Tomorrow was also expected to be mostly fine, Ms Flynn said, with some potential high cloud about the ranges, and some northerlies with a high of 18C.
A change in the weather would hit the region on Wednesday, as a system which is affecting eastern Australia moves over the country.
Ms Flynn said there would be rain throughout most of the region, which would be heavier around the ranges, with some heavy and possibly thundery falls later. Northerlies would become strong in exposed places. However, the day's high would reach 20C and the overnight low would be only 11C.
About 5mm to 10mm of rain was expected over Wednesday night.
Ms Flynn said Thursday was expected to be "a similar story" with rain across the region and possible thunderstorms about the ranges. The northerlies, which would be strong in exposed places, would ease later.
The week would end with showers and winds turning southwest, with the week's lowest temperature, 3C, expected overnight.