Australian Monthly Climate Summary: March 2007
Tuesday 5th April, 2007
March was a wet month through much of western and central Australia, especially in Western Australia where numerous records were set. Despite dry conditions in Queensland, the rain in other areas was enough to make it the 10th wettest March on record. Overnight minimum temperatures were generally above normal, but maxima were below normal in many of the wettest areas due to heavy cloud cover.
Maximum temperatures over Australia were 0.17°C above normal (28th warmest), with temperatures generally above normal in the eastern half of Australia and along the west coast, whilst they were below normal in the wetter areas of northern and central Western Australia and the Northern Territory. Queensland had its third warmest maxima on record for March and Western Australia its eighth coolest.
In Western Australia, most of the northern and eastern parts of the state were 2−4°C below normal, with record lows in the West Kimberley around Broome and Derby. In marked contrast, the west coast south of Onslow was rather warm, with anomalies generally in the 1−2°C range, and exceeding 2°C in the Shark Bay area. The first week of the month was particularly hot in this area and Carnarvon equalled the Australian record for March when it reached 47.8°C on the 6th.
The strongest warm anomalies were in the southern half of Queensland, with most areas (except the immediate coastal strip) 2−4°C above normal, although few records were broken. It was also rather warm (1−2°C above normal) in much of New South Wales except the far southwest and southeast, and central Victoria.
Minimum temperatures were above normal through most of the country and the national mean anomaly of +0.88°C was the eighth highest on record. In Queensland the statewide average was the highest on record. Anomalies were generally 2−3°C in the southwest and 1−2°C over most of the rest of the state except the far north, and records were broken in the southwest, the Central Highlands and the coast around Mackay. Anomalies exceeding 2°C also extended into north-western New South Wales (as well as a strip extending south to Canberra), north-eastern South Australia and the southern Northern Territory. The only significant areas of below-normal minima were in the southern half of Western Australia, particularly in the western Goldfields and inland Gascoyne where anomalies were generally around −1°C.
* Anomaly is the difference from the long-term average
Averaged over Australia rainfall was 45% above normal.
It was particularly wet in Western Australia (158% above normal, 4th highest on record), due largely to the influence of three tropical cyclones (George, Jacob and Kara). Whilst only George (provisionally a category 4 at landfall) caused severe wind damage, all three cyclones brought heavy rains to the Pilbara region, especially areas near and inland from Port Hedland which had their wettest March on record. Most of the north and east of Western Australia had very much above average rainfall (top 10% of all years). This wet area extended in a strip across South Australia as far east as the Mid-North around Clare. Rainfall was near to below normal in climatologically dry areas of south-western Western Australia, with some parts of the eastern Wheatbelt and Gascoyne regions receiving no rain.
Another wet area was the Top End of the Northern Territory, with some areas receiving record monthly rainfall, much of it as a result of very heavy rain which commenced at the end of February as a result of the tropical low which developed into TC George. Oenpelli, east of Darwin, received 827 mm in four days from 27 February – 2 March, whilst Darwin exceeded 100 mm on each of three successive days from 3−5 March, the first time this has happened. The Northern Territory as a whole was 67% above normal (9th wettest on record)and South Australia 61% above.
It was rather dry in most of Queensland (31% below normal), although only in a few patches, mostly in central Queensland, was it dry enough to fall within the lowest decile.
In the south-east, including Tasmania, rainfall was mostly fairly close to normal (New South Wales 17% below, Victoria 10% below), although there were heavy rains in the Victorian mountains late in the month, giving them their first month of above-normal rainfall since late 2005.
This continues a general pattern of a return to normal- to above-normal rains in early 2007 after the severe southern Australian drought of 2006, with all states except New South Wales above normal for the January-March period.