'EXTREME EVENT': 3000km rain bomb to smash Sydney weather records

Sydney’s wettest ever July, a record set in 1950, could be eclipsed in a single weekend with half a metre of rain on the way for the harbour city.

“We’ve got a big upper trough and a very long cloud band that’s extending over a lot of Queensland and northern NSW at the moment,” Joel Pippard, a meteorologist at Weatherzone, told Yahoo News Australia.

“And at the same time, we’ve also got a coastal trough that’s starting to form near the Sydney and Illawarra coasts.”

The double whammy of systems is expected to bring widespread rain across a 3,000 kilometre stretch of Australia's east coast, with Sydney in its target.

People in the rain
More than half a metre of rain is expected to wash over Sydney by Monday midnight. Source: AAP

“Over the coming days, particularly from tomorrow, we’ll start to see those rainfall totals really ramp up quite a lot,” Mr Pippard explained.

“Models suggest widespread falls of 80 to 120mm tomorrow over the Sydney and Illawarra regions, and then a similar total again on Sunday and also on Monday.

“This means that up until Monday midnight we could see pretty widespread falls of 100 to 300mm across that entire region with some isolated falls of greater than 500mm.”

In the Illawarra, the deluge is expected to hit Wollongong, Kiama, Nowra and all the way inland to Kangaroo Valley.

Broad scale rain will extend from Batemans Bay all the way up to the northern suburbs of Sydney and even the Central Coast, as well as out west to Katoomba and the Blue Mountains.

Historic rain records about to be smashed

Mr Pippard warns the “extreme weather event” may tip historic records.

“In Sydney, we’re already having one of our wettest years on record, so this could very likely push us up to potentially breaking the record annual rainfall total which was set in 1950 with 2,194mm for the year.

“So far this year Sydney has had 1,561mm.

Rain forecast map
Sydney could knock over historic rain records this for July. Source: Weatherzone

“[We’re currently] three quarters of the way there, with possibly another 100 to 300mm still to come this weekend.”

The wettest July on record came in 1950 with 336mm, while the wettest day was on July 7, 1931, with 198mm.

Surfers warned of hazardous conditions

While there’s no guarantee, Weatherzone says damaging winds are possible this weekend, but it all depends on the formation of the low pressure system.

“If one of those lows does form and strengthens near the coast, then we could be in for some damaging winds that will most likely affect the coast and then also the elevated areas like the Blue Mountains.”

What is more certain though, are rough conditions at sea.

“Something that is fairly likely regardless is hazardous and then maybe damaging surf as well,” Mr Pippard said.

“So there is a pretty high chance of beach erosion.”

Surfer in the sea
The Weatherzone is warning of hazardous surf conditions this weekend. Source: AAP

Conditions to ease but showers to continue for a fortnight

While the wet weather is set to lighten up from Tuesday, Weatherzone warns another system will sweep in later in the week.

“Definitely by Wednesday we're starting to see that system move offshore,” Mr Pippard said.

“But then we get another cold front coming in, so while it won't be as heavy, we still might have some showers from Wednesday.

“Worst case, Sydney could be in for showers for pretty much the next two weeks.”

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