After a typical run of dry winter weather, especially after we enjoy a balmy 25-degree day today, we will return to wet conditions later tonight, which will continue until next Saturday.

Stephen from the Bureau of Meteorology said there is a little bit of light patchy rain coming through the Northern Rivers tonight.

"There's not much rainfall in it for northeast New South Wales and the Northern Rivers District, maybe just a few millimetres or so.

"Then, on Monday, we start to see a coastal trough develop. That coastal trough will exist right through for much of the week; it's very close to the coast. We are not expecting much rainfall with it on Monday, maybe 5 to 10 millimetres around the Northern Rivers district. But, as the trough deepens a little on Tuesday and Wednesday, we might just see, along that coastal fringe, anywhere between 10 to 30 millimetres.

As the system is coastal, Ballina will see more rain than Lismore.

"For Lismore itself, on Tuesday and Wednesday, we would expect 24-hour totals of 5 to 10 millimetres, whereas, for coastal locations like Ballina, you could expect 24-hour totals on both Tuesday and Wednesday of between 10 and 30 millimetres.

"It's mostly active over the warm East Australian current, so it's mainly just the coastal fringe which looks like being most at risk. There will be some isolated thunderstorms over the water over the coming days. There's a slight chance one of those might find its way to the coast, and we might get isolated falls along the coast fringe of up to about 50 millimetres or so.

Stephen mentioned that the expected falls this week are not expected to reach heavy rainfall thresholds based on the latest model guidance.

The cause of the coastal trough is a high-pressure system approaching Tasmania on Tuesday. By Wednesday, it will be over Tasmania. A low-pressure system is ahead of the high, creating the south-to-southeasterly winds that will be close to the warm water source that the East Australian current provides, thus giving energy to these showers.

 "It could mean varying things for coastal parts of New South Wales, depending on where the low-pressure trough lies.

Unfortunately, the high-pressure system is slow-moving, creating unsettled conditions until Saturday.

"The high stays pretty much near Tasmania, right through to the remainder of the week. So, this activity we will see on Tuesday and Wednesday, there's a chance of it continuing along the coastal fringe for the remainder of the week right through to at least Saturday.

Forecasting the weather more than seven days out is more speculative; however, at this early stage, conditions could also be unsettled.

For now, enjoy the sun while it lasts and take the umbrella to work this week.