New Year's Day 2024 brings a severe weather warning from the Bureau of Meteorology for Lismore and the Northern Rivers with a Flood Watch still in place for Monday. This will be updated at 1pm by The Bureau.

The high-pressure system moving into the Tasman Sea is directing persistent and very humid east-to-sheasterly winds across northeastern parts of New South Wales. Persistent showers and thunderstorms with heavy rainfall, further supported by an upper trough to the west, are expected to continue during today (Monday).

HEAVY RAINFALL which may load to FLASH FLOODING is forecast for the Northern Rivers and Northern Tablelands districts during Monday. Three to six-hourly rainfall totals between 80 and 160 mm are possible, with isolated 24-hourly totals exceeding 250 mm possible.

The heaviest rainfall will be associated with shower and thunderstorm activity, which is likely to be somewhat hit-and-miss in nature across the warning area, though more likely about the ranges. These conditions are expected to ease during Tuesday.

Localised intense rainfall is possible under areas of persistent heavy thunderstorms. Separate severe thunderstorm warnings may be issued to highlight areas of intense falls if they are expected.

Locations which may be affected include Lismore, Tweed Heads, Murwillumbah, Byron Bay, Casino and Kyogle.

Significant 24 hour rainfall to 9am:

307 mm at Limpinwood (west of Murwillumbah)

297 mm at Numinbah (northwest of Murwillumbah)

A Flood Watch is still in place for the Wilsons and Richmond Rivers. This will be updated by The Bureau at 1pm.

While little rain has fallen in Lismore (airport) since 9am (0.2mm and 65.6mm to 9am), the flood watch is dependent on the amount of rain in the upper catchments in the Nightcap National Park and at the top of the Wilsons River catchment around Goonengerry and Rosebank that flow into Leycester Creek and Wilsons River respectively.

The majority of rainfall at this stage has fallen on the far north coast.

(The Bureau's weather radar at 12pm Monday January 1)

Due to the significant rainfall in the Tweed catchment area, Tumbulgum has a moderate flood warning and Murwillumbah has a minor flood warning for this afternoon. The Tweed also has a moderate flood warning.

The State Emergency Service advises that people should:

* Don't drive, ride or walk through flood water.

* Keep clear of creeks and storm drains.

* If you are trapped by flash flooding, seek refuge in the highest available place and ring 000 if you need rescue.

* Be aware that run-off from rainfall in fire affected areas may behave differently and be more rapid. It may also contain debris such as ash, soil, trees and rocks.

* After bushfires, heavy rain and the loss of foliage can make the ground soft and heavy, leading to a greater chance of landslides.

* Stay vigilant and monitor conditions. Note that the landscape may have changed following bushfires.

* For emergency help in floods and storms, ring your local SES Unit on 132 500.

The next Severe Weather Warning will be issued by 5:00 pm AEDT Monday.

You can keep up to date with the Bureau of Meteorology warnings and radar via the Lismore App Weather & Travel.