What is an air front? A front is a weather system that is the boundary separating two different types of air. One type of air is usually denser than the other, with different temperatures and different levels of humidity.
What does an air front often cause?
Many fronts cause weather events such as rain, thunderstorms, gusty winds, and tornadoes. At a cold front, there may be dramatic thunderstorms. At a warm front, there may be low stratus clouds. Usually, the skies clear once the front has passed.
What's an air mass and front?
An air mass is a large body of air with similar properties (like temperature or moisture content). Air masses over water are called maritime air masses, while air masses over land are called continental air masses. The borderline between two air masses is called a front.
Why is an air front called a front?
front, in meteorology, interface or transition zone between two air masses of different density and temperature; the sporadic flareups of weather along this zone, with occasional thunderstorms and electrical activity, was, to the Norwegian meteorologists who gave it its name during World War I, analogous to the ...
How do air fronts work?
Weather fronts mark the boundary between two different air masses, which often have contrasting properties. For example, one air mass may be cold and dry and the other air mass may be relatively warm and moist. These differences produce a reaction (often a band of rain) in a zone known as a front.
Where do fronts form?
Definition. Fronts are boundaries between air masses of different temperatures. Fronts are actually zones of transition, but sometimes the transition zone, called a frontal zone, can be quite sharp. The type of front depends on both the direction in which the air mass is moving and the characteristics of the air mass.
How are fronts created?
When two air masses meet together, the boundary between the two is called a weather front. At a front, the two air masses have different densities, based on temperature, and do not easily mix. One air mass is lifted above the other, creating a low pressure zone.
Why is it called a front?
Front comes from the Latin word for forehead, and it means the side of something facing out, or the part of something (a body, a weather system, a war), that's advancing into a new territory, or frontier.
Why is it called a cold front?
Temperature changes Cold fronts are the leading edge of cooler air masses, hence the name "cold front". They have stronger temperature changes during the fall (autumn) and spring and during the middle of winter.
What are the 4 types of weather?
There are five primary different types of weather that can occur: sunny, rainy, windy, stormy, and cloudy.
What does a cold front look like?
Cold fronts are depicted by blue line with triangles pointing in the direction of motion. Cold fronts demarcate the leading edge of a cold air mass displacing a warmer air mass. Phrases like "ahead of the front" and "behind of the front" refer to its motion.
How long do warm fronts last?
Precipitation associated with a warm front is typically steady and light to moderate in intensity. Due to the slow speed of these fronts, the rain can last several hours or even several days.
What is the difference between a warm front and a cold front?
If colder air is replacing warmer air, it is a cold front, if warmer air is replacing cold air, then it is a warm front.
How are air masses and fronts different?
An air mass is a body of air with a relatively constant temperature and moisture content over a significant altitude. Air masses typically cover hundreds, thousands, or millions of square kilometers. A front is the boundary at which two air masses of different temperature and moisture content meet.
How do fronts relate to air masses?
Fronts are boundaries between air masses. Depending on the air masses involved and which way the fronts move, fronts can be either warm, cold, stationary, or occluded. In the case of a cold front, a colder, denser air mass lifts the warm, moist air ahead of it.
What are the 4 types of air masses?
Air masses are commonly classified according to four basic source regions with respect to latitude. These are Polar (cold), Arctic (very cold), Equatorial (warm and very moist), and Tropical (warm).
How would you describe an air mass?
An air mass is a large body of air with generally uniform temperature and humidity. The area over which an air mass originates is what provides its characteristics. The longer the air mass stays over its source region, the more likely it will acquire the properties of the surface below.
What is the difference between a weather front and an air mass?
Air masses over land are called continental air masses and are much drier. A weather front is a boundary between air masses with different properties.
What is a warm front?
A warm front is an area of warm air displacing cold air. A cold front is an area of cold air displacing warm air. An occluded front is where a cold front catches up with a warm front. This usually happens when two fronts are heading northwards at angles.
What are the different types of weather fronts?
There are four main types of weather fronts: cold fronts, warm fronts, occluded fronts and stationary fronts. The diagram below provides the symbols that are used to represent the different types of fronts that we will examine. A warm front is an area of warm air displacing cold air.
What is the border between two air masses called?
The borderline between two air masses is called a front . There are various types of fronts, including cold, warm, occluded and stationary fronts. A warm front is an area of warm air displacing cold air. A cold front is an area of cold air displacing warm air. An occluded front is where a cold front catches up with a warm front. A stationary front is air of different temperatures that are alongside each other, and not moving relative to each other.
Why do cold fronts cause storms?
This happens because warm air is suddenly forced upwards by the cold air, forming giant clouds. Behind the front, there are usually clear, sunny skies. Formation of Rain Where a Cold Front Advances.
What happens when an occluded front forms?
So when an occluded front is about to form you have cold air behind, warm air in the middle, and cooler air ahead. The air ahead may be colder than the air at the back, or may be warmer. But it's always a cold-warm-cold sandwich.
How long do stationary fronts stay?
Stationary fronts often stay where they are for days, generally until the wind changes or they break up gradually through mixing. Lesson Summary. Let's take a couple of moments to review what we've learned in this lesson. Most weather conditions happen because of movements of air masses.
What is a front in weather?
A front is a weather system that is the boundary separating two different types of air. One type of air is usually dense r than the other, with different temperature s and different levels of humidity.
What are the two main types of fronts?
This clashing of air types causes weather: rain, snow, cold days, hot days, and windy days. Two major types of fronts are cold front s and warm front s . Cold fronts often come with thunderstorm s or other types of extreme weather. They usually move from west to east.
Why do cold fronts move faster than warm fronts?
Cold fronts move faster than warm fronts because cold air is denser, meaning there are more molecule s of material in cold air than in warm air. Strong, powerful cold fronts often take over warm air that might be nearly motionless in the atmosphere.
What is the movement of a cold front through a warm front called?
Because air is lifted instead of being pressed down, the movement of a cold front through a warm front is usually called a low-pressure system. Low-pressure systems often cause severe rainfall or thunderstorms.
What is the definition of a large volume of air that is mostly consistent, horizontally, in temperature and humidity?
Noun. a large volume of air that is mostly consistent, horizontally, in temperature and humidity. atmosphere. Noun. layers of gases surrounding a planet or other celestial body. boundary. Noun. line separating geographical areas. cold front.
What is the boundary between air masses of different temperatures and humidities?
boundary between air masses of different temperatures and humidities. high-pressure system. Noun. weather pattern characterized by high air pressure, usually as a result of cooling. High-pressure systems are usually associated with clear weather. humidity.
What are the lines on a weather map?
On weather maps, cold fronts are illustrated by blue lines with sharp "teeth" pointing in the direction of the wind. Warm fronts are illustrated by red lines with rounded bumps pointing in the direction of the wind. a large volume of air that is mostly consistent, horizontally, in temperature and humidity.
What is stationary front?
A stationary front is characterized by no movement of the transition zone between two air masses.
How do we identify fronts?
We identify fronts by the movement of this transition zone and the properties that move over a geographical location. What weather changes do you expect when TV weather person says a cold front is moving through the area?
What are the two fundamental assertions about weather and why there is weather?
Two fundamental assertions about weather and why there is weather: Differential heating of the surface of the earth. Heating of the lower atmosphere by energy transfer from the surface.
Where does Mt air come from?
mT -- wintertime source for the SW US is the subtropical East Pacific Ocean. mT air that influences weather east of the Rocky Mountains comes from the Gulf of Mexico, but only influences winter weather in the SE states.
How long can air masses control weather?
Air masses can control the weather for a relatively long time period: from a period of days, to months. Most weather occurs along the periphery of these air masses at boundaries called fronts.
What type of front is stationary?
Stationary Front. Another type of front that can be found on a weather map is stationary in nature. In a front of this kind, neither the cold air mass nor the warm air mass is moving. Winds tend to blow along it in opposing directions on each side.
What is an occluded front?
An occluded front occurs when a cold front overtakes a warm front. There are both cold and warm occlusions. In a cold occlusion, the colder air is found behind the front. Conversely, a warm occlusion is characterized by warmer air located behind the front. Winds are either from the east or south before the front passes.
What direction do winds turn when a cold front arrives?
Ahead of a cold front, winds will be southerly before turning toward the west as the front approaches. After the cold front arrives, winds will become northerly .
What is the transition between two different types of air masses called?
The transition between two different types of air masses is called a front. There are four basic types of fronts, and the weather associated with them varies. 1. Cold Front . A cold front is the leading edge of a colder air mass. Temperatures will usually change rapidly over a short distance. Also, there is a sharp change in moisture content; higher ...
Which front tends to move slower?
Thunderstorms sometimes develop ahead of these fronts as the warm air ahead of the front rises over the colder air. 2. Warm Front. Warm fronts tend to move slower than cold fronts and are the leading edge of warm air moving northward. Before the front passes, winds are easterly.
Where do winds shift after a front?
Winds are either from the east or south before the front passes. After the front, winds shift from the west or northwest. Understanding the various types of fronts can help you know what kind of weather to expect when looking at a weather map.
Why are fronts classified as fronts?
Because fronts are zones where temperature opposites meet, weather changes are usually found along their edge. Fronts are classified depending on what kind of air (warm, cold, neither) is advancing onto the air in its path. Get an in-depth look at the main types of fronts.
How does a front get its name?
A front takes its name from two places. It is the literal front, or leading edge, of air that's moving into a region. It is also analogous to a war battlefront where the two air masses represent the two clashing sides. Because fronts are zones where temperature opposites meet, weather changes are usually found along their edge.
How do occluded fronts get their name?
Occluded fronts get their name from the fact that when the cold air pushes underneath the warm air, it lifts the warm air up from the ground, which makes it hidden, or "occluded.". These occluded fronts usually form with mature low-pressure areas. They act like both warm and cold fronts.
What happens when winds blow across the air masses rather than toward one or the other?
This can happen when winds blow across the air masses rather than toward one or the other. Since stationary fronts move very slowly, or not at all, any precipitation that occurs with them can stall out over a region for days on end and cause a significant flood risk along the stationary front boundary.
What happens when one air mass pushes ahead and advances onto the other air mass?
As soon as one of the air masses pushes ahead and advances onto the other air mass, the stationary front will begin to move. At this point, it'll become either a warm front or a cold front, depending on which air mass (warm or cold) is the aggressor. Stationary fronts appear on weather maps as alternating red and blue lines, ...
What happens when a cold front is stationary?
This can happen when winds blow across the air masses rather than toward one or the other .
What happens when warm air moves?
If warm air moves in such a way that it advances onto and replaces the cooler air in its path, the leading edge of the warm air mass found at the earth's surface (the ground) is known as a warm front. When a warm front passes through, the weather becomes noticeably warmer and more humid than it was before.
What is the name of the front?
A front takes its name from two places: it is the literal front, or leading edge, of air that's moving into a region; it is also analogous to a war battlefront, where the two air masses represent the two clashing sides. Because fronts are zones where temperature opposites meet, weather changes are usually found along their edge.
What is an occluded front?
Rachelle Oblack. Updated October 09, 2019. An occluded front is a composite of two frontal systems that merge as a result of occlusion. Cold fronts generally move faster than warm fronts. In fact, the speed of a cold front is about double that of a typical warm front. As a result, a cold front will sometimes overtake an existing warm front.
How do occluded fronts get their name?
Occluded fronts get their name from the fact that when the cold air pushes underneath the warm air, it lifts the warm air up from the ground, which makes it hidden, or "occluded.". Occluded fronts usually form with mature low pressure areas. They act like both warm and cold fronts.
When warm and cold fronts meet, what is an occluded front?
She specializes in climate and weather. An occluded front is a composite of two frontal systems that merge as a result of occlusion. Cold fronts generally move faster than warm fronts.
What happens when a cold front passes through?
When a cold front passes through, the weather becomes significantly colder and drier. (It isn't uncommon for air temperatures to drop 10 degrees Fahrenheit or more within an hour of a cold frontal passage.)
What happens when warm air moves?
If warm air moves in such a way that it advances onto and replaces the cooler air in its path, the leading edge of the warm air mass found at the earth's surface (the ground) is known as a warm front. When a warm front passes through, the weather becomes noticeably warmer and more humid than it was before.
What is a weather front?
A weather front is a term used in meteorology to describe the front end or advancing edge of an air mass that will soon replace the air mass that’s over a specific region. These air masses are designated P for “polar” (cold), T for tropical (warm), M for maritime (wet) and C for continental (dry).
What is a cold front?
Cold fronts. Cold fronts are marked on weather maps with the symbol of a blue line of triangles/spikes (pips) pointing in the direction of travel, and are placed at the leading edge of the cooler air mass. That cold/dense air wedges its way under the warm air out ahead of it. Cold fronts are very much like atmospheric plows, pushing away warm, ...
How do warm fronts work?
Warm fronts are marked on weather maps with a red line of half circles pointing in the direction of travel and mark the edge of an advancing warm air mass; a flow of warmer air that overtakes and replaces colder air. They are usually found on the east side of low-pressure storm systems. Since the cold air is denser than the warm air, the cold air hugs the ground. The lighter warm air slides up and over the cold air (called “overrunning”) and lacks any direct push on the cold air. Thus, the cold air is slow to retreat in the rapid advance of the warm air. This slowness of the cold air to retreat produces an atmospheric slope that is more gradual than the sharper slope that accompanies a cold front.
How fast does a warm front move?
Warm fronts are seldom as well marked as cold fronts, and they usually move about half as fast, at about 10 to 15 mph, and sometimes even slower. This is why precipitation associated with warm fronts is, generally speaking, of a long duration.
What are stationary fronts?
Stationary fronts are depicted by alternating red half-circles and blue spikes (pips) pointing in opposite directions, indicating no significant movement. When neither air mass is replacing the other, the frontal boundary becomes more-or-less stationary; the opposing forces exerted by adjacent air masses of different densities are such that the frontal surface between them shows little or no movement (sometimes also referred to as a “quasi-stationary” front). In such cases, the surface winds tend to blow parallel to the frontal zone. The resultant weather is usually low cloud cover and long duration precipitation, and not much in the way of wind.
What is the metaphor for a cold front?
Another good metaphor for a cold front is that it’s like a hand plane.
Where are warm fronts usually found?
They are usually found on the east side of low-pressure storm systems.
What is frontal zone?
Frontal zones, where lighter air masses are forced over denser air masses, are regions of considerable weather activity. In this chapter, we will consider first the different types of air masses and the weather associated with them, and then the different kinds of fronts and frontal weather.
What is a body of air, usually 1,000 miles or more across, which has assumed uniform characteristics of temperature and moisture?
A body of air, usually 1,000 miles or more across, which has assumed uniform characteristics of temperature and moisture, is coiled an air mass.
What are the two regions of fire?
The region where an air mass acquires its characteristic properties of temperature and moisture is called its source region. Ocean areas, snow- or ice-covered land areas, and wide desert areas are common source regions. Those areas producing air masses which enter the fireoccurrence regions of North America are: 1 The tropical Atlantic, Caribbean, Gulf of Mexico, and the tropical Pacific, which are uniformly warm and moist. 2 The Northern Pacific and Northern Atlantic, which are uniformly cool and moist. 3 Interior Alaska, Northern Canada, and the Arctic, which are uniformly cold and dry during the winter months. 4 Northern Mexico and Southwestern United States, which are usually hot and dry during the summer months.
Where do polar air masses originate?
Continental polar air masses originate in the snow-covered interior of Canada, Alaska, and the Arctic in the colder months. Lower layers of the air become quite cold, dry, and stable. Much moisture from the air is condensed onto the snow surface. These air masses are high-pressure areas, and there is little cloudiness due to the lack of moisture and to the stability of the air mass.
Why do air masses move slowly in summer?
In summer, because of the weaker general circulation, air masses move more slowly and are subject to greater modification. In winter, when the general circulation is stronger, cold polar air masses move rapidly away from their source region and penetrate far southward with little modification.
Why is air mass cooled from below?
An air mass is cooled from below if it passes over a colder surface, or if the surface is cooled by radiation. This increases the stability of the lower layers, and further modification becomes a slow process.
How long does it take for air to cool?
Cooling of the air above the surface must take place by conduction and radiation, and these are slow processes. Thus, a longer time—up to 2 weeks —is required for the development of cold air masses, and even then these air masses are only a few thousand feet thick.
