Australian Monthly Climate Summary: July 2006
Tuesday 2 August, 2006
For the third successive month, the far west of the country was very dry, accompanied by much warmer than average maxima and cooler than average minima. Apart from some parts of the far east, remaining parts of the continent tended to be wetter than normal, with below average daytime maxima.
Averaged over the country as a whole, mean July maximum and minimum temperatures were both marginally below the median. Maximum temperatures were more than 1°C above average in a band running from southeast Queensland to northeast Victoria, and also in the west of WA. Values were in the top decile across southeast Queensland, inland southern to central NSW, northern Victoria and parts of the west coast of WA.
Maximum temperatures were below the 1961−90 normal over most of both the NT and SA, as well as eastern and northern WA, far north Queensland and far western NSW. A few patches, mainly in the tropics, had anomalies below −1°C, with isolated spots below −2°C. Most of Cape York Peninsula had maximum temperatures in decile 1.
The pattern of minimum temperature anomalies was somewhat different: conditions were mostly cooler than normal west of a line joining the coastal SA/WA border with the coastal NT/Qld border, with generally positive anomalies to the east. Large areas of the north and west more than 1°C cooler than average, with much of northern WA and the north of the NT having minima within the coolest one-tenth of the post−1950 record. A few small patches had record low mean minima.
In contrast, minimum temperatures were more than 1°C higher than the long-term average in a region covering the southern half of Queensland, parts of the southern NT and some of western SA. Similar anomalies occurred in the far southeast of the mainland and the far north of Tasmania. A large area in southeast to central Queensland had anomalies over +2°C, but decile 10 values were mainly confined to a few small patches in the southeast.
* Anomaly is the difference from the long-term average
For the third successive month, a significant fraction of western and/or southern WA had rainfall within the driest one-tenth of the historical record dating from 1900. The area-average for southwest WA was 32% below normal. For the May to July period in southwest WA, the area-average rainfall of 139 mm (−55%) was the driest on record by a very large margin. The second and third driest were 191 mm in 1976 and 206 mm in 1940.
Rainfall in July was also below average over parts of southern SA, in patches of western, southern and northeast Victoria, as well as in parts of Tasmania.
However, across Australia as a whole, July was wetter than normal (+6%) with a rank of 72 out of 107. Totals in decile ranges 8−10 covered most of the NT (+30%), eastern WA, the northern two-thirds of SA (+44%), the western two-thirds of Queensland (+37%) and a large part of western NSW (+18%). Spots of highest on record were observed in eastern WA, the west coast of SA and in Queensland just south of the Gulf of Carpentaria.