Massive amounts of rain are set to soak large parts of NSW, southern and central Australia with falls of up to 100mm starting from later today amid warnings of widespread flooding .

The drenching will be "one of the biggest rain events in recent history'' according to The Weather Channel.


Tom Saunders, Senior Meteorologist at The Weather Channel said this morning that the rain will start today over Victoria, South Australia and southern NSW.

"Thunderstorms will drop up to 100mm of rain, enough to cause severe flash flooding,'' he said.

"The rain and storms will head north on Tuesday and stall over NSW and central Australia until at least Friday.

"Daily rain will exceed 50mm in some regions, enough to cause flash flooding.

"With rain continuing through the week, weekly totals should easily climb above 100mm across the Murray Basin, northern South Australia and the southern Northern Territory.

"Canberra and Sydney's wettest days should be Wednesday and Thursday.''

Mr Saunders said the rain also has the potential to trigger widespread river flooding through much of northern South Australia and NSW.

Our nation is currently surrounded by very warm ocean temperatures, particularly off the west coast where the Indian Ocean has been steaming over three degrees higher than normal during the past few months,'' he said.

"The warmer seas have increased evaporation which has allowed the atmosphere over Australia to become saturated with moisture, the perfect recipe for heavy rain and flooding.''