Monday, 3 December 2007 - Monthly Climate Summary for Canberra area - Product code IDCKGC1xx0

Stormy and wet with record warm nights in Canberra during November

Summary

  • warm days, average maximum temperature 25.1°C or 2.5°C above the historic average
  • 6 consecutive years with above average November maximum temperatures
  • 8 hot days exceeded 30°C (normally 2 hot days)
  • warm nights, average minimum temperature 11.8°C was highest ever recorded in November
  • 5 out of last 6 years with above average minimum temperatures
  • persistent mild nights with temperature not falling below 5°C the whole month
  • well above average rainfall
  • 7thunderstorms, highest in November for 13 years.
  • below average sunshine hours

 

Rainfall

Canberra Airport recorded a total rainfall of 94.0 mm during November, which is significantly above the historic average of 63.8 mm, and the wettest November since 2000 (when 121 mm was recorded). Welcome rain and thunderstorms associated with a low-pressure system early in the month, and again on the 23rd, brought some relief from the dry conditions that had persisted in eastern parts of the ACT since June. There were 12 rain days during November, compared to the average of 10 days. Rainfall totals varied considerably over the ACT during November with the highest totals in the south-west and the lowest totals in central Canberra. The highest in the ACT was 150.4 mm at Mount Ginini AWS with the highest suburban total of 127.6 mm at Tuggeranong AWS. The lowest total was 63.0 mm at Deakin.

Persistent high-pressure systems near Tasmania for most of the month caused prevailing moist E to SE airstreams over NSW including Canberra. This combined with inland low-pressure troughs and cold, unstable air in the upper atmosphere to produce the above average rainfall for the month. Much of the month's rain occurred during thunderstorm activity.

Temperatures

Canberra experienced a warm November with the mean daily temperature (the average of the mean maximum and mean minimum temperatures) at Canberra Airport of 18.4°C, significantly above the historic average1 of 15.7°C.  The average maximum (day-time) temperature during November was a very warm 25.1°C which is well above the historic average1 of 22.7°C and ranks 9th highest since records commenced in 1939. There were 8 hot days when the maximum temperature exceeded 30°C - normally Canberra would expect only 2 hot days in November. The 8 days above 30°C were consecutive days (14th to 21st), which is the 2nd longest hot spell on record in November, the longest being in 2006 when there was 11 consecutive days above 30°C (records since 1939).

Canberra has now recorded 6 consecutive years with above average maximum temperatures in November.

Canberra also experienced very warm nights during November with an average minimum at the airport of 11.8°C being 3.0°C above the historic average1 of 8.8°C. This is the highest average minimum temperature on record for Canberra in November (previous highest 11.6°C in 2000). There was a distinct lack of cold nights with the temperature not falling below 5°C the whole month. Normally Canberra would expect 5 nights in November with a minimum temperature below 5°C.

The high minimum temperatures were in part due to moist, humid air from the north-east and a greater than normal cloud cover limiting radiative cooling at night. Over 34% of winds were from the E-NE which is double the normal frequency from this direction. For 5 out of the last 6 years, Canberra has recorded above average minimum temperatures in November.

Extremes of temperature at Canberra Airport ranged from a high of 33.4°C on the 20th and 21st to a low of 6.1°C on the 7th. Corresponding extremes for Tuggeranong ranged from a high of 33.4°C on the 20th to a low of 5.8°C on the 10th. The lowest temperature in the ACT was −1.0°C at the high elevation site of Mount Ginini AWS (1760 m) on the 5th, 6th and 7th.

 

Other phenomena

No frosts were recorded at Canberra Airport during November (historic average 2 frosts) and also no fogs (average 1 fog).  Cloud generally increased during the afternoons associated with diurnal heating and thunderstorms resulting in below average sunshine of just 7.9 hours per day, well below the historic average 9.0 hours per day and the cloudiest November for 7 years.  Canberra's average wind run of 167.6 km per day was below the historic average of 207 km per day. There were 3 strong wind days (average 3).

Canberra Airport recorded 7 thunderstorms during November which is the highest number of storms in November for 13 years (historic average 4 storms). No hail was reported. The average air pressure of 1017.1 hPA was well above the historic average of 1013.2 hPa. Canberra Airport recorded 176 mm of evaporation during November, below the historic average of 196.2 mm. This was due mainly to the lower than normal wind speeds and high levels of humidity experienced over the ACT during the month.

Further information

Mike De Salis
Climate Information Officer
NSW Climate Services Centre
Bureau of Meteorology
Phone (02) 9296 1555
Email mikede@bom.gov.au

Extremes for the ACT

Hottest day
Highest temperature
33.4°C at Canberra Airport on the 20th and 21st
33.4°C at Tuggeranong AWS on the 20th
Warmest days on average
Highest mean daily maximum temperature
25.1°C at Canberra Airport
Coolest days on average
Lowest mean daily maximum temperature
24.8°C at Tuggeranong AWS
Coldest day
Lowest daily maximum temperature
15.5°C at Canberra Airport on the 4th
4.0°C at Mount Ginini AWS on the 4th (elev 1760 m)
Coldest night
Lowest temperature
5.8°C at Tuggeranong AWS on the 10th
−1.0°C at Mount Ginini AWS on the 5th,6th and 7th.
Coolest nights on average
Lowest mean daily minimum temperature
11.1°C at Tuggeranong AWS
6.7°C at Mount Ginini AWS
Warmest nights on average
Highest mean daily minimum temperature
11.8°C at Canberra Airport
Warmest night
Highest daily minimum temperature
16.4°C at Canberra Airport on the 22nd
Wettest overall
Highest total rainfall
150.4 mm at Mount Ginini AWS and 143.8 mm at Tharwa
Driest overall
Lowest total rainfall
63.0 mm at Deakin
Wettest day
Highest daily rainfall
43.6 mm at Sullivan Creek (Southwell) on the 4th
Highest wind gust
85 km/h from NW at Canberra Airport on the 3rd
(to 25th)

Records

Record highest November mean daily minimum temperature
Mean daily minimum
temperature
for November 2007 (°C)
Previous highest
for November (°C)
Years of
record
Normal for
November
Canberra Airport
11.8
11.6
in 2000
69
8.8

Summaries

Summary statistics for November 2007
  Maximum temperatures
for November
(°C)
Minimum temperatures
for November
(°C)
Rainfall
for November
(millimetres)
Mean for
November
2007
Diff
from
normal
Highest for
November
2007
Mean for
November
2007
Diff
from
normal
Lowest for
November
2007
Total for
November
2007
Normal
for
November
Rank of
November
2007
Fraction of
November
normal
Canberra Airport
25.1
+2.4
33.4 20th,21st
11.8
+3.0
6.1 7th

94.0

63.8

high 147%
Tuggeranong
24.8
+1.1
33.4 20th
11.1
+1.8
5.8 10th

127.6

61.7

very high 207%

Mount Ginini (elev 1760 m)*

15.5

 

24.9

20th

6.7

 

−1.0

5th,6th,7th

150.4

 

 

 

* new station, no historic averages available


Notes

This statement has been prepared based on information available at noon on Monday 3 December 2007. Some checks have been made on the data, but it is possible that results will change as new information becomes available.

1Averages:  historic average temperatures for Canberra Airport are based on the period 1961 to 1990 which is a convention of the World Meteorological Organisation. The historic average temperatures for Tuggeranong AWS are based on all available records 1996−2007. Rainfall averages at Canberra Airport are based on all years of record 1939−2007.

Normals are long-term means based on observations from all available years of record, which vary widely from site to site. They are not shown for sites with less than 10 years of record, as they cannot then be calculated reliably.
The median is sometimes more representative than the mean of "normal" rain.

The Rank indicates how rainfall this time compares with the climate record for the site, based on the decile ranking (very low rainfall is in decile 1, low in decile 2 or 3, normal in decile 4 to 7, high in decile 8 or 9 and very high is in decile 10).
The Fraction of normal shows how much rain has fallen this time as a percentage of the long-term mean.