Depressions Warm Front Cold Front Warm front Cold

Depressions

Warm Front

Cold Front

• Warm front • Cold front • Advancing cold air • Advancing warm air • Receding cold air

Occluded Front • Warm air (lighter) disappears as it is pushed up by the cold front (denser air)

Moving Fronts Warm air mass Co nt o r f rm ld Wa n fro t Cold air mass

Occluded front

Anticyclones

Definition • Anticyclones areas of high pressure, where the air (cool) is sinking towards the ground exerting pressure below it. • Not as common as depressions • Can remain for days, even weeks. • Bring warm, stable conditions, with clear skies and lots of sunshine.

Summer

Summer • Summer Effects: • Anticyclones bring hot and sunny weather due to there being clear skies (because of the descending air). • Days are long and the sun high in the sky, which gives ample opportunity for the land to be heated up.

Winter

Winter • Winter Effects: • Anticyclones bring clear days in the winter • The sun is low in the sky and the days are short, meaning you get cool, crisp days. • Clear skies on a winter’s night will allow frost to form • Fogs are also caused by clear winter nights • As water/ water vapour cools it condenses

High pressure - anticyclone

Low pressure depression

Anticyclone

Depression

Depressions – anticlockwise Anticyclones – clockwise

Anticyclone and Depression