15 Weather How to read and understand weather

15 Weather How to read and understand weather maps and their symbols How to identify jobs that rely on weather maps How to identify weather systems displayed on weather maps Wind radar charts and rose diagrams

Chapter 15: Weather § Weather maps are used by various people and are produced for different purposes: § Daily and simplified weather maps are available in the papers and on television. These help people to prepare for the days ahead § Detailed forecasts are available and are crucial for people working on ships and for pilots § Farmers also use weather forecasts to help them prepare work for the next day as harvesting cannot be attempted unless a dry spell is forecasted

Chapter 15: Weather Meteorology § The study of the atmosphere, especially weather conditions

q Synoptic charts: q Front: q Air mass: q Barometric pressure: q Isobars: q Millibars: q High pressure: q Low pressure: Weather map or chart Boundary between two air masses (Warm front and cold front) Body of air with same temperature/conditions Same as atmospheric pressure – the state of the atmosphere temp/air/movement etc. Lines that join areas of equal pressure Unit of measurement of pressure AKA Anticyclone or Highs *** AKA depression or Lows ***

Fronts

Three main fronts Pg 169

Warm front: • Warm air is lighter so it rises = light drizzle / rain Cold front: • Cold air forces its way under warm air forcing it to rise quickly = • Bursts of heavy rain

Occluded front: • A cold front travels quickly and forces a warm front to rise = • Cloud cover and rain The symbol of a front tells you what direction the front is passing and its name tells you of the air mass behind the line of the symbol

Low pressure systems

Low atmospheric pressure: • Unsettled weather • Cloud cover • Precipitation • Strong winds L

High atmospheric pressure: • Settled weather • Clear, cloudless skies • Light winds • Cold, frosty nights in winter H

Wind radar charts

Wind radar chart

Wind radar chart

Wind rose diagrams

Wind rose diagrams

The colours show the wind strength /speed The ‘arms’ show the direction the wind was blowing from……

Other weather charts you might see….

Now test yourself…. Questions on pages 172 -174