This document discusses how air masses and fronts influence weather patterns. It explains that air masses are large bodies of air with uniform temperature and moisture content that form over land or water. Fronts are boundaries between differing air masses. There are three main types of fronts: cold fronts, which bring storms and precipitation; warm fronts, which produce steady rain and clearing weather; and stationary fronts, which can cause prolonged storms and flooding. The document also outlines weather map symbols and provides safety tips for severe weather like tornadoes, blizzards, and hurricanes.

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.