Melbourne Metropolitan Area and Environs in August 2010: A damp August

  • Above average rainfall
  • Cooler daytime temperatures
  • Normal nights

Rainfall

Following a slightly drier than normal July, above average rainfall was recorded across the central district in August. The highest total rainfall in the Melbourne region was 143.2 mm at Ferny Creek (Dunns Hill) compared to the long term August average of 92.3 mm. Cerberus and Coldstream also received over 120 mm of rain this month, almost three times the amount received in July 2010.

In line with the rest of the State, the wettest day in August across the central district was the 12th, due to the passing of a cold front stemming from a significant low pressure system centred in Bass Strait. The passing of this frontal system brought the highest daily rainfall for the month at several locations across the district including 33.4 mm at Ferny Creek and 13.8 mm at the Melbourne Regional Office.

Temperature

Maximum temperature

Maximum temperatures were significantly lower than average this month, affected by the prevailing cloud cover associated with frequent frontal systems restricting daytime temperatures. In fact, Moorabbin Airport observed their lowest August daytime temperatures on average for at least 20 years. Cool days were frequent across the Melbourne region, the coldest of which was the 25th with a chilly 4.9C at Ferny Creek, which also averaged the coolest days this month, just 8.3C.

The passing of frontal systems was interspersed with clear skies and warm days, such as those which occurred on the 9th and 30th, in particular. The warmest day was the 30th, with 18.6C recorded at the Melbourne Regional Office and 18.2C at Avalon Airport. As anticipated, the Melbourne Regional Office was the warmest location in the district with average daytime temperatures of 14.7C, which was below its long-term mean of 15.0C. This highlights the unusual conditions experienced in August 2010.

Minimum temperature

The dominance of high pressure systems observed in past months did not continue into August, with recurrent low pressure systems and their associated cloud bands frequenting the Victorian region throughout the month. As a result, overnight temperatures were very close to normal. The warmest nights on average were recorded at the Melbourne Regional Office (7.6C), but surprisingly Cerberus registered the warmest night of the month on the 15th, a very mild 11.1C.

Most of the central region observed overnight temperatures close to 2C on the coldest nights (7th, 8th and 25th). The coldest of these was the 8th, with an icy -0.6C recorded at Coldstream. A damp Ferny Creek experienced, on average, the coolest days (8.3C) and nights (4.0C) for the month, not to mention the highest rainfall in the Melbourne Metropolitan Area and Environs.

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Extremes in August 2010
Hottest day 18.6 C at Melbourne Regional Office on the 30th
Warmest days on average 14.7 C at Melbourne Regional Office
Coolest days on average 8.3 C at Ferny Creek (Dunns Hill)
Coldest day 4.9 C at Ferny Creek (Dunns Hill) on the 25th
Coldest night -0.6 C at Coldstream on the 8th
Coolest nights on average 4.0 C at Ferny Creek (Dunns Hill)
Warmest nights on average 7.6 C at Melbourne Regional Office
Warmest night 11.1 C at Cerberus on the 15th
Wettest overall 143.2 mm at Ferny Creek (Dunns Hill)
Driest overall 62.8 mm at Melbourne Airport
Wettest day 33.4 mm at Ferny Creek (Dunns Hill) on the 12th
Highest wind gust 94 km/h at Ferny Creek (Dunns Hill) on the 14th

Maps

Anomaly in mean maximum temperature

Map of Anomaly in mean maximum temperature

Anomaly in mean minimum temperature

Map of Anomaly in mean minimum temperature

Rainfall deciles

Map of Rainfall deciles


Lowest August mean daily maximum temperature for at least 20 years
Mean daily maximum
temperature
for August 2010 (C)
Most recent August
this low or lower
Years since
lower
Average for
August
Moorabbin Airport 13.6 13.4 in 1989 20 14.9



Summary statistics for August 2010
Maximum temperatures
for August
(C)
Minimum temperatures
for August
(C)
Rainfall
for August
(millimetres)
Mean for
August
2010
Diff
from
average
Highest for
August
2010
Mean for
August
2010
Diff
from
average
Lowest for
August
2010
Total for
August
2010
Average
for
August
Rank of
August
2010
Fraction of
August
average
East Central (district 86)
Bundoora (Latrobe University) 13.4 -1.5 17.0 30th 6.0 -0.1 2.0 7th 76.6 57.7 high 133%
Cerberus 13.4 -1.3 16.2 30th 6.6 0.0 2.1 18th 119.6 78.5 high 152%
Coldstream 13.1 -1.7 16.4 9th 4.6 +0.3 -0.6 8th 121.8 68.9 v high 177%
Cranbourne Botanic Gardens 13.4 -1.1 16.9 30th     2.5 7th 66.9 78.5 average 85%
Essendon Airport 13.5 -0.8 16.8 30th 5.9 +0.4 2.2 7th 65.0 49.3 high 132%
Ferny Creek (Dunns Hill) 8.3 -2.1 12.5 9th 4.0 -1.2 0.3 25th 143.2 89.1 high 161%
Melbourne Airport 13.4 -1.0 16.8 30th 5.5 -0.4 1.8 25th 62.8 46.9 high 134%
Melbourne Regional Office 14.7 -0.3 18.6 30th 7.6 +0.9 4.2 25th 63.0 50.2 high 125%
Moorabbin Airport 13.6 -1.3 17.2 30th 6.7 -0.1 3.7 8th 83.2 66.9 high 124%
Scoresby Research Institute 13.2 -1.0 16.5 9th 6.2 -0.1 2.2 7th 89.4 81.0 average 110%
Viewbank (ARPANSA) 13.6 -1.7 16.9 30th 6.1 -0.1 2.4 7th 84.0 59.5 high 141%
West Central (district 87)
Avalon Airport 14.1 -1.4 18.2 30th 5.4 -0.1 1.5 7th 65.0 44.9 high 145%
Laverton RAAF 13.9 -1.0 17.6 30th 5.9 +0.4 2.3 10th 63.6 45.3 high 140%

Notes

A Monthly Climate Summary is prepared to list the main features of the weather in Melbourne Metropolitan Area and Environs using the most timely and accurate information available on the date of publication; it will generally not be updated. Later information, including data that has had greater opportunity for quality control, will be presented in the Monthly Weather Review, usually published in the fourth week of the month.

This statement has been prepared based on information available at 11 am on Wednesday 1 September 2010. 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.
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

Media
(03) 9669 4057
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