How do fronts & air masses change the weather?

It’s a large body of air which have the same temperature & same

amount of water vapor.

Air masses

Air masses can be formed over:1) Land Dry air mass

2) Water Wet air mass “with lots of moisture”

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

It is the border between one mass & another.

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.

Types of fronts

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.

Difference between cold & warm fronts

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.

Weather map It helps us to know what the weather is like

in an area.{Made from information collected from weather stations}

Symbols on a weather map

Sunny

Sunny & cloudy

Rainy

Red Very hot weather

Orange Warm weather

Yellow Mild weather

Green Cool

Blue Very cold

Colored areas on a weather map

Weather Forecast

Is to predict the weather conditions.

Can you read this weather map?

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.

- They are severe snow storms that can last for hours.

- Blizzards have strong winds, blowing snow & very low air temperature “Cold”

(2) Blizzards:

- 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:

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

Weather Safety

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

Examples

Weather sirens are turned on when severe storm is detected.

Flags are used to warm people from a coming hurricane.

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