Chapter 24 Section 4 Chapter 24 Section 4 HandoutHandout

Forecasting the WeatherForecasting the Weather

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How did people of early civilizations meet How did people of early civilizations meet the challenges of weather prediction?the challenges of weather prediction? Many attributed weather conditions to gods, Many attributed weather conditions to gods,

and some tried to forecast the weather using and some tried to forecast the weather using the positions of the moon and stars.the positions of the moon and stars.

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Describe the origins of scientific weather Describe the origins of scientific weather forecasting.forecasting. It began with the invention of basic weather It began with the invention of basic weather

instruments such as the thermometer and the instruments such as the thermometer and the barometer.barometer.

The invention of the telegraph in 1844 allowed The invention of the telegraph in 1844 allowed meteorologist to share information quickly.meteorologist to share information quickly.

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List seven types of weather observations List seven types of weather observations reported from weather stations around the world.reported from weather stations around the world. Barometric pressureBarometric pressure Surface windSurface wind PrecipitationPrecipitation TemperatureTemperature HumidityHumidity Cloud coverCloud cover General weather conditionsGeneral weather conditions

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The data that weather stations collect are The data that weather stations collect are transferred:transferred: Onto weather mapsOnto weather maps

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What do meteorologists use to What do meteorologists use to communicate data on a weather map that communicate data on a weather map that can be understood around the world?can be understood around the world? Symbols and colorsSymbols and colors

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A pattern of meteorological symbols that A pattern of meteorological symbols that represents the weather at a particular represents the weather at a particular observing station and that is recorded on a observing station and that is recorded on a weather map is:weather map is: A station modelA station model

Science Word ReviewScience Word Review

Lines that connect points of equal Lines that connect points of equal temperature on a weather map are called:temperature on a weather map are called: IsothermsIsotherms

Science Word ReviewScience Word Review

Lines on a weather map that connect Lines on a weather map that connect points of equal atmospheric pressure are:points of equal atmospheric pressure are: IsobarsIsobars

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What do common weather symbols What do common weather symbols describe?describe? Cloud coverCloud cover Wind speedWind speed Wind directionWind direction Weather conditionsWeather conditions

Type of precipitationType of precipitation Storm activityStorm activity

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Besides cloud cover, wind speed and Besides cloud cover, wind speed and direction, and weather conditions, what direction, and weather conditions, what else do stations models indicate?else do stations models indicate? TemperatureTemperature Dew pointDew point Atmospheric pressureAtmospheric pressure Barometric tendencyBarometric tendency

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What is the dew point and what does it What is the dew point and what does it indicate about the air?indicate about the air? It is the temperature to which the air must cool It is the temperature to which the air must cool

in order for more water vapor to condense in order for more water vapor to condense than to evaporate in a given amount of time.than to evaporate in a given amount of time.

It indicates how high the humidity is, or the It indicates how high the humidity is, or the amount of water vapor there is in the air.amount of water vapor there is in the air.

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On a weather map, what identifies a front?On a weather map, what identifies a front? Sharp changes in wind speed and direction, Sharp changes in wind speed and direction,

temperature, or humidity.temperature, or humidity.

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How are areas of precipitation commonly How are areas of precipitation commonly marked on weather maps?marked on weather maps? With different symbols or colors for different With different symbols or colors for different

kinds and amounts.kinds and amounts.

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How do meteorologists forecast the How do meteorologists forecast the weather?weather? They regularly plot the intensity and path of They regularly plot the intensity and path of

weather systems on maps.weather systems on maps. They make comparisons with recent maps to They make comparisons with recent maps to

follow the progress of weather systems.follow the progress of weather systems. Then they make predictions based on their Then they make predictions based on their

observation.observation.

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What types of weather information can be What types of weather information can be predicted most accurately?predicted most accurately? TemperatureTemperature Wind directionWind direction Wind speedWind speed CloudinessCloudiness PrecipitationPrecipitation

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What types of weather information are What types of weather information are more difficult to predict accurately?more difficult to predict accurately? It is often difficult to predict exactly when It is often difficult to predict exactly when

precipitation will occur or the exact amount.precipitation will occur or the exact amount.

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nowcasts use radar and enable forecasters to focus on

timing precipitation and tracking severe weather

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daily forecasts predict weather for a 48-hour period

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extended forecasts predict weather accurately 3 to 7 days ahead

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medium-range forecasts predict weather 8 to 14 days ahead using

computer analysis of slowly changing large-scale movements of air

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long-range forecasts predict weather over monthly and seasonal

periods

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watch issued when the conditions are ideal for

severe weather

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warning issued when severe weather has been

spotted or is expected within 24 hours

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What is cloud seeding? Particles are added to clouds to cause the

clouds to precipitate

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How has cloud seeding been used in Russia? In Russia, cloud seeding has been used with

some success on potential hail clouds to produce rain rather than hail.

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How have scientists attempted to control hurricanes? Hurricanes have been seeded with freezing

nuclei in an attempt to reduce the intensity of the storm

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Why have scientists abandoned storm and hurricane control? Because it is not an attainable goal with

current technology

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How have scientists attempted to control lightning? by seeding potential lightning storms with

silver-iodide nuclei

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What have been the results of attempts at lightning control? Seeding potential lightning storms has

seemed to modify the occurrence of lightning, but results have been inconclusive.

The EndThe End