weather in the classroom

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WeatherIN THE OKLAHOMA CLASSROOM

Just log-on to News9.com and click on the Weather in the Classroom section under theWeather tab for interactive lessons, games and up-to-date weather information.

© COPYRIGHT 2008 BY CLASSROOM WEATHER. ALL R IGHTS RESERVED. 3

A GUIDE FOR UNDERSTANDING YOUR WEATHER

Weather IN THE OKLAHOMA CLASSROOM

SECTION 14 Introduction to Basic

Weather Understanding6 Layers of the Atmosphere7 Water Cycle9 Basic Air Pressure

SECTION 212 Weather Patterns13 Weather Variables15 Precipitation19 Seasons

SECTION 332 Why the Wind Blows33 High/Low Pressure36 Air Density37 Tornadoes41 Hurricanes

SECTION 448 Severe Weather Alerts49 Local Geography50 Safety Procedures52 Watches and Warnings

SECTION 554 Weather Terminology 54 Glossary

GARY ENGLAND

A recipient ofnumerous awards andhonors including twoEmmys and theSilver Circle Award

by the National Academy ofTelevision Arts & Sciences, HeartlandDivision, Gary England is Oklahoma'stop rated television meteorologist.Gary is a graduate of the Universityof Oklahoma with a Bachelor ofScience degree in mathematics andmeteorology. He is an internationallyrecognized authority in severe weatherand holds the distinction of being theperson who implemented withEnterprise Electronics, the world'sfirst commercial Doppler radar. In1981, Gary became the first person inhistory to use Doppler radar for directwarnings to the public. The author offour books and the subject of another,Gary is also a popular public speaker.Besides appearing in the StevenSpielberg movie, "TWISTER," he hasbecome a much sought after consultantfor weather specials produced byinternational channels from all areas ofthe globe. Of special distinction in2006 was his being asked to be a leadspeaker for the dedication of the newNational Weather Center in Norman,OK. Additionally and in conjunctionwith the Oklahoma Centennialcelebration in 2007, Gary wasimmortalized by the sculpting of hisbust which honored ‘100 Heroes and

Outlaws' of Oklahomarepute during thestate's first 100 years.

Intro to Basic WeatherUnderstanding

LAYERS OF THE ATMOSPHERE

WATER CYCLE

BASIC AIR PRESSURE

INTRO TO WEATHER BASIC UNDERSTANDING


TO BEST UNDERSTAND HOW THE WEATHERWORKS, YOU MUST FIRST UNDERSTANDHOW THE ATMOSPHERE (THE THINLAYER OF AIR THAT SURROUNDSOUR PLANET) IS STRUCTURED.As we will see as we begin tostudy weather more in detail,the sun is the driving forcebehind all of our weather. If thesun were to go away suddenly,we would not be able to live onour planet and the weather as weknow it would cease.

Look over the diagram on the nextpage and note how the atmospherictemperature changes as you go up. Noticethat the atmosphere extends over 80 milesup from the surface, but very little air is foundonce you go up just a few miles up. The airgradually thins out so much that eventuallyyou are in outer space, where there are no airmolecules.

Then look at the water cycle on thefollowing page. Notice how watercontinually moves about in a cycle. Pick astarting point and follow the “life” of a dropof water as it moves through the air, cloudsand ground. Notice that this cycle is on-going at all points, meaning there is alwayssome water in the air, always some water inthe clouds, always some water in the riversand oceans, etc.

Finally, read over the section on air pressure andyou’ll be set with the basics that you will need tounderstand how much of the weather happens!

Weather…The Basics


6 © COPYRIGHT 2008 BY CLASSROOM WEATHER. ALL R IGHTS RESERVED.

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Temperature( °C) shown as a dotted line on the chart above

Layers of the AtmosphereMILES

STRATOPAUSE

SHUTTLES

TROPOPAUSE


MESOPAUSE

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The Water Cycle



Layers of the Atmosphereand the Water CycleREVIEW

1 In what layer of the atmosphere do the temperatures get the warmest? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

2 What layer of the atmosphere is closest to the ground? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

3 As water evaporates from the surface and begins to lift up into cooler air, what process happens thatturns that moisture into clouds? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

4 When water does not runoff into lakes and rivers, it soaks into the soil into what we call _ _ _ _ _ _ _ _ _ _ _ _water.

5 When the clouds grow in size, they produce _________________________ which brings moisture from theair back down to the ground.

6 In the stratosphere there is a layer of ozone, a gas that absorbs incoming solar radiation. This makes the temperature go up in the stratosphere. When you get to the mesosphere, what happensto the temperatures as you go up in height? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

7 In what layer does most weather occur? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

8 Water that is given off by trees in the water cycle is known as _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

9 In what part of the atmosphere do most meteors burn up? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _



REVIEW

1 If you are on top of a mountain, would the pressure of the air be heavier or lighter than on the beach? _ _ _ _ _

2 Would you have more or less oxygen up in the mountains than on the beach? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

3 What causes so much air to cluster near the ground? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

Understanding Air Pressure


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AIR PRESSURE IS THE WEIGHT OF AIRON AN OBJECT. That means you areadding up all of the air molecules on top ofsomething. If you are standing on the beach(at sea level) there is approximately 14.7 lbs.of air sitting on top of every inch of yourbody. That means on top of your head thereis over 400 lbs. of air!

Size of your head* is approximately 30square inches

Weight of air at sea level is 14.7 lbs persquare inch.

(30x 14.7 = 441 lbs on top of your head!)

Consider the clustering of air moleculesnear the surface of the Earth. They arepulled down by gravity. As you go up in theatmosphere, the air is thinner and fewermolecules are present.

* Average size of a child’s head at age 10.

WeatherPatterns

WEATHER PATTERNS

WEATHER VARIABLES

PRECIPITATION

SEASONS


How Can You Measure Temperature?We use a thermometer to measure temperature. There areseveral different types of thermometers. Some are made ofglass and mercury, others are digital, while others look likea dial. How can all of these measure temperature? Well,everything reacts to temperature changes. When it gets hotoutside, your body can sense it. Also, when it gets hot,metal expands. Mercury, a liquid metal, does this as well.When it gets cold outside, your body can feel it, water canfreeze, metal contracts and so does mercury.

So many different types of materialcan be used in a thermometer tomeasure its reaction totemperature. Since thesedifferent materials react tohot and cold air, we canmeasure the changes inthem and figure out thetemperature! That is howa thermometer works.

EXPERIMENT: (Note to teachers: although many filled-glass thermometersare filled with mercury, we strongly recommend to not use mercury thermometers inthe classroom to ensure safety. Instead, do the experiment using alcohol-filled glass thermometers.)

1 Take an alcohol filled thermometer and look at where the level of alcohol is.

2 ...Now where is the level of alcohol? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

3 Where is the final level of alcohol? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _Why did the alcohol move inside the tube? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

What liquid other than alcohol would change its size because of the temperature? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

What is Temperature?TEMPERATURE IS THE WAY WEMEASURE THE AMOUNT OF HEAT WE CANFEEL. Actually, temperature is a measure ofthe speed of tiny particles in the air.Everything is made up of very tiny objectscalled molecules. These molecules movearound. The hotter it is, the faster they move,and the higher the temperature. So,temperature is really just a measure of howfast these little molecules are movingaround. The amazing thing is, temperaturenot only is a measure of how fast moleculesare moving, it also relates to how we feel.

As the temperature gets colder and colder,the molecules move slower and slower. Intheory, at some point the molecules stopmoving altogether. It cannot get any colderthan this. This temperature is known asabsolute zero. Although the word “zero” isused, the temperature in Fahrenheit (F) is -459°F and in Celsius is –273°C.

WEATHER PATTERNS TEMPERATURE


YOU SEE THEM ALL OF THETIME—UP IN THE SKY.Sometimes they are flat. Sometimes they arepuffy. Sometimes they are white. Sometimes theyare gray. Sometimes they are big and tall. Theyare clouds. Clouds are made up of water dropletsor ice crystals. They appear to hang in the sky, butthey are actually just resting on the air belowthem.

So what is a cloud, really? Well, first we have toknow what is in the air. Air is made up of gaseslike nitrogen, oxygen and carbon dioxide. Air isalso made up of water. Not liquid water, but watervapor. Water vapor is tiny drops of watersuspended in the air. We cannot see water vapor,but the water is there. On humid days, there ismore water vapor in the air. On dry days, there isnot much water vapor in the air.

When air is lifted, it cools. If the air cools downenough the water vapor condenses and turns intowater droplets. These droplets are bigger than thelittle pieces that make up vapor, so we can seethem. They appear to be white when the sunshines on them. If a cloud is thick enough thatenough water droplets block out the sun, thecloud appears grayish.

What are Clouds?

Types of clouds

CUMULUSThey are white, puffy clouds that are often flat onthe bottom. They are usually found when theweather is nice.

STRATUSThese are low, thick, flat, grayish clouds thatusually cover the whole sky. These clouds oftenare found on cool days and make it truly “cloudy.”

NIMBUSThese look much like stratus clouds, but nimbusclouds have rain or snow falling from them.

CIRRUSThese are very high in the sky. They are thin andwhite and sometimes the sun can shine rightthrough them.

CUMULONIMBUSThis is a thunderstorm cloud. When a cumuluscloud begins to grow taller and taller, it starts torain and sometimes hail, lightning, and tornadoescan occur from cumulonimbus clouds.

WEATHER PATTERNS CLOUDS


Identifying CloudsTry to identify the following clouds by the definitions given on the previous page. Write your answers below each picture.

WEATHER PATTERNS CLOUDS

14

DDIIRREECCTTIIOONNSSTape the black paper to the outside of the jar so that it onlycovers half of the jar. You should be able to look through oneside of the jar and see the black paper on the other side.(Make sure the paper does not touch the bottom of the jar)

1 Put two cups of hot water into the jar.

2 Make certain that the water is hot enough to make the air inside the jar very hot and humid.

3 Place nylon over mouth of jar and secure with the rubber band.

4 Place ice cubes on top of the nylon and watch the clouddevelop right below the nylon inside the jar.(You may need to peel back the nylon to let thecloud “escape” to see better.)

Note: This experiment can also be done by covering thejar with an aluminum pie plate in place of the nylon andrubber band. In that form, you would place the ice ontop of the aluminum pie plate.

MMAATTEERRIIAALLSS

1 large, large-mouthed glass jar

1 rubber band

1 piece of nylon (to cover jar mouth)

2 cups of warm water

5 ice cubes

1 piece of black paper

Tape

LESSON

What have you done?The warm, humid air in the jar represents the warm water near theearth’s surface. As it rises, the air around it cools (that is what theice on the nylon represents). As the warm, humid air is cooledby the cold air above it, it forms a cloud in the jar!

Making a Cloud

WEATHER PATTERNS EXPERIMENT MAKING A CLOUD


WHENEVER A CLOUD IS FULL OF DROPLETS OR ICE CRYSTALS, THEY CANGROW TO BECOME TOO LARGE TO REMAIN IN THE CLOUD. They start growingby sticking to a dust particle or a small piece of suspended material in the air. Moreand more droplets or crystals stick to it until it is too heavy to remain in the cloudand the droplet or collection of crystals begins to fall. This is called precipitation.

If the precipitation that falls is a large droplet (water), then it is called rain. Waterfreezes at 0°C (32°F). So, if the air in the cloud is very cold, then a large collectionof ice crystals may form into a flake and fall as snow. There are several other typesof precipitation, as well. If a raindrop falls from a warm cloud through some verycold air and it freezes, then it becomes sleet. Sleet is a raindrop that froze on theway down to the ground and hits the ground in the form of an ice pellet. Anothertype of precipitation is freezing rain. Freezing rain is a raindrop that is just aboutto freeze on the fall to the ground. It looks like rain, but coats everything it hits inice. It can form an icy glaze on roads, cars, trees, etc.

REVIEW

Now that you know so much about rain, sleet, freezing rain, and snow…see if you cananswer the following questions:

1 What season would you most likely find freezing rain, sleet and snow? ________________________________________________________

2 If a snowflake fell and melted on the way to the ground, what type of precipitation would it be?_____________________________________________________________________________________________________________________________________________________________________________________________________________________

3 What if that snowflake melted on the way down, but then re-froze just before hitting the ground.

What type of precipitation is that? ___________________________________________________________________________________________________________________

4 Can you have rain and snow falling at the same time? ___________________________________________________________________________________

BONUS Why or why not?_________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

The Sky is Falling!

WEATHER PATTERNS RAIN, SLEET, AND SNOW


DDIIRREECCTTIIOONNSS

1 Using the ruler and paper, make markings on the paper sothat it becomes a ruler. You can make it in whateverincrements you wish. Divide it up by inch, and then inquarters, and even smaller if you want to.

2 Once you have the ruler made, cut it out.

3 Cover the ruler with clear cellophane, front and back. Thiswill protect it from the rain, and make it sturdy so that theruler can stand straight.

4 Stand the ruler inside the container so that the rulerrests on the bottom of the container. Tape it at the top, to the inside of the jar, so that the ruler does not fall.

5 Place your rain gauge outside, and measure the amount ofrainfall that occurs each day. Place the rain gauge in a place away from trees and buildings, as this may affect theamounts. Also, you may wish to glue the jar to a block orplatform of wood, so that it does not tip over if it is windy.

MMAATTEERRIIAALLSS

1 straight-side clear plastic container(curved sides would skew the rain totals)

scissors

clear cellophane or plastic sandwich bag

tape

rainy days

graph paper

plain paper

ruler

Rain clouds are made of droplets of water so small that there are billions of them in a single cloud. How muchrain falls during a shower, or during a day, week, or month? You can find out by measuring it with a rain gauge.

RREECCOORRDD RREESSUULLTTSSRecord the amount of rain you receive every time it rains on your graph paper and compare that to the amountrecorded at the nearest official rain gauge. (You may want to record the official rain total on the same graphpaper in a different color.) You can see some of the state’s official amounts on the website: (note that the dailyamount is updated a couple times per day, but the official amount is not recorded for that day until just aftermidnight, so it may be best to compare the amounts on the next day)

Once on the website for “Weather in the Classroom,” (web link can be found on the front cover),simply follow the links for “Daily Weather and Climate Data”.

Making a Rain Gauge

WEATHER PATTERNS EXPERIMENT MAKING A RAIN GAUGE


IN ORDER TO UNDERSTAND THE SEASONS, YOU NEED TO FIRST UNDERSTAND HOW THE EARTHREVOLVES AROUND THE SUN ONCE PER YEAR. Look at the picture below showing the Earth at differentpositions in space during the year.

In this graphic, the thick, solid lineshows you where the north andsouth poles are. Notice thatthe Earth is tilted, that is tosay that it does not havethe North Pole at thevery top and theSouth Pole at thevery bottom.

The Earth revolvesaround the sun onceeach year. NearDecember 21st, theSouth Pole is facingtoward the sun and theNorth Pole is facing awayfrom the sun. This gives theNorthern Hemisphere (where welive) shorter days and less directsunshine. This makes our weather colder andwe call this season WINTER.

Then the Earth moves so that the sun shines directly over the Equator by March 20th. The Equator is a line thatmarks the halfway point between the North and South Poles. When the sun shines directly over this line, thedays and nights are nearly of equal length. The season changes at this point and we call it SPRING.

The Earth then moves around the sun so that the North Pole is facing the sun. The daylight becomes longerfor the Northern Hemisphere and the sunlight more direct. By June 21st, the sun is at its strongest for theNorthern Hemisphere and the temperatures warm up. We call this season SUMMER.

The Earth continues to revolve around the sun. By September 22nd, the sun is once again over the Equator.The days and nights are again nearly equal length. The Northern Hemisphere is cooling down and we begin aseason called AUTUMN or FALL.

WEATHER PATTERNS SEASONS

Understanding Seasons

Jun. 21st

Sept. 22nd

Dec. 21st

Mar. 20th


What to Expect in OklahomaRead the following descriptions of what to expect with each season in Oklahoma:

WINTER• Days are short, nights are long

• Sun is lower in the sky

• Sun is directly over the Southern Hemisphere

• Temperatures are colder

• Rain, ice or snow can fall

• Temperatures change often

• Most trees have no leaves on them

• Strong winds can produce dangerously cold wind chills

SPRING• Days and nights are equal length at

the beginning of Spring

• Days get gradually longer through the season

• Sun is directly over the Equator on the first day of Spring

• Flowers bloom and trees produce new leaves

• Temperatures gradually warm up

• Rain and thunderstorms are frequent

• Temperature changes often

WEATHER PATTERNS SEASONS

FALL• Days and nights are equal length at

the beginning of Fall

• Days get gradually shorter through the season

• Sun is directly over the Equator on the first day of Fall

• Leaves begin to change colors and fall from the trees

• Temperatures gradually cool down

• Rain and thunderstorms occassionally occur

• Temperature changes often

SUMMER• Days are long, nights are short

• Sun is higher in the sky

• Sun is directly over the Northern Hemisphere

• Temperatures are hotter

• Plants grow all season

• Thunderstorms occasionally happen during the afternoons and can produce heavy rain

• Temperatures do not change much day to day


Use the previous pages on the seasons to answer the following questions:

1 What would the season be on April 20th? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

2 On the first day of which season is the sun directly overhead the Northern Hemisphere? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

3 In which season would you expect to see the most sleet? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

4 What season are the days the longest? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

5 Complete the following picture by shading the side of Earth that would be dark. From this drawing, figure out which season it is.

What season is it in the picture above? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

Questions about the Seasons

WEATHER PATTERNS QUESTIONS SEASONS

NORTH POLE

SOUTH POLE


WATER IS PLENTIFUL ONEARTH. It covers nearly two-thirds of the surface of our planet.But water is also commonly found in large quantitiesin the air. You can see the effect of the suspendedwater droplets in the atmosphere. Rainbows, clouds,hazy skies, and even fog are all ways we can visiblysee the water droplets suspended in the air. However,even when it seems as though we cannot see thewater in the air, it is still there. Sometimes there is littlewater present and the air is dry. At other times there isa lot of water in the atmosphere and we say that it ishumid. These are ways to describe the humidity.

Humidity is often misunderstood. Relative humidity isdifferent for every temperature. Why? Because relativehumidity is a percentage showing how much water isin the air compared to how much water the air couldhold at that temperature. So if the temperaturechanges, so does the relative humidity. Warm air cansuspend more water than cold air. So, if the amount ofwater doesn’t change, then the relative humiditywould go down when it gets warmer (because the aircould hold more at that temperature) and the relativehumidity would go up if gets colder (since the aircannot hold as much water when cold). If the relativehumidity is 50%, then you are really saying that the airhas half of the amount of water it could hold at thattemperature. If the humidity is 100%, then theatmosphere cannot hold any more water. At that point,fog may form or dew may form on surfaces.

Keep in mind, since relativehumidity is dependent ontemperature, you cannot comparehumidity from one place to anotheror from one time to another unless thetemperatures are the same. Forexample, 100% humidity at 45 degreesactually has less water in the air than 75%humidity at 80 degrees. It may soundconfusing, but we have another way tohelp us compare humidities. Rememberthat dew may form when the humidity is100% because the air cannot hold anymore water. So, if you can figure out whendew will form, then you know how muchwater you have in the air. This is called thedew point temperature.

To find the dew point you need to takethe air you currently have and cool itdown without losing any of the water inthe air. As you cool the air, thehumidity will rise. When the humidityrises to 100%, you have reached thedew point. Now you can comparedew points from one place to another as a goodmeasure of the amount of moisture in the air.

INTERESTING NOTE: Sometimes people will exaggerate about the relative humidity. It is common forpeople on a hot, humid summer day to say that the temperature and humidity are high. However some peoplewill say that it is 95 degrees and 100% humidity. This could never happen on Earth. That would make the dewpoint 95 degrees, too, since the humidity is 100%. Dew points rarely go higher than 80, and we could notphysically handle dew points into the 90s on Earth for very long.

WEATHER PATTERNS HUMIDITY

What is Humidity?



1 Outside on a warm, humid day in the spring or summer, put a couple of inches of warm (about 75°F) water in a cup.

2 Measure the temperature of the water. Now add a fewdrops of ice cold water to your cup.

3 While you are adding water, keep stirring andmeasuring the temperature of the water.

4 Repeat this procedure by adding a small amount ofcold water to the cup until you see a thin film of waterform on the outside of the cup.

5 Make a note of the temperature of the water as soon as you see the water vapor form on the outside of the cup.

The temperature you measured is the DEW POINT!

MMAATTEERRIIAALLSS

a thin metal cup or a drinking glass (not thermal)

thermometer

ice water

a large dropper (a measuring cup with a pour spout will do)

LESSON

What happened?As you added colder water to the warm water inthe cup, the temperature of the water in the cupkept dropping. The sides of the cup got colderas the water inside got colder. The cup alsochilled the air right next to it! When thetemperature of the metal cup reached the dewpoint... The air just next to the cup was cooledto the dew point as well and water began tocondense from the air and stick to the cup!

REVIEW1 What was the temperature of the water when you started your experiment?

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

2 What was the temperature of the water when you saw the condensation form on the outside of the cup?_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

3 Would your cup of water have to be colder or warmer to reach the dew point if the air outside is very dry?_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

Measuring HumidityHow you can measure the dew point.

WEATHER PATTERNS EXPERIMENT MEASURING HUMIDITY



1 In one can, place several ice cubes.

2 In a separate can place a mixture of ice cubes and rock salt.

3 Wait a few moments and notice what happened to the two cans.

MMAATTEERRIIAALLSS

2 metal cans

rock salt

ice cubes

thermometer

LESSON

What have you done?The can with ice and salt will be colder.The reason for this is saltwater has alower freezing point than pure water (thesame reason salt is applied to roadwaysin winter). This lower freezing pointallowed for more water to evaporate andmore evaporative cooling of the saltwaterin the can. Thus, the final temperaturewas colder of the saltwater can.

REVIEW1 Which of the cans had the frost form on the outside?

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

2 Which of the cans had dew form?_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

3 What was the temperature of the two cans?_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

4 What made one can colder than the other?_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

Dew and FrostRecall that dew forms when the humidity reaches 100% and the atmosphere can no longer hold any morewater. Some of the water is deposited on surfaces as dew. This happens when the temperatures are abovefreezing. When the temperatures fall below freezing when the humidity hits 100%, something else forms.

Instead of droplets of water forming on the grass and on car windshields, we see ice crystals forming onsurfaces. This is called frost.

Demonstrating Frost & Dew in the Classroom

NOTE: During the winter months, the air can become very dry (especially on cold days) and it may be difficultto cool the cans down to the dew point temperature. On a very dry day, you may see only frost form on thecolder can, but no dew. If this is the case, wait and try again on day when the dew point is higher (more moisturein the air). You can find the dew point temperature by following weather observations online.

WEATHER PATTERNS EXPERIMENT DEMOSTRATING DEW AND FROST


Recording the Weather

Use the “Recording the Weather” DATA CHART to fill in the weather information for one week.


1 Pick a city in Oklahoma and log on to the Weather in the Classroom website.You can find the link for the website on the front cover of this booklet.

You will then be able to select “Current Weather” for the following areas of the state:

• Eastern Oklahoma• Central and Western Oklahoma

2 Click on the city on the map you have chosen to see the current conditions.

3 Record the temperature, wind direction, wind speed, air pressure, current weather type and relative humidity.

4 Do this at the beginning of the school day, the middle of the day and again at the end of the day.

5 Write down any interesting things that happened with the weather on the “Recording the Weather” INFORMATION PAGE. Be sure to include big changes from sunny skies to cloudy skies or when precipitation started to fall.

6 When you have finished recording the weather for the week, answer the questions on the “Recording the Weather” QUESTION SHEET.

WEATHER PATTERNS EXPERIMENT RECORDING THE WEATHER

• Oklahoma Panhandle• Extreme Southeastern Oklahoma


TEMPERATUREWIND

DIRECTIONWIND SPEED

RELATIVEHUMIDITY

AIR PRESSURESKY

CONDITION

MONDAY

Morning

Midday

Afternoon

TUESDAY

Morning

Midday

Afternoon

WEDNESDAY

Morning

Midday

Afternoon

THURSDAY

Morning

Midday

Afternoon

FRIDAY

Morning

Midday

Afternoon

Weather Data Chart



Information PageOOBBSSEERRVVAATTIIOONNSS

MONDAY:Were there clouds today? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

Was there any precipitation? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

*Describe the weather for the day? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

TUESDAY:Were there clouds today? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _


Describe the weather for the day? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

WEDNESDAY:Were there clouds today? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

Was there any precipitation? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _


THURSDAY:Were there clouds today? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _



FRIDAY:Were there clouds today? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _



* Weather might include partly cloudy, fog, rain, snow, sunny, windy, breezy, cold, warm, hot, etc.



Question SheetAfter recording weather conditions for the week, look over the weather data youcollected and answer the following questions:

1 What time of day did you notice the coolest temperatures? a. Morning b. Midday c. Afternoon

2 What time of day did you notice the highest temperatures? a. Morning b. Midday c. Afternoon

3 What time of day did you notice the lowest relative humidity? a. Morning b. Midday c. Afternoon

4 What time of day did you notice the highest relative humidity? a. Morning b. Midday c. Afternoon

5 If there was any precipitation during the week, what happened to the humidity during that time? Why do you think the humidity changed the way that it did? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

6 What was the strongest wind speed you recorded during the week? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _What was the weather during the time you recorded that wind speed? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

7 Did you notice a pattern with the air pressure during the times you recorded it? Was it going up? Was the air pressure dropping? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

8 Did a change of wind direction occur during the week? If so, what were the temperatures like the daybefore the wind shifted? What about the day after the wind shifted? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

9 Did clouds affect the temperatures for the week? (Were sunny days warmer than cloudy days?Were cloudy days warmer than sunny days?) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

10 What did you notice about the overall weather pattern for the week that lead to so many different types of weather to occur? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

WEATHER PATTERNS QUESTIONS RECORDING THE WEATHER


DDIIRREECCTTIIOONNSSUse the “Mapping the Weather” AREA MAP to completethe following activities:

1 Write the temperatures on the map above each city’sname.

2 Draw temperature contours for 35, 40, 45, 50, and 55.(Temperature contours are lines that connect equaltemperatures. You may need to ask an adult to help youcomplete this step.)

3 Color the area below 35 in dark blue.

4 Color the area between 35-40 in light blue.

5 Color the area between 40-45 in green.

6 Color the area between 45-50 in yellow.

7 Color the area between 50-55 in orange.

8 Color the area over 55 in red.

MMAATTEERRIIAALLSS

Colored pencils (dark blue, light blue, yellow, orange, green)

Mapping the Weather

TULSA: 53

MCALESTER: 51

LAWTON: 36

WOODWARD: 39

GUYMON: 29

MIAMI: 57

ARDMORE: 47

OKLAHOMA CITY: 46

DURANT: 54

STILLWATER: 47

PONCA CITY: 44

ALTUS: 32

IDABEL: 56

Use the following temperaturesfor your mapping:

WEATHER PATTERNS EXPERIMENT MAPPING THE WEATHER


Map

ping

the

Wea

ther

Are

a M

ap

WEATHER PATTERNS EXPERIMENT MAPPING THE WEATHER

NOTES _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

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_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

Why the Wind Blows

WHY THE WIND BLOWS

WEATHER VARIABLES

PRECIPITATION

SEASONS


HIGH PRESSUREHigh pressure is seen on a weather map as a blue capital “H”. Sincethe pressure is high, air needs to move away from a high pressure. Neara high pressure, the winds are usually light and circulate clockwise awayfrom the high. Because air is leaving the high pressure area, air from abovecomes down to replace the air that left. This sinking air keeps the skies mostlyclear and free from clouds that could develop into showers or thunderstorms. Highpressure is usually associated with nice weather.

LOW PRESSURELow pressure is seen on a weather map as a red capital “L”. Since the pressure is low, air needs to fill it in, soit moves toward the low, but around it counterclockwise at the same time. Often the winds can be quite strongaround a low pressure. Because the air is piling up at the low, some of the air is forced up. This rising air oftenbecomes clouds and even produces rain. If the atmosphere is “unstable” then the rising air can becomethunderstorms. Low pressure is often associated with stormy weather.

In the picture below, the winds are shown around areas of high and low pressure at the surface.

High Pressure & Low Pressure

WHY THE WIND BLOWS HIGH PRESSURE AND LOW PRESSURE

L H

NOTES _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

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_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _


FRICTION IS A FORCE THAT ACTS TO SLOW DOWN THE MOVEMENT OF AN OBJECT. Ice has a very lowamount of friction, so walking across it is very slick, but sandpaper has a high friction and you could get goodtraction walking across sandpaper.

If there were no friction at the surface of a non-rotating Earth (no trees, no grass, no hills, etc) then the windwould try to blow straight from high pressure to low pressure like this:

The Effect of Friction

But there since the Earth is constantly rotating, the wind “turns” as the world turns. This is known as theCoriolis force. So, when you have high and low pressure with a rotating Earth, but no friction, then the windblows like this:

But there is friction at the surface. Friction not only slows the speed of the wind, but it also changes the effectof the spin of the Earth. This causes the winds to blow like this:

H L

H L

H L

WHY THE WIND BLOWS HIGH PRESSURE AND LOW PRESSURE


MMAATTEERRIIAALLSS

Small coffee can

Plastic wrap

Rubber band

Drinking straw

Large index card

Making a Barometer


1 Take a small coffee can andcover it tightly with plastic wrap.Secure the plastic wrap with arubber band around the can asshown above.

2 Tape a straw to the top of yourplastic wrap cover with one end ofthe straw in the middle of the can’scover and the other end slightly offthe edge of the can. (see right)

3 Next place the can beside alarge index card. Use this card tomark and label where the straw ispointing on the card. Remember towrite down the day and time besideeach mark you make. Notice thechanges on the position of thestraw during each day of the week.

Looking down at the can:

REVIEWAfter recording your air pressure results for the week, answer the following questions:

1 What days had the highest pressure? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

2 What days had the lowest pressure? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

3 Why did the plastic wrap get pushed down by high pressure? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

4 What interesting weather happened when the pressure was changing? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

LESSON

Notice that when the airpressure is high, it pushesdown on the plastic wrapand the straw is tilted up.When the air pressure islow, the plastic wrap liftsupward and the strawpoints down.

Barometers are used to measure air pressure. Use the following directions to make your ownbarometer and measure changes in the air pressure.

WHY THE WIND BLOWS EXPERIMENT MAKING A BAROMETER

Plastic wrap

Rubber band

Coffee can

Straw

Coffee can

Large indexcard



Experiment 11 Fill a large bowl with ice cold water. Set aside.

2 Fill the glass bottle with very warm to hot water.This allows the bottle to get fairly warm, as well.

3 Empty the glass bottle and quickly cover the bottle’sopening with a balloon. This traps in very warm airinside the warm bottle.

4 Now place the bottle upright in the bowl of coldwater. This will cool the air inside the bottle down.Observe what happens to the balloon.Write down your results.

Experiment 21 Fill a large bowl with very warm water. Set aside.

2 Fill the glass bottle with cold water. This allows thebottle to get fairly cold, as well.

3 Empty the glass bottle and quickly cover the bottle’sopening with a balloon. This traps in cold air insidethe cold bottle.

4 Now place the bottle upright in the bowl of warmwater. This will heat the air inside the bottle. Observewhat happens to the balloon. Write down your results.

MMAATTEERRIIAALLSS

glass bottle

balloon

large bowl

water

LESSON

What did you learn?In Experiment 1, the air inside the bottle wascooled. When air is cooled, it contracts and thedensity is higher (more compact). Since the airwas contracting, it sucked the balloon into thebottle.

In Experiment 2, the air inside the bottle washeated. When air is heated, it expands and thedensity is lower (less compact). Since the airwas expanding, it caused the balloon to expandoutside the bottle, as well.In the atmosphere the warmer, lighter air risessince it is lighter, and the colder air sinks sincethe density is higher. Sinking cold, air can createareas of high pressure and rising, warm air oftencreates areas of low pressure.

Balloons & Air DensityIn this experiment, you will see how air density changes when the temperatures change. Density is a measureof the amount of mass (or amount of molecules) in a given volume. More simply, it is how compact or howthick a substance is. So what happens when air is heated and cooled? Does it become more or lesscompact? Find out and see!

WARNING: In the following experiments, avoid getting the glass bottle too hot or too cold. Temperature extremes may causethe bottle to break.

WHY THE WIND BLOWS EXPERIMENT BALLOONS & A IR DENSITY


TORNADOES CAN TAKE ONSEVERAL SIZES AND SHAPESAND SOMETIMES HAVE SEVERALDIFFERENT NAMES. It is importantto understand what differenttornado-related words mean andhow to use them.

A tornado (sometimes called a twister orcyclone) is an area of rapidly circulating windsthat blow around a small, but intense, low-pressure area. Tornadoes usually extend from thebase of a thunderstorm.

A funnel cloud is similar to a tornado, but its circulation isin the air and has not reached the ground. At the point thecirculation reaches the ground, a funnel cloud becomes atornado.

A wall cloud is a lowering out of the base of a thunderstorm (even lower than the bottom of thethunderstorm itself) which is rotating. Wall clouds are sometimes difficult to detect because of theirragged appearance. However, wall clouds are indicators of the most dangerous part of thethunderstorm base. It is in this area that tornadoes develop.

Why do tornadoes form?

What are Tornadoes?

WHY THE WIND BLOWS TORNADOES

Tornadoes form when conditions are right and caneven help large thunderstorms keep themselvesgoing. Without the tornado, many thunderstormswould lose their source of warm, humid surface airthat keeps them alive. Large thunderstorms take largeamounts of air from the surface up into the body ofthe thunderstorm. Some air must come back downto replace the air that was sucked up into thethunderstorm. This downward moving air is called adowndraft. Downdrafts are necessary, but they can“choke” a thunderstorm and give it no way to pullwarm, humid air up into the main body of the storm.That is where the tornado can be helpful to a

thunderstorm. It allows a thunderstorm to take inlarge amounts of air at a time into the storm’s body.Unfortunately, this process is very damaging toanything in its path.

Tornadoes can have wind speeds anywhere fromnear 65mph all the way up to more than 300mph.They vary in size, too. Small tornadoes may only be afew feet wide, but large tornadoes can reach adiameter more than one mile wide. Most tornadoesare between 300 and 2000 feet wide. Each year in theUnited States, about 1,000 tornadoes form.


TORNADOES ARE MADE ONLY INCERTAIN TYPES OF WEATHER PATTERNS. This allowsmeteorologists to issues forecasts and Tornado Watches towarn you ahead of time. To make a tornado, you need thewinds to be turning as you go higher and higher up in theatmosphere.

For example, say the wind on the ground is blowing from the southeast.But, if you go 500 feet above the ground, the winds are blowing from thesouthwest. That means that the winds are turning from the southeast to thesouthwest near the ground. Also remember that the air from the groundlevel feeds a thunderstorm. This air is “turning” already and as it is suckedinto the thunderstorm, the whole thunderstorm begins to turn, or rotate.

What happens when you take a glass of water and stir it up very fast witha spoon? As the water in the glass rotates faster and faster, a little funnelforms in the middle of the glass and tries to reach the bottom of theglass. In a similar way, a thunderstorm has air rotating around theinside of it and eventually a funnel cloud may form out of the bottomof the thunderstorm. If that funnel cloud reaches the ground it becomes a tornado!

The Invisible TornadoNOT ALL TORNADOES CAN BE SEEN CLEARLY. SOME ARE DISGUISED BY HEAVY RAIN. Some take placeat night in the dark. Some, however, are not wrapped in rain or at night, but you still can’t see them! These arelike invisible tornadoes.

So how do you know that a tornado is there? First of all, remember that tornadoes form beneath rotatingthunderstorms. A tornado is a tornado if its rotating winds have touched the ground. Sometimes the funnel-shaped cloud is not visible. At the point the tornado touches the ground, it begins to swirl dirt and debris. Thisis called a debris cloud. If you see a debris cloud—but no visible tornado—you have just spotted an invisibletornado. These are just as dangerous as any other tornado!


Why do Tornadoes rotate anyway?


Ranking the TornadoesTORNADOES ARE MEASURED BY THE AMOUNT OF DAMAGE THEY PRODUCE. It would be impossible foranyone to accurately measure a tornado the way we normally measure wind, because the tornado woulddestroy the equipment. Also, tornadoes form and go away before we could get the equipment to the tornado.So, the only way left to measure them is to look at the damage they did.

We use a scale to measure the damage caused by a tornado and from that damage, we can estimate thewinds. Look at the Fujita scale below for tornadoes and the description of the damage caused. This is the newwind damage scale that was first used in 2007.

EF-SCALENUMBER

INTENSITYPHRASE

WIND SPEED TYPE OF DAMAGE DONE

EF-0 Gale tornado 65-85 mph Some damage to chimneys; breaks branches offtrees; pushes over shallow-rooted trees; damagessign boards.

EF-1 Moderate tornado 86-110 mph

The lower limit of hurricane wind speed; peelssurface off roofs; mobile homes pushed offfoundations or overturned; moving autos pushed offthe roads; attached garages may be destroyed.

EF-2 Significant tornado 111-135 mph

Considerable damage. Roofs torn off frame houses;mobile homes demolished; boxcars pushed over;large trees snapped or uprooted; light objectmissiles generated.

EF-3 Severe tornado 138-167 mph Roof and some walls torn off well-constructedhouses; trains overturned; most trees in forestsuprooted

EF-4 Devastating tornado 168-199 mph

Well-constructed houses leveled; structures withweak foundations blown off some distance; carsthrown and large “missiles” generated.

EF-5 Incredible tornado More than200 mph

Strong frame houses lifted off foundations andcarried considerable distances to disintegrate;automobile-sized missiles fly through the air inexcess of 100 meters; trees debarked; steelreinforced concrete structures badly damaged.



REVIEW

Use your knowledge of tornadoes to answer the following questions to the best of your ability.

1 About how many tornadoes occur in the United States every year? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

2 According to the National Weather Service, Oklahoma averages around 53 tornadoes per year. In which season of the year do you think most of these tornadoes occur?_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

3 If a framed house was hit by a tornado and the damage consisted of a roof that was torn off, windows wereblown out, but most of the walls were still standing, then what would the Fujita-scale ranking be of this tornado? (use the chart on the previous page for assistance on this one) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

4 What type of cloud rotates at the bottom of a thunderstorm and is a warning sign of a possible tornado?_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

5 What is the name of the cloud of dust and broken materials that forms at the bottom of a tornado?_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

6 A tornado looks like it is developing from a thunderstorm. What would the name of this developing tornadobe BEFORE it reaches to the ground?_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

WHY THE WIND BLOWS QUESTIONS TORNADOES


What is a Hurricane?

WHY THE WIND BLOWS HURRICANES

A HURRICANE IS A LARGE, STRONG STORM THAT DEVELOPS OVER THE WARM WATERS OF THEOCEAN. This area of warm ocean water is known as the tropics. Hurricanes form when air moves toward anarea of low pressure over very warm water. At the low-pressure center, this air begins to rise forming a largearea of thunderstorms. If the air is allowed to “evacuate” from the top of the hurricane (high pressure in theupper-levels of the atmosphere causes wind to spread out) and the storm remains over warm water, then thehurricane will strengthen. (Note that the water off the west coast of the United States is much colder thanthe waters off of the East Coast. That, along with more favorable wind patterns in the East Coast areas,makes a land-falling West Coast hurricane a rare occurrence.)

Remember that air spins counter-clockwise around low pressure. Let’s say that at the ocean surface a lowpressure begins to develop. The air begins to move in toward the low pressure and around it counterclockwise.As all of this air comes together, too much “piles up” in this area and some has to rise to escape. This liftingair often develops into thunderstorms. As the pressure drops, the air spins faster and more air rises formingmore thunderstorms. This keeps going and going until the storm system is very strong. It has very fast windsspinning counter-clockwise with bands of thunderstorm rotating around it, too. This is now a hurricane.


SINCE HURRICANES DO SO MUCH DAMAGE, PEOPLEOFTEN WANT TO TALK ABOUT A CERTAIN HURRICANE. Theeasiest way to talk about something is if you give it a name. So,hurricanes are named. (The same could be done for tornadoes,but there are too many to name!)

As a storm in the tropics develops and gets stronger, it is givendifferent names. A tropical depression is a developing stormthat has maximum winds of 39mph or less. As the storm gainsstrength, and reaches winds of 40mph to 73mph, it is called atropical storm. A tropical storm becomes a hurricane when themaximum winds of the storm reach 74mph. Hurricanes canhave wind gusts more than 200mph.

Each year, there is a list of names that will be given to hurricanesor tropical storms in the order that they occur. The first namedstorm gets an “A” name, the second a “B” name, and so on. Thename list alternates men’s and women’s names through the listand each ocean has its own set of names. Hurricanes are alsoranked into categories by strength on the Saffir-Simpson Scale.

WIND SPEEDS

CATEGORY 1 74-95 mph




CATEGORY 5 156 mph or more

Where Most TropicalSystems Form

Naming the Hurricanes

WHY THE WIND BLOWS HURRICANES

PACIFIC BASIN

ATLANTIC BASIN


WHY THE WIND BLOWS QUESTIONS HURRICANES

REVIEW

Answer the following questions from what you have learned in the previous pagesand in class about hurricanes.

1 Residents of North Carolina watch which ocean for developing hurricanes and tropical storms? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

2 Why would you not be concerned about a hurricane hitting San Francisco, even though it sits right on the coast? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

3 Look up the link on hurricane names at the Weather in the Classroom website (see front cover forweb address) and fill in the names for this year’s hurricane season.

4 Put the following tropical systems in order from weakest to strongest: Hurricane, tropical depression and tropical storm.

Weakest __________________________________

Strongest _________________

“A” Name_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

“B” Name_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

“C” Name_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

“D” Name_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

“E” Name_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

“F” Name_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

“G” Name_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

“H” Name_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

“I” Name_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

“J” Name_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

“K” Name_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

“L” Name_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

“M” Name_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

“N” Name_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

“O” Name_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

“P” Name_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

“R” Name_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

“S” Name_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

“T” Name_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

“V” Name_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

“W” Name_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _


AUTUMN HEATWAVE SNOWFLAKE THUNDERSTORM

BLIZZARD HURRICANE SPRING TORNADO

BREEZY LIGHTNING SUMMER WINDY

HAILSTORM SEVERE THUNDER WINTER

J O X P C S H R R V N M U T U A D T J N

R K U H O O E A N E R D R A Z Z I L B E

D N Y U V D C P I O X S N O W F L A K E

K V F Y N V Y V T L I H Z O U S O Q L H

E Q Y U B A X S O Y S H K D Z P C I O W

W V H H B S R J O W U T P A Z R B K B T

S T A B R E U J N R S S O N V I A Y Z Y

Y P E W D L N M R Z X A V R A N F A J F

M V A N T X J I M E F B C O M G A U V E

W S U R Z A C B R E E Z Y T W L K D O J

R H P L S A E L X B R T C I Y I J Y M E

T U O C N D M H W M K R N Y O G V M Q N

U F N E R X K V I O Q T R D N H B G T S

E G T J V R M K J D E E H N X T D J J W

W R N D I K O M H R Y W B I F N O H G N

B K E B V F E K W X U S D W C I P L N K

Q L E V N D Y Z I G S V F H V N T S Y N

Y L A V E Q V Y D Z G K U E I G L E M J

V V N K H S Y D E N Z B K C U G K U Q B

A A V C O S E Z D F F Q J P F J B E U V

Weather Word Search

WHY THE WIND BLOWS GAMES WEATHER WORD SEARCH


Meteorology Crossword

ACROSS7. The measure of how much mass

(weight) is in a given volume.

9. A high, thin cloud made up of ice crystals.

11. Used to measure air pressure.

13. Used to measure air temperature.

14. This is violently rotating column of air.

15. The wind flows clockwise around an area of ______ pressure.

16. Frozen drops of rain that fall as pellets of ice in winter.

DOWN1. The scale by which we

categorize hurricanes.

2. A type of cloud that is associated with thunderstorms.

3. A measure of how much moisture is in the air.

4. The sun is directly overhead the Tropic of _________ on the summer solstice.

5. Used to measure wind speed.

6. The sun is directly overhead the Tropic of Capricorn on the _________ solstice.

8. The scale by which we rank tornadoes.

WHY THE WIND BLOWS GAMES METEREOLOGY CROSSWORD

9. This is an apparent force on the wind that is caused by the spin of the Earth.

10. When all molecules stop moving, you have reached the coldest possible temperature called ________ zero.

12. The wind flows counter-clockwise around an area of _______ pressure.

NOTES _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

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_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

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_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

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Severe WeatherAlerts

LOCAL GEOGRAPHY

SAFETY PROCEDURES

WATCHES AND WARNINGS

SEVERE WEATHER ALERTS


Where do You Live?Below is a map of Oklahoma.

When there is severe weather, warnings are issued for each county. Do you know the county in which you live? Find your county and shade it in red.

FILL IN THE FOLLOWING INFORMATION FOR YOUR USE:

In what state do you live? ______________________

In what country do you live? _____________________

In what city do you live? _______________________

Place a star on the map closest to where you live and go to school.



WHAT TO DO IN CASE OF A TORNADO:

Always try to get to a basement or storm shelter…you cannot find a better place of shelter thanbelow ground.

WHAT TO DO IF THERE IS NO BASEMENT OR STORM SHELTER:

Go to a small room in the center or your home on the lowest floor with no windows. A closet orbathroom is best. The best thing to do is to cover yourself with pillows, blankets, mattresses, etc.The idea is to protect yourself from flying objects. If you do not have a center room, go to a smallroom along the east wall of your home.

IF YOUR HOME IS NOT ON A PERMANENT FOUNDATION:

Do not trust a home that is not on a permanent foundation, such as a mobile home. You should havea place in mind, before the storm even forms, of where you can go. Make a storm safety plan. Youneed to choose the closest place of safety (a basement or storm shelter is best).

IF YOU ARE TRAVELING IN A CAR OR TRUCK:

Cars and trucks can be fatal shelters. If you are in the storm’s path, GET OUT OF YOUR VEHICLEand take shelter in a ditch or creek.

WHAT ABOUT OVERPASSES AND BRIDGES?

Recent studies have found that taking shelter under a bridge or overpass is more dangerous thanlying flat in a ditch. Winds underneath this bridge or overpass can accelerate and literally suck youout from underneath it. More than anything, it is NEVER a good idea to be anywhere outside of astorm shelter or basement during a tornado!

Tornado Safety



Severe Weather Safety

WHAT TO DO IN CASE OF A THUNDERSTORM:

If you are ever outside and a thunderstorm approaches, you need to find a place of shelter from thestorm. Unless there is a tornado, getting inside is the best form of shelter. (If there is a tornado, youneed to follow the tornado safety guidelines.) You should not stay outdoors during a storm. Even ina weak thunderstorm, lightning possesses enough energy to kill you. Because of this, you need totake shelter indoors away from the threat of lightning strikes.

WHAT TO DO IF YOU ARE IN A HAILSTORM:

Hailstorms can cause serious bodily injury. Although most hailstones are fairly small, they are fallingfrom heights of up to 9 miles high. They are moving very fast and can do more than just hurt you.Even medium size stones can render you unconscious, break bones, and, at the very least, bruiseyou. There is no need to be outside during any thunderstorm, especially a hailstorm.

LIGHTNING IS VERY DANGEROUS. REMEMBER THIS:

Lightning is the most frequent example of dangerous weather. Do not let this fool you into thinkingthat it is not as serious. More people are killed in the U.S. from lightning in a given year than fromtornadoes. Lightning is very dangerous and can strike up to five miles from the base of thunderstorm.As a storm approaches, you should take shelter indoors to avoid lightning strikes.

IF YOUR CAR IS STRUCK BY LIGHTNING:

Most cars will not allow you to be shocked if you are inside when it is struck. But, if you get out ofthe car and step on the ground while still touching the car, you can allow the remaining electricity inthe car to travel into the ground…and you will be shocked! You should always jump out of the carwithout touching the car and ground at the same time if you feel your car has been struck.



QUESTIONS ABOUT WEATHER SAFETY1 Which is more serious? a) Tornado Watch b) Tornado Warning

2 During a tornado warning, the best place to take shelter is: a) your garage b) a large room with plenty of windows c) basement or storm shelter.

3 It is safe to go outdoors during a Severe Thunderstorm Warning. True or False

4 At what point should you take shelter from a tornado? a) When a Tornado Warning is issued b) When a Tornado Watch is issuedc) When a Severe Thunderstorm Watch is issued d) Never

5 A severe thunderstorm is detected on radar moving toward your county. Which of the following would be issued? a) Tornado Warning b) Tornado Watch c) Severe Thunderstorm Warningd) Severe Thunderstorm Watch

6 There is plenty of time to move away when lightning begins to strike. True or False.

7 Hailstones are falling very fast and can hurt you if you don’t take shelter inside. True or False.

Watches & WarningsTHE NATIONAL WEATHER SERVICE, ALONG WITH LOCAL TELEVISION STATIONS, USE A SYSTEM OFWATCHES AND WARNINGS TO KEEP YOU ADVISED DURING SEVERE WEATHER. Read over the followingdefinitions of the watches and warnings and try to answer the questions below.

SEVERE THUNDERSTORM WATCH – This means that conditions are favorable for severe thunderstormsto develop (usually issued for a large number of counties).

SEVERE THUNDERSTORM WARNING – This means that a severe thunderstorm has been detected fora specific area (usually issued for one or two counties).

TORNADO WATCH – This means that conditions are favorable for storms to develop that could produce atornado (usually issued for a large number of counties).

TORNADO WARNING – This means that a tornado has been either detected on radar or sighted (usuallyissued for one or two counties).


NOTES _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

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WeatherGlossary

WEATHER GLOSSARY TERMINOLOGY


AADVECTION - The horizontal transfer of anyproperty in the atmosphere by the movementof air. Examples include heat and moistureadvection.

AIR -This is considered the mixture of gasesthat make up the earth's atmosphere. Theprinciple gases that compose dry air areNitrogen at 78.084%, Oxygen at 20.946%,Argon at .93%, and Carbon Dioxide .03%

AIR MASS - An extensive body of air through-out which the horizontal temperature andmoisture characteristics are similar.

BBAROMETER - An instrument used to meas-ure atmospheric pressure. Examples includethe aneroid barometer and the mercurialbarometer.

BAROMETRIC PRESSURE - The pressureexerted by the atmosphere at a given point.The measurement can be expressed in mil-libars(mb) or in inches of mercury(Hg).

BLIZZARD - A severe weather condition char-acterized by low temperatures, winds 35mphof greater, blowing snow that can reduce visi-bilities to 1/4 mile or less for more than 3hours. A severe blizzard is characterized bytemperatures at or below 10 degreesFahrenheit, winds exceeding 45mph, and visi-bility reduced by snow to near zero.

CCALM - Atmospheric conditions devoid ofwind or any other air motion.

CHINOOK - Refers to the warm downslopewind in the Rocky Mountains that may occurafter an intense cold spell when the tempera-tures may rise 20-40 degrees in a matter ofminutes.

CIRRUS - High clouds usually above 18,000feet, composed of ice crystals

CLIMATE - The historical record of averagedaily and seasonal weather events. Statisticsare generally drawn over several decades. Theword is derived from the Greek "klima" mean-ing inclination, and reflects the importanceearly scholars attributed to the sun's influence.

CLIMATOLOGY - The study of climate.Includes climatic data, the analysis of thecauses of the differences in climate, and theapplication of climatic data to the solution ofspecific design or operational problems.

CLOUDBURST - A sudden, heavy rainfall of ashowery nature.

COALESCENCE - The merging of two waterdrops into a single larger drop.

COLD FRONT - The leading edge of anadvancing cold air mass that is under runningand displacing the warmer air in its path.Generally, when a cold front passes the tem-perature and humidity decrease, the pressurerises, and the wind shifts from southwest tonorthwest. Precipitation is usually along orahead of the front in the form of thunderstorms.

CONDENSATION - The process by whichwater vapor undergoes a change in state froma gas to a liquid. It's opposite is evaporation.

CONVECTION - Motions in a fluid that trans-port and mix the properties of the fluid. Theseproperties could be heat and/or moisture.Often the term convection is used to describeupward motion of water vapor (moisture)forced to rise by surface heating in turn creat-ing rain or thunderstorms

CONVERGENCE - Wind movement thatresults in a horizontal net inflow of air into aparticular region. Convergent winds at lowerlevels are associated with upward motion.

CORIOLIS FORCE - A force per unit massthat arises solely from the earth's rotation,acting as a deflecting force. It is dependent onthe latitude and speed of the moving object.In the Northern Hemisphere the air is deflect-ed to the right, and in the SouthernHemisphere to the left. The coriolis effect isalmost non-existent at the equator.

CUMULONIMBUS CLOUD - A verticallydeveloped cloud, often capped by an anvilshaped cloud. This cloud is otherwise knownas a thundercloud. A cumulonimbus cloud canproduce tornadoes, hail, lightning, strongwinds and heavy rain.

CYCLONE - An area of closed pressure circu-lation with rotating and converging winds. Thecirculation is counterclockwise in theNorthern Hemisphere and clockwise in theSouthern Hemisphere. Also called a low pres-sure system and the term used for tropicalcyclone in the Indian Ocean. Other phenome-na with cyclonic flow may be referred to asdust devils, tornadoes, tropical and extratrop-ical systems.

DDEW - Condensation in the form of smallwater drops that form on grass and otherobject near the ground when the temperaturehas fallen to the dewpoint. Dew generallyforms during the nighttime hours and evapo-rates by mid to late morning.

DEW POINT - The temperature to which airmust be cooled at a constant pressure tobecome saturated. Example: If the air temper-ature is 70 degrees and the dewpoint temper-ature is 70 degrees the air is saturated anddew will form i.e, the relative humidity is 100%

DIVERGENCE - Wind movement that resultsin a horizontal net outlow of air from a particu-lar region. Divergence at lower levels is asso-ciated with a downward movement of air fromaloft.

DOPPLER RADAR - Weather radar thatmeasures the direction and speed of a movingobject, such as drops of precipitation, bydetermining whether atmospheric motion ishorizontally toward or away from the radar.

DOWNBURST - A severe localized downdraftfrom a thunderstorm or shower. This outwardburst of cool air creates damaging winds at ornear the surface.

DROUGHT - Abnormal, dry weather for a spe-cific area that is prolonged and causes serioushydrological imbalance.

DRY LINE - The boundary between the drydesert air mass of the southwestern U.S. andmoist air mass from the Gulf of Mexico. It usual-ly lies north-south across the central and south-ern High Plains states during the spring andsummer months. When a dry line passes itresults in a decrease in humidity, clearing skies,and wind shift from east/southeasterly towest/southwesterly. Its presence influencessevere weather development in the Great Plains.

EEASTERLIES - Usually applied to the broadpatterns of persistent winds with an easterlycomponent, such as the easterly trade winds.

ECHO - The energy return of a radar signalafter it has hit the target.

EQUATOR - The geographic circle at zerodegrees latitude on the earth's surface. It isequal distance from the North and SouthPoles and divides the Northern Hemispherefrom the Southern.



E (continued)EQUINOX - The point at which the eclipticintersects the celestial equator. Days andnights are most nearly equal in duration. In theNorthern Hemisphere, the vernal equinox fallson or about March 20 and the autumnal equi-nox on or about September 22.

EVAPORATION - The physical process bywhich a liquid, such as water is transformedinto a gaseous state, such as water vapor. It isthe opposite physical process of condensa-tion.

EVAPOTRANSPIRATION - The total amountof water that is transferred from the earth'ssurface to the atmosphere. It is made up ofthe evaporation of liquid or solid water plusthe transpiration from plants.

EXTRATROPICAL CYCLONE - Any cyclonenot of tropical origin. Generally considered tobe a migratory frontal cyclone found in themiddle and high latitudes.

EYE - The center of a tropical storm or hurri-cane, characterized by a roughly circular areaof light winds and rain-free skies. An eye willusually develop when the maximum sustainedwind speeds exceed 78 mph. It can range insize from as small as 5 miles up to 60 miles,but the average size is 20 miles. In general,when the eye begins to shrink in size, thestorm is intensifying.

EYEWALL - An organized band of convectionsurrounding the eye, or center, of a tropicalcyclone. It contains cumulonimbus clouds,intense rainfall and very strong winds.

FFAHRENHEIT TEMPERATURE SCALE - Atemperature scale where water at sea levelhas a freezing point of +32 degrees F and aboiling point of +212 degrees F. More com-monly used in areas that observe the Englishsystem of measurement. Created in 1714 byGabriel Daniel Fahrenheit (1696-1736), aGerman physicist, who also invented the alco-hol and mercury thermometers.

FAIR - This is a subjective description.Considered as pleasant weather conditionswith regard to the time of year and the physi-cal conditions. Also refers to no cloud coverbelow 10,000 feet.

FLASH FLOOD - A flood that rises and fallsquite rapidly with little or no advance warning,usually as the result of intense rainfall over arelatively small area. Flash floods can becaused by situations such as a sudden exces-sive rainfall, the failure of a dam, or the thawof an ice jam.

FLOOD - High water flow or an overflow ofrivers or streams from their natural or artificialbanks, inundating adjacent low-lying areas.

FOG - A visible aggregate of minute waterdroplets suspended in the atmosphere at ornear the surface of the earth, reducing hori-zontal visibility to less than 5/8 statute miles. Itis created when the temperature and the dewpoint of the air have become the same, ornearly the same, and sufficient condensationnuclei are present.

FORECAST - A statement of expected futureoccurrences. Weather forecasting includes theuse of objective models based on certainatmospheric parameters, along with the skilland experience of a meteorologist.

FREEZING DRIZZLE - Drizzle, falling as a liq-uid, but freezing on impact with the colderground or other exposed surfaces.

FREEZING RAIN - Rain that falls as liquid andfreezes upon impact to form a coating of glazeon the colder ground or other exposed sur-faces.

FRONT - The transition zone or interfacebetween two air masses of different densities,which usually means different temperatures.For example, the area of convergencebetween warm, moist air and cool, dry air.

FROST - The covering of ice crystals thatforms by direct sublimation on exposed sur-faces whose temperature is below freezing.

FUJITA SCALE - A scale that classifies theseverity of wind damage intensity based onthe degree of destruction as it relates to thewind speed as well as path length and pathwidth of the event. It is normally used to iden-tify the most intense damage exhibited by atornado. Developed by T. Theodore Fujita andAllen Pearson.

FUNNEL CLOUD - A violent, rotating columnof air visibly extending from the base of a tow-ering cumulus or cumulonimbus toward theground, but not in contact with it.

GGEOSTATIONARY SATELLITE - An orbitingweather satellite that maintains the same positionover the equator during the earth's rotation. Alsoknown as GOES, an acronym for GeostationaryOperational Environmental Satellite.

GRAUPEL - A form of frozen precipitationconsisting of snowflakes or ice crystals andsupercooled water droplets frozen together.

GRAVITY - The force of attraction of the earthon an object. The direction is downward rela-tive to the earth, and it decreases with eleva-tion or altitude away from the earth's surface.

GREENHOUSE EFFECT - The overall warm-ing of the earth's lower atmosphere primarilydue to carbon dioxide and water vapor whichpermit the sun's rays to heat the earth, butthen restrict some heat-energy from escapingback into space.

GUST - A sudden significant increase in orrapid fluctuations of wind speed. Peak windmust reach at least 16 knots (18 miles perhour) and the variation between peaks and lullsis at least ten knots (11.5 miles per hour). Theduration is usually less than twenty seconds.

GUST FRONT - The leading edge of the cool,gusty surface winds produced by thunder-storm downdrafts. Sometimes confused withan outflow boundary.

GUSTNADO - A weak, and usually short-lived,tornado that forms along the gust front of athunderstorm, appearing as a temporary dustwhirl or debris cloud.

HHAIL - Precipitation that originates in convec-tive clouds, such as cumulonimbus, in theform of balls or irregular pieces of ice, whichcomes in different shapes and sizes. Hail isconsidered to have a diameter of five millime-ter or more; smaller bits of ice are classified asice pellets, snow pellets, or graupel. Individuallumps are called hailstones.

HAZE - A suspension of fine dust and/orsmoke particles in the air. Invisible to thenaked eye, the particles reduce visibility bybeing sufficiently numerous to give the air anopalescent appearance.

HEAT - A form of energy transferred betweentwo systems by virtue of a difference in tem-perature. The first law of thermodynamicsdemonstrated that the heat absorbed by asystem may be used by the system to dowork or to raise its internal energy.



H (continued)HEAT INDEX - The combination of air temper-ature and humidity that gives a description ofhow the temperature feels. This is not theactual air temperature.

HEAT LIGHTNING - Lightning that appears asa glowing flash on the horizon. It is actuallylightning occurring in distant thunderstorms,just over the horizon and too far away forthunder to be heard.

HEAT WAVE - A period of abnormally anduncomfortably hot weather. It could last fromseveral days to several weeks.

HIGH CLOUDS - A term used to signify cirri-form clouds that are composed of ice crystalsand generally have bases above 20,000 feet.The main types of high clouds are cirrus, cir-rocumulus, and cirrostratus. This altitudeapplies to the temperate zone. In the polarregions, these clouds may be found at loweraltitudes. In the tropics, the defining altitudesfor cloud types are generally higher.

HIGH PRESSURE SYSTEM - An area of rela-tive pressure maximum that has divergingwinds and a rotation opposite to the earth'srotation. This is clockwise in the NorthernHemisphere and counterclockwise in theSouthern Hemisphere. It is the opposite of anarea of low pressure or a cyclone.

HOOK ECHO - A radar reflectivity patternobserved in a thunderstorm, appearing like afish hook and indicating favorable conditionsfor tornadic development. However, hookechoes and tornadoes do not always accom-pany each other.

HUMIDITY - The amount of water vapor in theair. It is often confused with relative humidityor dew point.

HURRICANE - The name for a tropicalcyclone with sustained winds of 74 miles perhour (65 knots) or greater in the North AtlanticOcean, Caribbean Sea, Gulf of Mexico, and inthe eastern North Pacific Ocean. This sametropical cyclone is known as a typhoon in thewestern Pacific and a cyclone in the IndianOcean.

HYDROLOGIC CYCLE - Often called thewater cycle, it is the vertical and horizontaltransport of water in all its states between theearth, the atmosphere, and the seas.

HYGROMETER - An instrument that meas-ures the water vapor content of the atmos-phere.

IICE - Water in a solid state. It can be found inthe atmosphere in the form of ice crystals,snow, ice pellets, and hail.

INCHES OF MERCURY - The name comesfrom the use of mercurial barometers whichequate the height of a column of mercury withair pressure. One inch of mercury is equivalentto 33.86 millibars. First devised in 1644 byEvangelista Torricelli, an Italian physicist andmathematician, to explain the fundamentalprinciples of hydromechanics.

INFRARED - The long wave, electromagneticradiation of radiant heat emitted by all hotobjects. On the electromagnetic spectrum, itcan be found between microwave radiationand visible light. Water vapor, ozone, and car-bon dioxide are efficient at absorbing or trans-mitting infrared radiation.

INSOLATION - Solar radiation or heatingreceived at the earth's surface. The name isderived from INcoming SOLar radiATION.

INSTABILITY - It is the condition of theatmosphere when spontaneous convectionand severe weather can occur. Air parcels,when displaced vertically, will accelerate upward.

INTERTROPICAL CONVERGENCE ZONE(ITCZ) - An area where the Northern andSouthern Hemispheric trade winds converge.It is a broad area of low pressure where boththe Coriolis force and the low-level pressuregradient are weak, occasionally allowing tropi-cal disturbances to form. The ITCZ fluctuates,moving northward over the south Atlantic dur-ing the Northern Hemisphere summer.

INVERSION - It refers to an increase in anatmospheric property with height. For exam-ple...A temperature inversion is when the tem-perature increases with altitude, which is adeparture from the usual decrease of temper-ature with height.

IONISPHERE - An atmospheric zone of ion-ized gases that extends between 50 and 400miles above the surface of the Earth. It islocated between the mesosphere and theexosphere.

ISOBAR - The line drawn on a weather mapconnecting points of equal barometric pres-sure.

ISOTHERM - The line of equal or constanttemperature.

JJETSTREAK - A region of accelerated windspeed along the axis of a jet stream.

JETSTREAM - A area of strong winds that areconcentrated in a relatively narrow band in theupper troposphere of the Northern andSouthern Hemispheres. Flowing in a semi-continuous band around the globe from westto east, it is caused by the changes in air tem-perature where the cold polar air movingtowards the equator meets the warmer equa-torial air moving northward toward the poles.

KKATABATIC WIND - A wind that is created byair flowing downhill. When the air is warm, itmay be called a foehn wind, and regionallymay be known as a Chinook, or Santa Ana.When this air is cool, it is called a drainagewind, mountain breeze or glacier wind.

KNOT - A nautical unit of wind speed equal tothe velocity at which one nautical mile is trav-eled in one hour. Used primarily by marineinterests and in weather observations. 1 knot= 1.151 statute miles per hour.

LLAND BREEZE - A diurnal coastal breeze thatblows offshore, from the land to the sea. It iscaused by the temperature difference whenthe sea surface is warmer than the adjacentland. Predominate during the night, it reachesits maximum around dawn.

LAPSE RATE - The change of an atmosphericvariable, usually temperature, with height. Asteep lapse rate implies a rapid decrease intemperature with height. This is a sign ofinstability.

LATITUDE - The location north or south in ref-erence to the equator, which is designated atzero degrees. Parallel lines that circle theglobe both north and south of the equator.The poles are at 90 degrees North and Southlatitude.

LEE/LEESIDE - The side of an object, suchas a ship's sail, a mountain, or a hill, furthestaway from the wind, and therefore protectedfrom the direct force of the wind.

LIGHTNING - A rapid, visible discharge ofelectricity hotter than the surface of the sun.Lightning is caused by the build up of electri-cal potential between cloud and ground,between clouds, or between clouds and thesurrounding air.



L (continued)LONGITUDE - The location east or west inreference to the Prime Meridian, which is des-ignated at 0 degrees longitude. The distancebetween lines of longitude are greater at theequator and smaller at the higher latitudes.Time zones are correlated to longitude.

LOW CLOUDS - A term used to describeclouds with bases below 6,000 feet. Types oflow clouds include stratus, stratocumulus,cumulus and cumulonimbus.

LOW LEVEL JET - Strong winds that are con-centrated in relatively narrow bands in thelower part of the atmosphere. It is often ampli-fied at night.

LOW PRESSURE SYSTEM - An area of a rel-ative pressure minimum that has convergingwinds and rotates in the same direction as theEarth...counterclockwise in the NorthernHemisphere and clockwise in the SouthernHemisphere. Also known as a cyclone.

LUNAR ECLIPSE - A eclipse of the moonoccurs when the Earth is in a direct linebetween the sun and the moon. The moondoes not have any light of its own, instead itreflects the sun's light. During a lunar eclipsethe moon is in the earth's shadow.

MMARE'S TAIL - The name given to thin, wispycirrus clouds composed of ice crystals thatappear as veil patches of strands, oftenresembling a horse's tail.

MEAN SEA LEVEL - The average height ofthe sea surface water level. For the UnitedStates, it is computed by averaging the levelsof all tide stages over a nineteen year period,determined from hourly height readings meas-ured from a fix, predetermined reference level.It is used as a basis for determining eleva-tions, as the reference for all altitudes in upperair measurements, and as the level abovewhich altitude is measured by a pressurealtimeter for aviation. Often referred to asMSL.

MESOCYCLONE - An area of rotation ofstorm size that may often be found on thesouthwest part of a supercell. Its circulationcan be larger than the tornado that may devel-op within it, but not necessarily. Originally aradar term for a rotation signature that metcertain criteria, it is best seen on Dopplerradar.

MESOSCALE - The scale of meteorologicalphenomena that range in size from severalkilometers to around 100 kilometers. Smallerphenomena are classified as microscale whilelarger are classified as synoptic-scale.

METEOROLOGY/METEOROLOGIST - Thescience and study of the atmosphere andatmospheric phenomena. Various areas ofmeteorology include agricultural, applied,astrometerology, aviation, dynamic, hydrome-teorology, operational, and synoptic, to namea few. A scientist who studies the atmosphereand atmospheric phenomena.

MICROBURST - A severe localized windblasting down from a thunderstorm. It coversan area less than 2.5 miles (4 kilometers) indiameter and is of short duration, usually lessthan five minutes.

MICROSCALE - The smallest scale of mete-orological phenomena that range in size froma few centimeters to a few kilometers. Largerphenomena are classified as mesoscale. Italso refers to small scale meteorological phe-nomena with life spans of less than a few min-utes that affect very small areas and arestrongly influenced by local conditions of tem-perature and terrain.

MIDDLE CLOUDS - A term used to signifyclouds with bases between 6,000 and 18,000feet. At the higher altitudes, they may alsohave some ice crystals, but they are com-posed mainly of water droplets. Altocumulus,altostratus, and nimbostratus are the maintypes of middle clouds. This altitude applies tothe temperate zone. In the polar regions,these clouds may be found at lower altitudes.In the tropics, the defining altitudes for cloudtypes are generally higher.

MIXED PRECIPITATION - Any of the follow-ing combinations of freezing and frozen pre-cipitation: snow and sleet, snow and freezingrain, or sleet alone. Rain may also be present.

MOISTURE - Refers to the water vapor con-tent in the atmosphere, or the total water, liq-uid, solid or vapor, in a given volume of air.

MONSOON - The seasonal shift of winds cre-ated by the great annual temperature variationthat occurs over large areas in contrast withassociated ocean surfaces. The monsoon isassociated primarily with the moisture andcopious rains that arrive with the southwestflow across southern India. The name isderived from the word mausim, Arabic for sea-son. This pattern is most evident on thesouthern and eastern sides of Asia, although itdoes occur elsewhere, such as in the south-western United States.

MULTICELL STORM - A thunderstorm madeup of two or more single-cell storms.

MULTIPLE VORTEX TORNADO - A tornadowhich has two or more condensation funnelsor debris clouds, often rotating around a com-mon center.

NNIMBOSTRATUS - This cloud exhibits a com-bination of rain or snow, and sometimes thebase of the cloud cannot be seen because ofthe heaviness of precipitation. They are gener-ally associated with fall and winter conditions,but can occur during any season.

NOR'EASTER - A cyclonic storm occurringoff the east coast of North America. Thesewinter weather events are notorious for pro-ducing heavy snow, rain, and tremendouswaves that crash onto Atlantic beaches, oftencausing beach erosion and structural damage.Wind gusts associated with these storms canexceed hurricane force in intensity. A nor'east-er gets its name from the continuously strongnortheasterly winds blowing in from the oceanahead of the storm and over the coastal areas.

OOBSERVATION - In meteorology, the evalua-tion of one or more meteorological elements,like temperature, pressure or wind thatdescribe the state of the atmosphere at agiven time. A trained observer is one whorecords the evaluations of the meteorologicalrecords.

OUTFLOW - Also referred to as an outflowboundary. It is the outward flow of air from asystem such as a thunderstorm. It is the resultof cold downdrafts and its passage includes awind shift and most often a temperature drop.Outflow boundaries sometimes help producethunderstorms as they move into regions ofinstability.

OVERCAST - When the sky is completelycovered by clouds.



O (continued)OVERRUNNING - This occurs when a rela-tively warm air mass is forced above a coolerair mass of greater density. Weather generallyassociated with this event include cloudiness,cool temperatures and steady precipitation.

OZONE LAYER - An atmospheric layer thatcontains a high proportion of oxygen thatexists as ozone. It acts as a filtering mecha-nism against incoming ultraviolet radiation. Itis located between the troposphere and thestratosphere between 9.5 and 12.5 milesabove the Earth's surface. Ozone at the sur-face is not healthy for humans to breathe.

PPARTLY CLOUDY - The state of the weatherwhen clouds are conspicuously present, butdo not completely cover the sky at a giventime. Sometimes interchanged with mostlysunny.

POLAR-ORBITING SATELLITE - A satellitewhose orbit passes over both of the Earth'spoles gathering cloud and temperature data.

PRECIPITATION - Any and all forms of water,liquid or solid, that falls from clouds andreaches the ground. This includes, drizzle,freezing drizzle, freezing rain, hail, ice crystals,ice pellets, rain, snow, snow pellets, and snowgrains.

PRESSURE - The force per unit area exertedby the weight of the atmosphere above apoint on or above the earth's surface.

PRESSURE GRADIENT - The amount ofpressure change that occurs over a fixed dis-tance at a fixed altitude.

PREVAILING WIND - A wind that blows fromone direction more frequently than any otherduring a given period, such as a day, month,season, or year.

PSYCHROMETER - An instrument used tomeasure the water vapor content of theatmosphere. It consists of two thermometers,a wet bulb and dry bulb. May also be referredto as a sling psychrometer.

RRADAR - Acronym for RAdio Detection AndRanging. An electronic instrument used todetect distant objects and measure their rangeby how they scatter or reflect radio energy.Precipitation and clouds are detected bymeasuring the strength of the electromagneticsignal reflected back.

RADIATION - The process by which energy ispropagated through any medium by virtue ofthe wave motion of that medium.Electromagnetic radiation, which emits heatand light, is one form. Sound waves areanother.

RADIATION FOG - Fog that is created whenradiational cooling at the earth's surface low-ers the temperature of the air near the groundto or below its dew point. Formation is bestwhen there is a shallow surface layer of rela-tively moist air beneath a drier layer, clearskies, and light surface winds. This primarilyoccurs during the night or early morning.

RAINBOW - A luminous arc featuring all col-ors of the visible light spectrum (red, orange,yellow, green, blue, indigo, and violet). It iscreated by refraction, total reflection, and thedispersion of light. It is visible when the sun isshining through air containing water spray orraindrops, which occurs during or immediatelyafter a rain shower. The bow is alwaysobserved in the opposite side of the sky fromthe sun.

REFLECTIVITY - A measure of the process bywhich a surface can turn back a portion ofincident radiation into the medium throughwhich the radiation approached. It also refersto the degree by which precipitation is able toreflect a radar beam. Related albedo.

RELATIVE HUMIDITY - A type of humiditythat considers the ratio of the actual vaporpressure of the air to the saturation vaporpressure. It is usually expressed in percent-age.

RIME - The rapid freezing of supercooledwater droplets as they touch an exposedobject, forming a white opaque granulardeposit of ice. It is one of the results of an icestorm, and when formed on aircraft it is calledrime icing. Related glaze

ROLL CLOUD - A relatively rare, low-level,horizontal, tube-shaped cloud. Although theyare associated with a thunderstorm, they arecompletely detached from the base of thecumulonimbus cloud.

SSAFFIR - SIMPSON DAMAGE-POTENTIALSCALE - Developed in the early 1970s byHerbert Saffir, and Robert Simpson, it is ameasure of hurricane intensity on a scale of 1to 5. The scale categorizes potential damagebased on barometric pressure, wind speeds,and storm-surge.

SATELLITE - Any object that orbits a celestialbody, such as a moon. However, the term isoften used in reference to the manufacturedobjects that orbit the earth, either in a geosta-tionary or a polar manner. Some of the infor-mation that is gathered by weather satellites,includes upper air temperatures and humidity,recording the temperatures of cloud tops,land, and ocean, monitoring the movement ofclouds to determine upper level wind speeds,tracing the movement of water vapor, monitor-ing the sun and solar activity, and relaying datafrom weather instruments around the world.

SCATTERING - The process by which smallparticles suspended in the air diffuse a portionof the incident radiation in all directions. Thisis a primary reason for colors, such as blueskies, rainbows, and orange sunsets.

SEA BREEZE - A diurnal coastal breeze thatblows onshore, from the sea to the land. It iscaused by the temperature difference when thesurface of the land is warmer than the adjacentbody of water. Predominate during the day, itreaches its maximum early to mid afternoon. Itblows in the opposite direction of a land breeze.

SEA LEVEL PRESSURE - The atmosphericpressure at mean sea level, usually deter-mined from the observed station pressure.

SEVERE THUNDERSTORM - A thunderstormwith winds measuring 50 knots (58 mph) orgreater, 3/4 inch hail or larger, or tornadoes.Severe thunderstorms may also produce tor-rential rain and frequent lightning.

SEVERE WEATHER - Generally, any destruc-tive weather event, but usually applies tolocalized storms, such as blizzards, intensethunderstorms, or tornadoes.

SHEAR - It is the rate of change over a shortduration. In wind shear, it can refer to the fre-quent change in wind speed within a shortdistance. It can occur vertically or horizontally.Directional shear is a frequent change in direc-tion within a short distance, which can alsooccur vertically or horizontally. When used inreference to Doppler radar, it describes thechange in radial velocity over short distanceshorizontally.

SKY COVER - The amount of the celestialdome that is hidden by clouds and/or obscu-rations.

SLEET - Also known as ice pellets, it is winterprecipitation in the form of small bits or pelletsof ice that rebound after striking the ground orany other hard surface.



S (continued)SNOW - Frozen precipitation in the form ofwhite or translucent ice crystals in complexbranched hexagonal form. It most often fallsfrom stratiform clouds, but can fall as snowshowers from cumuliform ones. It usuallyappears clustered into snowflakes.

SNOW FLURRY/FLURRIES - Light showersof snow, generally very brief without anymeasurable accumulation.

SNOW GRAINS - Frozen precipitation in theform of very small, white, opaque grains ofice. The solid equivalent of drizzle.

SNOW PELLETS - Frozen precipitation in theform of white, round or conical opaque grainsof ice. Their diameter ranges from 0.08 to 0.2inch (2 to 5 mm). They are easily crushed andgenerally break up after rebounding from ahard surface, unlike hail. Sometimes it iscalled small or soft hail.

SNOWFLAKES - An ice crystal or an aggre-gate of ice crystals which fall from clouds.

SOLAR ECLIPSE - An eclipse of the sunoccurs when the moon is in a direct linebetween the sun and the earth, casting someof the earth's surface in its shadow. Themoon's disk shaped outline appears to coverthe sun's brighter surface, or photosphere.That part of the earth that is directly in themoon's shadow will see a total eclipse of thesun, while the areas around it will see a partialeclipse.

SOLSTICE - The point at which the sun is thefurthest on the ecliptic from the celestial equa-tor. The point at which sun is at maximum dis-tance from the equator and days and nightsare most unequal in duration. The Tropic ofCancer and the Tropic of Capricorn are thoseparallels of latitude which lies directly beneatha solstice. In the Northern Hemisphere, thewinter solstice falls on or about December 21and the summer solstice on or about June 21.

SPRING - The season of the year whichoccurs as the sun approaches the summersolstice, and characterized by increasing tem-peratures in the mid-latitudes. Customarily,this refers to the months of March, April, andMay in the Northern Hemisphere, and themonths of September, October, andNovember in the Southern Hemisphere.Astronomically, this is the period between thevernal equinox and the summer solstice.

SQUALL - A sudden onset of strong windswith speeds increasing to at least 16 knots (18miles per hour) and sustained at 22 or moreknots (25 miles per hour) for at least oneminute. The intensity and duration is longerthan that of a gust.

SQUALL LINE - A narrow band of line ofactive thunderstorms that is not associatedwith a cold front. It may form from an outflowboundary or the leading edge of a meso-high.

STATIONARY FRONT - A front which is nearlystationary or moves very little since the lastsynoptic position. May be known as quasi-stationary front.

STRAIGHT-LINE WINDS - Any surface windthat is not associated with rotation. An exam-ple is the first gust from a thunderstorm, asopposed to tornadic winds.

STRATIFORM - Clouds composed of waterdroplets that exhibit no or have very little verti-cal development. The density of the dropletsoften blocks sunlight, casting shadows on theearth's surface. Bases of these clouds are gen-erally no more than 6,000 feet above the ground.They are classified as low clouds, and include allvarieties of stratus and stratocumulus.

STRATOCUMULUS - A low cloud composedof layers or patches of cloud elements. It canform from cumulus clouds becoming morestratiformed and often appears as regularlyarranged elements that may be tessellated,rounded, or roll-shaped with relatively flat topsand bases. It is light or dark gray in color,depending on the size of the water dropletsand the amount of sunlight that is passingthrough them.

STRATOPAUSE - The boundary zone or tran-sition layer between the stratosphere and themesosphere. Characterized by a decrease intemperature with increasing altitude.

STRATOSPHERE - The layer of the atmos-phere located between the troposphere andthe mesosphere, characterized by a slighttemperature increase and absence of clouds.It extends between 11 and 31 miles (17 to 50kilometers) above the earth's surface. It is thelocation of the earth's ozone layer.

STRATUS - One of the three basic cloudforms (the others are cirrus and cumulus). It isalso one of the two low cloud types. It is asheet-like cloud that does not exhibit individualelements, and is, perhaps, the most commonof all low clouds. Thick and gray, it is seen inlow, uniform layers and rarely extends higherthan 5,000 feet above the earth's surface.

SUBLIMATION - The process of a solid (ice)changing directly into a gas (water vapor), orwater vapor changing directly into ice, at thesame temperature, without ever going throughthe liquid state (water).

SUBSIDENCE - A sinking or downwardmotion of air, often seen in anticyclones. It ismost prevalent when there is colder, denserair aloft. It is often used to imply the oppositeof atmospheric convection.

SUBTROPICAL - The region between thetropical and temperate regions, an areabetween 35 and 40 degrees North and Southlatitude. This is generally an area of semi-per-manent high pressure that exists and is wherethe Azores and North Pacific Highs may befound.

SUBTROPICAL JET - Marked by a concen-tration of isotherms and vertical shear, this jetis the boundary between the subtropical airand the tropical air. It is found approximatelybetween 25 and 35 degrees North latitude andusually above an altitude of 40,000 feet. Itsposition tends to migrate south in theNorthern Hemispheric winter and north in thesummer.

SUMMER - Astronomically, this is the periodbetween the summer solstice and the autum-nal equinox. It is characterized as having thewarmest temperatures of the year, except insome tropical regions. Customarily, this refersto the months of June, July, and August in theNorth Hemisphere, and the months ofDecember, January, and February in the SouthHemisphere.

SUPERCELL - A severe thunderstorm charac-terized by a rotating, long-lived, intenseupdraft. Although not very common, they pro-duce a relatively large amount of severeweather, in particular, extremely large hail,damaging straight-line winds, and practicallyall violent tornadoes.

SUPERCOOLING - The reduction of the tem-perature of any liquid below the melting pointof that substance's solid phase. Cooling asubstance beyond its nominal freezing point.Supercooled water is water that remains in aliquid state when it is at a temperature that iswell below freezing. The smaller and purer thewater droplets, the more likely they canbecome supercooled.

SURFACE BOUNDARY LAYER - The lowestlayer of the earth's atmosphere, usually up to3,300 feet, or one kilometer, from the earth's sur-face, where the wind is influenced by the frictionof the earth's surface and the objects on it.



S (continued)SURGE - The increase in seawater heightfrom the level that would normally occur werethere no storm. Although the most dramaticsurges are associated with hurricanes, evensmaller low-pressure systems can cause aslight increase in the sea level if the wind andfetch is just right. It is estimated by subtract-ing the normal astronomic tide from theobserved storm tide.

SYNOPTIC SCALE - The size of migratoryhigh and low pressure systems in the lowertroposphere that cover a horizontal area ofseveral hundred miles or more.

TTEMPERATURE - The measure of molecularmotion or the degree of heat of a substance.

THERMOMETER - An instrument used formeasuring temperature. The different scalesused in meteorology are Celsius, Fahrenheit,and Kelvin or Absolute.

THERMOSPHERE - A thermal classification, itis the layer of the atmosphere locatedbetween the mesosphere and out space. It isa region of steadily increasing temperaturewith altitude.

THUNDER - The sound emitted by rapidlyexpanding gases along the channel of a light-ning discharge. Over three-quarters of light-ning's electrical discharge is used in heatingthe gases in the atmosphere in and immedi-ately around the visible channel. Temperaturescan rise to over 10,000 degrees Celsius inmicroseconds, resulting in a violent pressurewave, composed of compression and rarefac-tion. The rumble of thunder is created asone's ear catches other parts of the dis-charge, the part of the lightning flash nearestregistering first, then the parts further away.

THUNDER SNOW - A wintertime thunder-storm from which falls snow instead of rain.

THUNDERSTORM - Produced by a cumu-lonimbus cloud, it is a microscale event of rel-atively short duration characterized by thun-der, lightning, gusty surface winds, turbulence,hail, icing, precipitation, moderate to extremeup and downdrafts, and under the mostsevere conditions, tornadoes.

TORNADO - A violently rotating column of airin contact with and extending between a con-vective cloud and the surface of the earth. It isthe most destructive of all storm-scale atmos-pheric phenomena. They can occur anywherein the world given the right conditions, but aremost frequent in the United States in an areabounded by the Rockies on the west and theAppalachians in the east.

TORNADO ALLEY - A geographic corridor inthe United States which stretches north fromTexas to Nebraska and Iowa. In terms of sheernumbers, this section of the United Statesreceives more tornadoes than any other.

TOWERING CUMULUS - Another name forcumulus congestus, it is a rapidly growingcumulus or an individual dome-shaped cloudswhose height exceeds its width. Its distinctivecauliflower top often mean showers below, butlacking the characteristic anvil of a cumu-lonimbus, it is not a thunderstorm.

TRACE - Generally, a non-measurable orinsignificant quantity. A precipitation amountof less than 0.005 inch.

TRADE WINDS - Two belts of prevailingwinds that blow easterly from the subtropicalhigh pressure centers towards the equatorialtrough. Primarily lower level winds, they arecharacterized by their great consistency ofdirection. In the Northern Hemisphere, thetrades blow from the northeast, and in theSouthern Hemisphere, the trades blow fromthe southeast.

TRANSPIRATION - The process by whichwater in plants is transferred as water vapor tothe atmosphere.

TROPICAL AIR MASS - An air mass thatforms in the tropics or subtropics over the lowlatitudes. Maritime tropical air is producedover oceans and is warm and humid, whilecontinental tropical air is formed over aridregions and is very hot and dry.

TROPICAL CYCLONE - A warm-core lowpressure system which develops over tropical,and sometimes subtropical, waters, and hasan organized circulation. Depending on sus-tained surface winds, the system is classifiedas a tropical disturbance, a tropical depres-sion, a tropical storm, or a hurricane ortyphoon.

TROPICAL DEPRESSION - A tropical cyclonein which the maximum sustained surfacewinds are 38 miles per hour (33 knots) or less.Characteristically having one or more closedisobars, it may form slowly from a tropical dis-turbance or an easterly wave which has con-tinued to organize.

TROPICAL DISTURBANCE - An area oforganized convection, originating in the trop-ics and occasionally the subtropics, that main-tains its identity for 24 hours or more. It isoften the first developmental stage of anysubsequent tropical depression, tropicalstorm, or hurricane.

TROPICAL STORM - A tropical cyclone inwhich the maximum sustained surface windsare from 39 miles per hour (34 knots) to 73miles per hour (63 knots). At this point, thesystem is given a name to identify and track it.

TROPICAL WAVE - Another name for aneasterly wave, it is an area of relatively lowpressure moving westward through the tradewind easterlies. Generally, it is associated withextensive cloudiness and showers, and maybe associated with possible tropical cyclonedevelopment.

TROPICS/TROPICAL - The region of theearth located between the Tropic of Cancer, at23.5 degrees North latitude, and the Tropic ofCapricorn, at 23.5 degrees South latitude. Itencompasses the equatorial region, an area ofhigh temperatures and considerable precipita-tion during part of the year.

TROPOPAUSE - The boundary zone or transi-tion layer between the troposphere and thestratosphere. This is characterized by little orno increase or decrease in temperature orchange in lapse rate with increasing altitude.

TROPOSPHERE - The lowest layer of theatmosphere located between the earth's sur-face to approximately 11 miles (17 kilometers)into the atmosphere. Characterized by cloudsand weather, temperature generally decreaseswith increasing altitude.

TROUGH - An elongated area of low atmos-pheric pressure that is associated with an areaof minimum cyclonic circulation. The oppositeof a ridge.

TWILIGHT - Often called dusk, it is theevening period of waning light from the time ofsunset to dark.

TWISTER - A slang term used in the UnitedStates for a tornado.



T (continued)TYPHOON - The name for a tropical cyclonewith sustained winds of 74 miles per hour (65knots) or greater in the western North PacificOcean. This same tropical cyclone is knownas a hurricane in the eastern North Pacific andNorth Atlantic Ocean, and as a cyclone in theIndian Ocean.

UULTRAVIOLET - Electromagnetic radiationthat has a wavelength shorter than visible lightand longer than x-rays. Although it accountsfor only 4 to 5 percent of the total energy ofinsolation, it is responsible for many complexphotochemical reactions, such as fluores-cence and the formation of ozone.

UNIVERSAL TIME COORDINATE - One ofseveral names for the twenty-four hour timewhich is used throughout the scientific andmilitary communities.

UNSTABLE/INSTABILITY - Occurs when arising air parcel becomes less dense than thesurrounding air. Since its temperature will notcool as rapidly as the surrounding environ-ment, it will continue to rise on its own.

UPDRAFT - A small scale current of air withvertical motion. If there is enough moisture,then it may condense, forming a cumuluscloud, the first step towards thunderstormdevelopment.

UPPER AIR/UPPER LEVEL - The portion ofthe atmosphere which is above the lower tro-posphere. It is generally applied to the levelsabove 850 millibars. Therefore, upper levellows and highs, troughs, winds, observations,and charts all apply to atmospheric phenome-na above the surface.

UPSLOPE EFFECT - The cooling of an airflow as it ascends a hill or mountain slope. Ifthere is enough moisture and the air is stable,stratiform clouds and precipitation may form.If the air is unstable, there might be anincreased chance of thunderstorm develop-ment.

VVERNAL EQUINOX - Taking place in theNorthern Hemispheric spring, it is the point atwhich the ecliptic intersects the celestialequator. Days and nights are most nearlyequal in duration. It falls on or about March 20and is considered the beginning of spring inthe Northern Hemisphere and autumn in theSouthern Hemisphere.

VIRGA - Streaks or wisps of precipitation,such as water or ice particles, that fall fromclouds but evaporate before reaching theground.

VISIBILITY - A measure of the opacity of theatmosphere, and therefore, the greatest dis-tance one can see prominent objects with nor-mal eyesight.

VISIBLE LIGHT - The portion of the electro-magnetic spectrum that can be detected bythe human eye. It travels at the same speedas all other radiation, that is at 186,000 milesper second. It has a wave length longer thanultraviolet light and shorter than x-rays.

WWALL CLOUD - An abrupt lowering of acloud from its parent cloud base, a cumu-lonimbus or supercell, with no visible precipi-tation underneath. Forming in the area of athunderstorm updraft, or inflow area, itexhibits rapid upward movement and cyclonicrotation. It often develops before strong orviolent tornadoes.

WARM ADVECTION - The horizontal move-ment of warmer air into a location.

WARM FRONT - The leading edge of anadvancing warm air mass that is replacing aretreating relatively colder air mass. Generally,with the passage of a warm front, the temper-ature and humidity increase, the pressurerises, and although the wind shifts (usuallyfrom the southwest to the northwest in theNorthern Hemisphere), it is not as pronouncedas with a cold frontal passage.

WARNING - A forecast issued when severeweather has developed, is already occurringand reported, or is detected on radar.Warnings state a particular hazard or imminentdanger, such as tornadoes, severe thunder-storms, flash and river floods, winter storms,heavy snows, etc.

WATCH - A forecast issued well in advance ofa severe weather event to alert the public ofthe possibility of a particular hazard, such astornadoes, severe thunderstorms, flash andriver floods, winter storms, or heavy snows.

WATERSPOUT - A small, weak tornado,which is not formed by a storm-scale rotation.It is generally weaker than a supercell tornadoand is not associated with a wall cloud ormesocyclone. It may be observed beneathcumulonimbus or towering cumulus cloudsand is the water equivalent of a landspout.

WEATHER - The state of the atmosphere at aspecific time and with respect to its effect onlife and human activities. It is the short termvariations of the atmosphere, as opposed tothe long term, or climatic, changes.

WESTERLIES - Usually applied to the broadpatterns of persistent winds with a westerlycomponent. It is the dominant persistentatmospheric motion, centered over the midlat-itudes of each hemisphere.

WIND - Air that flows in relation to the earth'ssurface, generally horizontally. There are fourareas of wind that are measured: direction,speed, character (gusts and squalls), andshifts. Surface winds are measured by windvanes and anemometers, while upper levelwinds are detected through pilot balloons,rawin, or aircraft reports.

WIND CHILL INDEX - The calculation of tem-perature that takes into consideration theeffects of wind and temperature on the humanbody. Describes the average loss of body heatand how the temperature feels. This is not theactual air temperature.

WIND DIRECTION - The direction from whichthe wind is blowing.

WIND SHEAR - The rate of wind speed ordirection change with distance. Vertical windshear is the rate of change of the wind withrespect to altitude. Horizontal wind shear isthe rate of change on a horizontal plane.

WIND VANE - An instrument that indicatesthe wind direction. The end of the vane whichoffers the greatest resistance to the motion ofthe air moves to the downwind position.

WINDWARD - The direction from which thewind is blowing. Also the upwind side of anobject. The opposite of the downwind or lee-ward side.

WINTER - Astronomically, this is the periodbetween the winter solstice and the vernalequinox. It is characterized as having thecoldest temperatures of the year, when thesun is primarily over the opposite hemisphere.

ZZONAL FLOW - The flow of air along a latitu-dinal component of existing flow, normallyfrom west to east.

ZULU TIME - One of several names for thetwenty-four hour time which is used through-out the scientific and military communities.


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