When a prior passes end an area, it means a change in the weather. Numerous fronts reason weather occasions such as rain, thunderstorms, gusty winds, and also tornadoes. In ~ a cold front, there might be dramatic thunderstorms. At a warmth front, there might be short stratus clouds. Usually, the skies clear when the front has passed.

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What is a Weather Front?

A weather front is a shift zone in between two various air masses at the Earth"s surface. Every air mass has unique temperature and also humidity characteristics. Frequently there is disturbance at a front, i m sorry is the borderline wherein two different air masses come together. The disturbance can reason clouds and also storms.

Instead of leading to clouds and storms, part fronts just reason a change in temperature. However, some storm fronts begin Earth"s largest storms. Tropical waves are fronts that develop in the tropical Atlantic s off the shore of Africa. These fronts can construct into tropic storms or hurricanes if conditions allow.

Fronts move across the Earth"s surface ar over lot of days. The direction of activity is regularly guided by high winds, such together Jet Streams. Landforms prefer mountains deserve to also readjust the route of a front.

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

Cold Front


A side view of a cold front (A, top) and how the is stood for 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 transforms in the weather. They relocate fast, approximately twice as quick as a warm front. As a cold former moves right into an area, the heavier (more dense) cool waiting pushes under the lighter (less dense) warm air, resulting in it to climb up right into the troposphere. Lifted warm air front of the front produces cumulus or cumulonimbus clouds and also thunderstorms, like in the image on the left (A).

As the cold front passes, winds end up being gusty. Over there is a sudden drop in temperature, and also heavy rain, sometimes with hail, thunder, and also lightning. Atmospheric pressure alters from fall to rising at the front. After a cold front moves through your area, girlfriend may notification that the temperature is cooler, the rain has actually stopped, and also the cumulus clouds are changed by stratus and stratocumulus clouds or clear skies.

On weather maps, a cold prior is represented by a hard blue line through filled-in triangles along it, favor in the map ~ above the left. The triangle are like arrowheads pointing in the direction that the former is moving. Notice on the map the temperatures at the ground level change from heat to cold as you cross the former line.

Warm Front


A side see of a heat front (A, top) and also how that is represented on a weather map (B, bottom).

Credit: Lisa Gardiner

A heat front develops when a warm air mass pushes right into a cooler wait mass, displayed in the picture to the right (A). Heat fronts often lug stormy weather as the warmth air mass at the surface rises above the cool waiting mass, do clouds and storms. Warm fronts move much more slowly 보다 cold fronts due to the fact that it is more challenging for the warmth air to press the cold, thick air throughout the Earth"s surface. Warmth fronts often type on the east side that low-pressure solution where warmer wait from the south is thrust north.

You will often see high clouds prefer cirrus, cirrostratus, and also middle clouds choose altostratus front of a warm front. This clouds kind in the warm air that is high above the cool air. Together the prior passes over an area, the clouds become lower, and rain is likely. There deserve to be thunderstorms around the heat front if the wait is unstable.

On weather maps, the surface place of a heat front is represented by a hard red line through red, filled-in semicircles follow me it, like in the map top top the ideal (B). The semicircles show the direction that the front is moving. They space on the side of the line whereby the former is moving. Notice on the map that temperatures in ~ ground level space cooler in prior of the front 보다 behind it.

Stationary Front


A stationary prior is represented on a map by triangle pointing in one direction and also semicircles pointed in the other direction.

Credit:Lisa Gardiner

A stationary front develops when a cold former or warmth front stops moving. This happens when two masses that air are pushing versus each other, however neither is powerful enough to relocate the other. Winds blowing parallel to the front rather of perpendicular can assist it continue to be in place.

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

Because a stationary prior marks the boundary between two waiting masses, there are often differences in wait temperature and also wind top top opposite political parties of it. The weather is often cloudy follow me a stationary front, and also rain or snow regularly falls, particularly if the former is in an area of low atmospheric pressure.

On a weather map, a stationary prior is displayed as alternate red semicircles and blue triangles favor in the photo at the left. An alert how the blue triangles allude in one direction, and the red semicircles suggest in the contrary direction.

Occluded Front


An occluded prior is represented on a weather map through a purple line with alternative triangles and also semicircles.

Credit:Lisa Gardiner

Sometimes a cold front complies with right behind a warmth front. A warmth air fixed pushes right into a colder air mass (the warm front), and also then one more cold wait mass pushes into the warmth air fixed (the cold front). Because cold fronts move faster, the cold front is likely to overtake the heat front. This is known as one occluded front.

At an occluded front, the cold air mass indigenous the cold former meets the cool air the was front of the warm front. The warm air rises as these air masses come together. Occluded fronts usually form around areas of low atmospheric pressure.

There is often precipitation along an occluded front from cumulonimbus or nimbostratus clouds. Wind changes direction together the front passes and also the temperature either warms or cools. After the former passes, the sky is usually clearer, and also the waiting is drier.

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