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Forecasting the weather

 

  
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Building your 'weather' skills

Exercise on the movement of Cold Fronts

Tracking and predicting the movement of cold fronts is an important part of forecasting the weather, especially in southern Australia. In summer, an error of just a few hours in the forecast time of arrival of a front can result in a forecast maximum temperature error of 15°C. Another major challenge is forecasting the extent of rainfall associated with a front and, in particular, whether it will trigger thunderstorms. The scientific methods used by meteorologists to locate fronts and predict their behaviour, are too complex to deal with with here, but we have developed some exercises which will give you an appreciation of the movement of fronts across south-eastern Australia and the significance of variations in their speed of movement.


Referring to the cold front which passed across Southern Australia during the period 6-10 February 2001, let's consider how we might track a front and estimate its speed of movement. The map below shows two positions of a cold front 12 hours apart, as it moves across the Great Australian Bight.
Answers are listed at the bottom of the page.

Exercise 1

a) Use the scale on the chart (below) to estimate the distance the front has moved.
Is it:
i) 300 km ii) 600 km iii) 900 km


b)Divide the distance by 12 to get the speed (in km/h) of the front.
Is it:
i) 25 km/h ii) 50 km/h iii) 75 km/h

c) If the front continued to move at this same speed, at approximately what time would it reach Sydney?
Is it:
i) 1200 UTC Day 2 ii) 0000 UTC Day 3 iii) 1200 UTC Day 3


Position of cold-front

 

Exercise 2

The table (below) lists temperature and wind information (direction and speed (km/h) at 3 pm local time for several locations in southern Australia during the period 6-10 February 2001.

Use the table to answer the following questions.

Q1) Between which days did the front pass through:

a) Esperance

Is it:
i) 6-7
ii) 7-8
iii) 8-9
iv) 9-10

b)Eucla

Is it:
i) 6-7
ii) 7-8
iii) 8-9
iv) 9-10

c)Ceduna

Is it:
i) 6-7
ii) 7-8
iii) 8-9
iv) 9-10

d) Adelaide

Is it:
i) 6-7
ii) 7-8
iii) 8-9
iv) 9-10

e) Melbourne

Is it:
i) 6-7
ii) 7-8
iii) 8-9
iv) 9-10

 

Q2) Based on the answers to c), d), and e); What is the likely orientation of the cold front?
Is it:
i) North-South ii) East-West iii) Northwest-Southeast iv) Northeast-Southwest


Table of temperature and wind information

 

Exercise 3
If you live in southern Australia you might like to undertake this further exercise.

When as a result of watching a TV weather program or reading the newspaper, you see a reference to a cold front affecting your area in the near future, work your way through the following checklist:

Go to the Bureau's home page.

Look up the latest satellite picture. Can you identify a cloud band associated with the front?

Look up the latest radar images. Do these indicate rainfall associated with the front?

Check the latest forecasts for your location.

Continue to monitor those elements at regular intervals, like every 6 hours, and make notes on what you observe.

 

Answers:
Exercise 1
a) ii) 600 km, b) ii) 50 km/h, c) iii) 0000 UTC Day 3

Exercise 2
Q1)
a) i) 6-7, b) ii) 7-8, c) iii) 8-9, d) iii) 8-9, e) iii) 8-9
Q2)
iii) Northwest-Southeast

The table below uses a red underline to indicate when the front passed through each location.

Table highlighting front arrival

BackBack to the first page of A summertime cold front

 

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