Download Predicting the Weather

Weather Fronts
Air Mass
• A large body of air with properties
similar to the part of Earth’s surface
that it covers.
Air Mass
• Air masses with moisture form over water
and dry air masses form over land. Air
masses that form at the poles are cold and
the ones that form in the tropics (near the
equator) are warm.
Frontal Boundaries
• Where air
masses meet a
boundary, known
as a front, is
created.
• 4 kinds of
fronts:
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Cold front
Warm front
Occluded front
Stationary front
Cold Front
• Shown on a weather map by a blue line with
Back to
activity
triangles pointing in the direction that the cool
air is moving.
Cold Front
• A cold air mass forces a warm air mass to rise.
• As the warm air rises, clouds and precipitation are
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•
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activity
formed.
If the air is pushed upward quickly, cumulus and
cumulonimbus clouds can form and violent storms can
result.
As the front advances, temperatures usually drop.
Warm Front
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activity
• Shown on a weather map by a red line with half
circles pointing in the direction that the warm
air is moving.
Warm Front
• A warm air mass catches up to and slides over a
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•
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activity
cooler air mass.
Many miles ahead of the front high cirrus clouds form.
As the front approaches, steady rain or snow can
occur over a wide area as a result of the nimbostratus
and cumulonimbus clouds that form.
After the front passes, wind direction changes and
temperature rises.
Comparing Warm
and Cold Fronts
• Cold fronts move faster than warm fronts.
• The weather activity in a cold front is often
violent and happens directly at the front.
• Cold fronts have sudden gusty winds high in
the air creating turbulence.
• The weather activity in a warm front generally
happens before the front passes.
Occluded Fronts
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activity
• Shown on a weather map by a purple line with
alternating triangles and semicircles pointing in
the direction that the front is moving.
Occluded Fronts
• When a slow moving warm air mass is trapped
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activity
between two fast moving cold air masses and
forced to rise.
• Stratus, nimbostratus & cumulonimbus clouds
form and short steady precipitation often result.
Stationary Fronts
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activity
• Shown on a weather map with alternating red
semicircles pointing away from the warm air
and blue triangles pointing away from the
cold air.
Stationary Fronts
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activity
• A warm air mass and a cold air mass meet, but
•
neither move forward.
This can result in days of steady precipitation
in the same area as a result of nimbostratus
and cumulonimbus clouds.
Locate the 4 types of fronts
on this weather map.
Hint
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Hint
2
Hint
3
Hint
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Cold Fronts
Warm Fronts
Stationary Fronts
Occluded Fronts
Be a Weather Forecaster
You are
planning to
travel to
Alabama in 2
days. The high
temperature
there for today
is 68º F.
Use the map to help you predict whether the temperature in
Alabama will increase, decrease, or stay the same. Explain
why you think so.
Be a Weather Forecaster
There is a cold front approaching.
The temperatures will probably be
cooler behind the front.
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Be a Weather Forecaster
• Of course, meteorologists
(weather forecasters) use
much more data than fronts
and air masses to help them
forecast the weather more
accurately. But any forecast
is just a prediction of what
might happen. Even with the
best data, weather forecasts
can be wrong.
MAP TAP 2002-2003
Weather Fronts
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MAP TAP 2002-2003
Weather Fronts
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MAP TAP 2002-2003
Weather Fronts
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