Autumn goes AWOL in south as heat records fall - Sydney Morning Herald

Australia's record heat has stretched beyond summer with forecasters wondering when autumn is going to arrive over much of southern Australia.

The Bureau of Meteorology may issue a special climate statement for Tasmania and beyond as mercury in the southern state hovers almost seven degrees above normal for March.

Temperatures in Melbourne on Tuesday exceeded 32 degrees for a ninth consecutive day, smashing the record of seven such days last reached during February 1961.

Even Sydney, which missed out on most of the heat scorching southern regions, is midway through what forecasters expect will be 14 days in a row of 25 degrees or warmer weather - the third-longest on record for March.

''Sydney's been experiencing a long spell without a significant cool change, just like everywhere else,'' said Brett Dutschke, senior meteorologist at Weatherzone.

The harbour city's maximum temperatures will range between 26 and 30 until Saturday, before easing to 24 on Sunday and Monday, the Bureau of Meteorology says.

Dr Dutschke said that warmer-than-normal ocean temperatures and a southerly shift in the jet stream meant there had been little sign of autumn.

''It's probably a few weeks away yet,'' Dr Dutschke said. ''From now, the fronts should start to get a bit more frequent and a bit stronger over the next fortnight but they probably won't get to the strength you'd expect for autumn.''

While the run of warm and dry days and nights owes a lot to a dominant, slow-moving high pressure system over the Tasman Sea, climate scientists say record ocean temperatures are playing a role.

At the end of February, sea-surface temperatures in the Australian region were almost 24 degrees, or about two-thirds of a degree above average. The February reading was also 0.22 degrees higher than the previous record, set only a year ago.

''This summer, temperatures have been really high and it's highlighting the changes,'' said Karl Braganza, head of climate monitoring at the Bureau of Meteorology.

Warm waters in the western Pacific are usually an indication that a La Nina weather pattern is dominant, bringing wetter conditions over much of Australia.

''In fact, we have had consistently high pressure, which has overridden the sea-surface temperature signal,'' Dr Braganza said. ''This is actually a short-term example of the long-term trend - sea-surface temperatures going up but pressure going up as well and being the ultimate driver of lower rainfall, especially in autumn and winter [in southern Australia].''

Weatherzone is owned by Fairfax Media, publisher of this newspaper.