warm air mass slides over a cold air mass.

When warm, less dense air moves over the colder, denser air, the atmosphere is relatively stable. Imagine that you are on the ground in the wintertime under a cold winter air mass with a warm front approaching.

The transition from cold air to warm air takes place over a long distance so the first signs of changing weather appear long before the front is actually over you. Initially, the air is cold: the cold air mass is above you and the warm air mass is above it. High cirrus clouds mark the transition from one air mass to the other. Over time, cirrus clouds become thicker and cirrostratus clouds form. As the front approaches, altocumulus and altostratus clouds appear and the sky turns gray.

Since it is winter, snowflakes fall. The clouds thicken and nimbostratus clouds form. Snowfall increases. Winds grow stronger as the low pressure approaches. As the front gets closer, the cold air mass is just above you but the warm air mass is not too far above that. The weather worsens. As the warm air mass approaches, temperatures rise and snow turns to sleet and freezing rain.

Warm and cold air mix at the front, leading to the formation of stratus clouds and fog. An occluded front usually forms around a low pressure system. The occlusion starts when a cold front catches up to a warm front. The air masses, in order from front to back, are cold, warm, and then cold again.