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

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

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

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

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

6. Types of fronts
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.

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

14. Stationary front:
-
-
It is formed when fronts don’t move for many
days.
It causes storms & rain “Flooding” for many
days.
No change in the weather is followed by
stationary front.

17. Weather map
 It helps us to know what the weather is like in an
area.
{Made from information collected from weather stations}

18. Symbols on a weather map




Sunny

Sunny & cloudy

Rainy

19. Colored areas on a weather map
 Red
Very hot weather
 Orange
Warm weather
 Yellow
Mild weather
 Green
Cool
 Blue
Very cold

20. Weather Forecast
 Is to predict the weather conditions.

21. Can you read this weather map?

22. Severe storms
(1) Tornadoes:
-It’s a fast spinning spiral strong wind that stretches
From the cloud of the thunderstorm to the ground.
-Tornadoes can have wind speeds greater than
400 km per hour.
-USA has more tornadoes in a year than any other
Place.

23. (2) Blizzards:
- They are severe snow storms that can last for
hours.
- Blizzards have strong winds, blowing snow &
very low air temperature “Cold”

24. (3) Hurricanes:
- They are formed over warm water of oceans, it
has a speed of 119 km per hour.
- Hurricanes can last for weeks at the sea.
- The wind of the hurricane spins around the
calm center of the storm called: “Eye”
- Hurricanes can cause flooding.

25. Weather Safety
•
There are certain weather safety rules
that we should follow in order to be
safe from severe weather conditions.

26. Examples
 Watching TV during severe “bad” weather to
get directions about what to do.

27.  Weather sirens are turned on when severe
storm is detected.

28.  Flags are used to warm people from a coming
hurricane.

29.  Evacuation signs are used to tell people to
evacuate “empty” an area when a hurricane is
coming.