Weather TEKS Essential Questions 8.10 B Identify how global patterns of atmospheric movement influence local weather using weather maps that show high and low pressures and fronts. 8.10 C Identify the role of the oceans in the formation of weather systems such as hurricanes. Essential Questions How do global patterns of atmospheric movement influence local weather? How are weather maps used to identify global patterns of atmospheric movement? What is the role of oceans in the formation of weather systems?

Warm-Up Are weather and climate the same thing? BEFORE AFTER WEATHER CLIMATE What do you know about weather and climate? Fill out the before section of this comparison chart. How is weather different from climate or are they the same thing?

If you said that weather and climate were different things, you’re right! The happenings in the atmosphere at a certain time. The meteorological conditions, including temperature, precipitation, and wind, that characteristically prevail in a particular region. A region of the earth having particular meteorological conditions: lives in a cold climate. Climate Weather

So, in other words: Climate is how the weather usually is in a particular area. For example, Austin is usually very hot in the summer, and we have mild winters. Weather is what it is like outside right now. For example, a cold front came in this morning, and now I want to stay inside. But what causes our weather to change?

Our weather depends a lot on the wind. Wind is simply the movement of air, but what causes it and how does have such an impact on our weather?

Explore Activity 1: The Movement of Air Masses Everyone stand very close together. Imagine all of the students in every class in the school were tightly packed into their classroom with standing room only. All doors and windows were closed. This room then would be a high pressure area. Now imagine that there is no one in the hall outside the classroom. It is totally empty. The hall then is a low pressure area. Someone opens the door… Where would you want to go? Discuss different senerios (e.g. what if there were people in the hall, how would that change your movement?)

Reflection… In your journal, revise your warm-up. Are climate and weather the same thing? Next write a paragraph about the information you gained today and your experiences in a high pressure system. Be specific. What did you learn? What new questions do you have about the weather?

Exit Ticket Your teacher has given you a post-it. Look back in your notebook to today’s lesson. Write either something you learned or a question you have on the post-it. Stick your post-it to the chart your teacher has prepared for your class.

Warm-Up 2 Think back on what you learned in our last class, in your interactive notebook answer the following question: How do you think the movement of air in our atmosphere affects what the weather is like here and around the world? Explain your answer. If you think that air moving does not affect weather around the world, explain why.

We know that weather is… The happenings in the atmosphere at a certain time.

We also know that weather is caused by wind…

What causes wind? diferences in pressure

What does that mean? It means, that wind is produced by the uneven heating of the earth’s surface by the sun (remember, the Earth is tilted, so we don’t all get the same amount of sun) Since the earth’s surface is made of both land and water formations, it absorbs the sun’s radiation unevenly. This means it does not all heat the same way.

When you were in a high pressure situation… You wanted to move…So does the air. Warm air, which weighs less than cold air, rises. Then cool air moves in and replaces the rising warm air. Warm air is LESS DENSE than cold air. This movement of air is what makes the wind blow. It is called a convection current.

Or look at it this way…

Wind blows from areas of This Wind blows from areas of to areas of high pressure low pressure

High Pressure System In a high atmospheric pressure system the atmospheric pressure of the air is higher than that of the air around it. (It’s less dense) High atmospheric pressure systems are marked by an H on a weather map They mean clear weather.

Low Pressure System In a low atmospheric pressure system the atmospheric pressure of the air is lower than the air around it. The air is more dense. Low atmospheric pressure systems are symbolized by an L on a weather map. They mean storminess and precipitation

Front A place where two air masses of different temperatures meet.

Jet Stream The jet stream is a fast flowing, river of air. They form at the boundaries of connecting air masses that have big differences in temperature, such as of the polar region (VERY COLD AIR) and the warmer air to the south (VERY HOT AIR). Because of the Earth's rotation the streams flow west to east.

Measurements wind speed air pressure anemometer barometer [ORIGIN from Greek anemos ‘wind’] [ORIGIN from Greek baros ‘weight’]

Weather Map A map that shows weather conditions

Atmospheric Movement This is the large scale movement of air throughout the atmosphere. This movement, by air currents, is how heat is distributed all over our planet.

Global Pattern A global pattern is something that affects the entire world. It is a pattern that is seen throughout the world. Weather patterns are examples of global patterns. Climate has global patterns. These are systems that are important because they affect our entire planet.

Read the passage and complete the map of global wind patterns Easterlies Westerlies Trade Winds Doldrums

Easterlies Westerlies Trade Winds Doldrums

Is air rising or sinking at 30°N?

Is air rising or sinking at the equator?

Reading a Weather Map

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What Does It All Mean? Remember: The H stands for a High Pressure system This means CLEAR WEATHER The L stands for LOW pressure system This means STORMY weather

What are Air Masses???? Large areas (blobs) of air that have the same weather, temperatures and humidity Weather changes occur with changes in air masses

What Are Fronts??? Fronts are the boundary between two air masses They bring changes in the weather (from west to east) Fronts are named for the air that is behind them

Cold Front Cold dense air pushes warm air out of the way Cold fronts move very quickly and bring short periods of rain/thunderstorms Lower temperatures are behind the front SYMBOL – the direction of the “arrows” points towards the direction the front is MOVING

Cold Front Diagram

Cold Front

Warm Front Warm air moves up the cold front as it slowly displaces the cold air Warm fronts move slowly, and bring many days of steady precipitation Higher temperatures are behind the front SYMBOL – direction of “half-moons” is the direction the front is moving

Stationary Front The air from the warm front and cold front meet, but do not move These fronts have the same weather as warm fronts SYMBOL – warm and cold fronts are moving in opposite directions, thus making a stationary condition

Let’s see it on the map! Stationary Front Cold Front Warm Front

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