Tuesday, July 2, 2013

Australia posts second hottest start to a year

Peter Hannam Carbon, economy editor   
The Age, July 2, 2013

Australia remains on course to post one of its hottest years on record even as conditions favour above-average rainfall across much of the country, the Bureau of Meteorology said.

In the first six months of 2013, the country's average daily maximum temperature was 1.05 degrees higher than the long-term norm, placing the period behind only 2005 in terms of unusually warm conditions.

While above-average rainfall across much of south-eastern Australia during June kept a lid on maximum daily temperatures for that period, the increased cloud cover meant minimum temperatures were above normal in all states and territories for the month.

High pressure systems - with the warmer conditions they typically bring - have continued to dominate weather patterns over much of central and southern Australia, said Rob Smalley, a climatologist at the weather bureau's National Climate Centre.

Air pressure has "been higher than normal, and that would probably [see] less of the frontal activity bringing the cooler conditions through," Dr Smalley said.

Neutral conditions in the key El Nino Southern Oscillation weather system over the Pacific Ocean suggest that calendar year 2013 is likely to be among Australia's hottest in records going back more than 100 years.

"If Australia were to maintain an anomaly of at least one degree, or a little higher, we'd actually approach or come close to exceeding the previous mean temperature record," Dr Smalley said.

Australia has experienced a series of relative heatwaves moving over much of the continent for the past nine months or so.

As a result, Australia's average maximum temperature for the 12 months to June 30 was the hottest on record, exceeding the previous high set in 2002-03.

The anomaly for 2012-13 is 1.18 degrees compared with the 1.1-degree anomaly for 2002-03, Dr Smalley said.

The bureau's national temperature outlook suggests cooler-than-normal days for the coming three months, with Tasmania and the south-western tip of WA two of the exceptions. Night-time temperatures, though, should continue to track well-above average for much of the country, including most of Victoria, south-eastern NSW and all of Tasmania.

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