The document discusses different air masses and fronts that occur when air masses meet. Cold fronts occur when cold air pushes under warm air, forcing the warm air rapidly upwards and creating clouds, rain and storms. Warm fronts happen more gradually when warm air glides over cold air, producing clouds and light showers. Stationary fronts can form when a warm or cold front stops moving, typically resulting in several days of clouds and showers. Low pressure systems form along fronts and are areas of rising air that cause clouds and precipitation, while high pressure systems are areas of sinking air that prevent cloud formation and bring sunny weather.

1. Mr. Fetch’s Earth Science Classroom
Fronts
A boundary between two air masses:

2. Mr. Fetch’s Earth Science Classroom
When air masses meet…
mT
Maritime Tropica
Moist, warm air to south
east coast of the US.
mP
Maritime Polar
Moist, cold air to west
coast of the US.

3. Mr. Fetch’s Earth Science Classroom
Cold Fronts
- When cold air hits warm air.
- Warm air is forced violently up.
- Rising air creates clouds, rain, and storms.
(FRONTAL LIFTING)

4. Mr. Fetch’s Earth Science Classroom
Cold Fronts
- When cold air hits warm air.
- Warm air is forced violently up.
- Rising air creates clouds, rain, and storms.
(FRONTAL LIFTING)

5. Mr. Fetch’s Earth Science Classroom
Cold Fronts
“COLD FRONT” … umm its gets colder , duh!

6. Mr. Fetch’s Earth Science Classroom
Cold Fronts

7. Mr. Fetch’s Earth Science Classroom
Warm Fronts
- When warm hits cold air.
- Warm air gently glides up over the cold air.
- Rising air creates clouds and showers. (Less Violent).

8. Mr. Fetch’s Earth Science Classroom
Warm Fronts
“WARM FRONT”… right, it gets warmer, good.

9. Mr. Fetch’s Earth Science Classroom
Warm Front

10. Mr. Fetch’s Earth Science Classroom
The General Pattern

11. Mr. Fetch’s Earth Science Classroom
Stationary Front
- When a warm or cold front stops moving.
- Usually several days of clouds and showers.

12. Mr. Fetch’s Earth Science Classroom
The high’s and low’s of weather…
LOW PRESSURE: cyclones
1. Low pressure systems form along fronts.
(Unstable)
2. Low pressure systems are areas of rising air.
(As along fronts)
3. The wind blows from HIGHS into LOWS.
4. Earth’s rotation causes the winds to rotate
counter-clockwise around low pressure systems.

13. Mr. Fetch’s Earth Science Classroom
LOW PRESSURE:
5. The rising air creates clouds and precipitation.
6. Low pressure systems created rainy, stormy
weather.
The high’s and low’s of weather…

14. Mr. Fetch’s Earth Science Classroom
HIGH PRESSURE: anticyclones
1. High pressure systems are areas of sinking air.
(Stable)
2. The wind blows out of HIGHS to LOWS.
3. Earth’s rotation causes the winds to rotate
clockwise around high pressure systems.
The high’s and low’s of weather…

15. Mr. Fetch’s Earth Science Classroom
HIGH PRESSURE:
4. The sinking air stops clouds from forming.
5. No clouds = Sunny, clear weather conditions.
The high’s and low’s of weather…