Air Masses and Fronts
• Drill: Would you rather “Know Everything”
or be able to “Figure Out Anything”?
Why?
• Objective: SWBAT identify types of air
masses in order to compare air masses
and fronts.
• HW: Test on Monday
– Check HAC
Air Masses
• Four types of air masses:
– Tropical: warm air from tropics
– Polar: cold air from North.
– Maritime: moist air produced over oceans.
– Continental: dry air produced over land.
• What two characteristics do scientists use
to classify air masses?
• Label Tropical/Polar as high or low
pressure.
Which food is which?
• Maritime Polar
• Continental Polar
• Maritime Tropical
• Continental Tropical
Draw the movement of the mass.
Tornado Alley
Fronts
Air masses move creating fronts
• Front: Two or more air masses meet and
do not mix.
– Different temps and densities.
– Can be 15-200 km wide and 10 km
upwards.
• Named after place where two opposing
armies meet.
• How are these things related?
4 Types of Fronts
• Cold Fronts: Fast moving cold air strikes
slow moving warm air forcing the warm air
to rise. Strong Storms followed by cold.
• Warm Front: Slow moving warm air mass
moves over a cold air mass funneling the
air upwards. Cloudy days followed by
warm days.
• What kind of weather should these fronts
bring?
Predictions
• Cold Front
– Moist warm air forced upwards.
• Prediction:
– Dry warm air forced upwards.
• Prediction
– After Cold Front leaves, cool dry air moves in
bringing in clear skies and cooler temps.
Predictions
• Warm Front
– Warm humid air slowly moves over cold air.
• Prediction:
– Dry warm air slowly moves over cold air.
• Prediction:
• Which type of front lasts longer Cold or
Warm? Why?
Cold vs. Warm Front
2 More Fronts
• Stationary Fronts: Cold and warm air
meets but neither has enough force to
move the other.
– Weather: floods or blizzards
• Occluded Fronts:
– Warm air is trapped between two cooler air
masses.
– They layer according to density and the cooler
air can mix.
– The warm air is cut off from escape causing it
to cool and condense.
Cyclones
• Cyclone: A swirling center of low air
pressure.
– Spin counterclockwise in Northern
hemisphere.
– Bring storms and precipitation
• Anticyclone: High pressure centers of dry
air.
– Clockwise in the Northern hemisphere
– Descending air brings dry, clear weather.
March 1st. Tools of the Trade
• Drill: Collect 1 computer per team.
– Open your power point.
– Collect your “Tools of the Trade” lab.
– Check to see if you answered all of the questions on
the power point.
• Objective: Students will be able to identify and
describe tools used in meteorology in order to
interpret data and make weather predictions
based on the data.
• HW: Lab due tomorrrow.