1. NATIONAL 4 and 5 GEOGRAPHY
WEATHER
ST. ANDREW’S HIGH SCHOOL
MRS CARRUTHERS, MISS CURLEY AND MS LYNAS

2. Checklist – What do I need to know?
What will I learn?
What factors affect temperature
What factors affect precipitation
How to read synoptic symbols
How to read a synoptic weather chart and base forecasts on it
What the main air masses affecting the UK are
What type of weather we associate with a cold front, warm front and depressions
How wind speed and direction is connected to isobar patterns
What type of weather we associate with anticyclones

3. INTRODUCTION Visibility Sunshine Cloud Cover Wind Speed Air Pressure
WEATHER
ELEMENTS
Precipitation
Cloud Cover
Wind Speed
Sunshine
Air Pressure
Humidity
Visibility

4. Factors that affect Weather in the UK

5. 1. LATITUDE (how far North or South you are from the Equator)

6. - Places closer to the equator are warmer
- The further North or South you travel the colder it gets
- This is because the Sun’s energy is concentrated at the equator
- The distance that energy travels through the atmosphere is less at the equator so less heat is reflected by clouds, gas and dust
- The equator is green and absorbs the sun’s energy but the poles are white and reflect the sun’s energy

7. 2. ALTITUDE (how high up you are)

8. - The higher up you go the colder it gets
- E.g. as you climb a mountain the temperature drops
- Wind speed also increases at altitude
- Rain is common higher up as warm air is forced to rise and starts to condense

9. 3. ASPECT
- In the Northern Hemisphere, north facing slopes make good ski runs as they receive little sunlight during the day
- South facing properties often have conservatories as they receive a lot of sunlight during the day.
- South facing slopes are better for growing crops on
In the Southern hemisphere the opposite would be true
In the UK, West facing slopes receive more rain because the Atlantic Ocean is to the west, bringing moist winds.

10. Distance from the sea affects temperature.
In summer places which are inland are usually warmer than places near the coast.
In winter, inland places are colder than places near the coast.
Distance from the sea affects temperature since the sea takes longer to heat up than the land.
Once warm, however, the sea keeps its heat for longer.

11. Inland areas are away from the influence of sea air.
4. DISTANCE FROM THE SEA (continued)
In summer, the sea is cooler than the land and coastal regions are cooled by sea air.
In winter, the sea is warmer than the land and coastal regions are warmed by sea air.
Inland areas are away from the influence of sea air.
Inland areas get very hot in summer.
Inland areas get very cold in winter.

12. Coastal Area Cooled By Sea Breeze on A Summer’s Day

13. Coastal Area Warmed By Sea Breeze on a Winter’s Day

14. AIR MASSES

15. Main Air Masses affecting the UK

17. QUICK SUMMARY OF AIR MASSES
Area air mass has come from
Weather characteristics
Arctic
Cold
Tropics
Warm
Land
Dry
Water
Wet

18. WINTER WEATHER CONDITIONS SUMMER WEATHER CONDITIONS
AIR MASS
WHERE IT CAME FROM
WINTER WEATHER CONDITIONS
SUMMER WEATHER CONDITIONS
Arctic Maritime
Arctic Ocean
Very cold and snow
Cold and wet
Polar Continental
Northern Europe and Siberia in Russia
Very cold and dry
Hot, dry and sunny
Polar Maritime
North Atlantic Ocean
Cool, cloudy and rain showers
Tropical Continental
Northern Africa and Southern Europe
Mild, dry and sunny
Very hot, dry and sunny
Tropical Maritime
South Atlantic Ocean
Mild and wet
Warm and wet

19. QUESTION CLEARER ON NEXT SLIDE
2014 n5 EXAM QUESTION
QUESTION CLEARER ON NEXT SLIDE
(3 marks)

20. Describe how a prolonged spell with a tropical continental air mass in summer would affect the people of the British Isles? (3 marks)

21. MARKING SCHEME ANSWER
A tropical continental air mass will bring hot dry weather in summer which could result in droughts (1);
there might need to be hosepipe bans (1);
grass might wither and die causing problems for livestock farmers (1);
ice cream sales might rise (1) as people make the most of the sunny weather and head for the beach (1);
it could be very hot and difficult to do physical work outside (1); heavy rain from thunderstorms might cause flash floods (1).

22. WEATHER STATION CIRCLES

23. Weather station circles

25. LETS TRY TO MAKE YOUR OWN WEATHER STATION CIRCLES

26. A B Temperature 14 C 3C Wind Speed 10 knots 25 knots Wind Direction
3C
Wind Speed
10 knots
25 knots
Wind Direction
West
North
Weather
Rain
Snow
Cloud Cover
6 Oktas
8 Oktas

27. C D Temperature 22 C -5C Wind Speed 15 knots Calm Wind Direction
-5C
Wind Speed
15 knots
Calm
Wind Direction
South West
Weather
Drizzle
Fog
Cloud Cover
8 Oktas
Sky Obscured

28. Weather Fronts

29. What happens at fronts? A warm front means that warm air is coming.
At a warm front, warm air is rising over cold air.
This usually produces clouds and rain.
A cold front means that cold air is coming.
At a cold front, cold air pushes under the warm air.
This produces strong winds and heavy rain.

30. AIR PRESSURE SYSTEMS (Depressions & Anticyclones)

31. AIR PRESSURE SYSTEMS Cold air falling causes HIGH pressure.
LOW pressure is when air is light and rises up into the upper atmosphere.
HIGH pressure is when air is heavy and is pressing down on the surface.
Warm air rising causes LOW pressure.
Cold air falling causes HIGH pressure.
wind
The Earth’s surface
is warmed by the sun’s rays.
AIR PRESSURE SYSTEMS

32. Each of these systems brings different weather!
AIR PRESSURE SYSTEMS
Low pressure systems (less than 1000mb) are called DEPRESSIONS. They spin in an anti- clockwise direction.
High
High pressure systems (more than 1000mb) are called ANTICYCLONES and they spin slowly in a clockwise direction.
Low
Each of these systems brings different weather!

33. Passage of a Depression
This is a satellite photograph of a depression. Note the swirling pattern of white clouds.
The dark is the sea below the system.

34. LOW Pressure is also known as a DEPRESSION
Cold Sector
Warm Sector
Depressions are made up of different air masses. Where these air masses meet is known as a ‘front’.

35. When depressions move, the weather changes.

36. Describing and Explaining DEPRESSIONS
NOTE:
Explaining weather in a depression is very difficult. The following sentence enders should help:
…as warm air is forced to rise over cold air, condensing and forming clouds
…as there is warm/cold air overhead
…as the isobars are close together 36

37. DESCRIBING
and EXPLAINING
DEPRESSIONS

38. Passage of a Depression
COLD SECTOR
AT THE COLD FRONT
IN THE WARM SECTOR
WARM FRONT
WEATHER
Temperature starts to decrease because there is cold air overhead.
Air pressure starts to increase.
Cumulonimbus clouds
Heavy rain/ thunderstorms because warm air is forced to rise over cold air as it is less
dense.
Warm air starts to condense and form as clouds leading to rain.
The rain here is heavier than the warm front due to the gradient between the two air masses.
Wind speed starts to increase
Stratus clouds
Temperature starts to increase because there is warm air overhead.
Rain showers
Wind speed starts to increase because isobars are closer together
Air pressure drops as warm air is rising.  
Cirrus clouds can be seen high in the sky
Rain begins because warm air is forced to rise over cold air as it is less dense.
Green Text = Describe
Red Text = Explain

39. HIGH Pressure is also known as an ANTICYCLONE
There are no ‘fronts’ in an Anticyclone – it is just one air mass.

40. Differences between SUMMER and WINTER ANTICYCLONES

41. HIGH PRESSURE LOW PRESSURE
Anticyclones
Pressure increases towards the centre
Isobars are widely spaced
Light winds
Winds move in a clockwise direction
Little cloud
Dry
Depressions
Lowest pressure in the centre
Isobars are close together
Strong winds
Winds move in an anti-clockwise direction
Warm and cold fronts
Unsettled weather
Rain at the fronts
Cloudy skies

42. How to Answer a popular weather question
SIMILAR TO NATIONAL 5
2014 EXAM QUESTION
PAY ATTENTION TO THE STRUCTURE

43. Synoptic Chart for the British Isles at 0700h on 31 August
A yacht race from Wick to Stornoway was due to start from Wick harbour at 8.00am on 31 August
At 7.00am the Met Office advised the race organisers to cancel the race.
With reference to the synoptic chart, explain why this advice was given.
5 marks

44. What are the key words? use the information on the map
type of boat : think!
place : see map
A yacht race from Wick to Stornoway was due to start from Wick harbour at 8.00am on 31 August
direction : see map
time : compare with map
At 7.00am the Met Office advised the race organisers to cancel the race.
change of plan!
use the information on the map
With reference to the synoptic chart, explain why this advice was given.
5 marks
number of points to make

45. Link question to the map
31 August
Where?
Wick and Stornoway
Direction?
From Wick to Stornoway
When?
Race due to start at 0800h
Map is for 0700h

46. Study the map for information
Occluded front:
broad belt of very heavy rain, low cloud and poor visibility
Centre of low pressure : likely to bring stormy weather
Cold mP air
Tightly packed isobars : strong winds
South westerly winds
Warm mT air
Associated weather is moving west to east

47. Back to the question …. Why was the race cancelled?
Competitors would risk very strong winds and therefore high seas
They would be sailing straight into the wind so it would be difficult to make progress
Temperatures would be low
There would be heavy rain
There would be thick cloud and probably poor visibility
But this is not enough. Why not?

48. “Explain.. With reference to the map”
Strong winds – close isobars
Head winds – wind direction SW
Low temperatures – mP air mass
Heavy rain – occluded front
Low cloud and poor visibility – occluded front
5 marks

49. 2014 EXAM QUESTION

50. QUESTION
Give reasons for the differences in the weather conditions between Ballycastle and Lerwick? (5 marks)

51. MARKING SCHEME ANSWER
It is much windier at Ballycastle than Lerwick because the isobars are much closer together in Ireland (1);
it is raining heavily at Ballycastle because it is next to the cold front whereas Lerwick is not close to any fronts (1);
the wind direction is north west at Ballycastle and south east at Lerwick because the wind goes anticlockwise around the low pressure and the isobars show the approximate direction (1);

52. the cloud cover is 8 oktas at Ballycastle because it is so close to the cold front where there is likely to be cumulonimbus cloud whereas Lerwick is not near any fronts so is less likely to have cloud (1);
the temperature is warmer at Ballycastle as it is still in the warm sector whereas Lerwick is not (1); the weather is mostly worse in Ballycastle than Lerwick as it is closer to a depression (1).
It is warmer in Ballycastle because the clouds trap the heat whereas it is colder in Lerwick because there are no clouds (1)

53. LET’S TRY THE 2014
N5 EXAM PAPER