Chapter 24 Section 2 Chapter 24 Section 2 HandoutHandout

FrontsFronts

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When two unlike air masses meet, what When two unlike air masses meet, what usually keeps them separate?usually keeps them separate? Differences in densityDifferences in density

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The boundary that forms between two air The boundary that forms between two air masses when they meet is called a:masses when they meet is called a: FrontFront

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Cold front:Cold front: The front edge of a moving mass of cold air The front edge of a moving mass of cold air

that pushes beneath a warmer air mass like a that pushes beneath a warmer air mass like a wedge.wedge.

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Warm front:Warm front: The front edge of an advancing warm air The front edge of an advancing warm air

mass that replaces colder air with warmer air.mass that replaces colder air with warmer air.

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Stationary front:Stationary front: A front of air masses that moves either very A front of air masses that moves either very

slowly of not at all.slowly of not at all.

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Occluded front:Occluded front: A front that forms when a cold air mass A front that forms when a cold air mass

overtakes a warm air mass and lifts the warm overtakes a warm air mass and lifts the warm air mass off the ground and over another air air mass off the ground and over another air mass.mass.

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Describe the storms that form along a cold Describe the storms that form along a cold front.front. They are usually short-lived and sometimes They are usually short-lived and sometimes

violent.violent. A long line of heavy thunderstorms , called a A long line of heavy thunderstorms , called a

squall line, may occur in the warm, moist air squall line, may occur in the warm, moist air just ahead of a fast moving cold front.just ahead of a fast moving cold front.

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What kind of weather does a warm front What kind of weather does a warm front generally produce?generally produce? It produces precipitation over a large area and It produces precipitation over a large area and

may cause violent weather.may cause violent weather.

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The boundary where cold polar air meets The boundary where cold polar air meets the tropical air mass of the middle the tropical air mass of the middle latitudes, especially over the ocean, is latitudes, especially over the ocean, is called the called the ________________.. polar frontpolar front

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Bends that form in a stationary or cold Bends that form in a stationary or cold fronts that are the beginnings of low-fronts that are the beginnings of low-pressure storm centers are called pressure storm centers are called __________.. waveswaves

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Also known as midlatitude cyclones, Also known as midlatitude cyclones, ______________ are low-pressure storm centers. are low-pressure storm centers. wave cycloneswave cyclones

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An area of low pressure that is An area of low pressure that is characterized by rotating wind that moves characterized by rotating wind that moves toward the rising air of the central low-toward the rising air of the central low-pressure region is called a _________ pressure region is called a _________ ____________..

midlatitude cyclone.

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Unlike the air in a midlatitude cyclone, the Unlike the air in a midlatitude cyclone, the air of a(n) air of a(n) __________________ sinks and flows sinks and flows outward from a center of high pressure.outward from a center of high pressure. anticycloneanticyclone

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Describe an anticyclone.Describe an anticyclone. The air of a anticyclone sinks and flows The air of a anticyclone sinks and flows

outward from a center of high pressure.outward from a center of high pressure. Because of the Coriolis effect, the circulation Because of the Coriolis effect, the circulation

of air is clockwise in the Northern of air is clockwise in the Northern Hemisphere.Hemisphere.

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What kind of weather does an anticyclone What kind of weather does an anticyclone Bring?Bring? Dry weatherDry weather If it stagnates for a few days it causes air If it stagnates for a few days it causes air

pollution problemspollution problems If it lingers for a few weeks, it may cause If it lingers for a few weeks, it may cause

droughts.droughts.

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List three weather events that are List three weather events that are considered severe weather.considered severe weather. Large amounts of rainLarge amounts of rain LightningLightning HailHail Strong windsStrong winds TornadoesTornadoes

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Thunderstorms:Thunderstorms: A usually brief, heavy storm that consists of A usually brief, heavy storm that consists of

rain, strong winds, lightning, and thunder.rain, strong winds, lightning, and thunder.

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Lightning:Lightning: Electricity that is discharged during a Electricity that is discharged during a

thunderstorm.thunderstorm.

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Mature stage:Mature stage: The second stage of a thunderstorm, in which The second stage of a thunderstorm, in which

condensation continues as the cloud rises condensation continues as the cloud rises and becomes a dark cumulonimbus cloud, and becomes a dark cumulonimbus cloud, perhaps producing torrential rain and hail.perhaps producing torrential rain and hail.

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Dissipating stage:Dissipating stage: The third stage of a thunderstorm, in which The third stage of a thunderstorm, in which

strong downdrafts stop air currents from rising strong downdrafts stop air currents from rising and the storm dies out as water vapor and the storm dies out as water vapor deceases.deceases.

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Cumulus stage:Cumulus stage: The first stage of a thunderstorm in which The first stage of a thunderstorm in which

warm, moist air rises and water vapor in the warm, moist air rises and water vapor in the air condenses to form a cumulus cloud.air condenses to form a cumulus cloud.

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Thunder:Thunder: An effect created when electricity heats the An effect created when electricity heats the

air, and the air expands rapidly.air, and the air expands rapidly.

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A severe storm that develops over tropical A severe storm that develops over tropical oceans and whose winds of more than oceans and whose winds of more than 120 km/h or 74.56 mph spiral in toward the 120 km/h or 74.56 mph spiral in toward the intensely low-pressure storm center is intensely low-pressure storm center is called a(n) called a(n) ________________.. hurricane.hurricane.

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During a hurricane, large amounts of During a hurricane, large amounts of ____ ____ ________ are released, increasing the force of are released, increasing the force of the rising air.the rising air. latent heatlatent heat

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A fully developed hurricane consists of a A fully developed hurricane consists of a series of thick series of thick ____________________________________________ that spiral upward around the center of the that spiral upward around the center of the storm.storm. cumulonimbus cloud bandscumulonimbus cloud bands

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Winds increase toward the calm, clear Winds increase toward the calm, clear ______ of the storm and may reach speeds of 275 of the storm and may reach speeds of 275 km/h or 170.88 mph.km/h or 170.88 mph. eyeeye

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The most dangerous aspect of a hurricane The most dangerous aspect of a hurricane is a rising sea level and large waves, is a rising sea level and large waves, called a called a ____________________.. storm surge.storm surge.

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Every hurricane is categorized on the Every hurricane is categorized on the ________________________________.. Safir-Simpson scale.Safir-Simpson scale.

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Define tornado:Define tornado: A tornado is a destructive, rotating column of A tornado is a destructive, rotating column of

air that has very high wind speeds and that air that has very high wind speeds and that may be visible as a funnel-shaped cloud.may be visible as a funnel-shaped cloud.

The EndThe End