Australian Monthly Climate Summary: February 2009
Monday 2 March, 2009
February 2009, averaged over Australia as a whole, was slightly above normal for both rainfall and temperature. As in January, there were marked contrasts between northern and southern Australia, with the northern half of the continent again being generally wetter and cooler than normal, and the southern half warm and dry. The month was marked by two extreme events which were only partially reflected in the monthly totals and averages: the heat which affected the south-east in the first week of February, and the severe flooding which affected parts of Queensland during the month.
Maximum temperatures averaged over Australia were 0.14°C above normal (22nd highest on record). They were above normal over most areas south of a Broome-Tennant Creek-Birdsville-Bundaberg line, except for parts of the Pilbara, the south-east of Western Australia, and east Gippsland. The strongest warm anomalies were found in South Australia (7th warmest February on record), where maxima were 2−3°C above normal over most of the state except along the eastern border and on the Eyre Peninsula. Similar anomalies extended to the interior of Western Australia and the southern Northern Territory, as well as to an area on both sides of the Murray River centred around Echuca and Deniliquin.
The extreme heat of the first week of February is described more fully in a Special Climate Statement. Conditions were particularly exceptional in Victoria where most of the state had its hottest day on record on 7 February, including an all-time state record at Hopetoun (48.8°C) and an all-time record at Melbourne (46.4°C). The extreme heat was not as prolonged as that of the last week of January, and near-normal conditions through the remainder of the month meant that monthly anomalies were generally modest.
As in January, maximum temperatures were mostly below normal in the tropics, particularly in the east where they were 2−4°C below normal in a belt extending across Queensland from Charters Towers to Mount Isa, and westwards into the eastern Northern Territory around Brunette Downs. Whilst well below normal, these temperatures were not record-breaking. The mild conditions were particularly notable for their consistency, with a number of north-west Queensland stations not having their first day for 2009 with above-normal maximum temperatures until the final days of February.
Overnight minimum temperatures averaged 0.44°C above normal (16th highest on record). As for maxima, most cool anomalies were in the tropics, although they were both weaker and less extensive, with most of coastal Queensland and the Top End of the Northern Territory slightly above normal, and peak anomalies of 1−3°C below normal in north-western inland Queensland. Most of the southern half of the continent had minima slightly above normal, with anomalies exceeding +1°C largely confined to northern South Australia, southern inland New South Wales, and the interior of Western Australia.
* Anomaly is the difference from the long-term average
Rainfall averaged across Australia was close to normal (3% above normal). Matching the January pattern, most areas which were above normal were in the tropics, with the chief changes from January being the spread of wet conditions into the northern half of New South Wales, and a dry month in most of southern Western Australia.
It was an extremely dry month in Victoria, South Australia and parts of southern inland New South Wales. Many stations away from the coasts had a rainless month (not an unprecedented event in February in most cases), and Victoria and South Australia had their eighth and fourth-driest February on record respectively.
In contrast it was very wet in parts of northern Queensland. Extreme rainfalls were not as widespread in tropical Queensland as they had been in January, but were instead concentrated on the coast between Mackay and Innisfail, and in the state’s far northwest. Both regions had rainfalls widely in the highest decile, with February records set around Townsville and Ingham. The heavy rains led to significant flooding on the coast during the first half of the month, especially in the Ingham area, and a continuation of long-lived flooding in north-western Queensland, both in rivers draining towards the Gulf of Carpentaria and those draining south towards Lake Eyre (which floodwaters began to reach by the end of the month).
Other areas to experience heavy rains in February were the Mid-North Coast region of New South Wales, which was widely in the highest decile, a level also reached locally in the northern inland (especially at Bourke, which had an all-time daily record of 198 mm on 14 February as a result of a single storm). Rainfall also reached the highest decile in the Western Australian Pilbara around Karratha, and locally in the Kimberley and adjacent north-western Northern Territory.