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Air massess-Fronts—3 minutes
WEATHER FRONTS
Air mass—
a large body of air (1/2 mile across and several miles
thick) with properties like the part of Earth’s surface over
which if formed. Weather patterns are a result of these
air mass movements
CLASSIFYING AIR MASSES
Putting air masses into groups depends on 2 things:
1. the latitude the air mass formed at indicates
temperature
2. whether it formed over land or water will indicate the
moisture of the air mass
Air mass classification is represented by a 2 letter code
cA
cP
cT
mT
mP
mE
continental arctic
continental polar
continental tropical
maritime tropical
maritime polar
maritime equatorial
FRONTS
•A front is a boundary between two air masses of different
densities.
•Clouds, precipitation and storms occur at frontal
boundaries
3 TYPES OF FRONTS:
1. WARM FRONT: where warmer air advances over
colder air
Warm air cools as it gets pushed up over the cold air
mass
The moisture in the warm air condenses into clouds that
span for miles along the front
•Produce light to moderate
precipitation over a large area
for an extended period of time
After the front passes, there are
warmer temperatures and a wind
shift from the southwest
2. COLD FRONT: where cold air advances under warm air
Move very fast, rapidly pushing warm air up
Rapid uplifting of moist air makes for very tall clouds called
cumulonimbus
•Have very heavy downpours, thunderstorms, and fast
winds
Precipitation occurs over a much smaller area
Clear skies are seen after the front passes, and cooler
temperatures
Animation of Cold &
Warm Fronts
3. STATIONARY FRONT: air masses and their boundaries
stop advancing
• Have light to moderate precipitation
Video Clip on
Fronts
FRONT SYMBOLS
_______________
_______________
_______________
_________________
What types of fronts do you see on this weather map?
What fronts do you see on this weather map?
Today's Frontal Weather Map
OTHER WEATHER SYMBOLS YOU NEED TO
KNOW WHEN READING A WEATHER MAP
ISOBARS: connect areas of equal pressure
The closer the lines the higher the wind speed.
ISOBAR MAP FOR APRIL 16th, 2007
ISOTHERMS: Lines on a weather map that connect
points of equal temperature.
Weather Station Models:
•A record of weather data for a particular site at a
particular time. You can fit a lot of information into
a small space.
Example of a Weather Station Model
Weather Station Models
REMEMBER THIS:
Cold Air
Warm Air
AMAZING EARTH SCIENCE FACTS
Cold
1. __________
fronts move quickly and produce rain
at the front
Warm
2. __________
fronts move slow and produce miles
and miles of clouds
cool and dry
3. High pressures are _____________________
warm and rainy
4. Low pressures are _______________________
Question #1:
• What
type of
front can
be found
close to
point D ?
COLD
FRONT
Question #2
• Which of these
fronts would you
expect to have
greater
precipitation,
but be short
lived as the front
passes?
COLD FRONT
Question #3
• Give the name
of the air mass
that would
have the
following
characteristics:
• cool, moist,
unstable
mP
Question #4
•If there is a big H
H on the weather
map where you
live, would you
expect fair or
stormy weather?
FAIR
H