Saturday has been called “danger day” across much of New South Wales as a punishing rain deluge approaches major cities.
A 400km stretch of the NSW coast – which encompasses the cities of Sydney, Newcastle and Wollongong – is the subject of a severe weather warning from the Bureau of Meteorology (BOM) for heavy rainfall and possible flash flooding.
The NSW Government has said it is “highly likely” Sydney’s main dam will overflow this weekend, which could lead to flooding in the city’s west.
It comes as Melbourne was hit with half a month’s rain in less than an hour on Friday. The SES received 600 emergency calls.
In the east and south, if you don’t get hit by rain this weekend you’ll probably feel the falling temperatures or gale force winds.
“The rain and storms re-intensifies again on Saturday morning and then runs out into the east of the state into the afternoon and evening,” said Sky News Weather meteorologist Rob Sharpe.
“Through Saturday night the low pressure system will form and move off the coast and cause windy weather to take shape.
“That will also help to take the rain away from the coastline so that by the end of Sunday, it’s all going to be done,” he said.
“But until then there’s still a fair bit of rain across those regions, with totals still possibly as high as about 80 or 90mm for isolated pockets.”
Dams set to overflow
NSW Emergency Services Minister Steph Cooke said it wouldn’t take much to cause flooding.
All the rain – added to that which has already fallen – meant Saturday was the “danger day” for the state.
“Our catchments are saturated, our dams are full, and our rivers are already swollen,” she said.
Water NSW has warned the huge Warragamba Dam could see more overflow this weekend as it reaches capacity.
It flows into the Hawkesbury and Nepean rivers that pass several western Sydney suburbs.
Currently 15 gigalitres is being let out daily, but on Sunday afternoon that could go up to 275 gigalitres.
“Based on the BOM forecast as it stands, these dams have a high likelihood of spilling to some extent,” said Tony Webber from Water NSW, reported ABC News.
The more water that can be kept behind the dam wall, the less the risk of flooding downstream.
Four other dams inland, which lead to rivers that flow through towns such as Moree, Gunnedah and Forbes, are also close to full.
NSW Police has warned that the chief cause of death during heavy rain events is motorists driving over flooded roads and being swept away.
400km long warning areas – including Sydney
On Friday, Sydney saw a relative lull in the rain. After almost 100mm fell on Thursday, just over 5mm was measured in the gauge the day after.
It’s a different story on Saturday however with 50-60mm forecast and a top up of around 15mm on Sunday morning.
Thunderstorms are possible on Saturday afternoon and evening which could lead to heavy rain over a short period – a recipe for flash flooding.
Temperatures will drop from a high of 23C on Saturday to 17C on Sunday and a low of 12C.
The BOM’s weather warning covers an areas of 400km from Newcastle to the south coast.
It states that heavy rainfall could lead to flooding in the Central Tablelands, Hunter and Sydney areas. There could also be damaging winds of up to 90 km/from Newcastle all the way south to Ulladulla as the system moves out to sea late on Saturday and into Sunday.
Bathurst to be soaked
Inland, Dubbo could see 45mm on Saturday and Mount Panorama up to 50mm during the Bathurst 1000.
Already drenched Bourke could pick up another 10-20mm on Saturday while Inverell is forecast to see 35-65mm of rain over the weekend. For Coffs Harbour anything from 25-40mm could come down, with Sunday the wettest.
The rain will be light in Canberra with up to 15mm on Saturday and then 5-10mm on Sunday. Temperatures will drop to a maximum of 15C on Sunday and bottom out at 5C.
Brisbane will be dry on Saturday with a high of 26C. But showers and up to 8mm of rain are possible on Sunday.
Melbourne’s half a month’s rain in minutes
Parts of Melbourne saw 30mm of rain in little more than 20 minutes on Friday.
“In Melbourne city itself we saw around half the October average falling in just an hour,” BOM senior meteorologist Michael Efron said.
Things will settle down for Melbourne on the weekend. A shower of not much consequence is possible on Saturday and then it’s dry at least until midweek.
There are highs this weekend of 15C, which is 5C below normal with minimums in the mid-single digits.
It’s mostly dry in Hobart with highs of 14-15C but a chilly 4C low on Sunday morning. Saturday could see snow falling on Kunanyi/Mount Wellington, as low as 700 metres.
It’s a dry and partly sunny weekend in Adelaide with mid teen highs and a low of 6C on Sunday.
Meanwhile it will be bright and 23C in Perth for Saturday with not a spot of rain. Similar on Sunday with some cloud.
Storms are forecast fore Darwin with around 10mm of rain most days with the mercury reaching the mid-thirties.