Fronts

The different types of fronts and how they are caused

Air Masses

• An air mass is a large body of air that has similar temperature and humidity
• If an air mass forms over land (continental) it has low humidity
• If an air mass forms over an ocean (maritime) it has high humidity
• Air masses are either hot or cold

Low Pressure Demonstration

What happens when air masses run into each other?

• FRONTS!
• Air masses don’t mix together
• The boundary where the air masses meet is called a front
• The “teeth” that you see on a front represent which way the front is moving

Example: The warm front is moving to the North East.

What happens when air masses run into each other?

• Air masses have different temperatures and humidity levels
• When they collide one the more dense air mass goes under the less dense air mass

4 types of fronts

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• Each bring different types of weather

Cold front

• Occurs when a polar (cold) air mass runs into a tropical (warm) air mass

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• The warm air is less dense and gets pushed above the cold air mass

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Cold Front

• Temperatures drop, and there is usually precipitation
• Thunderstorms are usually a result of a cold front

Warm Front

• Occurs at the place where a warm air mass replaces a cold air mass

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• The warm air mass is less dense and will slowly push the cold air, eventually rising above it

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Warm Front

• Results in warmer temperatures
• Usually precipitation

Let’s Review….

Video

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Stationary Front

• Occurs when neither the warm air or the cold air is advancing
• The denser warm air will rise above the cold air

Stationary Front

• Clouds and precipitation occur
• If a stationary front stays for too long, flooding can occur

Occluded Front

• Occurs when a cold front catches up with a warm front
• Cold fronts move twice as fast as warm fronts

Occluded Front

• Causes cloudiness and precipitation