Australian Seasonal Climate Summary: Spring 2007
Thursday 6th December, 2007
Spring 2007 was warmer than average over most of the country, particularly the south and west where decile 10 values were widespread for both maxima and minima. Averaged across the nation it was the third warmest spring in the post−1950 era. On the whole, spring rainfall totals tended to be average to below average, with the most anomalously dry areas being in the south. Over the country as a whole, spring rainfall was ranked 46 of 108; marginally in the lower half of the historical record.
Mean maximum temperatures were 1°C or more above normal over much of Australia, except for parts of the northern tropics, most of Queensland, western Tasmania and parts of the southern coastal fringe. Anomalies exceeded +2°C over a large part of southern WA and in a broad zone extending southeastward from northwest SA to northern Victoria and inland NSW. Two patches, one in western Victoria and one in central NSW, had anomalies above +3°C.
Spring maximum temperatures were in the warmest 10% of all years over much of WA, nearly all of SA, NSW and Victoria, all of Tasmania and much of the northern NT. Record high means occurred in parts of northern WA, southern SA, central Victoria and northern Tasmania. Area-averages for the post−1950 era were the highest on record for Tasmania, the second-highest for SA and Victoria, the third-highest for WA and the fourth highest for NSW and the country as a whole.
Negative anomalies, mainly less than 1°C in magnitude, occurred about eastern and northern Queensland, although seasonal means in these areas were mainly ranked in the middle of the historical record.
The pattern of overnight minimum temperature anomalies was less structured than that for the maxima. Positive anomalies dominated south of the tropics, with large parts of southern Queensland, northern SA and western to central WA having anomalies in the +1 to +2°C range. Parts of central and southern NSW as well as eastern Victoria, also had departures in this range. Minima were in the highest 10% of the historical record over large parts of the southern half of the mainland, with record high observations in northeast SA and in an area of southern to central NSW to the northwest of the ACT.
The largest area of negative anomalies occurred in the north of the Northern Territory and adjacent parts of far northern WA, where a few spots had departures in the −1 to −2°C range. However, only a narrow strip near the northern coast had minima in the coolest 30% of the historical record.
* Anomaly is the difference from the long-term average
Large parts of the country had near-average (deciles 4−7) spring rainfall. Those areas that were wetter than normal tended to be in the north, while regions that were drier than normal were more prevalent in the south. Nationally-averaged rainfall was 16% below normal, the 46th driest spring in 108 years of record. Queensland was the only state with an area-average above the 50th percentile (median).
The only significant area with falls in the highest 10% of the historical record was centred around Tambo in Queensland's central highlands. In contrast, some large patches in southern WA and in SA (generally to the northeast of Ceduna) recorded spring totals in the driest 10% of the historical record, as did a few patches in southern NSW, southern Victoria and eastern Tasmania. Below-normal rainfall in the far southeast worsened the multi-year drought in that part of the country.