Earth Science Textbook Chapter 8 Weather

Standards Preview Topography is by the weathering oi rod and soil and by the trans nation and of . As a uh tor understanding this concept . Students know . aria floods ( hang human and . Many phenomena on rants sun lace ue by the ot energy through radiation and currents . As basis tor understanding this content a . Students know the sun IS the major scene of energy lor phenomena on Earths , it powers winds , ocean ( and the water ( we . Students know in pressure , neat . air movement , and humidity result in changes in weather . scientific progress Is made by asking meaningful questions and careful investigations . As I basis tor understanding this concept and addressing the content in the other three strands . students should develop their own questions and Investigations Students . whether ( is lIl with a proposed explanation . interpret events by sequence and time from natural phenomena ( the relative ages at and intrusions ) identity ( in natural phenomena overtime without manipulating the phenomena ( a tree limb , a grave oi trees , a stream , Hurricane Nora approaches California on September ?

1997 .

urns on the I BIG Ideal Which weather factors produce changes in weather ?

Check What You Know Think about the last time you took a hot shower . You may have noticed when you got out that the mirror was covered with a thin film of moisture . Where do you think this moisture came from ?

How did it get there ?

Would the same film of moisture appear if you took a cold shower ?

Why or why not ?

. The images shown here represent some of the key terms in this chapter . You can use this to help you understand the meaning of some key terms in this chapter . Identify Multiple Meanings Some words have more than one meaning . Words you use everyday may have different meanings in science . Look at the different meanings of the words below . Word I Everyday Meaning I Scientific Meaning . A windstorm with a violent whirling movement . a tornado A center of low air pressure Example The forecaster said Example When the touched down , it destroyed the barn . The forward part or surface Example Enter by the door in the front of the house . not the one in back . A member oi your family Example Her brother is her closest relative . the would have clouds . light rain . and moderate winds . The boundary between two air masses of different temperatures and Example Storms often develop along ( toms . Having a particular quality compared to something else Example The temperature here is mild the temperature in Alaska . Apply ! Complete the sentences below with the correct word from the list above . Identify the sentence that uses the scientific meaning . I . A warm will arrive in this area tomorrow . The of the store has a window display of skateboards .

Chapter Vocabulary Vi ' I , Se ( water cycle I I ' evaporation ) I relative humidity I . I , dew point ( cumulus stratus A I , i psychrometer i , condensation I . precipitation Section air mass tropical polar maritime continental front occluded cyclone anticyclone Section storm thunderstorm lightning tornado hurricane storm surge Se ( ti meteorologist isobar isotherm Science ma , Usc Chapter 291

It ?

Compare and Contrast Science texts often make comparisons . When you compare and contrast , you examine the similarities and differences between things , You can compare and contrast by using a table . Follow these steps to set up a table . List the characteristics to be compared across the top of the table List the things to be compared in the left column , Complete the table by filling in information about each characteristic , In this chapter you will learn the term front , which is the area where unlike air masses meet There are four types of fronts . Look at Figure 14 . Then look at the following table . Front I How Forms I Type of Weather ( aid from A air mass overtakes a warm air mass Stationary Apply It ! Answer the following questions in complete sentences . What are the items being compared in this table ?

what are the characteristics that are being compared ?

How does a cold front form ?

After reading Section , make a table for types of precipitation . Complete the table above after you read Section .

. The Weather Tomorrow When the sky turns dark and threatening , it not hard to predict the weather . A storm is likely on its way . But you rather know about an approaching storm before it arrives ?

In this investigation , you will get a chance to make your own weather forecasts and compare them to the forecasts of professionals , Good luck ! Your Goal Predict the weather for your own community and two other locations in the United States . To complete this investigation you must compare weather maps for several days at a time look for patterns in the weather I draw maps to show your weather predictions Plan It ! Begin by previewing the chapter to learn about weather maps and symbols . Stan a project folder to store daily national weather maps and a description of the symbols used on the maps . Choose two locations that are at least kilometers away from your town and from each other . As you collect weather maps , look for patterns in weather changes . Then predict the next day weather and compare your predictions to the professional forecasts and to the actual weather .

Focus 00 Section Water in the Atmosphere Students know the sun is the molar source of energy for phe an Earth surface it ers winds . ocean currents , and the water ( li . Students know differences in presure , heat , air movement , and humidity result in changes in weather . What is humidity and how is it measured ?

How do clouds form ?

What are the three main types ol Key Terms I water cycle ' evaporation I humidity relative humidity I I condensation I dew point ( cumulus I stratus How Does Fog Form ?

Fill a plastic bottle with hot tap water . Four out most of the water . leaving about at the bottom . Avoid spilling hot water . Do not use water that is ro hot that you can not safely hold the bottle . Place an ice cube on the mouth of the bottle . What happens ?

Repeat Steps and using cold water instead of hot water . What happens ?

Think It Over Developing Hypotheses How can you explain your observations ?

Why is there a difference between what happens with the hot water and what happens with the cold water ?

During the air moist . On clear , day , air may dry . As the sun hearts the land and . of ' in the atmosphere . is always moving between the atmosphere and surface . The continuous movement of water between the sphere and Earth surface is called the water cycle . The energy in the form of powers the ' cycle . ever . the Cli . itself has no real beginning or end . As you can see in Figure iter vapor enters the air by oration from the oceans and other bodies of water . Evaporation is the process by which water in liquid water absorb energy and escape into the air as water vapor . vapor is also added to the air by living things . Waiter enters the roots of plants . rim to the leaves . and is ' as vapor . part of the water cycle . some of the miter vapor in ilk condenses to form clouds . Rain and snow fall from the clouds toward the surface . The ' then runs oil the face or moves through the ground . hack into the lakes . streams . and the oceans .

Humidity How is the of water vapor in the sum ?

Humidity is a the amount vapor in the air . ability In hold water vapor depends on ils . air can hold water vapor than cool air . Relative Humidity usually in the in the air in relative humidity . Relative humidity is lhe of vapor that is in lo amount of walL ' vapor air ( air hold at a particular . For , ul ( I cubic nuclei of air can hold at moat gums of vapor . actually were grams ot ' vapor in the . ilk relative humidity of the air would ( Air with relative of lull percent is said In bu , If air grams . relative humidity be half . or 50 . Evaporation lrom oceans . lakes , and streams must Water Cycle In the water cycle , water moves from , lakes , rivers . and plants into the atmosphere and then falls bark to Earth Go Online ( i For Wow ( activity . om Web ( ode Surface runoff

Measuring Relative Humidity Relative humidity . A psychrometer ( sy uh tur ) has two . a thermometer and a , shown in Figure . The bulb of the thermometer has a cloth covering that is moistened with water . When the is slung . or spun by ! its handle . air blows over both thermometers . Because ' the thermometer is cooled by evaporation . its is used to measure . humid , wading drops below that of the . It the relative humidity is high . the water on the wet bulb evaporates slowly , and the does not change much . relative humidity is low , the water on the wet bulb evaporates rapidly , and the temperature drops . The relative humidity can be found by comparing the temperatures of the and thermometers . What instrument measures relative humidity ?

Math Mathematical Reasoning i ) Dal . 31 ' 21 Nadine . 27 to as 76 salsa 43 Determining Relative Humidity Relative humidity is affected . Use the data table to answer the questions below . First . find the temperature in the left column of the table . Then find the difference between the and temperatures across the top of the table . The number in the table where these two readings intersect indicates the relative humidity in percent . interpreting Data At noon , the readings on a sling psychrometer are for the thermometer and for the thermometer . What is the relative humidity ?

interpreting Data At , the psychrometer is used again . The reading on the . Interpreting Data How did relative thermometer is ' and the reading on the humidity change during the course of thermometer is . Determine the day ?

he . Drawing Conclusions How was the relative interpreting Data How did the temperature humidity affected by air temperature ?

change between noon and Explain your answer .

Water vapor , on tiny particles in the air , forming a cloud . Cloud Clouds form when warm . mom moist air rises and cools . air rises from the At a certain Water ' surface As , mo go ' onto tiny particles in the air . rises , it cools . the dew point and condensation begins . How Clouds Form When you look at a cloud , you are seeing millions water or ice crystals . Clouds form when water vapor in the air condenses to form liquid water or to crystals . Molecules of water vapor in the air become liquid water in the process of condensation . How does water in the condense ?

Two are required for cooling of the air and the presence of particles in the air . The Role of Cooling As you learned . cold air holds less water vapor than air . As air cools , the amount of water vapor it can hold decreases . The water vapor condenses into tiny droplets of water or ice crystals . The temperature at which condensation begins is called the dew point . If the dew point is above freezing . the water vapor forum water ' if the dew point is below , the water vapor change directly into ice crystals . The Role of Particles But something else besides in temperature is needed for cloud formation . For water vapor to condense . tiny particles must be present so the water has on which to condense . cloud formation . most of these particles are salt crystals . dust from soil . and smoke . Water vapor also condense onto solid , such at blade of gram or window panes . liquid water that condenses from the air onto Home cooler surface is called dew Ice that has been deposited on a Condensation that is below is called frost . Wale ' Inna to form dew . Predicting what two factors are required for condensation to What Would happen ' SUV , were below freezing ?

a 303 Cirrus Clouds Cumulus Clouds Stratus Clouds types of Clouds Clouds unite in many different ' as in Figure . Scientists classify clouds into three main types based on their shape cirrus . cumulus . and stratus . are further by their altitude . Each type of cloud is with a different type . Cirrus Clouds Wispy . clouds are known as ( Slim us clouds . Cirrus from at word a curl of hair . Cirrus clouds only at high levels . above about kilometers . where are very low . As a result , cirrus clouds are made of ice crystals . Cirrus clouds that have ( hooked ends are sometimes called mare tails . clouds . which look like rows of cotton balls , often indicate that storm is on its way The of clouds look like the scales of a . For this reason . the term mackerel sky is used to describe a sky full of clouds . Cumulus Clouds ( that look like Huffy . rounded piles of cotton are called cumulus ( clouds . The word means heap or in Latin . Cumulus clouds form less than kilometers above the ground . but they may grow in size and height until they extend upward as much as kilometers . Cumulus clouds that are not very tall usually indicate fair weather . These clouds . which are common on sunny days . are called weather cumulus . Towering clouds with tops , called clouds . often produce thunderstorms . The rain . Stratus Clouds Clouds that form in flat il ' are called stratus ( us ) clouds . Recall that straw means spread out . Stratus clouds usually cover all or most of the sky and are a uniform dull . gray color . As stratus clouds thicken . they may produce drizzle . rain . or snow . They are then called clouds . What an stratus clouds ?

Flaunt Fog Around the Golden Gate The cold ocean water of San Francisco Bay is often covered by fog in the early morning . Predicting What will happen as the sun rises and warms the air ?

Section Vocabulary Skill Identify Multiple Meanings Review the two meanings of the word . Then use the meaning in a sentence . Reviewing Key Concepts . Reviewing What is humidity . Comparing and Contrasting How are humidity and relative humidity ?

Calculating Suppose a sample can at most hold grams of water vapor . the actually has grams of water vapor . what is its relative humidity ?

Identifying What process in cloud ?

Summarizing What two conditions are needed for clouds to form ?

Inferring When are ( formed by ice crystals instead of drops of liquid water ?

I a . Listing What are the three main types of clouds ?

Assessment and Part name may be based on its height . The names of clouds that between and kilometers above Earth surface have the , which means The two main types of clouds are and . These an clouds that are higher than regular cumulus and stratus clouds . but lower than citrus and other high clouds . Fog ( that form at or near the ground are called log . Fog often forms when the ground cools at night warm . humid day . The ground cools the air just above the ground to the air dew point . The next day the heat of the morning sun burns the fog off as its water droplets evaporate . Fog is more common in areas near bodies of water or marshy areas . lit mountainous areas . fog can form as warm , moist air moves up the tain slopes and cools . cu . leading . Describing Briefly describe each of the three main types of clouds . Classifying Classify each of the ( loud types as , or . cirrus . cumulus , fog . and stratus . What Is tog ! Water in the Air Fill a large glass half full with cold water . Show your members what happens as you add ice cubes to the water . Explain to your family that the water that appears on the outside of the glass comes trom water vapor in the atmosphere . Also explain why the water on the outside of the glass only appears after you add ice to the water in the glass .

Section Precipitation Focus How Can You Make Hail ?

Put on your goggles . Put 15 of salt into a beaker . Add 50 of water . Stir the solution until most of the salt is . Put 15 of cold water in a clean test tube . Place the test tube in the beaker . Fill the beaker almost to the top with crushed ite . Stir the ice mixture every minute for sin minutes . Remove the test tube from the beaker and drop an ice chip into the test tube . What happens ?

Think it Over Inferring Eased on your observation , what conditions are necessary for nail to form ?

Students know differences In pressure , heat . air movement . and humidity result in changes In weather What are the common types of precipitation ?

Key Term precipitation , Chile . the average rainfall is less than I millimeter per year . But in Hawaii . the average rainfall on Mount is about meters per year . As you can see , rainfall varies greatly around the world . a ( evaporates from every water surface on Earth and from living things . This water eventually returns to the surface as precipitation . Precipitation pree sip uh shun ) is any form of water that falls from clouds and Earth surface . Not all clouds produce precipitation . For Drop an to occur . cloud droplets or ice crystals ( Diameter ) must grow heavy enough to fall through the Om way that cloud droplets grow is by colliding ' and combining with other droplets . As the ) lets grow larger . they move faster and collect more small droplets . the droplets become heavy enough to fall out of the cloud as raindrops . Water Droplets ?

Droplets come In many sizes . Believe it or not , a raindrop has about one million times as much water in it as a cloud droplet . 0307 of Precipitation In warm parts of the world , precipitation is almost always in the form of rain . colder . precipitation may fall as For Links on snow or ice . Common types of include rain , hail , snow , sleet , and freezing rain . Wet Code Rain The most common kind of precipitation is rain . Drops all water are called rain it they are at least millimeter in . Precipitation up of smaller drops of water is called drizzle . Precipitation of even smaller drops is called mist . Drizzle and mist usually fall from stratus clouds . Hail Round pellets larger than millimeters in diameter are called . Hail forms only inside cumulonimbus clouds during thunderstorms . A hailstone starts as an ice pellet inside a region ofa cloud . Strong updrafts carry the stone up through the cold region many times . Each time the HOW Hill goes through the cold region , a new layer of ice forms ' around it , Eventually the hailstone becomes heavy enough to ice in cumulonimbus clouds . They . grow lame , we , fall to the ground . If you cut a In half , you often see up am down , mu they shells of ice . like the layers of an onion , as shown in Figure . WONG 50 IVY MY Because hailstones can grow quite large before falling to the ground . hail can cause tremendous damage to crops . ings , and . Interpreting Diagram Why do grow larger as they are tossed up and down in a ( loud ?

Tiny Ice pellets are tossed up and down In cumulonimbus clouds , Eventually the ice pellets grow heavy Enough to fall to the ground as MIL Target Reading ( compare and Contrast Reviewing Key Concepts . Snow Often water vapor in is converted directly into ice called . Snowflakes have an endless number of shapes and patterns , all with six sides or . snow it produced when snow falls , dry air . When mow falls through humid air that is clow to , tend to join together into larger clumps in which the individual crystals are hard to see . raindrops fall through a layer of air that is ( the point of water . As they fall . the raindrops into solid particles of ice . ice particles smaller than in are . Freezing Rain raindrops lalling through cold air near the ground do not in the air . Instead . they freer when they touch a cold surface . This kind of precipitation is rain . In an ice storm . thick layer til builds up on . This can produce beautiful as it ' trees and . weight of the ice may tree branches and cause them to fall onto power lines . causing failures . min and can make and road slippery and dangerous . What is sleet ?

Assessment Section a table for type uf , Huw du rain , sleet . and hail ?

a . Listing Name the live common types ul . Comparing and Contrasting I and and elect . Haunt are tiny ice crystals . They all have six sides or . Reading . Ell Relating Cause and du in clouds ?

a . Relating Cause and What condition an necessary rain to ( ing in Science Account Think about the most . Classifying A exciting experience you have had with precipitation in form of ice ) 5500 that an about ( in . type of wuuld ( hi . precipitation itself as well as the effect it 309 Ell

Section Air Masses and Fronts . Focus Students know differences in pressure , heal . air movement , and humidity result changes in weather . What are the major types of air mass in North America , and how do they move ?

What are the main types of ?

what type of weather is associated with cyclone and ?

Key learns a moss I tropical I polar I maritime I continental I from I occluded I cyclone I anticyclone Finn ! Ill Major In winter , humid air masses bring heavy to areas like New City . 310 How Do Fluids of Different Densities Behave ?

Put on your apron . Place a cardboard divider across the middle of a plastic shoe box . Add a few drops of red food coloring to a liter of warm water . Pour the red liquid . which represents warm air , into the shoe box on one side divider . Add about 100 of table salt and a few drops oi blue food coloring to a liter of cold water . Pour the blue liquid . which represents cold air , into the shoe box on the other side of the divider . What do you think will happen it you remove the divider ?

Now quickly remove the divider . Watch carefully from the side . What happens ?

Think It Over Developing Hypotheses Based on this activity , write a hypothesis stating what would happen it a mass of cold air ran into a mass of air . Listen to the evening news in the winter and you may hear a weather forecast like this A huge mass of Arctic air is moving our way . bringing freezing weather can be by air from thousands of kilometers perhaps from Canada or the Ocean . A huge body of air that has similar . humidity . and air pressure at any given height is called an air mus . A single air mass may spread over millions of square kilometers and be up to 10 kilometers deep .

Types of Masses Air Masses Scientists classify air according to two tem and humidity . Four major types of air masses the weather in North America maritime tropical , continental tropical . maritime polar , and continental polar . The characteristics of an air mass depend on the and moisture content of the region over which the air mass forms , Remember that temperature air pressure . Cold , dense air has a higher pressure . while warm , less dense air has a lower pressure . Tropical , or warm . air masses form in the tropics and . have low air pressure . Polar . or cold , air masses form north of St ) north latitude and south of south rude . Polar air have high air pressure . Whether an air mass is humid or dry depends on whether it forms over water or land . Maritime air masses form ( tropical 11 Air masses can be over oceans . evaporates from the oceans . so the air can merging 10 meg , humid . air masses form over land . and humidity Identifying ( air have less exposure to large amounts ' ol moisture from bodies of water . Therefore , continental arr mom masses are drier than maritime air masses . Maritime Tropical , humid air masses form over tropical oceans . Maritime tropical air that form over the Gull of Mexico and the Atlantic Ocean move tirst into the southeastern United States . These air masses then move north and northeast . where they influence weather in the central and eastern United States . in the west , maritime tropical air form over the Ocean . They mainly the weather on the West Coast . As they cross the coastal mountain ranges . the air masses lose moisture . in summer . maritime tropical air masses usually bring hot . humid weather Many summer showers and in the United States develop in air that have formed over the Gulf of Mexico In winter . a humid air mass can heavy rain or snow .

your air masses from the Pacific bring cool . humid air to the West Coast . air man from the Pacific Ocean bring warm . humid air to California and the Coast . Frau 11 Air masses ( an be warm or cold . and humid or dry . As an air mass moves into an area . the weather changes . 31 ! North American Air Masses polar mum from central and northern Canada bring cold air to the central and eastern United States . pol tram the Atlantic Ocean are often pushed out to sea by westerly winds . continental tropical air masses from the South bring hot , dry air to the southern plains tropical air mum from the Gulf of bring warm , the eastern United States . Maritime Polar Cool . humid air masses form over the icy cold North and North Atlantic oceans . Maritime polar air masses affect the West Coast more than the East Coast . Even in summer . these masses of cool . humid air often bring fog . rain . and cool temperatures to the West Coast . Continental Tropical Hot , dry air masses form mostly in summer over dry areas of the Southwest and northern Mexico . Continental tropical air masses cover a smaller area than other air masses . occasionally move northeast . bringing hot , dry weather to the southern Great Plains . Continental Polar Large continental polar air masses form over central and northern Canada and Alaska , as shown in Figure . Air masses that form the Arctic Circle can bring bitterly cold weather with very low humidity . In winter . polar air masses bring clear , cold , dry air to much of North America . In summer , the air mass is milder . Storms may occur when continental polar air masses move south and lide with maritime tropical air masses moving north . Where do continental polar ii masses come horn !

How Air Masses Move When an air mass into an area and ?

with other air masses . it causes the weather to change . In the continental United States . air masses are commonly moved by the prevailing westerlies and jet streams . Prevailing Westerlies The prevailing . the major wind belts over the continental United States . generally push air masses west to mist . For . maritime polar air the Ocean are unto the ( bringing low and . Jet Streams within the are jet streams . Recall that jet are hands of winds about ) kilometers Earth surface . streams blow from west to ' are carried along their tracks . Fronts As huge ol air move across the land and the oceans , collide with each other . But the air do not easily mix . Think about a bottle and water . The less dense oil limits on top of the denser waiter . Something similar when two air with temperatures and collide . The air do not easily mix . The boundary where the masses meet a front . and changeable develop tilting fronts . as shown in Figure 13 . Warm air mass Calculating When planes fly from west to east , they fly with the jet stream , and can fly faster . When traveling from east to west . planes fly against the jet stream , and travel slower . To calculate the rate at which the planes fly , divide the distance traveled by the time it takes . Rate a Dish Time If a plane flies from Denver , Colorado . to New York City . a distance of about kilometers , it takes about hours and 30 minutes . The return takes about hours . Calculate the rates of air travel . in , in each direction . How much extra speed does the jet stream add to the ?

Flaunt 13 How Front Forms The boundary where unlike air masses meet is called a front . A front may he to 600 kilometers wide and extend high into the troposphere . 313 Types of Fronts there are four types oi cold fronts , warm fronts . stationary fronts . and occluded fronts . Interpreting Diagrams What kind of weather occurs at a warm front ?

Classifying At home . watch the weather forecast on television . Make a note of each time the weather reporter mentions a hunt . Classify the fronts mentioned or shown as cold , wann , stationary , or occluded . What type oi weather is predicted to occur when the front arrives ?

Note the specific weather conditions . such as temperature and air pressure , associated with the front . each type of front always associated with the same type of weather ?

A Warm From A warm air mass overtakes a cold air mass . Cold Front A cold air mass overtakes a warm air mass . of Fronts air masses can form four types of fronts cold fronts . warm fronts . stationary fronts . and fronts . The kind of front that develops depends on the characteristics of the air masses and how they are moving . Cold Fronts As you have learned . cold air is dense and tends to sink . Warm air is less dense and tends to rise . When a rapidly moving cold air mass runs into a slowly moving warm air mass . the denser cold air slides under the lighter warm air . The warm air is pushed upward along the leading edge of the colder air . as shown in Figure 14 . A cold from farms . As the warm air rises . it expands and tools . Remember that air can hold more water vapor than cool air . The rising air soon reaches the dew point , the temperature at which the water vapor in the air condenses into droplets of liquid water or forms tiny ice crystals Clouds . if there is a lot of water vapor in the warm air . heavy rain or snow may fall . the warm air mass contains only a little water vapor . then the cold front may be accompanied by only cloudy skies . Since cold mats tend to move quickly . they can cause abrupt weather changes , including thunderstorms , After a cold front passes through an area . colder . drier air moves in . often bringing clear skies . a shift in wind . and lower temperatures . gram ) What type of weather do cold bring ?

314 stationary from Cold and warm air masses meet , but neither can move the other . warm air occluded Front A warm air mass is caught between two cooler air masses . Go Online . For activity Warm Fronts Clouds and precipitation also accompany Visit warm fronts . At a warm front . a warm air mass ' overtakes a slowly moving cold air mass . Because cold air is denser than warm air . the warm air moves over the cold air . If the warm air is humid , light rain or snow falls along the front . if the warm air is dry . scattered clouds form . Because warm fronts move slowly . the weather may be rainy or cloudy for eral days . After a warm front passes through an area . the weather is likely to be warm and humid . Stationary Fronts Sometimes cold and warm air masses meet . but neither one can move the other . The two air masses face each other in a standoff . In this case . the front is called a stationary from . Where the warm and cool air meet . water vapor in the warm air condenses into rain . snow . fog , or clouds . if a stationary front remains stalled over an area . it may bring many days of clouds and precipitation . occluded Fronts The most complex weather situation occurs at an occluded front . where a warm air mass is caught between two cooler air masses . The denser cool air masses move underneath the less dense warm air mass and push the warm air upward . The two cooler air masses meet in the die and may mix . The temperature near the ground becomes cooler . The warm air mass is cut off , or occluded , from the ground . As the warm air cools and its water vapor condenses . the weather may turn cloudy and rain or snow may fall . 315

FIGURE 15 Structure of and Winds spiral inward toward the pressure ( enter of a cyclone . Winds spiral outward from the center of an . Diagrams Do cyclone winds spin clockwise or counterclockwise in the Northern Hemisphere ?

Cyclone ( Low ) High ) 316 Cyclones and As air masses to form fronts , the boundary between the fronts sometimes becomes distorted . This distortion can be caused by surface features , such as mountains . or strong winds , such as the jet stream . When this happens , bends can develop along the front . The air begins to swirl . The swirling air can cause a pressure center to form . Cyclones If you look at a weather map . you will see areas marked with an The stands for and indicates an area of relatively low air pressure . A ing center of low air pressure is called a cyclone , from a Greek word meaning . As warm air at the center of a cyclone rises . the air pressure decreases . Cooler air blows toward this pressure area tram nearby areas where the air pressure is higher . As shown in Figure winds spiral inward toward the center of the system . Winds in a cyclone spin counterclockwise in the when viewed from above . in the Southern Hemisphere . winds spin in a clockwise direction . Cyclones play a large part in the weather of the United States . As air rises in a cyclone , the air cools . forming clouds and precipitation . and decreasing air pressure are associated with clouds . wind . and precipitation . As its name suggests , an is the opposite of a cyclone . are pressure centers of dry are usually called highs on a weather map . Winds spiral ward from the center of an anticyclone . moving toward areas of lower pressure . Because of the . winds in an anticyclone spin clockwise in the Northern Hemisphere . Because air moves out from the center of the anticyclone . cool air moves downward From higher in the . As the cool air falls . it warms up , so its relative humidity drops . The descending air in an generally causes dry . clear weather . What is an

mun 16 Highs and Lows The satellite image shows a area ( over the Northeast and pressure areas ( over the South and West . areas usually have clear skies . areas often bring . Reading section Assessment , Vocabulary Skill Identify Multiple Meanings Identifying What is I cyclone ?

913317 UM he ( in a . and Huw dug , air Then use the everyday meaning in sentence . iii an ?

dues ' I I Ev ew ey ( Comparing and Contrasting MINT i MINT i . Reviewing What two characteristics are used and What ' lly all 35 ?

is each ?

INT . Classifying Classify the four major types according to are dry . i i . Applying Concepts ' In would form over the Atlantic ( ci ani ' Suppose You we a . Defining a ?

wad , pom wring . Describing Name the types ! iron ! and . a mid upon to plain describe the type of weather each brings . to he ! used the i mi ?

i i . What iif would most be for several days 01 rain and ?

Section Storms AL ! Standards Students know quakes . volcanic eruptions . slides , and floods ( hange human and habitats . Students know differences in pressure , heat , air movement , and humidity result in changes in weather . What are the main kinds of storms and how do they form ?

what measures can you take to ensure safety in a storm ! Key Terms ' storm I thunderstorm I lightning I tornado I storm surge Can You Make a Tornado ?

Fill a large jar full with water . Add a drop of liquid dish detergent and a penny or a marble . Put the lid on the jar tightly . Now move the jar in a circle until the water inside begins to spin . Think It Over Observing What happens to the water in the jar ?

Describe the pattern that form . How is it like a tornado ?

Unlike a tornado ?

As a storm rages . lightning and thunder rumbles . After the sky . dripping trees and numerous puddles are the only of the passing storm Right ?

Nut ) Scientists search for other ! When lightning strikes sand or sandy soil . the sand grains are fused together to form . The shape of the fulgurite reflects the path of the light ning ball that it , as shown in Figure . These structures i show the power of storms . A storm is violent in the . Storms sudden in air pressure . which in turn cause air . Conditions bring one kind til storm often cause other kinds of in the same area . For . the conditions that cause can also cause tornadoes . There are types ul severe storms . 318 17 A forms when lightning strikes sand or sandy soil . The temperature of the lightning is so high that it the sand and forms a UR

I lY Vil I Cold air moves A downward . Warm . humid ' air rises . Thunderstorms Do you thunderstorms frightening ?

Exciting ?

As you watch the brilliant flashes of lightning and listen to long rolls of thunder . you may wonder what caused them . How Thunderstorms Form A thunderstorm is a small often accompanied by heavy precipitation and frequent thunder and lightning . form in large cumulonimbus clouds . also known as thunderheads . Most cumulonimbus clouds form on hot , humid afternoons . They also form when warm air is forced upward along a cold front . In both cases . the warm . humid air rises rapidly . The air cools . forming dense . Heavy rain falls . sometimes along with hail . Within the thunderhead are strong upward and downward and shown in Figure . Many thunderstorms form in the spring and summer in southern states or on the Plains . Lightning and Thunder During a thunderstorm , areas of positive and negative electric charges build up in the storm clouds . lightning is a sudden spark , or electric discharge , as these charges between parts of a cloud . between nearby clouds . or between a cloud and the ground . Lightning is similar to the shocks you sometimes feel when you touch a metal object on a very dry day . but on a much larger scale . What thunder ?

A lightning bolt can heat the air near it to as much as , much hotter than the sun . The rapidly heated air expands suddenly and explosively . Thun der is the sound of the explosion . Because light travels much faster than sound . you see you hear thunder . Raul ! Thunderstorm Formation A thunderstorm forms when warm . humid air rises rapidly within I cumulonimbus cloud . Applying Concepts clouds often along ( old fronts ?

ram Lightning Distances Because light travels faster than sound . you see a lightning flash before you hear the clap of thunder . Here how to calculate your from a thunderstorm . CAUTION do this activity inside a building . Count the number of seconds between the moment when you see the lightning and when you hear the thunder . Divide the number at seconds you counted by three to get the approximate distance in kilometers . Example 155 ' Calculating Wait for another lightning flash and calculate the distance again . How can you tell whether a is moving toward you or away from you ?

319 Thunderstorm Damage Thunderstorms can cause . The heavy with can areas . Lightning can also cause . lightning strike the ground . the hut . expanding air can shatter tree trunks or start forest . When lightning strikes people or animals . it acts like a powerful electric shock . lightning can cause ) serious , or even heart failure . Floods A major danger during severe thunderstorm is . occur when so much water pours into at or river that its banks , the rounding land . In urban areas . can occur when the ground is already saturated by heavy . The water can ! soak into the ground or the many areas covered with buildings . roads . and parking lots . can bury or away human and wildlife . However , may also have . For example . river can provide rich new soil for agriculture . Thunderstorm safety The safest place to be during a thunderstorm is indoors . if you are inside a house . avoid touching telephones , electrical , or plumbing . all of which can conduct . It is usually sale to stay in a car with a hard top during a thunderstorm . The will move along the metal akin ofthe car and to the ground . During , avoid places where lightning may strike . Also avoid objects that can conduct electricity . such as metal objects and bodies of water . How can you stay safe if you are caught outside during a ?

Do seek shelter under a tree , ning may strike the tree and you . Instead . at low area from trees . fences . and poles . If you are swimming or in 19 a boat , get to shore and find shelter away from the water . Lightning Striking Earth lightning occurs when electric charge jump within clouds . between , or between clouds and the ground . Lightning can cause fires or serious injuries . A tornado is one most frightening and types tornado is a rapidly whirling . cloud Mine that reaches down from a storm cloud to touch surface . If a tornado occurs over lake or ocean . the storm is known as a . Tornadoes are usually brief . but can be deadly . They I uy touch the ground for I minutes or lots and be coda ( only a few hundred meters across . But wind speeds iii the most intense tornadoes may approach 500 kilometers per ) How can lightning be dangerous ?

For More on thunder and lightning 3200 warm air begins to rotate as , moist air In at the bottom of a cumulonimbus cloud and moves upward . A low pressure area forms inside the cloud . How Form Tornadoes can form in any ation that produces severe weather , Tornadoes most commonly develop in thick cumulonimbus some clouds that bring thunderstorms . Tornadoes are most likely to occur when thunderstorms are spring and early summer . often late in the when the ground is wann , The Great Plains often have the kind of weather pattern that is likely to create tornadoes A warm , humid air mass moves north from the Gulf of Mexico into the lower Great Plains A cold . dry air mass moves south from Canada . When the air masses meet . the cold air moves under the warm air . forcing it to rise . A squall line , or narrow band of , is likely to . with storms traveling from southwest to east . A single squall line can produce ten or more tornadoes . Tornado Alloy Tornadoes are rare in California . but about 800 tornadoes occur in the United States every year . Weather patterns on the Great Plains result in tornado alley . as shown in . However . tornadoes can and do occur in nearly every part of the United States . tornado Safety The safest place to the basement of a building . Stay away from windows and doors to avoid debris Lie on the floor under sturdy piece of furniture . such as a large table . if you are outdoors , lie flat in ditch . Wa . humid alr it meets winds blowing in different directions at diflerent altitudes . QA tornado forms as part of the cloud descends to earth In a tunnel . Tornado Alley Tornadoes in the . are most to occur in a region known as Tornado Alley . Interpreting Maps Name states that Tornado crosses . moves north from the Gull of Mexico . 311

In the winter in the northern United and at high tions , a amount of precipitation falls as snow . All year round , most precipitation begins in clouds as snow . the air is colder than all the way to the ground , the precipitation falls snow . In California . generally occur only at high tions . such as on Mount Shasta or the Sierra Nevada mountain range . However . Californians depend on snow to provide part of their fresh water needs . of the snow that accumulates in the mountains during the winter months melts in the spring and summer . This provides fresh water for a variety of needs . including irrigation and electricity production . Science and History Weather That Changed History storms have caused incredible damage , killed large of people , and even changed the course of history . 3220 1558 England II of Spain sum the Spanish Armada , a fleet of ships . to Invade England . Strong In the Channel trapped the Armed near shore . Some ships escaped , but storms wrecked non .

Imagine being caught in a snowstorm when the wind picks up High winds can blow falling snow sideways or pick up snow from the ground and suspend it in the air . This situation can be extremely dangerous because the blowing snow limits your vision and makes it easy to get lost . Also , strung winds cool a person body rapidly . Heavy can block roads , trapping people in their homes and making it hard for vehicles to move . If you are caught in a snowstorm , and Ma try to shelter from the wind . lover exposed parts of your Many of em body and try to stay dry . If you are in a car , the driver should happened before keep the engine running only if the exhaust pipe is clear of snow . had he equipment to predict ' i . now , may weather scientifically . we Research one of the events in the . Write an expository essay describing the event and how history might have been different it the people involved had had accurate weather predictions . 1900 and 1915 Texas when a hurricane struck the port city of In it killed at least ! people and destroyed much of the city . I result . a meters high and 16 kilometers long was . When another hurricane struck in . the seawall the amount of damage . 1337 North Carolina The steamship Home unit during a hurricane off . North Carolina . In one of the worst used dinner at sea . 90 people died . in response . the us . Congress passed a law requiring ships to any a life preserve or every Chapter 323

near the top at the hurricane . Warm . moist air rises around the eye and in spiraling bands of clouds . of Hurricane In a hurricane , air moves rapidly around a area called the eye . Video Field Trip I ) School Weather Patterns a . sinks In the eye . the center of the hurricane . Hurricanes A hurricane is a tropical cyclone that has winds of I ters per hour or higher . A typical hurricane is about 600 meters across . Hurricanes form in the Atlantic . and Indian oceans . in the western Ocean . hurricanes are called . How Hurricanes Form A typical hurricane that strikes the United States forms in the Atlantic Ocean north ol . the equator in August . September . or October . A hurricane begins over warm ocean water as a area , or tropical disturbance . If the tropical disturbance grows in size and strength , it becomes a tropical storm , which may then a hurricane . A hurricane draws its energy from the warm . humid air at the oceans surface . As this air rises and forms clouds . more air is drawn into the system . Inside the storm are hands of very high winds and heavy rains . spiral inward toward the area of lowest pressure at the center . The lower the air pressure at the center of a storm . the faster the winds blow toward the center , Hurricane winds may be as strong as 320 per hour . Look at Figure 22 . Hurricane winds are strongest in a nar row band around the center of the storm . At the center is a ring of clouds . called the . that enclose a quiet eye . The wind gets stronger as the eye approaches . When the eye arrives , the changes suddenly . The air grows cairn and the sky may clear . After the eye passes . the storm resumes , but the wind blows i from the opposite direction .

How Hurricanes Move ' il last longer than other . usually week or more . luring that period . they can quite fair . a form in the ! steered hy trade ( the islands and the United August 25 States , After hurricane passes over land . no longer has warm . moist air to draw energy I August 24 from . It loses , although ' 13 tut several . Hurricane Damage When hurricanes crime ashore . they high ' and severe at well as wind . path of Andrew The low ' and high winds til over the ocean ave , hue days ( in be mite the level oi the water up to meters above normal sea seen in this photo montage . level . The result is it storm surge , dome til ' the roast where the lands . Storm surges can great , along the eroding . Hurricane Safety Until the . could strike with little . People now receive tion well in advance of an . hurricane that are expected within 24 hours . If you hear a hurricane warning and are told to evacuate . leave the area immediately . section Assessment Vocabulary Skill Identify Multiple Meanings a . Defining ! HINT how A it . Explaining form ! i ) the , of cause and men an as ?

Reviewing Key Concepts . Defining is a ?

Describing What AC you ' during ?

tire likely to ( Developing Hypotheses often in ' Alley ?

A Explaining dues reach the ground as snow ?

should you do it you in ?

Eyewitness Interview a family member or other adult about a storm that he or she has experienced . Before the interview , make a list of questions you would like to ask . For example , when and where did the storm occur ?

Write up your interview in a format , beginning with a short introduction .

kills Lab Guided , Tracking a Hurricane ' Problem How can you predict when and where a hurricane will come ashore ) Skills Focus Interpreting data . predicting . drawing conclusions tracing paper Procedure . Look at the plotted path of the hurricane on the map . Each dot the location of the eye of the hurricane at intervals . The last dot shows where the hurricane was located at noon on August red , blue , green , brawn . Predict the path you think the hurricane will take . Place tracing paper over the map below . Using a red pencil . place an on your tracing paper where you think the hurricane will first reach land . Next to your write the date and time you think the hurricane will come ashore . Hurricane warnings are issued for an area that is likely to experience a hurricane within 24 hours . On your tracing paper . shade in red the area for which you would issue a hurricane warning , i ) III in ! ii 3260

. Using the following data table , plot the next five positions for the using a blue pencil . Use your ruler to connect the dots to show the hurricane path . Data Table mime ' Data and Time Aqua . I . August . midnight Run at . A . AL ' 31 , 2535 ii , Based on the new data , decide if you need to change your prediction of where and when the hurricane will come ashore . Mark your new predictions in blue pencil on your tracing paper . During September you obtain four more positions . Plot these points only after you have completed Step . Based on these new data , use the green pencil to indicate when and where you now think the hurricane will come ashore . Data Table Data and Time Latitude , a , MA . The next day . September you plot four more positions using a brown pencil . Plot these points only after you have completed Step . Data Date and Time Latitude ' 1675 , mint run . Analyze and conclude . Interpreting Data Describe in detail the complete path of the hurricane you tracked . Include where it came ashore and identify any cities that were in the vicinity . Predicting How did your predictions in Steps . and compare to what actually happened ?

Interpreting Data What was unusual about your hurricane path ?

Inferring How do you think hurricanes with a path like this one affect the issuing of hurricane warnings ?

Drawing Conclusions Why do you have to be so careful when issuing warnings ?

What problems might be caused if you issued an unnecessary hurricane warning ?

What might happen if a hurricane warning were issued too late ?

Communicating In this activity you only had data for the hurricane position . If you were tracking a hurricane and issuing warnings , what other types of information would help you make decisions about the hurricane path ?

Write a paragraph describing the additional information you would need . More to Explore With your teacher help , search the Internet for more hurricane tracking data . Map the data and try to predict where the hurricane will come ashore .

Section Predicting the Weather 55 Up What the Weather ?

Look at the weather report in your local newspaper . Note what weather conditions are predicted for your area today , including temperature , precipitation , and wind speed . Look out the window or think about what it was like the last time you were outside . Write down the actual weather conditions where you are . It Over Observing Does the weather report match what you observe ?

What is the same ?

What is different ?

Students know differences in pressure , heat , on movement , and humidity result in ( in weather ( How do weather forecasters predict the weather ?

What can be learned the information on weather maps ?

Key Terms I meteorologist isobar ' Every culture folklore includes weather sayings . Many of ' on ( Il ' pilots , and others who work outdoors are usually of clouds . winds . and other signs of changes in the weather . arc below . Why ( Yl ) agree that a red sky bad ' Recall that in the United usually move from west to cast . Clouds in the west may cate an low area . bringing stormy weather . there are high clouds in the west in the rising sun in the . turm clouds red . The is at sunset . As the sun sets in the west . it turns clouds in the cast . Clouds in the cast may indicate that at storm is moving to the east , A red sky is one kind of that helps 24 people to predict the weather . led sky The red sky shown in this sunrise may indicate an approaching storm . th ! and morning Will Bring down rain uPon his head .

Haunt 25 Meteorologist at Work use computers to help track and forecast the weather . Inferring Why might need to refer to more than one computer screen Weather Forecasting tint lap in is In coll clam , either lI tun . direct or through the use of ' tan ' in . uit usually . possibly ' rain or web Making Simple Observations can in ( lI ( warm ' uit ' you we taller . you can expect them to . may ' li ( you can sec thin ( tut high in sky . 11 . Even ' li ) turn to lot . tee uh uh are scientists who the ot try In it . Interpreting Complex Data able to ul ' local , instrument carried by . satellites . around the world . use maps , charts , and to analyze weather data and to prepare weather forecasts . They use to track ' rain ' and to locate severe storms such as . um i . When du . I gel ?

from the nu . iu . radar . and ta gather data . Whatis a meteorologist ?

Frau ! 16 from many weather stations . I 20 25 31 32 37 43 45 50 54 55 60 El 66 57 71 72 77 . Activity Interpreting Data Use Figure 2610 help you answer questions about this weather station data . 30 . What is the temperature at this station ?

What is the wind speed ?

which way is the wind blowing ?

What is the air pressure ?

What percent of the sky is covered by clouds ?

What type of precipitation , if any , is failing ?

3300 Reading a Weather Map The below shows what various weather symbols mean . At right , the weather map shows data collected speed ( Reading Weather Maps A weather map is a of conditions at a particular time over it large area . There are many types of weather maps . Weather forecasters often present maps generated by ers from surface data . radar . or satellite information . Weather Service Maps Data from many local weather tions all over the country are assembled into weather maps at the National Service , The data collected by at typical tion is summarized in Figure 26 above . The weather map on the next page includes most of the weather station data shown in the key . On some weather maps , you see curved lines . These litres connect places where certain or air the same . Isobar are lines joining places on the map that have the same air pressure . lsu means equal and bar means i The numbers on the arc the pressure readings . Air pressure readings may be given in inches of mercury or in or both . The in Figure 26 are shown in both and inches of mercury . are lines joining places that have the same . The isotherm may be labeled with the temperature in degrees Fahrenheit . degrees Celsius , or both .

Newspaper Weather Maps Maps in versions of maps produced by the National Weather Service . Figure 27 on the next page shows a typical per weather map . From what you have in this ter . you can probably interpret most of the symbols on this map . symbols on show fronts , areas of high and low pressure , types of . and temperatures . Note that the high and low temperatures are given in degrees Fahrenheit instead of Celsius . Limits of Weather Forecasts computers have grown more , and new satellites and radar technologies have been developed , scientists have been able to malt better casts . But even with extremely fast computers . it is unlikely that forecasters will ever be able to predict the weather I month in advance with great accuracy . This has to do with the butterfly The atmosphere works in such way that a small change in the weather today can mean larger change in the weather a week later ! The name refers to a scientist gestion that even the of a wings causes a tiny disturbance in the atmosphere . This tiny event might cause a larger disturbance that could grow into a large storm . What is the often ?

le In and Fog A Hail Run Hurricane Iain cold from on . warm mint Stationary from A trout Snow Thunderstorm FIGURE 27 Newspaper Weather Map Weather maps in newspapers use symbols Mai to show fronts . and areas are areas . and precipitation . Color bands with an indicate different temperature ranges . I High pressure areas are shown with an line , and snowflake symbols show . Triangles point in . the direction a cold the direction a warm front is moving . front is moving , an Reading section Assessment . a Target Reading Compare and Contrast Interpreting Diagrams Figure HINT Make a table for the types of a hurricane located ! the air lines on weather near its center compare to the iii ! pressure in and . Include units of measure and Bay . Florida ?

Reviewing Key Concepts Writing in ' a . Describing What is a ?

I ' I . Explaining What tonic do meteorologists a current weather map rely on to forecast the weather ?

from a newspaper . use the map to write a i I Identifying What it the symbol for a 73993997 ' cold hunt on it weather map ?

HINT I . Explaining Huw is wind indicated ' on at map ?

Interpreting Diagrams tu 27 , what is the weather in ?

How might this change in a few hours ?

Guided Inquiry Reading a Weather Map . Problem How does a weather map communicate data ?

i FOCUS interpreting maps . observing . drawing conclusions Procedure . Examine the symbols on the weather map below . For more information about the symbols used an the map . refer to Figure 26 and Figure 27 earlier in this section . Observe the different colors on the weather map below . Find the symbols for snow and rain . Locate the warm fronts and ( old fronts . Locate the symbols for high and low pressure . Analyze and Conclude . Interpreting Maps What color represents the highest temperatures ?

What color represents the lowest temperatures ?

Interpreting Maps which city has the highest temperature ?

which city has the lowest temperature ?

Interpreting Maps Where on the map is it raining ?

Where on the map is it snowing ?

Interpreting Maps How many different kinds of fronts are shown on the map ?

Observing How many areas of low pressure are shown on the map ?

How many areas of high pressure are shown on the map ?

Drawing What season does this map represent ?

How do you know ?

Communicating The triangles and on the front lines show way the front is moving . What type of front is moving toward Minneapolis ?

What kind of weather do you think it will bring ?

More to Explore Compare this weather map to one shown on a television news report . which symbols on these maps are similar ?

which symbols are ?

333 Technology and Society Let look at our Doppler radar says a IV pointing to a weather map with moving of color . colon represent different and of . the purple area here show I worm moving Into Doppler radar helps make forecasts by tracking the speed and ol . What Is Doppler Radar ?

Doppler radar gets its name from the Doppler , term out radio which describes the changes that occur in radio waves as ' me they bounce off a moving ' object , Nearly 150 Doppler radar stations throughout the United States continuously send out ' 70190 90 ' radio waves . These waves bounce ' to a . of ! particles in the air , such as raindrops . hail , and even dust . Some of these radio waves are reflected back to the Doppler radar station where computers process the data . Computer Doppler Radar Station process data and Rotating ( I ( image the protective . housing , the station is supported by a tower that may be as tall as 30 meters .

Tornado Doppler radar can detect the air movements in thunderstorms that may lead to tornadoes . A tornado is a rapidly spinning , tunnel shaped cloud formed of condensed water particles The amount of precipitation is shown above The colors above show the speed by using colors and direction of precipitation How Effective Doppler Radar ?

Before Doppler radar , it was hard to track storms such as tornadoes Tornado warnings were issued an average ol just Vive minutes in advance . Today , Doppler radar can give people several extra minutes to prepare . People also use Doppler images to make decisions about everyday activities But the technology does have limitations Doppler radar see everything . Sometimes mountains or buildings block the radio waves . In addition , Doppler radar does always pick up light precipitation such as drizzle . Meteorologist must review the completeness of the data and decide how it might the forecast . Weigh the Impact . Identify the Need How is Doppler radar an important technology in weather ?

Research Using the Internet . research Doppler radar reports for your city Examine a Doppler image and explain each element on the map , including the different colors and the direction of , Write As a meteorologist , write the script for a local weather forecast Describe areas with precipitation , the amount oi precipitation and the direction of weather systems . For More on Doppler radar Visit Web Code Doppler Radar Screens

Chapter Water in the Atmosphere Key Concepts , an can with an i ! called ) lauds when vapor in the air to turn ) liquid wait or iu ) clouds into three main type used all their shape . cumulus , are aim hy altitude . Key Terms water I ' i ' humidity psy ' dew cirrus Precipitation ( Key Concept of include ram . hat , sleet . and . Key Term precipitation Air Masses and Fronts Key Concepts Maritime . maritime palm . and polar air Ilu in . In the United states , ire moved by prevailing and . air inane can type of culd , warm fronts . fronts . and fronts . 3360 Study Guide Differences In air pressure . air temperature . winds . and product In weather . and ( with , precipitation . The descending air in generally dry . clear . Key Terms air polar Storms Key concepts . limn in Large ) clouds . During ' place lightning may . in illicit . The safest place during a tornado is storm ( or the . I ' mund , begin in Clouds as snow . are in the wind . A begun over water as area . or . If yuu . hurricane , and An to , Key Terms I ! I lightning I . Predicting the Weather Key Concepts Met the In ! I on maps shun . and . Key Terms )

Compare and Contrast Th I ?

ine vi i . um for ( Visit Web ( ode Review and Assessment Target Reading Skill table ( and ( lUT ' and ( on Th ' slice ! ul Thun buds it and Add title . Spring . Tornado ' Mum Evacuate or Hurricane ?

building Reviewing Key Terms Choose the letter of the best answer . type of cloud that forms in layers and Complete the following sentences so that your answers dearly the key . rim , he ' The iii condensation when ! cirrus . Cyclones . are , bring HINT . Rain . hail are all ul , and . Ill , hic i ii ( i . Tornadoes , which LIT ! in thick . mil . it ill a , mum ( your , 10 . maps lI iS ( i ) iII , which in Science . mid from . Very large ' wiih are called . i , are a hurricane scientist who into a hurricane to collect data . Describe what it would feel like as you through the hurricane into its eye . iii ! lines places that have the temperature are . UL ( Li . Amy , Chapter 337

Review and Assessment Concepts 11 . Why do high in the instead of near Earth 12 . hail . and mow in terms ut huw each one forum . huw wind the trusses in . 14 . How do mid form ?

15 . What safely you if a tornado is in your arcs ?

hurricane is predicted ?

16 . What happens in it hurricane it land ?

Why ?

Thin ally 17 . Problem Solving , gives the same reading hoth . What is the I ' humidity ?

18 . Relating Cause and How do in air density the ul ' air along and warm ?

19 . Interpreting Diagrams ) journey in A small particle of water the water cycle . using the terms in the diagram below . Evaporation 20 . Comparing and Contrasting ( and . are they ' Huw are they ?

21 . pressure is , what kind in weather is likely to occur ?

3380 22 . Applying Contents expect to form over the oft the . the United States ?

Explain . 23 . Applying ' forecast the weather a Applying Skills Use the map to answer Questions . 24 . Interpreting Maps Does the imp show or an ?

How can tell ?

25 . Interpreting Data do the the ' the winds in this pressure center ?

What else wind ?

26 . Making Models as an ( similar to illustrate area . to indicate direction in your ( 27 . Posing Questions II ) pressure center like the one . I . tan is what you predict about the weather ?

What you need to ask in order to ?

Standards Investigation Assessment Present your weather maps and to the ) your ( wart . any in ' forecasts .

Standards Practice Oahu at Choose the letter of the best answer . use the graph below and your knowledge of science to answer Questions and . The major source of energy for the water cycle is 2001 A the ocean . I the sun . the wind . surface runoff . How are air mum ?

A by temperature and pressure I and humidity by temperature and density 59 by temperature and humidity . A rapidly moving cold air mass meets a slowly 50 moving warm air mass and forms a front . What will most likely occur at this front ?

i A The two air masses will mix together . I A A The warm air will slide under the cold air . The cold air will rise and get warmer . Cold air will slide under the warm air . Warm air will rise and cool . Clouds will form . The lees dense warm air will sink and cool . Clouds will form . According to the graph , which two months in 2001 had the most tornadoes ?

A April and May May and May and lune lune and July which best summarizes the trend shown in the graph ?

A Tornadoes always occur most frequently in May and lune . I occur when lit weather is warmest . In tornadoes were most frequent in April , May . and lune . Tornadoes are generally most frequent in the winter . The diagram above at A cold front . warm front . Idea occluded front . my from , 55 , Compare and contrast and in terms of air pressure . direction . and humidity . What type of weather dues bring ?

Thunderstorms can cause severe damage through A lightning and thunder . hurricanes and flooding , flooding and lightning . thunder and hurricanes . 339