Heavy rain and potentially severe thunderstorms will hit parts of eastern NSW and southeast QLD on the Queen’s memorial public holiday this Thursday.

September 22 will be a one-off public holiday as a National Day of Mourning for Australia following the death of Queen Elizabeth II.

Unfortunately, for those spending Thursday's public holiday in northeast NSW and southeast QLD, there will be a threat of flooding rain and severe thunderstorms.

The sequence of satellite images below shows a thick band of cloud passing over eastern Australia during the last 48 hours ahead of a well-defined upper-level low pressure system.

The video above shows that this dynamic weather setup caused frequent thunderstorms across central and eastern Australia on Tuesday and Wednesday.

As the system moves further east on Thursday, dangerous storms and heavy rain will also spread over parts of northeast NSW and southeast QLD.

An area of persistently heavy rain and embedded thunderstorms will develop over northeast NSW on Thursday into Friday morning as a low pressure system forms near the coast.

Some areas in the Mid North Coast could see 100 to 200 mm of rain within 24 hours from this system, which has prompted a severe weather warning for flash flooding and a flood watch for riverine flooding.

The image below shows how much rain one computer model is predicting during the 48 hours ending at 10 am on Friday.

Image: Forecast accumulated rain during the 48 hours ending at 10am AEST on Friday, September 23, according to the ECMWF-HRES model.

In addition to this heavy rain, potentially severe thunderstorms are also likely to develop over northeast NSW and southeast QLD on Thursday. These dangerous storms are possible along the coast and adjacent inland from the Mid North Coast in NSW up to Queensland’s Capricornia district.

Numerous flood warnings also remain in place over inland districts of NSW, Qld and Vic in response to recent rain.

Be sure to check the latest severe weather and thunderstorm warnings this public holiday Thursday if you live in northeast NSW or southeast QLD.