Most areas bounded by Lightning Ridge down to Condobolin then east to Bathurst and north to the border can expect 10-25mm through Wednesday into Thursday.

A number of weather systems are combining for the falls, that are likely to come via stormy events. A trough over central NSW will be fed by moist air flowing in from the Tasman Sea, with another trough just off the coast, coupled with upper air instability. Also later on Thursday a low is likely to form off the central NSW coast bringing heavier falls to the Newcastle, and Central Coast areas of between 40-70mm.

Weatherzone forecaster Joel Pippard said he expected falls in the North-West Slopes, Central-West Slopes, Central Tablelands and Northern Tablelands to average around 10-25 mm on Wednesday. The rain would come mainly in storm events and so could be hit and miss in some districts, he said.

It was possible some falls could be up towards 50mm in these areas, he said.

The system will move into the Northern Tablelands, then the Northern Rivers and Mid-North Coast trough Thursday.

The rain will be helpful with many farmers saying they just needed "another inch" of rain to get paddocks ready for winter crops as the 'Anzac Day' planting timeline looms. It will also help forage crops already planted on the back of the good falls a few weeks ago.