Lesson 7: Mapping Weather and Fronts
Getting Started
When air masses meet, they're called fronts. The four kinds of fronts that move across the globe are warm, cold, stationary, and occluded. Find out what they are and what kind of weather happens when they meet. You will also learn how to read different kinds of weather maps in this lesson.
NOTE: If you didn't prepare your colored ice cubes for Activity 1 yesterday, do that now. You will need to wait until the water is frozen before doing the activity.
Weather journal: Fill out your weather journal for today. Use today's clouds and/or air pressure reading to forecast the weather for later today or tomorrow.
NOTE: If you didn't prepare your colored ice cubes for Activity 1 yesterday, do that now. You will need to wait until the water is frozen before doing the activity.
Weather journal: Fill out your weather journal for today. Use today's clouds and/or air pressure reading to forecast the weather for later today or tomorrow.
Stuff You Need
- Eyewitness Weather by Brian Cosgrove (revised edition)
- apron* (Activity 1 - optional)
- colored pencils
- glass pan or clear plastic box
- ice cube tray* (Activity 1 - optional)
- measuring cup
- red and blue food coloring (kit)
- small cups (kit)
* - denotes an optional material that may or may not be needed
Ideas to Think About
- How do global air masses affect your local weather?
- How does the temperature of an air mass affect its behavior?
Things to Know
- A cold front is a mass of cooler air pushing under a mass of warmer air. Cold fronts bring cooler temperatures and often produce strong storms.
- A warm front is a mass of warmer air pushing over a mass of cooler air. Warm fronts often bring clouds and rainy or snowy weather.
- A stationary front is when a mass of warm air and a mass of cool air meet and either do not move or move very slowly. Stationary fronts often bring cloudy weather with rain or snow that can last for several days.
- An occluded front is when a warm air mass becomes trapped between two cold air masses and the warm air mass gets lifted up off the ground. This type of front is not as common. It can bring rain, snow, or thunderstorms.
- A depression is an area of low air pressure. A depression is marked with a red "L" on a weather map.
- Tropical describes air masses that are warm. They form closer to the equator.
- Polar describes air masses that are cold. They form closer to the North and South Poles.
- Continental describes air masses that are dry. They form over land.
- Maritime describes air masses that are wet or humid. They form over oceans.
Skills
- Explain how global atmospheric movement patterns affect local weather. (S)
- Learn to read weather maps and data to predict local weather. (S)
- Demonstrate that when fronts meet, cold air sinks and warm air rises. (S)
Introducing the Lesson
The place where air masses meet is called a front. Explain to your child that in this lesson, he will find out about the four kinds of fronts that move across the globe and what kind of weather happens when they meet. He will also find out how to read a weather map.
Materials: Eyewitness Weather by Brian Cosgrove (revised edition)
Read pages 32-35 in the book Eyewitness Weather by Brian Cosgrove, and find out more about air masses and fronts on the pages at the following web links. Then answer the questions.
Web Link
Web Link
Questions
- Where do warm and cold air masses come from or form?Warm air masses usually form in tropical areas, while cold air masses usually form near the poles.
- What is a front?A front is the boundary where two air masses meet.
- How long does a storm caused by a depression or warm front usually last?Less than 24 hours.
- How long does a storm caused by a cold front usually last?About an hour.
- What is a squall?It is a sudden burst of strong winds and rain; it is brought on by a cold front.