During the past week, a low pressure system formed in the Southern Ocean to the south-west of Tasmania.
It then moved towards Victoria and remained mostly over Tasmania for a few days before heading across the Tasman Sea last weekend.
It did not bring much rainfall to the Albury-Wodonga region but temperatures fell quite markedly, resulting in snowfalls on Alpine resorts and the first frosts of the season at many rural centres.
Tasmania was swamped by heavy rain, with some violent thunderstorms at many centres, which was most unusual being so late at this time of year.
The first four months this year in Tasmania have been notably warmer than usual ...
Hobart had a deluge of 85.2mm to last Friday morning, May 6. This is Hobart's second wettest May day in 180 years of records. The wettest ever May day was 129.2mm in 2018.
The first four months of this year in Tasmania have been notably warmer than usual, and sea surface temperatures over the past three months notably above normal as well.
The low pressure centre, as it stayed over Tasmania, had developed an occluded front, which caused violent thunderstorms.
Last April in Hobart was the eighth warmest April since 1848.
There was an isolated heavy rainfall in Victoria at Wilsons Promontory, which had a record two-day rainfall for May in 150 years of records, with a total of 102mm.
The previous two-day record was in May 1955, which was a very wet year in the Albury Wodonga region.
Several places in Queensland had heavy rainfalls to 9am on Wednesday, May 11.
Most noteworthy was Charters Towers, which received 123mm, which is the town's wettest ever May day in 140 years of records.
In addition, this month's rainfall total to date has reached 155.8mm.
This is already the wettest ever May recorded at Charters Towers.
The previous wettest May day was 82.8mm in 1977, and the previous wettest May was 138.7mm in 1998.
Bollon received 64.8mm to 9am Thursday, its wettest May day since 71mm in 1919.
Emerald received 63.4mm - its second highest wettest May day behind 2005 in the last 140 years and this town is heading to its wettest April to May since 1989.
Very high dew point temperatures preceded this heavy rain in outback Queensland, up to 22 degrees. Such readings normally occur in February.
Maximum temperatures have continued to be two to three degrees above normal this month and it has been that way since March across the Northern Territory into Queensland.
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