Rain relief for Sydney as storms move north, but BoM still forecasts wetter than average winter

Sydneysiders can expect some much-needed relief from the deluge that has swamped the city, as conditions begin to settle from Thursday, but the north of the state may be next in line for a drenching.

Record rainfalls have been hammering the NSW coastline all week, resulting in more than 100 evacuation orders being issued and 23 local government areas being declared natural disaster zones.

Jonathan How, a forecaster at the Bureau of Meteorology, said the focus on Wednesday would be on the Hunter, and then the mid north coast.

On Tuesday the NSW premier, Dominic Perrottet, confirmed that resources were being diverted from Sydney and the Illawarra to the Hunter and north coast.

How warned that Sydney and Illawarra residents should still be wary of further flooding, due to the saturation of the rivers, but there should be no further heavy falls before the weekend.

“This event will start to see conditions really ease off on early Thursday morning, and it should be returned to just kind of coastal showers for now. It is looking like a dry Thursday and Friday, with a couple more showers coming into the weekend," hy het gesê.

Egter, the reprieve will be short-lived with more rain expected, adding to one of the wettest winters in memory across many parts of eastern Australia.

“Looking to the longer term, the climate outlook does still indicate wetter-than-average conditions across eastern Australia,” How said.

“It looks like it might dry out nicely in the next month or so, but then we are expecting a wetter-than-average August to October, met 'n 50% chance of another La Niña forming towards the end of the year.”

How said the driving factor behind much of the wet weather had been the warm sea surface temperatures left over from La Niña. He said as temperatures rose due to climate change, such events would become increasingly common.

Die 2018 State of the Climate report by the CSIRO and the Bureau of Meteorology predicted that for “for heavy rain days, total rainfall is expected to increase by around 7% per degree of warming”. The same report observed that a larger proportion of the total rainfall had been coming from heavy rainfall days, which increases the chance of flooding.

The report also pointed to the extreme variations in Australia’s weather caused by alternating La Niña and El Niño periods.

How said “it’s been a couple of wet years in Sydney and Nieu-Suid-Wallis, but then remember that just three years ago, it was Black Summer.

“So we’re still going to get dry periods and wet periods but these will likely be more intense.”

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