Australian Monthly Climate Summary: August 2007
Wednesday 5th September, 2007
Although August 2007 was a dry month over large parts of the continent, exceptional rain fell along parts of the east coast. It was also a very warm month in most of southern Australia but a rather cool one in the tropics. Overall, mean temperatures were 0.88°C above the 1961−90 normal (6th warmest of 58 years) and rainfall was 30% below normal (35th driest of 108 years).
Temperatures, particularly daytime maxima, were above normal through most of the southern half of Australia. Most areas south of a line Port Hedland-Alice Springs-Brisbane, except for Tasmania and the southwest of Western Australia, had maxima in the highest decile and at least 1°C above normal. Anomalies exceeding +2°C (locally +3°C) were found in a belt extending from most of western NSW across SA into the southeast of WA, with monthly records set in a few places, notably the NSW north coast and the southern Eyre Peninsula and Kangaroo Island in SA. State-wide maxima were the third-warmest on record for August in Victoria, and the fourth-warmest in South Australia and New South Wales. The last week of the month was especially warm and many records were broken, especially in SA. Adelaide (30.4°C on the 30th) reached 30°C in winter for the first time.
Maxima were generally below normal in the tropics, but not exceptionally so. The largest negative anomalies (−1 to −2°C) were found in the northwest of the NT and the eastern Kimberley in WA, as well as a few patches in northern inland Queensland. No areas were in the lowest decile.
Minima were above normal through most of the four eastern states, except for parts of northwestern Victoria. Warm anomalies were most marked in eastern NSW and southern Queensland, widely exceeding +1°C, and reaching +2°C in the Darling Downs and the central NSW ranges. Most of this area had minima in the highest decile and records were set in the Canberra-Nowra area, around Nyngan and in far east Gippsland. Similarly warm conditions also extended to eastern Victoria and Tasmania, and state-wide means ranked in the top six in NSW, Queensland and Tasmania.
Below-normal minima covered most other parts of the country, apart from the southwest of Western Australia and parts of South Australia. The northwestern part of the continent was particularly cool with anomalies in the −1 to −3°C range widespread in the northern half of WA and the central west of the NT. Only a few areas, however, had minima in the lowest decile, with the largest centred on Halls Creek in the far north of WA.
* Anomaly is the difference from the long-term average
The most significant area of above-normal rainfall covered most of Queensland south of the Tropic of Capricorn (except for the far southwest), as well as north-eastern New South Wales east of a Sydney-Moree line. The most exceptional rains occurred along the coast north of Brisbane, particularly in the Sunshine Coast-Wide Bay region, during the fourth week of the month. The Australian daily rainfall record for August (previously 466 mm) was easily broken, with Rainbow Beach registering 713 mm on 24 August, and there was considerable local flooding. Monthly totals were also the highest on record in this area, whilst falls in the highest decile covered most of the rest of southeast Queensland and the Darling Downs, as well as the coast and adjacent ranges of northern NSW from Newcastle northwards. Rainfall was also in the highest decile in most of the northern NT, but totals were modest (mostly less than 25 mm) in what is normally the driest time of year.
Most of the remainder of the country was drier than normal, except for the southwest of WA (west of a line Perth-Albany) and western and northern Tasmania. South Australia had its tenth driest August on record (69% below normal), and Victoria was 58% below normal. Rainfall was in the lowest decile in most of Victoria north of the Great Dividing Range (as well as around Melbourne), most agricultural areas of SA except the far south-east, and the south-west of NSW. Locally it was the driest August on record, especially in far south-west NSW. Decile 1 rainfalls also occurred across the Gascoyne and Goldfields regions of WA.