Download Air Masses - Madison Public Schools

Study Guide
Test 12/16
Topics Include:
Relative Humidity
Dew Point
Cloud Formation
Air Masses
Fronts
Make Sure You Understand:
Relative humidity is the amount of moisture (water vapor) in the
air compared to the amount of moisture the air can hold at that
temperature.
When the air is Saturated, it has 100% relative humidity.
Dew Point is when air cools to the temperature at which air is
saturated.
Assuming the amount of water vapor in the air stays the same…
• If the temperature increases, then the relative humidity
decreases.
• If the temperature decreases, then the relative humidity
increases.
What is a cloud?
• A cloud is made of water droplets.
• Clouds form when warm air rises and cools
Be able to answer the following:
Name of Cloud
Appearance
Effect
1. Cumulus
White, puffy, cotton ball clouds
Fair weather. Nice day outside.
2. Cirrus
Feathery, wispy clouds.
Fair at present, BUT rain in 24 –
48 hours (a day or two).
Made of ice crystals!
Warns of a warm front
approaching.
3. Stratus
Flat layers of gray clouds
Brings gentle steady rain.
Forms in a warm front.
4. Cumulonimbus
Thunderhead!
Dark flat bottoms building into
anvil shaped tops
Thunderstorms! Heavy rain,
thunder, lightning, and possible
hail.
Forms in cold front.
Key Terms
• Precipitation - water that falls to the Earth’s
surface as rain, snow, sleet, or hail
• Condensation - process in which water vapor
cools and turns to liquid
• Weather- condition of the atmosphere at a
certain time and place
• Humidity- the amount of moisture in the air
Key Terms, continued
• Anticyclone- area of high pressure where air
moves apart and sinks
• Cyclone- area of low pressure where air
masses meet and rise
• Dew Point- the temperature at which a gas
condenses into a liquid
Measuring Weather
• Anemometer - measures wind speed
• Barometer - measures air pressure
• Radar - locates precipitation
• Thermometer - measures air temperature
• Windsock - measures wind direction
Air Masses
A. mP
B. cP and/or cA
C. mP
D. cT
E. mT
F. mT
G. What is the origin of
each of the 3 mT air
masses?
The Pacific Ocean, the
Gulf of Mexico, and the
Atlantic Ocean
Air Masses
An air mass is named for it’s temperature and
moisture level.
When two air masses meet the warm air mass will rise
and the cool air mass will sink.
Continental
Dry
Maritime
Wet
Polar
Cold
Tropical
Warm
Air Masses
An air mass is a body of air.
• A Continental Polar (cP) air mass brings cold,
dry weather.
• A Maritime Polar (mP) air mass brings cold,
moist (wet) weather.
• A Continental Tropical (cT) air mass brings dry
and warm weather.
• A Maritime Tropical (mT) air mass brings warm,
moist (wet) weather.
Fronts
Fronts are the boundary between different air masses.
• Cold fronts create short, heavy, violent periods of rain
followed by cool fair weather
• Warm fronts occur when warm air rises and condenses
into long areas of clouds which bring gentle rain or
snow followed by warmer weather
• Stationary fronts create clouds and fog at the site of
the front and can bring days of rain or snow
• Occluded fronts occur when warm air is cut off from
the ground which can bring heavy wind and
precipitation
Make sure you know:
1. Which symbol belongs to which front.
2. The color of each front symbol.
3. The type of weather does each front bring.
Warm front
(red)
Occluded front
(purple)
Cold front
Stationary front
(blue)
(red and blue)
Topics to Review
• Dew Point Lab
– Words to know: Dew Point, Saturated,
Condensation, Water Vapor
• High Pressure System
• Low Pressure System