Form 4 Option Lesson

1. Winter and Summer
Anticyclones
Mr. T. Tonna

2. Index
• What causes an Anticyclone?
• Your Opinion
• Summer vs Winter
• What is the Difference?
• Quiz Time
• Summary
• Homework
Mr. T. Tonna

3. Anticyclones
• Anticyclones are formed from an area of high
pressure.
• They tend to bring clear, settled weather.
• In an anticyclone, air descends and pressure
increases. This brings very light winds (which
blow outwards from the centre in a clockwise
motion), clear skies and dry conditions
(because the air is descending and warming
up, there are no clouds and no rain).
Mr. T. Tonna

4. • They are large masses of air circulating in a
clockwise motion in the Northern Hemisphere
and Anti-clockwise in the Southern
Hemisphere.
• They form because the air within a certain
area cools quicker than its surrounding
environment causing it
to descend.
Mr. T. Tonna
An Anticyclone
Near Tasmania

5. Do You think the weather in
depressions will change in winter in
comparison to summer?
Mr. T. Tonna

6. Mr. T. Tonna

7. Mr. T. Tonna

8. Mr. T. Tonna

9. Mr. T. Tonna

10. Anticyclonic Weather Conditions:
Winter Anticyclones Summer Anticyclones
Dry and bright with very little
cloud.
Very little cloud
Sun low in the sky, so cold
conditions.
Dry with light winds
Clear evening skies mean that
nights can be very cold.
Sun high in the sky, so hot and
sunny
Early morning frost and fog may
last all day.
Cloudless skies at night allow heat
to escape, so nights can be cool.
Extensive low cloud or fog may
produce overcast or ‘gloomy’
conditions.
Risk of thunderstorms at end of
‘heat wave’ conditions
Early morning dew and mist.
Mr. T. Tonna

11. Quiz
• This is a class quiz so everyone will get the
opportunity to give their opinion and explain
their decisions.
• The quiz will be based on the past two
lessons.
• All questions will be open for discussion and
analysis.
Mr. T. Tonna

12. What is the difference
between a Cyclone and an
Anticyclone?
Mr. T. Tonna

13. Which front is associated with
the ‘wettest’ weather?
Mr. T. Tonna

14. On the Following Map, what
do the lines represent?
Mr. T. Tonna

15. Clear skies and high pressure
are associated with what
Weather system?
Mr. T. Tonna

16. The Following photograph of an area
experiencing an Anticyclone was
taken in which season ?
Mr. T. Tonna
ANALYSE THE
PICTURE
PROPERLY!!

17. Despite the fact that Anticyclones are
usually associated with clear skies,
Thunderstorms are common in which
season?
Mr. T. Tonna

18. Summary
• Anticyclones form as a result of a high
pressure air mass sinking as a result of a fast
warming process.
• Winter and Summer cyclones have similar
conditions such as the clear skies both during
the day and at night.
• In the summer the heating air can cause
thunderstorms to occur.
Mr. T. Tonna

19. Homework
‘Weather conditions in Anticyclones are
different in Winter and Summer’ Discuss
using examples. (150-300 words).
Mr. T. Tonna