The NSW State Emergency Service (SES) is urging people to prepare their homes and not drive through flood waters should flash flooding occur during forecast heavy rain and damaging winds this week.
Unsettled weather with showers and thunderstorms is expected to continue through the week. Isolated severe thunderstorms are possible today which will present a risk of damaging wind gusts and large hail along the central and northern ranges, and some adjacent coastal areas including western parts of Sydney.
Today's storms may also generate locally heavy rain in Alpine areas and locally heavy rain and damaging wind gusts in the far west. Thunderstorm activity will escalate on Tuesday with thunderstorms possible in all areas except the southern coast.
The main risk associated with these storms will be localised heavy falls, large hail, and damaging wind gusts. An area of severe storms in the west may also see giant hail and destructive winds. Storms will persist throughout Tuesday night, and into Wednesday. A low pressure system will deepen on Tuesday with storm activity increasing, especially across southern and central inland areas.
On Wednesday localised heavy rainfall totals of over 200mm on the south coast are a possibility. Localities around Moruya will be the main area of concern. The remainder of the south east may see widespread totals of 20 - 40mm.
NSW SES has personnel and assets prepositioned to respond in the South Eastern Zone, where the weather is expected to impact the most.
NSW SES Senior Manager of State Operations, Chief Superintendent Dallas Burnes said additional resources had been deployed ahead of the expected weather, including flood rescue technicians, aviation assets and high clearance vehicles.
"It's important people prepare, by doing simple tasks around their home to minimise the impact of storms," Chief Superintendent Burnes said.
"Trimming trees around your property, securing loose items in your yards, moving your cars under cover and cleaning your gutters will help minimise the impacts of strong winds and significant rain."
On the south coast, the Moruya and Deua river catchments could see moderate to major flooding from Wednesday, and people are being urged not to take a risk and drive through flooded areas.
River rises are also expected, with flooding possible at: Tuross River, Bega River, Peel River, Namoi River, Castlereagh River, Macquarie River to Bathurst, Orange, Molong and Bell River, Turon and Macquarie Rivers to Burrendong Dam, Macquarie River d/s Burrendong Dam, Bogan River, Tumut River, Upper Murrumbidgee River to Burrinjuck Dam and Cooma Ck, Murrumbidgee River to Wagga Wagga, Mirrool Creek, Queanbeyan and Molonglo Rivers. A minor flood Warning is also current for the Paroo River.
NSW SES is continuing to monitor conditions in those areas and urge the public to heed any warnings that may be issued.
Chief Superintendent Burnes said flash flooding was a real risk and can happen anywhere there is localised heavy rainfall.
"If it's flooded, stop and find an alternative route. Flash flooding can be deeper than it appears and can contain sewage and poisons, as well as hidden debris," Chief Superintendent Burnes said.
"If you live, work or regularly commute through a low-lying area, there may be no official warning for flash flooding. It is critical you assess the conditions and also check live traffic before travelling."
If you are trapped by rising flash floodwater, seek the safest refuge position and call Triple Zero (000) if life threatening.
The NSW SES advises that people should:
* Keep clear of creeks and storm drains.
* Don't walk, ride your bike or drive through flood water.
* If you are trapped by flash flooding, seek refuge in the highest available place and ring 000 if you need rescue.
* Unplug computers and appliances.
* Avoid using the phone during the storm.
* Stay indoors away from windows, and keep children and pets indoors as well.
* For help in floods and storms, ring the NSW SES on 132 500.
