Air masses are large bodies of air with uniform temperature and moisture content that form over land or water. There are four main types of air masses: cold and dry, cold and wet, warm and wet, warm and dry. Fronts form at the boundary between different air masses. A cold front occurs when a cold air mass pushes under a warm one, forcing the warm air to rise quickly and form rain clouds. A warm front happens as a warm air mass slides over a cold one more slowly, producing layers of clouds and steady rain. Cold fronts typically bring stormy weather while warm fronts often result in rain and then clear, warm conditions.

1. How do fronts & air masses
change the weather?

2.  It’s a large body of air which have the same
temperature & same
 amount of water vapor.
Air masses

3.  Air masses can be formed over:
1) Land Dry air mass
2) Water Wet air mass “with lots
of moisture”

4. Types of air masses
Cold & dry Cold & wet Warm & wetWarm & dry
Causes cool
weather with
no or little
precipitation
Causes cool
weather with
snow.
Causes warm
weather with
little or no
precipitation
Causes
precipitation

5.  It is the border between one mass & another.
Fronts

6. Cold front:
- It is formed when a cold air mass pushes under
a warm air mass.
- The cold air mass forces the warm air mass up
quickly.
- Thick clouds forms as the warm air rises &
cools & rain falls.
- Cold fronts often bring stormy weather.
Types of fronts

9. Warm front:
- It is formed when a warm air mass pushes a
cold air mass.
- The warm air mass slides up over the cold air.
- It forms layers of clouds.
- Warm fronts often bring steady rain ,
followed by clear warm weather.

13. Difference between cold & warm fronts