As the coastal crossing of Tropical Cyclone Alfred becomes clearer, the potential rainfall for Lismore and the Northern Rivers increases.

Jonathon How, Meteorologist with the Bureau of Meteorology said Alfred is likely to make landfall somewhere between Brisbane and the Sunshine Coast late Thursday or early Friday.

"We are expecting to see the most significant impacts, on the southern flank of the cyclone. So that does include places like Brisbane, the Gold Coast and also the Northern Rivers."

In terms of numbers, Lismore is now looking at ranges of rainfall of 15-70mm tomorrow (Wednesday), 15-100mm Thursday, 20-130mm Friday and 20-110mm on Saturday.

The rainfall is forecast to decrease on Sunday.

There is a Tropical Cyclone Watch for the Northern Rivers.

"We can expect to see gale force winds developing within the next 24 to 48 hours. In addition to this, we also do have a flood watch, and that covers large parts of South East Queensland and also North East New South Wales," Jonathon How said this morning.

"So, with the rainfall we're expecting and fairly wet catchments and wet soils, we can expect to see widespread, moderate to major flooding, particularly for New South Wales, but also South East Queensland. This includes quite a few major rivers through major population centers with rainfall totals expected to exceed 200 to 400 millimeters across a wider area from later this week, as tropical cyclone Alfred makes landfall, there are also a number of coastal hazard warnings current.

"They extend all the way from Gary Fraser Island and down towards the northern parts of New South Wales. So we do have marine wind warnings for strong to gale force winds. They'll increase the storm force winds for some parts of the coastline from tomorrow. In addition to that, we still do have those very powerful easterly waves coming through, combining with high tides, and that's causing quite significant and severe coastal erosion and causing a lot of those beaches to be eaten away.

Alfred is currently moving slowly in a south-to-southeast direction about six kilometres per hour, and is expected to slow even further and then make its turn west, back towards the Queensland coast later today.

"Into Wednesday, that's when we'll start to see the areas of rain and wind becoming more widespread and more severe. So on Wednesday, we are expecting to see a significant increase in rain, particularly heavy rainfall, and those very strong to damaging winds developing about coastal areas, and then into Thursday, that's when we'll start to see Tropical Cyclone Alfred move even closer to the coast. Rain will increase. It will see heavy to intense rainfall, as well as flash flooding and the possibility of riverine flooding developing later on Thursday.

"As the system gets even closer, damaging to destructive winds may cause damage to property and trees. And importantly, these damaging to destructive winds will be sustained over quite a long period of time, and so that will mean that we could see quite significant damage to properties and also trees, and then into Friday, as it does make landfall, we can expect to see quite widespread and dangerous flash flooding developed, in addition to those very strong winds moving on to the coast.

"Overall, for today, we are expecting to see those coastal hazards continue, rainy showers along the coast, as well as those large waves. And then for Wednesday, we'll continue. We'll see a significant ramping up in rain and winds really peaking on Thursday to Friday as tropical cyclone Alfred makes landfall."

You can stay up to date through the Bureau of Meteorology through the Lismore App Weather, Weather Radar or download the Hards Near Me app.

The NSW SES will have a further update at 12:30pm today.