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