Reading Weather Maps

Weather Maps are also referred to as synoptic charts. It is a record of the weather conditions being experience at a particular point in time. It provides information about air pressure, wind speed and direction, and the distribution (location) of rainfall.

 

Synoptic charts enable geographers and meteorologists (a person who studies weather) to view current weather conditions and predict weather into the future.  Being able to read weather maps is an important geography skill.

Features of a Weather Map

Air Pressure

One of the most important features of the atmosphere is air pressure (or the weight of the air).

Atmospheric air pressure measurements are given in hectopascals (hPa).

The main lines that we see on weather maps are called isobars. Isobars are lines joining places of equal pressure

Isobars across a map of Australia

What is Air Pressure?

  • The weight of air at ground level
  • The amount of air in the atmosphere
  • The movement of air
  • How people inflate tyres

What unit of measurement is used for air pressure?

  • hectopascals (hPa)
  • litres (L)
  • centimentres (cm)
  • degrees celsius (oC)

Lines on a weather map

 

Lines on a weather map joining areas of equal area pressure are called .

Types of Air Pressure

High Pressure Systems

  • High-pressure systems are areas of stable atmospheric conditions: gentle winds, clear skies and little chance of rain.
  • Air pressure increases towards the centre of the pressure system. Air flows out from the high pressure system in an anticlockwise direction.

Low Pressure Systems

  • Low-pressure systems form when warm air rises. They are often associated with unstable weather conditions: cloudy skies, rain and relatively strong winds.
  • Air pressure decreases towards the centre of the pressure system.
  • Air flows in a clockwise direction in the Southern Hemisphere.

High and Low Pressure Systems over southern Australia

Locate the High Pressure System

On the map below, click on the centre of the high pressure system

Locate the Low Pressure System

On the map below, click on the centre of the low pressure system

Fronts

Cold Fronts

Cold fronts occur when a mass of cold, dense air pushes in under a mass of warm air, forcing it to rise.

As the warm air rises, it cools and condensation takes place.

Lower temperatures are experienced once the front has passed.

Cold fronts often bring rain as well.

Warm Fronts

Warm fronts occur when a warm parcel of air overtakes a colder, denser parcel of air.

Like cold fronts, light rain often results as air rises. However, this rainfall tends to last for a longer period of time and to be less intense than that resulting from a cold front.

Warm fronts are not common in Australia.

A cold front is a body of cool air pushing under a mass of warm air forcing it to rise.

  • Is the above statement true or false?

Rainfall

An area of diagonal lines indicates where rain has occurred in the past 24 hours in the location. 

Click on all cities which have received rainfall in the past 24 hours.

Which THREE cities have received rainfall in the past 24 hours.

Winds

Wind direction and strength for selected locations are shown using lines with small barbs or tails. With the aid of the legend we can determine wind speed.

Winds are named after the direction from which they blow. A southerly, for example, blows from the south.

When isobars are located far apart, wind is gentle. Isobars that are located close together indicate strong winds.

Winds occur when air moves from areas of high pressure to areas of low pressure.

Winds are named after the direction which they are...

  • blowing TO.
  • blowing FROM.

Complete the blanks below.

Winds blow from a pressure system to a pressure system

State the direction the wind is blowing for the indicators below

A. Wind is blowing from the EAST

B. Wind is blowing from the  

C. Wind is blowing from the  

D. Wind is blowing from the  

E. Wind is blowing from the  

F. Wind is blowing from the 

G. Wind is blowing from the 

 

 

Drag and drop the labels to their correct location

  • Isobars
  • Cold Front
  • Warm Front
  • High Pressure System
  • Low Pressure System

Which weather features are associated with a low pressure system?

  • Overcast skies
  • Clear skies
  • Strong winds
  • Little wind
  • Rain
  • No rain

Click on the image of a High Pressure System

Match the terms and definitions below

  • A body of warming air rises over colder air
    Warm Front
  • A body of cold air pushes under existing warm air
    Cold Front
  • The lines that join places that have the same air pressure.
    Isobars
  • The unit of measurement for air pressure
    Hectopascals (hPa)

Reading Weather Maps

Its time to take all that learnt knowledge and apply it to reading real weather maps.

Using the map below indicate whether the statements are TRUE or FALSE

  • Central Australia would be experiencing calmer weather conditions than New Zealand
  • Hobart will experience cooler weather and potential rainfall in the next 24 hours
  • Perth is experiencing higher air pressure than Alice Springs
  • This weather map was recorded in winter

Examine the weather map below and answer the following questions

  1. During what season were these weather conditions recorded? 
  2. What is the air pressure at Rockhampton? hPa
  3. What is the air pressure at Kalgoorlie? hPa
  4. What is the air pressure at Adelaide? hPa
  5. What is the air pressure at Hobart? hPa

Complete the table below

Location Wind Direction Wind Speed
Alice Springs km/h
Townsville km/h
Darwin km/h

 

What weather conditions are being experienced in Brisbane?

  • Stable atmospheric conditions with a change in wind direction, an increase in wind velocity and the increased chance of rain
  • Unstable atmospheric conditions with generally clear skies, gentle winds and little chance of rain
  • Stable atmospheric conditions with generally clear skies, gentle winds and little chance of rain
  • Unstable atmospheric conditions with a change in wind direction, an increase in wind velocity and increased chance of rain

Click on the area of synoptic chart which would be experiencing the strongest winds

Select TRUE or FALSE for the statement below

  • Sydney would be experiencing finer weather conditions than Port Headland
  • Cairns and Townsville would be experiencing similar air pressure
  • Adelaide will shortly experience an increase in temperature
  • Alice Springs has a lower air pressure than Sydney
  • Perth has a lower air pressure than Darwin

Rank the city's air pressure, from highest to lowest.

  • Adelaide
  • Sydney
  • Canberra
  • Cairns
  • Hobart

Complete the blanks below about the synoptic chart.

  1. The capital city which has received rain in the past 24 hours is 
  2. What is the air pressure at Port Headland?  hPa
  3. What is the air pressure at Hobart?  hPa
  4. What is the air pressure at Cairns?  hPa
  5. What is the air pressure at Adelaide?  hPa
  6. What is the air pressure at Sydney?  hPa
  7. What is the wind direction at Perth? 
  8. What is the wind speed at Perth? km per hour
  9. What is the wind direction east of Cairns?  
  10. What is the wind speed east of Cairns? km per hour
  11. Name the synoptic chart feature influencing Tasmania: