I hope you got most of your outdoor chores done over a beautiful weekend because the change that has been sweeping over the southern parts of NSW will arrive tonight bringing a lot of rain with it.

This is not good news for sport lovers who have had most of their games cancelled due to sodden fields and pitches. The trough is set to affect the Northern Rivers all week and potentially next weekend.

How much are talking in mm?

Jordan Notara from the Bureau of Meteorology says between 30 and 60mm tomorrow with chance of flash flooding due to the amount of rain that recent storms have dumped in our area making the ground already saturated.

"This is a frontal system bringing a more dominant cool change with it," said Jordan, "when you combine this system with the tropical moisture from Queensland you can expect quite a bit of rainfall."

This change will then hang around the Northern Rivers most of the week with rainfall predicted to be 0 to 10mm on Tuesday, 3 to 15mm Wednesday, 6 to 25 on Thursday and 3 to 15mm on Friday.

The reason for the variances is due to the potential thunderstorms that will occur with the change. One part of a suburb may get virtually nothing while the other side could be hit with a 15mm deluge.

Jordan explained that this is a line of intense rainfall with the chance of recurring heavy rainfall for the rest of the week.

A reminder that if flash flooding does occur please do not drive through flood waters.