Australian Seasonal Climate Summary: Autumn 2007 (March-May)
Monday 4th June, 2007
Australia experienced a very warm and rather wet autumn in 2007. It was particularly warm in the east of the country, where all four eastern states had their warmest autumn on record. Near-normal conditions in Western Australia prevented the national mean temperature from setting a record, with the national mean anomaly of +1.03°C ranking fifth-highest since 1950.
Record high mean temperatures covered most of the south and east of the country. The statewide anomalies for the season were +1.64°C for Queensland, +1.53°C for New South Wales, +1.33°C for Victoria and +1.19°C for Tasmania, all of which were records, while South Australia’s +1.52°C ranked second.
Daytime maximum temperatures and overnight minima made similar contributions to the very high mean temperatures over the eastern two-thirds of the continent. Over Australia as a whole, maxima were 1.08°C above normal (6th highest on record). They were below normal only over the eastern part of Western Australia and in parts of the northern tropics of Queensland and the Northern Territory. They were at least 1°C above normal over almost all of a region south and east of a line running Townsville-Tennant Creek-Uluru-Port Augusta (including Tasmania), with anomalies reaching +2 to +3°C over most of the southern half of Queensland (except the coastal strip), around Alice Springs, and in scattered patches in inland New South Wales. A few locations in southern inland Queensland were more than 3°C above normal. Record high seasonal values occurred over most of Queensland except for the north and far west, southern and eastern Tasmania, and Victoria away from the north-west. The seasonal mean anomaly set a record in Queensland (+2.02°C) and equalled one in Victoria (+1.52°C).
Overnight minima were also warm in the east and cool in parts of the west, leaving a national anomaly of +0.98°C (8th highest on record). There was a statewide record in South Australia (+1.71°C). Minima were below normal in the southern half of Western Australia (anomalies of −1°C around Perth), but above normal elsewhere. The areas with large positive anomalies were broadly similar to those for maxima, with anomalies exceeding +1°C over most of Victoria, eastern Tasmania, most of South Australia (except the far west), the Northern Territory except for the Top End, and inland New South Wales and Queensland (except the far north). The largest anomalies, in the +2 to +3°C range, occurred in western Queensland, the southern Northern Territory and patches in inland New South Wales, with record highs covering an area centred on the border of Queensland, the NT and SA, extending south as far as the Eyre Peninsula.
* Anomaly is the difference from the long-term average
It was a rather wet season over large parts of the continent, particularly in north-western and central areas. The national mean was 15% above normal (21st highest on record). It was particularly wet in the northern half of WA (which was affected by three tropical cyclones during March) and in most of the NT, with a few areas of record autumn rainfall east of Port Hedland and in Kakadu National Park. Western Australia (74% above normal) had its eighth-wettest autumn on record, and the Northern Territory (+48%) its ninth-wettest. It was also a rather wet season through most of SA, extending into north-western Victoria and the far west of New South Wales.
In contrast, it was another dry season in south-eastern Queensland, with most of the area south of Rockhampton in the lowest decile, continuing the severe drought conditions there, and there was a dry start to the growing season in south-western WA. Over most of the Murray-Darling Basin rainfall was near or slightly below normal, but it continued to be below normal in southern Victoria from the Melbourne area eastwards.