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

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What is a Weather Front?

A weather front is a transition zone between two various air masses at the Earth"s surface. Each air massive has distinct temperature and humidity characteristics. Regularly there is turbulence at a front, i beg your pardon is the borderline where two different air masses come together. The turbulence can cause clouds and storms.

Instead of leading to clouds and storms, part fronts just cause a readjust in temperature. However, some storm fronts start Earth"s largest storms. Dry waves space fronts that build in the tropical Atlantic ocean off the coast of Africa. This fronts can develop into dry storms or hurricanes if problems allow.

Fronts move across the Earth"s surface over multiple days. The direction of activity is often guided by high winds, such as Jet Streams. Landforms favor mountains deserve to also readjust the path of a front.

There are four different species of weather fronts: cold fronts, warm fronts, stationary fronts, and occluded fronts.

Cold Front


A side view of a cold prior (A, top) and also how the is represented on a weather map (B, bottom).

Credit:Lisa Gardiner

A cold front forms when a cold wait mass pushes right into a warmer wait mass. Cold fronts can produce dramatic alters in the weather. They move fast, approximately twice as fast as a warmth front. Together a cold prior moves right into an area, the more heavier (more dense) cool air pushes under the lighter (less dense) warm air, resulting in it to rise up right into the troposphere. Lifted heat air ahead of the prior produces cumulus or cumulonimbus clouds and thunderstorms, like in the image on the left (A).

As the cold former passes, winds end up being gusty. Over there is a sudden drop in temperature, and additionally heavy rain, periodically with hail, thunder, and also lightning. Atmospheric pressure transforms from fall to climbing at the front. After ~ a cold former moves v your area, girlfriend may an alert that the temperature is cooler, the rain has actually stopped, and also the cumulus clouds are changed by stratus and also stratocumulus clouds or clean skies.

On weather maps, a cold prior is stood for by a heavy blue line with filled-in triangles follow me it, choose in the map top top the left. The triangles are choose arrowheads pointing in the direction the the prior is moving. An alert on the map that temperatures at the soil level adjust from heat to cold as you overcome the front line.

Warm Front


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

Credit: Lisa Gardiner

A warmth front creates when a warmth air massive pushes right into a cooler wait mass, shown in the photo to the right (A). Warm fronts often carry stormy weather as the warm air mass at the surface ar rises above the cool air mass, make clouds and storms. Warmth fronts move much more slowly than cold fronts because it is more difficult for the heat air to push the cold, dense air across the Earth"s surface. Warm fronts often form on the east side that low-pressure systems where warmer air from the southern is pushed north.

You will often see high clouds favor cirrus, cirrostratus, and middle clouds choose altostratus front of a heat front. This clouds form in the warmth air that is high over the cool air. Together the front passes end an area, the clouds become lower, and also rain is likely. There have the right to be thunderstorms about the heat front if the wait is unstable.

On weather maps, the surface place of a heat front is represented by a solid red line with red, filled-in semicircles follow me it, favor in the map on the right (B). The semicircles suggest the direction that the prior is moving. They space on the next of the line where the prior is moving. Notification on the map the temperatures in ~ ground level room cooler in prior of the front 보다 behind it.

Stationary Front


A stationary former is represented on a map by triangle pointing in one direction and also semicircles sharp in the various other direction.

Credit:Lisa Gardiner

A stationary front develops when a cold former or heat front stops moving. This happens once two masses that air space pushing versus each other, but neither is powerful enough to relocate the other. Winds blowing parallel to the front instead of perpendicular can aid it remain in place.

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

Because a stationary former marks the boundary between two air masses, there space often differences in wait temperature and wind ~ above opposite sides of it. The weather is frequently cloudy along a stationary front, and also rain or snow regularly falls, particularly if the former is in one area of low atmospheric pressure.

On a weather map, a stationary prior is shown as alternate red semicircles and blue triangles choose in the photo at the left. Notification how the blue triangles suggest in one direction, and the red semicircles point in the opposite direction.

Occluded Front


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

Credit:Lisa Gardiner

Sometimes a cold front follows right behind a heat front. A warm air mass pushes right into a colder air fixed (the warmth front), and also then an additional cold wait mass pushes right into the warmth air massive (the cold front). Because cold fronts relocate faster, the cold front is most likely to overtake the heat front. This is known as an occluded front.

At an occluded front, the cold wait mass from the cold front meets the cool air that was front of the warm front. The heat air rises as these wait masses come together. Occluded fronts usually type around locations of short atmospheric pressure.

There is regularly precipitation follow me an occluded front native cumulonimbus or nimbostratus clouds. Wind transforms direction as the former passes and the temperature one of two people warms or cools. After the former passes, the skies is generally clearer, and also the wait is drier.

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On a weather map, presented to the left, one occluded front looks like a violet line with alternate triangles and also semicircles pointing in the direction that the former is moving. It ends at a low pressure area shown with a big ‘L’ top top the map, begins at the other end when cold and warm fronts connect.