All Things Weather Wise

Weather Instruments, Pressure Systems and Fronts

Warm Up1. What is air pressure?2. What happens to the

molecules when air warms up?

3. Why does air move out of a filled balloon when you untie the end?

Warm Up

1. Why is it hot at the equator and cold at the poles?

2. What is needed to create an area of high pressure?

3. What causes low pressure?4. What happens to air at the poles? At

the equator?5. What is wind?

Warm Up

1. What type of clouds are associated with good weather?

2. How is weather described? List 7 factors.

3. How do clouds form?4. Describe a convection current.

Warm Up

1. What causes low pressure on the Earth’s surface?

2. What type of weather is associated with a cold front?

3. What is wind? What causes it? Which way does air move?

4. What is the role of ozone in the stratosphere?

5. What happens to temperature in the troposphere?

What Is Weather?

…Conditions of the atmosphere at a given place and time.

Air pressure Temperature Wind speed, wind direction Cloud cover, type precipitation

Weather Instruments: Anemometer

Measures wind speed Wind turns the cups;

faster wind turns cups faster

Faster wind = higher wind speed

Wind speed measured in mph or kph

Weather Instrument: Barometer

Measures air pressure

• When air pressure increases, the air pushes down on the mercury, which then rises in the tube.

• Changes in air pressure can help to forecast weather

Wind Sock

Wind fills the cone shaped bag

Tells the direction of the wind

Always name winds by where they are blowing FROM - A southeast winds blows from the southeast

High Pressure System

Cooler, sinking airCreates generally

clear days, good weather

May be small cumulus clouds, if any

Low Pressure SystemWarmer, rising

airStratus clouds

form if there is enough moisture in the air

Drizzle or rain may occur

Warm Front

When a warm air mass overtakes a cooler air mass

Warm air rises over cool air Light to moderate, but steady rain at

frontal boundary Temperature increases after front

passes

Warm Front

Cold Front Cold air mass overtakes warmer air mass Cooler air nudges under warmer air Heavy, short periods of showers at frontal

boundary Temp drops!

Cold Front

And Just a Bit About Hurricanes

Form in the tropics over water that is greater than 79 degrees Fahrenheit

Gathers strength as it remains over sea A storm must have winds of 75mph to be

considered a hurricane; otherwise, it’s just a tropical storm or depression

As it makes landfall, storm weakens, but can still have disastrous effects

Hurricane - A low pressure system where winds blow counterclockwise

Eye

Warm Up

Draw a Venn diagram comparing warm and cold fronts. Include at least two differences and two similarities.

Warm vs. Cold FrontsWarm Warm air rises

slowly over cold Stratus clouds

form Moderate

precip over a long time

Cold Warm air rises

quickly Cumulonimbus

Thunderstorms can include

lightning and hail and tornadoes

Both•Change the air temp•Occur when air masses meet•Happen over land or water•Can happen anytime