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Air Masses and Fronts
Air Masses
• Air masses have the same properties as
the surface over which it develops:
Maritime = Wet
mP = wet/cold
Continental = Dry cP = dry/cold
Polar = Cold
mT = wet/warm
Tropical = Warm
cT = dry/warm
Air Masses in North America
Fronts
•
•
A front is the boundary where two air
masses meet.
WARM AIR
Types of fronts:
1.
2.
3.
4.
Warm Front
Cold Front
Occluded Front
Stationary Front
FRONT
COLD AIR
Warm Front
• Warm air slides over
departing cold air.
• Brings drizzle
followed by clear
and warmer weather
Cold Front
• Cold air pushes
under a warm air
mass.
• Warm air rises
quickly.
• Brings heavy rain
followed by cooler
weather.
Occluded Front
• Two cold air masses merge and force
warm air between them to rise quickly.
• Brings cooler temperatures and large
amounts of rain and snow.
Stationary Front
• Warm and cold air meet
but remain separated.
• Brings many days of
cloudy wet weather.
Cyclones and Anticyclones
• Areas of HIGH and LOW pressure
• Cyclone = LOW PRESSURE = spin
counterclockwise = associated with storms and
precipitation
• Anticyclone = HIGH PRESSURE = spin clockwise
= associated with fair weather.
Cyclones and Anticyclones in the
USA
Rising air in CYCLONE (Low pressure) forms clouds
and rain. Falling air in an ANTICYCLONE (High
pressure) forms dry clear weather.
Fronts - Video