The timing of this rain will help many farmers sowing crops.

According to WeatherZone data, southern parts, including all agricultural areas can expect widespread falls of 10 to 20 millimetres with 20 to 40mm likely across the peninsulas.

This widespread rain event is evolving in Western Australia where moisture from the Indian Ocean is linking up with a developing trough.

This sort of moisture has been missing for many months and it will get tapped into by a significant cold front to bring heavy falls to SA.

Rain will be spread over three-or-four days with the wettest period being Thursday and Thursday night.

However, the rain will be accompanied by strong winds and thunderstorms which will prompt the issue of many warnings.

Winds will become cold on the weekend as a second front crosses the region. Showers will clear early next week.

Parts of the state are having one of their driest starts to the year on record with barely a drop falling over the Riverland and parts of the Murray Mallee.

This is the first time in 95 years that Karoonda has not gained at least 10mm by April 20.