Air Masses and Fronts Science 6 th Grade Slide 2 MAP TAP
2002-2003Weather Fronts2 Air Mass A large body of air with similar
temperature, humidity, and air pressure. A large body of air with
similar temperature, humidity, and air pressure. Air masses form
over large land or water masses. Air masses form over large land or
water masses. Slide 3 Whether an air mass is warm or cold depends
on the temperature over which the mass forms. Whether an air mass
is warm or cold depends on the temperature over which the mass
forms. 4 types of air masses 4 types of air masses 1. Tropical warm
air masses that form over the tropics. 2. Polar cold air masses
that form over the poles. 3. Maritime air masses that form over the
ocean (very humid) 4. Continental form over land (are dry) MAP TAP
2002-2003Weather Fronts3 Slide 4 Continental - Means land. Means
land. A Continental air mass forms over land. A Continental air
mass forms over land. Weather Fronts4 Slide 5 Maritime - Means
water. Means water. Maritime air masses form over water. Maritime
air masses form over water. MAP TAP 2002-2003Weather Fronts5 Slide
6 Polar Polar means it forms over the poles. Polar means it forms
over the poles. COLD! COLD! MAP TAP 2002-2003Weather Fronts6 Slide
7 Tropical Form over the tropics (near the equator) Form over the
tropics (near the equator) WARM!! WARM!! MAP TAP 2002-2003Weather
Fronts7 Slide 8 MAP TAP 2002-2003Weather Fronts8 Slide 9 MAP TAP
2002-2003Weather Fronts9 Fronts Fronts Where air masses meet but do
not mix due to different temperatures and densities. becomes a
front Where air masses meet but do not mix due to different
temperatures and densities. becomes a front Slide 10 Fronts 4 kinds
of fronts: 4 kinds of fronts: Cold front Warm front Occluded front
Stationary front MAP TAP 2002-2003Weather Fronts10 Slide 11 Cold
Front A cold air mass is replacing a warmer air mass. A cold air
mass is replacing a warmer air mass. Shown on a weather map by a
blue line with triangles pointing the direction the cool air is
moving. Shown on a weather map by a blue line with triangles
pointing the direction the cool air is moving. Slide 12 Cold Front
Cold Front Rapidly moving cold air mass runs into a slowly moving
warm air mass. Rapidly moving cold air mass runs into a slowly
moving warm air mass. The denser cold air slides under the lighter
warm air pushing it upward. The denser cold air slides under the
lighter warm air pushing it upward. The rising air cools and
condenses, forming clouds. The rising air cools and condenses,
forming clouds. Heavy rain or snow may fall. Heavy rain or snow may
fall. If the warm air mass contains only a little water vapor,
there may be only cloudy skies. If the warm air mass contains only
a little water vapor, there may be only cloudy skies. MAP TAP
2002-2003Weather Fronts12 Slide 13 NSF North Mississippi GK-8
Fronts: Five Types of Fronts 1. Cold Front: The zone where cold air
is replacing warmer air Air gets drier after a cold front moves
through Slide 14 Cold Front Cold Front Cold fronts move quickly and
can cause abrupt weather changes including violent thunderstorms
Cold fronts move quickly and can cause abrupt weather changes
including violent thunderstorms After a cold front passes through,
cool, dry air moves in. After a cold front passes through, cool,
dry air moves in. Clear skies and cooler temperatures often follow.
Clear skies and cooler temperatures often follow. MAP TAP
2002-2003Weather Fronts14 Slide 15 MAP TAP 2002-2003Weather
Fronts15 Warm Front Warm air mass collides with a slowly moving
cooler air mass. Warm air mass collides with a slowly moving cooler
air mass. Shown on a weather map by a red line with half circles
pointing the direction the warm air is moving. Shown on a weather
map by a red line with half circles pointing the direction the warm
air is moving. Slide 16 Warm Front Warm Front Moving warm air mass
collides with a slowly moving cold air mass. Moving warm air mass
collides with a slowly moving cold air mass. The warm air moves
over the denser cold air. The warm air moves over the denser cold
air. If the warm air is humid, showers and light rain fall along
the front where the warm and cold air meet. If the warm air is
humid, showers and light rain fall along the front where the warm
and cold air meet. If the warm air is dry scattered clouds form. If
the warm air is dry scattered clouds form. MAP TAP 2002-2003Weather
Fronts16 Slide 17 NSF North Mississippi GK-8 Fronts: Five Types of
Fronts 2. Warm Front: The zone where warm air is replacing colder
air Air gets more humid after a warm front moves through Slide 18
Warm Front Warm Front Because warm fronts move more slowly than
cold fronts, the weather may be rainy or foggy for several days.
Because warm fronts move more slowly than cold fronts, the weather
may be rainy or foggy for several days. After the warm front
passes, the weather is likely to be warm and humid. After the warm
front passes, the weather is likely to be warm and humid. In
winter, warm fronts bring snow. In winter, warm fronts bring snow.
MAP TAP 2002-2003Weather Fronts18 Slide 19 MAP TAP 2002-2003Weather
Fronts19 Comparing Warm and Cold Fronts Cold fronts move faster
than warm fronts. Cold fronts move faster than warm fronts. The
weather activity in a cold front is often violent and happens
directly at the front. 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. 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. The weather activity in a warm front generally happens
before the front passes. In a warm front the cloud formation is
very low often creating situations of poor visibility. In a warm
front the cloud formation is very low often creating situations of
poor visibility. Slide 20 MAP TAP 2002-2003Weather Fronts20
Occluded Fronts When a warm front is trapped by 2 cold fronts. When
a warm front is trapped by 2 cold fronts. Shown on a weather map by
a purple line with alternating triangles and semicircles pointing
the direction the front is moving. Shown on a weather map by a
purple line with alternating triangles and semicircles pointing the
direction the front is moving. Slide 21 Occluded Fronts Occluded
Fronts A warm air mass is caught between two cooler air masses. A
warm air mass is caught between two cooler air masses. The denser
cool air masses move underneath the less dense warm air and push it
upward. The denser cool air masses move underneath the less dense
warm air and push it upward. The temperature near the ground
becomes cooler. The temperature near the ground becomes cooler. MAP
TAP 2002-2003Weather Fronts21 Slide 22 Occluded Fronts Occluded
Fronts MAP TAP 2002-2003Weather Fronts22 The warm air mass is cut
off, or occluded, from the ground. The warm air mass is cut off, or
occluded, from the ground. As the warm air cools and its water
vapor condenses, the weather may turn cloudy and rainy or snowy. As
the warm air cools and its water vapor condenses, the weather may
turn cloudy and rainy or snowy. Slide 23 NSF North Mississippi GK-8
Fronts: Five Types of Fronts 4. Occluded Front: Formed when a cold
front overtakes a warm front This occurrence usually results in
storms over an area In U.S., the colder air usually lies to the
west Slide 24 MAP TAP 2002-2003 Stationary Fronts A front that
stops moving or is moving very slowly. A front that stops moving or
is moving very slowly. Shown on a weather map with alternating red
semicircles pointing away from the warm air and blue triangles
pointing away from the cold air. Shown on a weather map with
alternating red semicircles pointing away from the warm air and
blue triangles pointing away from the cold air. Slide 25 Stationary
Fronts Stationary Fronts Sometime cold and warm air masses meet,
but neither has enough force to move the other. Sometime cold and
warm air masses meet, but neither has enough force to move the
other. They meet in a standoff They meet in a standoff MAP TAP
2002-2003Weather Fronts25 Slide 26 Stationary Fronts Where the warm
and cool air meet, water vapor in the air condenses into rain,
snow, fog, or clouds. Where the warm and cool air meet, water vapor
in the air condenses into rain, snow, fog, or clouds. It may stall
over an area and bring many days of clouds and precipitation. It
may stall over an area and bring many days of clouds and
precipitation. MAP TAP 2002-2003Weather Fronts26 Slide 27 NSF North
Mississippi GK-8 Fronts: Five Types of Fronts 3. Stationary Front:
When either a cold or warm front stops moving When the front starts
moving again it returns to either being a cold or warm front Slide
28 Locate the 4 types of fronts on this weather map. Slide 29 Cold
Fronts Slide 30 Warm Front Slide 31 Stationary Front Slide 32
Occluded Front Slide 33 Weather Fronts33 Be a Weather Forecaster
You are planning to travel to Alabama in 2 days. The high
temperature there for today is 68 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. Slide 34 34 Be a
Weather Forecaster There is a cold front approaching. The
temperatures will probably be cooler behind the front. Slide 35 MAP
TAP 2002-2003Weather Fronts35 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. 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.
