Australian Monthly Climate Summary: March 2009
Wednesday 1 April, 2009
In marked contrast with January and February, March was a dry month through most of Australia’s northern tropics, while near-normal rainfall returned to much of the south. Daytime temperatures were warm through most of the continent, but not exceptionally so, while overnight minimum temperatures were fairly close to normal.
Daytime maximum temperatures, averaged nationally, were 0.95°C above normal (11th highest on record). The warmth was quite consistent with no state or territory ranking in the top 10, and only a few areas in the highest decile, principally in the Top End of the Northern Territory and scattered patches through the southern NT and south-western Queensland. Maxima were at least 1°C above normal over a large area covering most of the Northern Territory, the southern half of Queensland away from the coast (along with the adjacent north-west of NSW and far north-east of SA) and the north-east quarter of Western Australia, along with parts of eastern NSW. They reached 2−4°C above normal in parts of the southern NT and south-western Queensland. In contrast, maximum temperatures were slightly below normal along much of the coastline between Carnarvon and Melbourne (except near Perth and in central South Australia), as well as in Western Australia and parts of the Queensland coast.
Overnight minimum temperatures were close to normal (0.11°C below). The most substantial anomalies in either direction occurred in the inland tropics, with a band extending from the Queensland Central Highlands through the state’s northwest into the northern Northern Territory (away from the Top End) widely 1−3°C below normal. The Queensland part of this region was mostly in the lowest decile. Elsewhere, large departures from normal were confined to central Australia (1−2°C above normal in the southern NT, far north-eastern SA and south-western Queensland), although parts of eastern Tasmania were locally 1°C above normal, and parts of western WA and the Victorian Wimmera 1°C below.
* Anomaly is the difference from the long-term average
Australian area-averaged rainfall was 56% below normal (13th lowest on record). Rainfall was below normal almost throughout tropical Australia, the only exception being a band extending inland from the coast east of Port Hedland into the east Pilbara, which received heavy rain in the first few days of the month from a tropical low. After 5 March there was no significant rain south of Broome in WA or Katherine in the NT, or west of Richmond in Queensland, and even north and east of these boundaries rainfall was well below average. Many areas were in the lowest decile, including north-western Queensland, much of the northern half of the Northern Territory, and the north Kimberley coast. Queensland (70% below normal, 6th lowest on record) and the Northern Territory (78% below normal, 9th lowest on record) both had their driest March since 1991.
Rainfalls in the lowest decile also covered much of inland south-eastern Queensland extending north to the Central Highlands, and records were set locally in both southern inland Queensland and in parts of the northwest. After having 717 mm for the year up until February 10 (more than 50% above the average for the whole year), Mount Isa had no rain in March, while other locations with a rainless March included Julia Creek, Tennant Creek, Burketown Airport, Brunette Downs and Charleville.
Rainfall was closer to normal in southern Australia, many parts of which had had a very dry start to the year. Nevertheless, except in Tasmania which was mostly slightly wetter than normal (except in the northeast), totals were still on the dry side, with above-average totals only occurring in parts of the WA Wheatbelt, the Northern Rivers region and around Broken Hill in New South Wales, the Nullarbor and western Eyre Peninsula, and patches in south-western Victoria. Totals reached the highest decile on parts of the South Australian Nullarbor coast. While Victoria’s rainfall for March was only 30% below normal, this was still sufficient to give the state its third-driest first quarter on record, after 1965 and 1923.