"We've got an inland trough... so we're getting a lot of monsoon activity moisture driven further south around New South Wales (NSW) State and southeastern Australia," Bureau of Meteorology Forecaster Abrar Shabren told Xinhua news agency.
"The usual weather pattern that we have at this time of the year, that is what's triggering these inland troughs which are developing moisture, forming convective clouds, and that's why we're seeing a lot of thunderstorm activity."
Still locked in the gruelling battle against Australia's worst-ever bushfire crisis, the NSW Rural Fire Service (RFS) took to social media on Friday morning to share their elation.
"Rain has fallen across most fire grounds over the last 24 hours which is great news! Our fingers are crossed that this continues over the coming days," the RFS said.
But, while authorities and fire-affected communities have collectively breathed a sigh of relief, the downpour is not expected to fully neutralize the bushfire threat.
Despite heavy rain and even flash flooding in some areas, there are currently 82 bushfires still blazing throughout NSW, with a further 17 raging across the border in the state of Victoria.
"This rainfall will bring some relief to the firefighting efforts on the fire grounds but the rainfall is quite isolated at the moment though, around NSW, the Australian Capital Territory and parts of Victoria," Shabren explained.
"There's so many fires going on. We need a lot more rainfall in the coming days to extinguish or even or suspend those fires."
Likewise, it will also take much more rain to break the east coast's severe drought, which is now the worst on record, bringing heartbreak and uncertainty to the region's agricultural communities.
The bushfires have so far claimed the lives of 28 people and billions of animals since it first erupted last September.
The fires have also destroyed more than 80,000 sq.km, an area larger than Ireland or Panama, charring more than 2,000 houses.
( With inputs from IANS )