THE CRUEL September heatwave, which slashed hundreds of thousands of tonnes in grain production through NSW and Queensland in particular culminated with Australia’s hottest September day on record.
The Bureau of Meteorology (BOM) reported September 22 was the hottest day across Australia since national area-averaged temperature records began in 1911.
The figure is reached by averaging maximum temperatures readings recorded at the BOM network of weather stations.
The unseasonable heat saw New South Wales and Queensland had their warmest September days on record, while South Australia, Victoria and the Northern Territory each had days in their top-10 warmest ever for September.
Amazing, the heatwave gripped a massive chunk of the country, with more than 20pc of Australia by area recorded its hottest September day on record during 22–29 September.
BOM officials said the catalyst for the heat was a high pressure system centred over New South Wales which kept much of eastern and northern Australia mostly cloud free, despite some frontal cloud crossing the southern coastline.
With very low rainfall during most of the month, and below-average soil moisture, the sunny days quickly led to rapid heating of the land surface and overlying air in Central Australia, Queensland, and much of New South Wales.
By the 22nd, the high pressure system was located over the northern Tasman Sea, with an associated weak ridge over the southeast maintaining generally clear skies.
On the 23rd, maximum temperatures were more than 16 degrees warmer than average in some parts of the country.
Warm air was drawn along a vigorous surface trough extending from central and northern Australia into southern and eastern parts of the country.
Hot, dry northerly winds ahead of the trough and cold front contributed to New South Wales, southern Queensland, and areas in neighbouring States experiencing unprecedented hot weather for this time of the year.
As the cold front crossed the southeast of the country overnight on the 23rd to 24th, a cool change moderated temperatures in many regions.
A new high pressure system crossed the southeast into the Tasman Sea during the 26th and 27th, with northerly winds and exceptionally high temperatures again returning to much of Queensland, the east of the Northern Territory, and northern New South Wales.