What kinds of information might you hear in a weather forecast?
Lesson 2: Relative Humidity
List the objective of this lesson:
Define humidity-
Which type of air can hold more water vapor- warm or cold air?
What does it mean if the air is saturated?
What is the unit of measure for humidity?
Which is a higher humidity- 23 g/m3 or 68 g/m3?
What is relative humidity?
Do weather forecasters report humidity or relative humidity?
What does 65% relative humidity mean?
Can the air hold more water on a cold day or a hot day?
What happens when the air reaches 100% relative humidity?
The dew point is the point at which the air is saturated with water vapor and cannot hold any more water vapor. At the dew point, it will rain or condensation will form. The dew point is the same thing as 100% relative humidity.
Define dew point temperature-
When the air temperature is equal to the dew point temperature, the relative humidity is 100%. What will happen when the relative humidity is at 100%?
The dew point temperature cannot be greater than the air temperature. Why not?
Dew forms on the grass in the morning. Think about why this happens. Is the temperature in the morning typically warmer or cooler than during the day? And can warm air or colder air hold more water vapor?
After watching the video on page 7, answer question #1 on the Check-In page:
How is humidity usually measured?
How is relative humidity measured?
Lesson 3: Air Pressure
List the objective of this lesson:
Define the Key Words:
• Air Pressure-
• High-Pressure System-
• Low-Pressure System-
What are the two types of air pressure systems that impact our weather? How do meteorologists (scientists who study weather) label these on weather maps?
1.
2.
What kinds of information might you hear in a weather forecast?
Lesson 2: Relative Humidity
List the objective of this lesson:
Define humidity-
Which type of air can hold more water vapor- warm or cold air?
What does it mean if the air is saturated?
What is the unit of measure for humidity?
Which is a higher humidity- 23 g/m3 or 68 g/m3?
What is relative humidity?
Do weather forecasters report humidity or relative humidity?
What does 65% relative humidity mean?
Can the air hold more water on a cold day or a hot day?
What happens when the air reaches 100% relative humidity?
The dew point is the point at which the air is saturated with water vapor and cannot hold any more water vapor. At the dew point, it will rain or condensation will form. The dew point is the same thing as 100% relative humidity.
Define dew point temperature-
When the air temperature is equal to the dew point temperature, the relative humidity is 100%. What will happen when the relative humidity is at 100%?
The dew point temperature cannot be greater than the air temperature. Why not?
Dew forms on the grass in the morning. Think about why this happens. Is the temperature in the morning typically warmer or cooler than during the day? And can warm air or colder air hold more water vapor?
After watching the video on page 7, answer question #1 on the Check-In page:
How is humidity usually measured?
How is relative humidity measured?
Lesson 3: Air Pressure
List the objective of this lesson:
Define the Key Words:
• Air Pressure-
• High-Pressure System-
• Low-Pressure System-
What are the two types of air pressure systems that impact our weather? How do meteorologists (scientists who study weather) label these on weather maps?
1.
2.
Complete the following table:
Type of System
How Does the Air Move?
Does the Air Rise or Sink? Does it get warmer or colder?
Type of Weather Caused by this System
High-pressure
System
Low-pressure System
On the “Check In” on page 8, answer Question #1:
How does air usually move?
Which type of pressure system is associated with severe storms like hurricanes or blizzards?
Lesson 4: Air Masses:
List the objective of this lesson:
Define the Key Words:
• Air Mass-
• Front-
You must watch the video on page 2 to learn the information about air masses. Complete the table below while watching the video. You may need to pause or rewind the video to get all of the answers.
Type of Air Mass
Does it form over land or water?
Moist or Dry?
Is the air warm or cold?
Continental arctic/polar
Continental tropical
Maritime arctic/polar
Maritime tropical
What will happen to a continental polar air mass that remains over warm water for a few days?
What happens when 2 or more air masses meet?
What is formed when 2 or more air masses meet?
When 2 air masses meet, what happens to the warmer air mass?
The image below shows types of air masses and their characteristics.
Answer both practice questions on page 7:
What is true about all continental air masses? What is true about all maritime air masses?
What might happen if an arctic air mass passed over warmer ocean water?
Complete the check-in activity #1 on page 9 to make sure you understand the terms continental, maritime, tropical, and polar.
Lesson 5: Air Mass Interactions
List the objective of this lesson:
What are air masses and what causes them to have their specific characteristics?
Define front-
How are cold fronts shown on a weather map?
How are warm fronts shown on a weather map?
Weather changes as a result of moving air masses that have different temperatures and levels of moisture.
Cold Fronts:
• Occur when _________ air moves under __________ air
• The cold air pushes _______ the warm air
• When the warm air hits the cooler upper air, it __________
• The moisture in the air condenses, forming _____________
• If there are big temperature differences, ______________ _____________ may form
Cold Fronts are characterized by temperature drop, increased wind, heavy precipitation, and lower humidity.
Warm Fronts are characterized by increased temperatures, increased humidity, light precipitation, and lower wind speeds.
Make sure you practice the Interactive on Question #1 on page 6.
Look at the pictures above, which air mass will always rise- warm or cold?
The air behind a warm front is warmer and more humid. With this in mind, the air behind a cold front is _____________ and less ____________.
Decide which type of front passed through the area in the following two examples from the video on Page 7:
1. The weather starts out warm, with some humidity, and low winds. It’s partly cloudy and there is no precipitation. As the front passes through the area, the temperature drops, the wind speed increases, and it rains heavily during a thunderstorm. After the front has passed, the temperature has decreased by 20 degrees, the humidity is lower, and the sky is clear.
Cold Front or Warm Front (circle one)
2. The temperature starts out at 65 degrees, with some humidity, the wind speed at nine miles per hour with partly cloudy skies. As the front passes over the area, the temperature increases to 72 degrees, the humidity increases, the wind speed increases, and it rains. After the front passes, the temperature has increased to 82 degrees, the humidity has increased to 72 percent, and the wind speed is lower. And it is partly cloudy.
Cold Front or Warm Front (circle one)
On the Check-In on page 8, answer question #2:
What happens when a front passes through an area?
In a weather forecast, you might hear information about the temperature, precipitation, wind speed and direction, cloud cover, and any severe weather alerts.
The objective of the lesson on Relative Humidity is to understand the concept of humidity and how it is measured.
Humidity is the amount of moisture or water vapor present in the air.
Warm air can hold more water vapor than cold air.
If the air is saturated, it means it is holding the maximum amount of water vapor it can hold at a given temperature and pressure.
The unit of measure for humidity is grams per cubic meter (g/m3).
68 g/m3 is higher humidity than 23 g/m3.
Relative humidity is a measure of how much water vapor the air is holding compared to the maximum amount it can hold at a given temperature and pressure.
Weather forecasters typically report relative humidity.
65% relative humidity means that the air is holding 65% of the maximum amount of water vapor it can hold at that temperature and pressure.
The air can hold more water on a hot day because warm air has a higher capacity to hold water vapor.
When the air reaches 100% relative humidity, it is saturated and cannot hold any more water vapor. This can lead to rain or condensation.
The dew point temperature is the temperature at which the air becomes saturated and condensation occurs.
When the relative humidity is at 100%, it means the air is saturated and cannot hold any more water vapor. This can lead to rain or condensation.
The dew point temperature cannot be greater than the air temperature because the air cannot hold more water vapor than it is capable of at a given temperature.
Dew forms on the grass in the morning because the temperature in the morning is typically cooler than during the day, and cooler air can hold less water vapor. Warm air can hold more water vapor than colder air.
Humidity is usually measured with instruments called hygrometers.
Relative humidity is measured using a hygrometer and a thermometer to measure the air temperature.
The objective of the lesson on Air Pressure is to understand the concept of air pressure and its impact on weather.
Air pressure is the force exerted by the weight of the air above a given point.
A high-pressure system is an area where the atmospheric pressure is greater than the surrounding areas.
A low-pressure system is an area where the atmospheric pressure is lower than the surrounding areas.
The two types of air pressure systems that impact weather are high-pressure systems and low-pressure systems. High-pressure systems are labeled with an "H" on weather maps, while low-pressure systems are labeled with an "L."
The objective of the lesson on Air Masses is to understand what air masses are and their characteristics.
An air mass is a large body of air with relatively uniform temperature and humidity characteristics.
A front is a boundary between two air masses with different characteristics.
Cold fronts are shown on a weather map with blue lines and triangles indicating the direction of movement.
Warm fronts are shown on a weather map with red lines and semicircles indicating the direction of movement.
When a cold front passes through an area, cold air moves under warm air, pushing the warm air up. This can lead to the formation of clouds and precipitation.
Cold fronts are characterized by a temperature drop, increased wind, heavy precipitation, and lower humidity.
Warm fronts are characterized by increased temperatures, increased humidity, light precipitation, and lower wind speeds.
The air behind a cold front is colder and less humid compared to the air behind a warm front.
The air behind a warm front is warmer and more humid compared to the air behind a cold front.
When a front passes through an area, there can be changes in temperature, humidity, wind speed, and precipitation.
In the example provided, the first scenario describes a cold front passing through the area, while the second scenario describes a warm front passing through the area.
When a front passes through an area, the weather conditions can change, such as temperature, humidity, wind speed, and precipitation.