Cold fronts occur when a colder air mass replaces a warmer one, pushing the warm air up and causing heavier precipitation. Warm fronts are more gradual, with lighter and more widespread precipitation. When a cold front passes, temperatures can drop more than 15 degrees in an hour, while warm fronts bring warmer and more humid conditions.

1. Weather Fronts
NRHS Physical Science

2. Weather and Fronts
Worksheet 1
Cold fronts occur
when a colder air
mass replaces a
warmer air mass. In a
cold front the cold air
follows the warm air,
and, because cold air
is denser, pushes
warm air out of its
way, forcing the warm
air to rise.
Animation of a cold front, author: Dr. Horst Rudolf, university of Bielefeld in cooperation with his pupils
source: http://www.learn-line.nrw.de/angebote/klima/medio/bilder/kfront.gif

3. Weather and Fronts
Worksheet 1 (cont.)
The lifting warm air
mass becomes
cooler, and clouds start
to form. Precipitation at
cold fronts are usually
heavier although less
extensive (50-70 km) and
less prolonged. The
reason for this is that the
uplift of warm air there is
more strong due to the
undercutting of cold
air, so towering clouds
form, and
rain, thunderstorms, hail
and tornadoes can occur.
Animation of a cold front, author: Dr. Horst Rudolf, university of Bielefeld in cooperation with his pupils
source: http://www.learn-line.nrw.de/angebote/klima/medio/bilder/kfront.gif

4. Weather and Fronts
Worksheet 1 (cont.)
The air behind a cold
front is noticeably
colder and drier than
the air ahead of it.
When the cold front
passes
through, temperature
s can drop more than
15 degrees within the
first hour
Animation of a cold front, author: Dr. Horst Rudolf, university of Bielefeld in cooperation with his pupils
source: http://www.learn-line.nrw.de/angebote/klima/medio/bilder/kfront.gif

5. Worksheet 2
Satellite View: A cold front
above Middle Europe
Impressive swirl-structure of a
strong cyclone with its centre
above the East sea:
Having almost completely
occluded the cold air moves
along a broad bow above
Northwest-, Middle- and East
Europe into the centre of the
cyclone (well observable by the
aerated and cellular picture of
clouds. The plains of Po-delta, in
the lee-side of the Alps, are
almost free of clouds. Further
eastwards a broad, bright band
of clouds marks the border to
continental warm air above
southeast Europe; at this border
extreme weather appearances
are normal.

7. Worksheet 3
Warm Fronts
Warm fronts occur,
when a warmer air
mass approaches a
colder air mass and
goes over the colder
air. Warm fronts are
usually more gentle
than cold fronts, move
slowly, gently settling
over the cold front
and moving it out of
the way.

8. Worksheet 3
Precipitation at warm fronts are usually less heavy although
Warm Fronts
more extensive (300-400 km), than at the cold fronts.
The air behind a warm
front is warmer and
more moist than the air
ahead of it. Warm fronts
bring more
steady, lighter rain or
snow in front of
them, which can last
from a few hours to The first signs of the warm front
several days. When a are the cirrus clouds, followed by
warm front passes the cirrostratus, altostratus,
through, the air nimbocumulus and stratocumulus
becomes noticeably types of clouds.
warmer and more humid

9. Weather Maps Front Maps
•What is a low-pressure
system? What is a high-
pressure system? What
kind of weather does
each typically bring?
•What is a cold front?
What is a warm front?
What types of weather
does each typically
bring?
•Explain how the map
key shows each of the
terms above.

10. Weather Maps Satellite Maps
•What do satellite
images show? Why is
this information
important?
•How do we get
satellite images? How
do satellites travel?
•What can
meteorologists learn
by the shade of the
clouds on a satellite
image?

11. Weather Maps Radar Image Maps
•What does radar
show?
•How do you use the
map key on a radar
map?
•How do we get radar
images?
•What are some of the
limitations of radar
maps?

12. Weather Maps Precipitation Maps
•What is
precipitation?
•What are some
examples of
precipitation?
•Define the different
types of precipitation
on the map.
•What causes different
types of precipitation?

13. Weather Maps Temperature Maps
•What is temperature?
(For the clearest
definition, see the
“Weather terms” chart
in the background
article.)
•What are the two most
important factors in
temperature?
•Why is it usually cooler
at night?
•Why does temperature
change during the
seasons?

14. Weather Maps Wind Speed Maps
•Explain the main
cause of winds.
•Why are some
winds stronger
than others?
•How does wind
affect the
weather?
•How are winds
named?

15. Bars/Lines/Circles Showing Pressure
are Called Isobars

16. Bars/Lines/Circles Showing Pressure
are Called Isobars
When Isobars are far apart When Isobars are
Gentile Wind close together
Fast Wind
And Gusts

17. Discussion Questions
• Using the maps from the activity, choose one
place in the country that had different
weather from your hometown’s.
• How do you think this weather affected kids in
that area? How might their days have been
different from yours? Think about what they
wore, what they did for recess, and what they
planned for after school.

18. Discussion Questions
• Why is it helpful to use different types of
weather maps?
• When might some maps be more helpful than
others?
• For example, why might you be more
interested in precipitation one day and wind
speed the next?

19. Discussion Questions
• Describe other maps you’ve seen in weather
reports (examples: UV index, snowfall, pollen
count).
• Why are these maps important?