When a prior passes over an area, it way a change in the weather. Plenty of fronts cause weather occasions such together rain, thunderstorms, gusty winds, and tornadoes. At a cold front, there might be dramatic thunderstorms. In ~ a warmth front, there may be short stratus clouds. Usually, the skies clear when the front has passed.

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What is a Weather Front?

A weather former is a transition zone in between two different air masses at the Earth"s surface. Each air mass has distinct temperature and also humidity characteristics. Often there is disturbance at a front, which is the borderline wherein two different air masses come together. The disturbance can cause clouds and also storms.

Instead of resulting in clouds and also storms, some fronts just cause a adjust in temperature. However, some storm fronts start Earth"s biggest storms. Tropic waves are fronts that construct in the tropic Atlantic s off the coastline of Africa. This fronts can build into dry storms or hurricanes if conditions allow.

Fronts move throughout the Earth"s surface ar over lot of days. The direction of motion is frequently guided by high winds, such together Jet Streams. Landforms like mountains can also change the course of a front.

There are 4 different varieties of weather fronts: cold fronts, warm fronts, stationary fronts, and also occluded fronts.

Cold Front


A side watch of a cold front (A, top) and also how that is stood for on a weather map (B, bottom).

Credit:Lisa Gardiner

A cold front creates when a cold air mass pushes into a warmer waiting mass. Cold fronts can develop dramatic transforms in the weather. They move fast, approximately twice as rapid as a heat front. Together a cold front moves right into an area, the heavier (more dense) cool air pushes under the lighter (less dense) warmth air, resulting in it to climb up into the troposphere. Lifted warmth air ahead of the front produces cumulus or cumulonimbus clouds and thunderstorms, choose in the image on the left (A).

As the cold front passes, winds become gusty. Over there is a suddenly drop in temperature, and likewise heavy rain, sometimes with hail, thunder, and also lightning. Atmospheric pressure changes from falling to rising at the front. After ~ a cold prior moves v your area, girlfriend may notification that the temperature is cooler, the rain has actually stopped, and the cumulus clouds are changed by stratus and stratocumulus clouds or clear skies.

On weather maps, a cold prior is represented by a heavy blue line through filled-in triangles along it, choose in the map ~ above the left. The triangles are prefer arrowheads pointing in the direction the the former is moving. Notice on the map the temperatures at the floor level adjust from heat to cold as you overcome the former line.

Warm Front


A side check out of a warm front (A, top) and how that is represented on a weather map (B, bottom).

Credit: Lisa Gardiner

A warm front creates when a warm air fixed pushes into a cooler waiting mass, shown in the photo to the appropriate (A). Heat fronts often carry stormy weather together the warm air mass at the surface ar rises over the cool air mass, do clouds and storms. Heat fronts move more slowly than cold fronts because it is more daunting for the warm air to press the cold, thick air across the Earth"s surface. Warmth fronts often kind on the east side the low-pressure equipment where warmer waiting from the southern is moved north.

You will regularly see high clouds like cirrus, cirrostratus, and also middle clouds like altostratus front of a warmth front. This clouds kind in the warmth air that is high above the cool air. As the former passes end an area, the clouds come to be lower, and rain is likely. There have the right to be thunderstorms roughly the heat front if the waiting is unstable.

On weather maps, the surface ar of a heat front is stood for by a solid red line with red, filled-in semicircles follow me it, favor in the map on the ideal (B). The semicircles show the direction that the front is moving. They space on the next of the line where the prior is moving. Notification on the map that temperatures at ground level are cooler in prior of the front 보다 behind it.

Stationary Front


A stationary prior is stood for on a map by triangles pointing in one direction and semicircles spicy in the other direction.

Credit:Lisa Gardiner

A stationary front forms when a cold prior or warm front stop moving. This happens when two masses that air are pushing against each other, however neither is powerful enough to relocate the other. Winds blow parallel to the front instead of perpendicular can help it remain in place.

A stationary front might stay put for days. If the wind direction changes, the front will start relocating again, ending up being either a cold or heat front. Or the front may break apart.

Because a stationary front marks the boundary in between two wait masses, there room often distinctions in waiting temperature and wind top top opposite sides of it. The weather is often cloudy follow me a stationary front, and rain or snow regularly falls, particularly if the prior is in an area of short atmospheric pressure.

On a weather map, a stationary front is displayed as alternating red semicircles and also blue triangles choose in the picture at the left. An alert how the blue triangles suggest in one direction, and the red semicircles suggest in opposing direction.

Occluded Front


An occluded prior is represented on a weather map by a violet line with alternating triangles and also semicircles.

Credit:Lisa Gardiner

Sometimes a cold front adheres to right behind a warmth front. A warmth air massive pushes into a chillier air mass (the warm front), and then one more cold waiting mass pushes right into the warm air fixed (the cold front). Due to the fact that cold fronts relocate faster, the cold front is most likely to overtake the warmth front. This is well-known as one occluded front.

At an occluded front, the cold waiting mass native the cold former meets the cool air the was ahead of the warmth front. The warm air rises together these waiting masses come together. Occluded fronts usually kind around areas of short atmospheric pressure.

There is regularly precipitation follow me an occluded front native cumulonimbus or nimbostratus clouds. Wind transforms direction together the front passes and the temperature one of two people warms or cools. After ~ the front passes, the skies is commonly clearer, and the air is drier.

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On a weather map, displayed to the left, one occluded prior looks choose a purple line with alternate triangles and semicircles pointing in the direction the the front is moving. It end at a low press area shown with a huge ‘L’ on the map, starts at the other finish when cold and also warm fronts connect.