Forecasting the weather

 

  
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Building your 'weather' skills

Passage of a summer cold front - Exercise using data tables

A summertime cold front: 6-10 February 2001

This section presents two data tables for you to use to identify when the cold front passed. Note changes in pressure, wind direction and speed as well as temperature change.
This cold front brought very little rainfall.

Answers are listed at the bottom of the page.


The table below gives snapshots of Adelaide's weather at six-hourly intervals.

Q1) When did the cold front pass?
Is it:
i) 1200 - 1800 UTC 9 Feb
ii) 0600 - 1200 UTC 8 Feb
iii) 0600 - 1200 UTC 7 Feb

ADELAIDE (FEBRUARY 2001)

DATE

TIME (UTC)

WIND DIR (DEGREES)

SPEED (KTS)

TEMP OC

MSL PRESSURE HECTOPASCALS

RAINFALL (PREVIOUS 6 HOURS (mm))

6 FEB

1200
1800

120
020

08
04

30.3
29.2

1013.3
1011.8

0
0

7 FEB

0000
0600
1200
1800

360
240
Calm
030

08
08
05

34.8
39.1
33.2
31.2

1013.3
1009.7
1009.2
1007.1

0
0
0
0

8 FEB

0000
0600
1200
1800

330
250
230
300

08
09
07
06

36.6
39.3
28.1
26.6

1009.2
1006.2
1008.1
1008.3

0
0
0
0

9 FEB

0000
0600
1200
1800

180
200
160
130

07
04
08
05

21.9
24.8
18.2
17.3

1013.1
1011.7
1014.5
1013.2

0
0.8
0
0

10 FEB

0000

020

04

19.8

1015.5

0

To convert UTC to Eastern Standard Time add 10 hours
i.e. 1200 UTC 6 Feb = 2200 EST 6 Feb
1800 UTC 6 Feb = 0400 EST 7 Feb

 

The next table gives Melbourne's weather elements.

Q2) When did the cold front pass?
Is it:
i) 0000 - 0600 UTC 9 Feb
ii) 0600 - 1200 UTC 7 Feb
iii) 0600 - 1200 UTC 8 Feb

MELBOURNE (FEBRUARY 2001)

DATE

TIME (UTC)

WIND DIR (DEGREES)

SPEED (KTS)

TEMP OC

MSL PRESSURE HECTOPASCALS

RAINFALL (PREVIOUS 6 HOURS (mm))

6 FEB

1200
1800

120
360

06
04

25.3
19.8

1017.6
1017.8

0
0

7 FEB

0000
0600
1200
1800

010
010
360
360

19
12
08
10

26.2
33.5
29.2
24.6

1018.9
1015.3
1013.7
1012.0

0
0
0
0

8 FEB

0000
0600
1200
1800

360
360
200
360

21
23
11
07

29.1
34.8
25.4
23.7

1011.4
1007.8
1007.4
1005.5

0
trace
0
0

9 FEB

0000
0600
1200
1800

190
180
190
230

05
08
08
08

21.6
19.6
18.9
16.4

1009.6
1011.4
1011.8
1012.2

0
0
0
0

10 FEB

0000

210

10

17.9

1013.7

0

To convert UTC to Eastern Standard Time add 10 hours
i.e. 1200 UTC 6 Feb = 2200 EST 6 Feb
1800 UTC 6 Feb = 0400 EST 7 Feb

Answer: When did the cold front pass?

The chart sequence showed the front moving through both Adelaide and Melbourne between the afternoon of 8 February and the afternoon of 9 February.

  • Adelaide's table of data shows a sharp temperature drop (39.3°C at 0600 UTC to 28.1°C at 1200 UTC on 8 February) and a change in wind flow from NNW at 8 knots at 0000 UTC to WSW at 9 knots at 0600 UTC......suggesting the front passed soon after 0600 UTC, 8 February 2001.

  • Melbourne's table of data shows a similar temperature drop (from 34.8°C at 0600 UTC to 25.4°C at 1200 UTC) and a change in wind flow from N at 23 knots at 0600 UTC to SSW at 11 knots at 1200 UTC...suggesting the front passed through between these two times.

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