A multi-day midwinter heavy rainfall event is looking increasingly likely for the North Coast of New South Wales and immediately adjacent areas, including just over the Queensland border.

According to Weatherzone meteorologist Joel Pippard, four-day totals of 100-200mm are expected from Thursday through to next Monday, with isolated totals around 250mm, along a strip of coastline stretching roughly from Coffs Harbour to the Gold Coast.

Falls should be heaviest along the northernmost reaches of the NSW coastline as the event kicks off on Thursday, with 24-hour totals of 60-120mm expected in the area around Lismore and Grafton from Thursday afternoon to Friday morning.

Equally heavy totals could be recorded on Sunday around Coffs Harbour and the nearby Dorrigo Plateau.

What will cause the heavy rain?

The first ingredient for this impending spell of wet weather is a flow of moist air pushing onshore from the Tasman Sea, circulating around a high which will be centred over inland parts of southeastern Australia.

The available moisture will be enhanced by sea surface temperatures in the Tasman Sea which are around 1°C higher than usual for this time of year away from the immediate coastal strip. 

According to Joel Pippard, a coastal trough supported by an upper trough and offshore low will then develop from Thursday. This set-up will fuel the heavy rainfall over the Northern Rivers and the northern part of the Mid North Coast.

Flood risk enhanced by high tides

Image: Predicted 7-day total precipitation for the NSW North Coast and nearby areas up until July 21, 2026, according to the ECMWF model. Source: Weatherzone.

“Significant wave heights of 3.5-4.0 metres are expected along the northern coast of NSW,” Joel Pippard says.

“Tides will also be elevated, and since Thursday is the Highest Astronomical Tide (HAT or Spring Tide) of the year, high tide will still be quite high by the weekend, and contribute to the potential flood risk in tidal parts of rivers.”

Please check the Weatherzone warnings page for the latest weather and flood warnings and the NSW SES for up-to-date flood information.

Image: Predicted mean sea level pressure and precipitable water for SE Australia on Thursday, July 16, 2026. Source: Weatherzone.

Will the heavy rain reach Sydney or Brisbane?

The most severe weather from this system is expected to occur along the sections of NSW coastline and adjacent ranges already mentioned.

While the Gold Coast could see heavy rainfall with potential flooding, Brisbane is only expecting showers from Thursday through to Monday, with no persistent heavy rainfall forecast.

Like Brisbane, Sydney can expect a showery spell lasting four or five days, however it should also miss the heaviest rain in what is expected to be a fairly localised intense weather event.

Image: 28-day rainfall calendar for Coffs Harbour, NSW, on the Weatherzone app.