Tuesday, 1 September 2009 - Monthly Climate Summary for Brisbane Metro - Product code IDCKGC24R0

Brisbane Metro in August 2009

A hot, dry month

  • Record high August daily maximum temperatures
  • Record high August daily minimum temperatures
  • 21% or less of long-term average rainfall

Information current at 1 September 2009

This statement was prepared using the most timely and accurate data available on 1 September 2009.  This document will not be updated.  Final values, which have had greater opportunity for data quality control, will be presented in the Monthly Weather Review, which is usually published during the fourth week of the month.  Further major quality control statements may also appear in Annual Climate Summaries.

An archive of previous monthly summaries for Brisbane Metro is also available, as are summaries for other states and many other climate summaries and diagnostics.

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Rainfall

August was a very dry month in the metropolitan area. While low rainfall is normal between July and September, this August has been particularly dry.   The six sites in the metropolitan area received rainfall totals for the month that were between 1 and 21% of their long-term averages.

The wettest overall was 7.3 mm at Logan City Water Treatment, followed by 6.0 mm at Amberley AMO, followed by 4.4 mm at Archerfield Airport.

The wettest single day was 5.0 mm at Amberley AMO on the 31st, followed by 4.8 mm at Logan City Water Treatment on the 31st, followed by 2.8 mm at Brisbane City on the 13th.

In the 24 hours to 9am on the 13th, isolated shower and thunderstorm activity occurred in an unstable airmass to the east of a surface trough over the southern interior of the state.  In the 24 hours to 9am on the 31st, a mid-level cloud band entered the southeast of the state overnight, producing patchy light rain.

See a map of total rainfall. See a map of rainfall deciles.

Temperature

The major heat episode in the Brisbane metro area during the month occurred between the 22nd and 29th. This unseasonably hot weather occurred when warm to hot and gusty north to northwesterly winds mixed down to the surface from much warmer than average air aloft.  This sort of weather pattern would normally be expected in September or October and the occurrence of such strong northwesterlies in August is unusual.  

The northwesterlies on the 24th and 25th were strong enough to keep sea breezes out from coastal locations in the southeast and Redcliffe on the 24th and Brisbane Aero on the 25th August recorded their hottest days of 2009 so far, surpassing anything reached in January, February or March.

Maximum temperature

All six sites in the Brisbane Metro area included in this summary had their highest August temperature on record on the 24th or 25th of the month, with the previous maximum temperature records at these sites being broken by between 2.6 and 5.1oC.  These record maximum temperatures were above average by between 11.7 and 13.8oC. 

In addition to their highest August 2009 temperatures, Amberley, Archerfield and Brisbane City also broke their previous August maximum temperature records on the 25th, Brisbane Aero on the 26th, Redcliffe on the 25th and 26th and Logan City on the 22nd, 23rd, 25th, 26th and 28th. 

The hottest day was 36.4 °C at Amberley AMO on the 24th, followed by 35.7 °C at Archerfield Airport on the 24th, followed by 35.4 °C at Brisbane on the 24th.

Above average daytime temperatures persisted over the Brisbane Metro area for almost the entire month, due to a lack of cold outbreaks bringing air of Southern Ocean origin northwards, as well as a lack of moisture and consequent persistent clear skies. 

The warmest days on average were 26.6 °C at Amberley AMO, followed by 25.5 °C at Archerfield Airport, Brisbane City and Logan City Water Treatment station.  Some sites had their highest August mean daily maximum temperature on record.

The coolest days on average were 23.8 °C at Redcliffe, followed by 24.0 °C at Brisbane Aero.  

The coldest days occurred at Redcliffe, with 19.4 °C on the 8th, followed by 19.7 °C on the 9th, followed by 20.0 °C on the 4th.

See a map of mean maximum temperatures. See a map of maximum temperature anomalies.

Minimum temperature

All six sites in the Brisbane Metro area included in this summary had their warmest August night (highest daily minimum temperature) on record.  The previous minimum temperature records at these sites were broken by between 1.1 and 2.7oC.  In addition to their highest August minimum temperatures, Amberley also broke its previous August minimum temperature record on the 29th and 30th, Brisbane City and Redcliffe on the 26th and 30th, Logan City on the 22nd, 24th, 25th, 26th, and 30th and Brisbane Aero equalled its previous record on the 29th.

The warmest night was 20.2 °C at Redcliffe on the 25th, followed by 19.8 °C at Amberley AMO on the 25th, followed by 19.2 °C at Brisbane City on the 29th.

The warmest nights on average were 12.7 °C at Redcliffe, followed by 12.1 °C at Brisbane City, followed by 12.1 °C at Logan City Water Treatment, followed by 11.2 °C at Brisbane Aero.  Logan City had its highest August mean daily minimum temperature on record.

The coldest nights during the month occurred at Amberley AMO, with 1.3 °C on the 9th and 27th, followed by 1.6 °C at Amberley AMO on the 1st, followed by 2.1 °C at Amberley AMO on the 2nd.

The coolest nights on average were 6.7 °C at Amberley AMO, followed by 9.5 °C at Archerfield Airport, followed by 11.2 °C at Brisbane Aero.

See a map of mean minimum temperatures. See a map of minimum temperature anomalies.

Wind

The strongest wind gust was 57 km/h at Brisbane Aero on the 17th and the 29th, followed by 56 km/h at Redcliffe on the 8th and Brisbane City on the 12th, followed by 54 km/h at Archerfield Airport on the 12th.

Further information

Queensland Climate Services Centre
Bureau of Meteorology
Phone (07) 3239 8700
Email climate.qld@bom.gov.au

Extremes

Hottest day
Highest temperature		 36.4 °C at Amberley AMO on the 24th
35.7 °C at Archerfield Airport on the 24th
35.4 °C at Brisbane on the 24th
Warmest days on average
Highest mean daily maximum temperature		 26.6 °C at Amberley AMO
25.5 °C at Archerfield Airport
25.5 °C at Brisbane
25.5 °C at Logan City Water Treatment
Coolest days on average
Lowest mean daily maximum temperature		 23.8 °C at Redcliffe
24.0 °C at Brisbane Aero
Coldest day
Lowest daily maximum temperature		 19.4 °C at Redcliffe on the 8th
19.7 °C at Redcliffe on the 9th
20.0 °C at Redcliffe on the 4th
Coldest night
Lowest temperature		 1.3 °C at Amberley AMO on the 9th
1.3 °C at Amberley AMO on the 27th
1.6 °C at Amberley AMO on the 1st
2.1 °C at Amberley AMO on the 2nd
Coolest nights on average
Lowest mean daily minimum temperature		 6.7 °C at Amberley AMO
9.5 °C at Archerfield Airport
11.2 °C at Brisbane Aero
Warmest nights on average
Highest mean daily minimum temperature		 12.7 °C at Redcliffe
12.1 °C at Brisbane
12.1 °C at Logan City Water Treatment
11.2 °C at Brisbane Aero
Warmest night
Highest daily minimum temperature		 20.2 °C at Redcliffe on the 25th
19.8 °C at Amberley AMO on the 25th
19.2 °C at Brisbane on the 29th
Wettest overall
Highest total rainfall		 7.3 mm at Logan City Water Treatment
6.0 mm at Amberley AMO
4.4 mm at Archerfield Airport
Driest overall
Lowest total rainfall		 0.4 mm at Redcliffe
2.0 mm at Brisbane Aero
4.0 mm at Brisbane
Wettest day
Highest daily rainfall		 5.0 mm at Amberley AMO on the 31st
4.8 mm at Logan City Water Treatment on the 31st
2.8 mm at Brisbane on the 13th
Highest wind gust
 57 km/h at Brisbane Aero on the 17th
57 km/h at Brisbane Aero on the 29th
56 km/h at Redcliffe on the 8th
56 km/h at Brisbane on the 12th
54 km/h at Archerfield Airport on the 12th

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Records

Please note that the pink shading in the tables below indicate sites that have less than 30 years of record.  All other sites have been included in the Special Climate Statement available on our website via the following link:
http://www.bom.gov.au/climate/current/special-statements.shtml.
Record highest August temperature
Highest temperature
in August 2009 (°C) 		Previous highest
for August		 Years of
record		 Average for
August
Amberley AMO 36.4 on the 24th 33.3 on the 13th in 1946 69 22.6
Archerfield Airport 35.7 on the 24th 32.2 on the 14th in 1946 35 22.4
Brisbane Aero* 33.7 on the 25th 28.7 on the 10th in 1993 61 21.7
Brisbane* 35.4 on the 24th 32.8 on the 14th in 1946 86 21.8
Logan City Water Treatment 34.3 on the 24th 29.2 on the 22nd in 1995  17 22.4
Redcliffe* 33.4 on the 24th        29.0 on the 18th in 1992  22 21.7



Record highest August mean daily maximum temperature
Mean daily maximum
temperature
for August 2009 (°C) 		Previous highest
for August		 Years of
record		 Average for
August
Amberley AMO 26.6 25.5 in 1946 68 22.6
Archerfield Airport 25.5 24.5 in 1946 34 22.4


Record highest August daily minimum temperature
Highest daily minimum
temperature
in August 2009 (°C) 		Previous highest
for August		 Years of
record		 Average for
August
Amberley AMO 19.8 on the 25th 17.1 on the 21st in 1957 69 6.3
Archerfield Airport 18.6 on the 29th 17.3 on the 30th in 1996 35 7.9
Brisbane Aero* 18.7 on the 25th 17.6 on the 26th in 1969 61 10.0
Brisbane* 19.2 on the 29th 17.8 on the 13th in 1950 86 10.3
Logan City Water Treatment 17.8 on the 29th 15.6 on the 16th in 1998  17 9.1
Redcliffe* 20.2 on the 25th            18.3 on the 31st in 2004  22 11.2


Record highest August mean daily minimum temperature
Mean daily minimum
temperature
for August 2009 (°C) 		Previous highest
for August		 Years of
record		 Average for
August
Logan City Water Treatment 12.1 11.8 in 1998 17 9.1


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Summaries

This table is very wide and may not fit if printed.

Summary statistics for August 2009
Maximum temperatures
for August
(°C)		 Minimum temperatures
for August
(°C)		 Rainfall
for August
(millimetres)
Mean for
August
2009		 Diff
from
average		 Highest for
August
2009		 Mean for
August
2009		 Diff
from
average		 Lowest for
August
2009		 Total for
August
2009		 Average
for
August		 Rank of
August
2009		 Fraction of
August
average
Moreton South Coast (district 40)
Amberley AMO 26.6 +3.9 36.4 24th 6.7 +0.4 1.3 9th 6.0 28.5 low 21%
Archerfield Airport 25.5 +3.1 35.7 24th 9.5 +1.5 4.1 1st 4.4 36.8 very low 12%
Brisbane* 25.5 +3.7 35.4 24th 12.1 +1.8 8.2 9th 4.0 35.6 very low 11%
Brisbane Aero* 24.0 +2.4 33.7 25th 11.2 +1.8 7.2 1st 2.0 35.2 low 6%
Logan City Water Treatment 25.5 +3.1 34.3 24th 12.1 +3.0 8.1 9th 7.3 43.6 low 17%
Redcliffe* 23.8 +2.1 33.4 24th 12.7 +1.5 9.1 1st 0.4 39.7 very low 1%

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Notes

This statement has been prepared based on information available at 12 pm on Tuesday 1 September 2009. Some checks have been made on the data, but it is possible that results will change as new information becomes available.

Averages 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.  *In this case, averages from a nearby suitable site have been used instead (these are marked with an *). 

The median is sometimes more representative than the mean of long-term average 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, average in decile 4 to 7, high in decile 8 or 9 and very high is in decile 10).
The Fraction of average shows how much rain has fallen this time as a percentage of the long-term mean.

Further information

Queensland Climate Services Centre
Bureau of Meteorology
Phone (07) 3239 8700
Email climate.qld@bom.gov.au