Sydney is in line for three days of heavy showers while the rain is set to continue in the soggy state of Queensland.
Forecasters are warning of a triple threat to the harbour city, which is experiencing its wettest start to the year since records began 164 years ago.
“We’ve got a near stationary low pressure trough just offshore, we’ve got fairly cold air in the upper atmosphere, and we’ve got relatively moist winds blowing off the water,” Weatherzone Senior Meteorologist Brett Dutschke told Yahoo News Australia.
“The combination of those three factors is giving us frequent showers, occasionally heavy.”
The eastern suburbs are set to cop the brunt of the weather system with 20 to 50 millimetres predicted to fall before the end of Wednesday, while the rain is likely to ease off in the west.
“The further west you go in Sydney, the longer the dry breaks will be, and the showers won’t be as heavy,” Mr Dutschke said.
Across the city, Sydneysiders aren’t expected to see a dry day until Thursday or Friday.
“It is pretty normal for this time of year, it is just this time the rain is falling on pretty saturated grounds,” Mr Dutschke said, “so it is not taking much rain to waterlog the ground and for the water to just accumulate on the ground.”
Rolling rain record in Sydney
It’s been nearly three months since Sydney broke historic weather records, surpassing the 1890 record for the dampest start to a year.
So far, the city has received 1,450 millimetres of rain, way in excess of the average of 603.
“The previous record to this date was 1,260 millimetres in 1890, so we’re almost 200 millimetres on top of that.”
It is the most rain ever recorded in Sydney since records began in 1858.
A very wet east coast braces for more rain
While showers will pummel the NSW capital this week, much of the state’s coast is in for a drenching until Thursday.
It will be the wettest on the north coast, with Queensland also set for more rain, especially on the state's south coast.
The state has already suffered through weeks of downpours, inundating many areas and cutting off residents.
“While it is generally drying out over the inland of Queensland, and flooding is generally easing, showers can be expected each day about the south coast of the state through to about Wednesday or Thursday,” Mr Dutschke said.
“A good stretch of the Queensland coast will see showers until at least through to the middle of the week, but it will last a bit longer on the north coast.”
Brisbane is set to receive 15-40 millimetres before Thursday.
Flood warnings issued for south-east Queensland
With a weekend of wet weather, Queensland's south-east is back on flood watch.
The Sunshine Coast's Maroochydore recorded 122 millimetres in the 24 hours to 9am on Sunday, while nearby Mooloolaba saw 122mm.
The Bureau of Meteorology has issued more than a dozen flood warnings across the region.
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