Download FRONTS Front Narrow region between two air masses with different

FRONTS
Front
Narrow region between two air masses with different densities.
Cold front
 Cold, dense air forces the warm air, which
is less dense up.
 As the warm air rises, it cools and
condenses.
 Intense precipitation (heavy rain/snow)
and sometimes thunderstorms are
common.
 Blue triangles point in the direction of the
front’s movement.
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Warm front
 Warm air displaces cold air and can
cause light precipitation or drizzly rain.
 Red semicircles point in the direction of
the front’s movement.
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Stationary front
 When two air masses meet but neither
advances, the boundary between them
stalls.
 There can be light winds and precipitation.
 The wet weather can last for several days.
 Alternating cold and warm front symbols
pointing in opposite directions represents
this.
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Occluded front
 Sometimes a cold air mass moves so
rapidly that it overtakes a warm front
and forces the warm air upward.
 As the warm air is lifted, the advancing
cold air mass collides with the cold air
mass in front of the warm front.
 Strong winds and a lot of precipitation
are common.
 This front is represented by purple
triangles and semicircles pointing in the
direction of the front’s movement.
Pressure systems
 High-pressure areas have sinking air
 Low-pressure areas have rising air
 Air always flows from an area of high pressure to an area of low pressure.
Low-pressure systems
o Air rises here.
o When air outside the pressure system replaces the rising air, the air spirals inward toward the center
and then upward.
o Northern hemisphere, the low-pressure system moves counter clockwise
o Southern hemisphere, it moves clockwise.
o As the air rises, it cools and condenses into clouds and creates cloudy weather with precipitation.
High-pressure system
 Sinking air moves away from the center.
 Northern hemisphere, the high-pressure system moves clockwise
 Southern hemisphere, it moves counter clockwise.
 High-pressure systems are usually associated with fair weather.
 These are common in the subtropical oceans on Earth.