An urgent flood alert and severe thunderstorm warning has been issued to residents of Goulburn.
The Bureau of Meteorology (BOM) this afternoon warned wild weather may hit overnight and carry through until the end of the week.
There is an 85 per cent chance of the Wollondilly River reaching its peak on Wednesday, causing minor to moderate flooding, the Bureau says.
The SES and Goulburn Mulwaree council are currently in talks to develop a disaster management plan.
It is predicted that a large rain band will move into New South Wales tomorrow night bringing with it large hailstones, damaging winds and strong rainfall.
A spokesperson from the BOM says the storm cell will stall over central parts of the state including Goulburn.
The southern half of the state is predicted to be hit the hardest, with Goulburn to experience the heaviest amount of rain.
“This flood watch means that people living or working along rivers and streams must monitor the latest weather forecasts and warnings and be ready to move to higher ground should flooding develop,” the spokesperson said.
"Goulburn has been placed on flood watch, not flood alert, this means that the river has not yet exceeded its peak but with a great likelihood it may.
“Flood Warnings will be issued if Minor Flood Level is expected to be exceeded at key sites along the main rivers for which the Bureau of Meteorology provides a flood warning service."
Areas set to be effected by the wild weather include;
1. Nepean Hawkesbury - minor to moderate flooding possibly resulting in closure of the Richmond and Windsor bridges during Thursday and Friday.
Heaviest rain is expected in the Wollondilly River catchment which will also affect Goulburn.
2. Queanbeyan Molonglo - moderate to major flooding.
3. Murrumbidgee - minor to moderate flooding. Cooma is likely to have major flooding. Cootamundra Shire may also experience moderate to major flooding.
4. Lachlan - including Mandagery Creek and the Belubula River - minor to moderate flooding.
5. Macquarie - Molong, Orange and the Bell River catchment - minor to moderate flooding.
6. Shoalhaven - minor to moderate flooding
7. South coast - including Bega and Moruya valleys - minor flooding.
Local flooding is also expected in the Lower Western district of the state south of Tibooburra, White Cliffs and Cobar during Tuesday and Wednesday. Severe Weather Warnings will be issued for these areas as the event unfolds.
Across NSW, about 75% of Flood Watches are followed by flooding.
FloodSafe advice is available at www.ses.nsw.gov.au
For emergency assistance call the SES on telephone number 132 500.
For life threatening emergencies, call 000 immediately.
The weather warning can be viewed directly at; www.bom.gov.au