How do fronts and air masses change the weather.

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

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

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

24. - 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.
(3) Hurricanes:

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

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

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.