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Weather and Climate

S8.D.2.1.1-3

Unit 4

Lesson 5

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Weather• Is the condition of the atmosphere including

temperature, pressure, and humidity at a particular time and place

Climate• Is the average weather of an area over a long period

of time• Warmer climates exist near equator and colder

climates exist near poles

Earths Atmosphere

3Temperature changes and the atmosphere

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Air Masses• A large body of air that has the same

temperature and humidity throughout the amt of water vapor in the air

• air masses take on the characteristics of the area over which they form

• over sea (maritime) wet

• over land (cont.) dry

• they move in certain directions

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Air Pressure• Also called Barometric Pressure• Is the weight of the air pushing down on a

particular area

Pressure system

region of atmosphere that has a similar barometric pressure throughout

Two types

1. High Pressure System

2. Low Pressure System

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High Pressure System

• Generally produces clear, dry skies

• If the barometric pressure is rising, a high pressure system is moving in and weather will clear up

Predicting Weather

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Low Pressure System

• Often brings rain or snow

Predicting Weather

•If the barometric pressure is dropping, a low pressure system is moving in and weather will become cloudy and rainy/stormy

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Clouds• When air rises it cools and the water vapor in the air

condensed into tiny liquid droplets which make up a cloud

Nimbus

• producing precipitation

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Stratus clouds

• associated with overcast days

Cumulus Clouds

• puffy white clouds on fair days

•Can turn into storm clouds

Cirrus Clouds

• high, feather-like clouds associated with clear sunny days

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Clouds

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Prevailing Winds• Winds close to the earth’s surface that consistently blow in the same direction

• Can affect an area’s climate

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Effect of Water on Weather

• Large bodies of water (oceans) can store large amounts of heat

• During Cold Months: If water is warmer than air, heat will move to air, bringing warmer weather to cold areas

• During Hot Months: If air is warmer than cool water, heat will move to the water, bringing cooler weather to warm areas

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Effect of Water on Weather

• Because water warms and cools so slowly relative to land and air, areas near large bodies of water tend to have more stable temperatures

• Places located near large bodies of water have warmer winters and cooler summers.

Myrtle Beach will have warmer winters and cooler summers than Columbia

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Lake-Effect Snow• Cold arctic air blows over warmer Great lakes• Air close to lake becomes warm and moist and rises• As it rises, water vapor condenses into clouds• As clouds move over opposite shore, they release snow

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Lake-Effect Snow

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