Extract from ABC News
Unseasonable heat across Australia this winter has resulted in all but one capital experiencing temperatures ranking in the top three warmest on record.
Key points:
- The outgoing winter season broke temperature records this year
- Winter rainfall was drier than normal on the east coast, but wet across the north
- Well above normal temperatures can be expected for the rest of 2023
The greatest deviations were observed through inland Queensland where winter temperatures were as much as three degrees above the long-term average, a substantial figure when averaged across an entire season.
The main source of this winter's warmth was the ever-increasing background influence of climate change along with the absence of cold fronts pushing across south-east states. The lack of these fronts allowed sub-tropical air from the north to lay stagnant over central and eastern Australia for extended periods and cumulated in near record high temperatures near the southern coast this week.
Atmospheric and oceanic patterns surrounding Australia heavily favour a continuation of well above normal temperatures for the remainder of the year.
Winter 2023 breaks records
Hobart and Adelaide registered their warmest winter on record based off the mean temperature (average of all minimums and maximums) with data extending well back into the 1800s.
Hobart's old record was obliterated and the city's regular winter background, a snow-capped Mt Wellington, was noticeably absent through most of the season. The mean temperature this winter of 10.6 degrees Celsius was 2C above average and half a degree above the previous record from 1988.
Adelaide just edged out its previous record from 2009 by 0.2C, recording a mean winter temperature above 13C for the first time.
Both Brisbane and Melbourne came within 0.1C of a new record for mean temperatures, however Brisbane's maximums of 23.5C and Melbourne's minimums of 8.8C were more than two above average and the highest on record.
Sydney and Canberra's winter warmth was second only to the records from 2013. Daytime temperatures in Sydney were particularly high at 19.5C, two and half above the long-term average.
The only capital where winter was cooler than average was Perth.
Snow season one of the worst on record
The absence of prolonged cold weather led to a disappointing winter for the Alps, where the lack of snow caused resorts to operate at limited capacity, and even forced some to close in the middle of peak season.
Lower elevations suffered through a near snowless winter where rain became the dominant precipitation and a snow pack failed to develop. The deepest snow depth at Three Mile Dam near Selwyn Snowfields as measured by Snowy Hydro was just 13.5 centimetres, the lowest in 50 years.
Deep Creek, another Snowy Hydro site, has not had any measurable snow lying on the ground for the past three weeks, a record for August with data back to the late 1950s.
Higher slopes fared slightly better, but still suffered from near record low snowfalls and frequent rain. Spencers Creek and Mt Hotham recorded their lowest peak snow depths since 2006.
Dry winter for east coast
Rainfall was variable across Australia this winter; it was wet across the north and interior and drier than normal near the east coast.
Sydney was particularly dry, receiving just above 100 millimetres, well below the city's winter average of 311mm and the driest in 21 years.
Melbourne's total was just below 100mm and the lowest in 12 years
Brisbane, Canberra and Hobart also received well below average rain this winter.
Spring scorcher close to sure thing
The dice are heavily loaded in favour of a continuation of well above average temperatures this spring, and for most of Australia below average rainfall.
The confidence level of a warm spring is high and it would be no surprise if it ranks as one of the warmest on record. This bold prediction is due to numerous climate drivers occurring concurrently:
- Climate change ensures nearly all seasons are warmer than normal
- A positive Indian Ocean Dipole (IOD) has developed
- El Niño is forming
The likely prevalence of a positive IOD and El Niño also favour below average rainfall for most of Australia this spring, particularly across the interior and the southern coastline.
The only region which the Bureau forecast to have a greater than 50 per cent chance above median rain is a small pocket of the New South Wales coast near Port Macquarie.
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