Frontal weather systems.

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Frontal weather systems.
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Relief Rainfall.
Cooler air.
Wind direction.
Warmer air.
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Convectional Rainfall
Cooler air.
Warm air rises, taking water vapour with it.
Ground warms up and, in turn, warms air.
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Frontal Rainfall
Warm Air Mass
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Frontal Rainfall.
Triangles, sometimes coloured blue a cold front.
Semi-circles, sometimes coloured red a warm
front.
A mix of symbols, an occluded front. This is
when a cold front pushes under a warm front.
More on this later.
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Fronts from the Atlantic pass over the UK every
few days. Britain's weather is dominated by the
passing of these depressions. These form when
warm, moist air meets colder, drier air. They
are areas of low pressure which bring cloud, rain
and wind to the British Isles.
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Weather fronts change weather...
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As fronts from the Atlantic pass over us the
weather changes.
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So, as fronts pass over the UK they change the
weather as they go. Using what you know
describe the changes in temperature and rainfall
for the South-eastern corner of the UK as the
frontal systems pass over. Now in your books copy
the notes on the next slide.
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Characteristics of a typical Western Maritime
Temperate Climate (Case study - the UK)

• Prevailing winds are from the west or south-west.
• Mixing of warm equatorial air masses and cold
  polar air masses create areas of turbulence.
  These can be seen as swirling masses of cloud on
  satellite photos. Each one represents a low
  pressure system with fronts and they tend to move
  from west to east.
• Successions of low pressure systems and their
  fronts bring pulses of rainfall for much of the
  year. Rainfall is fairly constant all year
  around
• Temperatures are stabilised by the large areas of
  ocean. In Western Europe the North Atlantic
  Drift ocean current (Gulf Stream) keeps
  temperatures higher than would be expected.