The entire region has a near 100 per cent chance of rain on Friday, as well as possible thunderstorms.

The first of the rains arrived in western parts of the Riverina on Thursday night, with reports of 49mm falling at Hay and 34mm at Hillston to 8am Friday.

“This pattern is drawing a humid tropical airmass into New South Wales, and is resulting in unsettled and wet conditions across much of the state,” the Bureau of Meteorology outlined in a weather situation report on Friday.

“Rainy or showery conditions will generally shift to the east today and Saturday as the trough slowly moves east. Thunderstorms are a risk for some parts of the state.

“By late Saturday or early Sunday conditions are expected to ease as the trough moves away to the east, although a shower or thunderstorm may persist in the northeast with a trough lingering there.”