Australia Weather News

Adelaide could receive its most rain in one day in nine years on Sunday, as the Bureau of Meteorology says the downpour is certain to set records in parts of South Australia.

The Bureau of Meterology said between 5 to 10 millimetres of rain had fallen across Adelaide between 6am and 7am on Saturday.

Severe weather warnings are in place for large parts of the state, along with flood watches and warnings in certain areas.

On Friday, Bureau of Meteorology meteorologist Jonathan Fischer said a tropical low that had caused heavy rain in the state's outback was set to move south and collide with a trough sweeping east across the state on Sunday afternoon.

He said this would result in heavy rain and possibly flash flooding.

"We don't just have the risk of nuisance flooding, we have the risk of intense rain and potentially life-threatening flash flooding," he said.

"We will see flooding; just exactly when and where is the question."

The bureau is forecasting totals of 100 millimetres could fall in some parts of the state — more than the 61mm that caused flooding in Adelaide in December 2016 and 75mm in February 2014.

Mr Fischer said it was almost certain multi-day rainfall records would be broken somewhere.

"Even if Adelaide doesn't get hit, other parts ot the state likely will," he said.

The Bureau of Meteorology's Dean Narramore said some areas of the state have not seen rainfall for months.

"It's been a very dry summer," he said.

"Some areas could see a summer's worth of rainfall in just a few days and multiple summers in some areas once we start talking about falls in excessive of 100 millimetres."

Premier Peter Malinauskas urged people to get ready for the downpour.

"There are some simple actions that we would ask South Australian households to turn their minds to if they haven't already," he said on Friday.

"There is still a narrow window, although it is getting tighter for people to turn their minds to basic actions to prepare their homes — clearing their gutters, making sure drains are unblocked so that rain and water can flow as is appropriate."

Both the premier and acting State Emergency Service chief officer Kristy Phelps urged people to be careful in floodwater.

"We have seen reports of people driving through floodwaters as well as kids playing," Ms Phelps said.

"Again, I remind people that it's incredibly dangerous.

"When you approach the floodwater, it's difficult to tell how fast moving it is and there's often a lot of debris and wildlife like snakes."

The SES is providing sandbags at locations both in Adelaide and regional areas.

The rainiest day on record in Adelaide was February 7, 1925, when 141.5mm fell in a 24-hour period.