Download Anticyclones

Anticyclones
THE WEATHER THEY BRING,
AND WHAT THEY LOOK LIKE
ON A WEATHER MAP.
What is an Anticyclone?
• It is an area of HIGH
PRESSURE.
•They are made when air
sinks downwards.
•The air presses down on
Earth.
•Winds moves clockwise
around them
What is an Anticyclone?
Air piles up once it lands (like the
bottom of an egg timer) and spills
clockwise around the centre
High and Low
Pressure
High
Pressure (air
pushing down
on Earth)
Low Pressure
(air lifting off
the ground)
What weather do they bring
in summer?
• We get heat waves
when an anticyclone
is over the UK.
• Winds are light
• Hardly any clouds
and this means NO
RAIN.
Why do they bring this
weather?- SUMMER
High
temperatures
Light winds
No clouds
The sky is clear
and the sun is high
in the sky
Isobars are far apart
Air is sinking so water
evaporates (because it
warms up). To make a cloud
you need condensation
(cooling down).
Spot the deliberate mistake?
• Anticyclones do
actually bring some
rain……..eventually.
• The dead hot weather
(for days or weeks on
end) means the ground
gets so hot, that some
air does rise and make
a convection cloud like
this one.
• It only rains in a small
area though
Air
rising
Hot
ground
What weather do they bring
in winter?
• Very low
temperatures
• Light winds
• No clouds
• Fog and frost
Why do they bring this
weather? - WINTER
• Cold
temperatures
Rays more
concentrated
Rays more
spread out
Fog and frost
• Clear skies mean
heat escapes easily
and the sun is low
in the sky (so it
doesn’t warm
things up very well
like in summer)
•The ground stays
cold so moisture
condenses making
fog. After this it can
freeze making frost.
Synoptic Charts
Where are
the
anticyclones?
Synoptic Charts
The isobars are all
wide apart and
there are no fronts
Synoptic Charts
But where are the
depressions?
Synoptic
Charts
The
difference
between a
cyclone
(depression)
and an
anticyclone
is….
Depression
Anticyclone
Synoptic
Charts
Depression
Anticyclone
Isobars close together
Fronts
Isobars count downwards
towards middle
Cloudy
Winds blow anticlockwise
Isobars far apart
No fronts
Isobars count upwards
towards middle
Clear skies
Winds blow clockwise
Satellite Images
How do you
spot an
anticyclone
on a
satellite
image?
Clear skies!!
Tasks
• Describe the
weather an
anticyclone would
bring in the
summer?
•Explain the term
‘Blocking Anticyclone
• Warm
temperatures,
clear skies, no rain
light winds
•When an anticyclone
forms, it gets in the way of
other weather systems and
they have to go around it.
Tasks
Which weather
symbol shows the
real weather for
Edinburgh in July?
Explain your answer
X- winds are light
(isobars far apart)
and are south
westerly
(clockwise), high
temperatures and
clear skies (the sun
is high in the sky in
July)
Tasks
This is an anticyclone
over Europe.
Explain why there are
some small areas of
cloud around Italy and
southern France
Convectional
(storm) clouds
formed as pockets
of hot are rise up
through the
anticyclone
Tasks
• How are
peoples daily
lives affected
by
anticyclones?