Parts of southern Australia could see their best rain so far this year during the second half of this week.

A northwest cloud band drawing on moisture from the Indian Ocean will cause widespread rain across parts of South Australia, Tasmania, Victoria and southern NSW between Thursday and Saturday.

While northwest cloud bands like this one are typical at this time of year, they have been noticeably absent in recent months, and so has the rain they usually bring.

As of 9am on Wednesday 6th June, a large area of South Australia, northern Victoria, western NSW and southwest Queensland had received less than 20 per cent of its average annual rainfall so far during 2018.

Within this region, a number of places are having their driest start to a year in a decade or more, including Mildura (14 years), Renmark (14 years), Adelaide (13 years) and Ceduna (10 years).

Further north, Deniliquin's 43mm of rain so far during 2018 is its lowest running total to this point in a year since 1967, while Broken Hill's 12mm makes this it driest start to a year in more than a century of records.

The impending northwest cloud band is likely to bring widespread falls of 10-20mm across northern Victoria, southern inland NSW, northern and western Tasmania and the agricultural areas of SA. Some places are likely to see a bit more than this, particularly with thunderstorm activity.

While this rain will most certainly be welcome to parched soils, it won't be enough to entirely make up for the rainfall deficit from the last five months.

There are early signs that another rain-bearing system could sweep over the nation's south and southeast early next week, although it's too early to know how much rain this next system will being, and where.