st. andrew’s high school mrs carruthers, miss curley and ms lynas national 4 and 5 geography
TRANSCRIPT
ST. ANDREW’S HIGH SCHOOL
MRS CARRUTHERS, MISS CURLEY AND MS LYNAS
NATIONAL 4 AND 5 GEOGRAPHY
WEATHER
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
WEATHER ELEMENT
S
Precipitation
Cloud Cover
Wind Speed
SunshineAir
Pressure
Humidity
Visibility
INTRODUCTION
Factors that affect Weather
in the UK
1. LATITUDE (how far North or South you are from the Equator)
- 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
2. ALTITUDE (how high up you are)
- 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
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.
4. DISTANCE FROM THE SEA
• 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.
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.
COASTAL AREA COOLED BY SEA BREEZE ON A SUMMER’S DAY
COASTAL AREA WARMED BY SEA BREEZE ON A WINTER’S DAY
AIR MASSE
S
MAIN AIR MASSES AFFECTING THE UK
Area air mass has come from Weather characteristics
Arctic Cold
Tropics Warm
Land Dry
Water Wet
QUICK SUMMARY OF AIR MASSES
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
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
2014 N5 EXAM QUESTION
QUESTION CLEARER ON NEXT SLIDE
(3 marks)
Describe how a prolonged spell with a tropical continental air mass in summer would affect the people of the British Isles?
(3 marks)
• 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).
MARKING SCHEME ANSWER
WEATHER
STATION CIRCLES
Weather station circles
LETS TRY TO MAKE YOUR OWN
WEATHER STATION CIRCLES
Temperature 14 C Temperature 3C
Wind Speed 10 knots Wind Speed 25 knots
Wind Direction
West Wind Direction North
Weather Rain Weather Snow
Cloud Cover 6 Oktas Cloud Cover 8 Oktas
A B
Temperature 22 C Temperature -5C
Wind Speed 15 knots Wind Speed Calm
Wind Direction
South West
Wind Direction
Weather Drizzle Weather Fog
Cloud Cover 8 Oktas Cloud Cover Sky Obscured
C D
Weather Fronts
What happens at fronts?
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.
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.
AIR PRESSURE SYSTEMS
(Depressions & Anticyclones)
The Earth’s surfaceis warmed by the sun’s rays.
Warm air rising causes LOW
pressure.
Cold air falling causes HIGH
pressure.
wind
HIGH pressure is when air is heavy and is pressing down on the
surface.
LOW pressure is when air is light and rises up into the upper
atmosphere.
AIR PRESSURE SYSTEMS
Low pressure systems (less than 1000mb) are called DEPRESSIONS. They spin in an anti- clockwise direction. High pressure systems
(more than 1000mb) are called
ANTICYCLONES and they spin slowly in a clockwise direction.
Low
High
Each of these systems brings different weather!
AIR PRESSURE SYSTEMS
This is a satellite photograph of a
depression. Note the swirling pattern of white
clouds.
The dark is the sea below the system.
Passage of a Depression
LOW Pressure is also known as a DEPRESSION
Depressions are made up of different air masses. Where these air masses meet is known as a ‘front’.
Warm Sector
Cold Sector
When depressions move, the weather changes.
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
Describing and Explaining DEPRESSIONS
DESCRIBING and
EXPLAINING DEPRESSIONS
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.
Warm air starts to condense and form as clouds leading to rain.
Passage of a Depression
Green Text = Describe
Red Text = Explain
HIGH Pressure is also known as an ANTICYCLONE
There are no ‘fronts’ in an Anticyclone – it is just one air mass.
Differences between SUMMER and WINTER ANTICYCLONES
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
HOW TO ANSWER A POPULAR WEATHER QUESTION
SIMILAR TO NATIONAL 52014 EXAM QUESTION
PAY ATTENTION TO THE STRUCTURE
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
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
WHAT ARE THE KEY WORDS?place : see map
direction : see maptime : compare
with map
type of boat : think!
change of plan!use the
information on the map
number of points to make
LINK QUESTION TO THE MAP
Where?
0700 h
31 August
When?
Wick and Stornoway
From Wick to Stornoway
Direction?
Race due to start at 0800h
Map is for 0700h
STUDY THE MAP FOR INFORMATIONCentre of low pressure : likely to bring stormy weather
Occluded front:
broad belt of very heavy rain, low cloud and poor visibility Tightly
packed isobars : strong winds
South westerly winds
Associated weather is moving west to east
Warm mT air
Cold mP air
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?
“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
2014 EXAM QUESTION
Give reasons for the differences in the weather conditions
between Ballycastle and Lerwick?(5 marks)
QUESTION
• 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);
MARKING SCHEME ANSWER
• 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)
LET’S TRY THE 2014
N5 EXAM PAPER
