How can weather be predicted
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The document discusses how weather is predicted by analyzing large bodies of air called air masses. There are different types of air masses - cold/warm and dry/moist - that form over land or water and influence weather conditions. Weather maps use symbols to show features like air pressure, temperature, wind and precipitation across an area based on data collected from weather instruments at stations. Analyzing air masses, fronts where they meet, and weather maps helps predict changes in weather conditions.
How can weather be predicted
- 1. How can weather be predicted? Grade 4
- 2. Have you ever wondered why the weather changes?
- 3. When a large body of air moves it causes weather changes. Air mass Large body of air.
- 4. Air masses can be: Hot air mass Cold air mass All of an air mass has the same temperature and same amount of moisture level (amount of water in the air).
- 5. Blue arrows are cold air masses Red arrows are hot air masses
- 6. Temperature and moisture level depend on where the air masses where formed. Dry air mass Formed over land Wet air mass Formed over oceans or seas Hot air mass Come from the south Cold air mass Come from the north
- 8. Type of weather caused by different air masses: Cold, dry air masses Cool weather, with little or no precipitation Warm, moist air masses Lot of precipitation Warm, dry air masses Warm weather + little or no precipitation Cold, Wet air masses Snow
- 9. Air masses Stay separate Why? Because warm air is lighter than cold air. So, warm air masses are pushed upward and cold air masses sink.
- 10. Air masses move The border between one air mass and the other is called a front.
- 13. 1) Cold Front Cold air moves under warm air. Warm air mass moves up and cools down. Water vapor condenses and moves up. It might rain or thunderstorms develop along the front As the cold air mass moves forward the weather becomes cooler.
- 15. 2) Warm Front Warm air moves slides over cold air. Warm fronts moves slowly. Steady rain instead of thunderstorms. Warm fronts are followed by clear, warm weather.
- 18. 3) Stationary front A front that stays in one place for many days Happens when two air masses do not have enough energy to move. Steady rain instead of thunderstorms. Weather along the stationary front is often cloudy and wet This kind of front can leave inches of snow or cause flooding.
- 19. Types of clouds
- 22. Cumulus clouds Common on clear, war m days.
- 25. Weather maps
- 26. Weather maps help you know what the weather is like in an area. Weather maps use symbols to show the weather.
- 29. Many weather maps show temperatures. The temperature can be: Written on a map. Shown using colors. Red (Very hot) Orange (Warm) Green (Cool) Yellow (mild) Blue (Very cold)
- 30. L(Low air pressure) H(High air pressure)
- 31. In the USA the temperature unit is Fahrenheit (°F)
- 38. Where does all the information on a weather map come form? Weather stations
- 39. Some Weather instruments 1) Barometer Measures air pressure
- 40. 2) Thermometer Measures air temperature
- 41. 3) Wind vane Shows which direction wind is moving
- 42. 4) Anemometer Measures wind speed
- 43. 5) Rain gauge Measures amount of precipitation