Powerful ‘bomb cyclone’ to smash NSW, residents urged to prepare now

Aussies in one state are being urged to prepare now for a powerful “bomb cyclone”, with a major city tipped to cop 200mm of rain within days.

Residents in NSW are being urged to prepare now as a powerful “bomb cyclone” bears down on the state.

The Bureau of Meteorology’s Daniel Hayes said “bomb cyclone” - or “bombogenesis” - described a low pressure system that formed “very quickly”, causing pressure to drop significantly within a short period of time.

He said the trough was sitting off NSW and would start bringing rainfall and possible thunderstorms to northern parts of the coast on Monday.

“Pretty much from the Mid-North Coast up towards the Northern Rivers,” Mr Hayes said.

“As we see that continue to deepen and strengthen up, the focus for the rainfall will be on the south side of that low pressure system.

“So around more Central Coast areas through (Tuesday) and potentially further south along the coast, as the low pressure system itself shifts further south through Tuesday and into Wednesday.”

Pressure is expected to drop around 23hPa in a day. Picture: Supplied

Sydney could cop more than 200mm of rain in the next week, and parts of the Mid-North Coast could record up to 300mm.

NSW SES has now activated all 11,000 of its volunteers in preparation for the wild weather, and are urging members of the community to get ready.

NSW SES Acting Assistant Commissioner Allison Flaxman said property damage from destructive winds and flash flooding were significant risks amid the “dynamic” weather system.

“People should prepare now by tying down any loose items around their homes so they don’t become projectiles and damage property in the forecast wind,” she said.

“Be alert today so you’re safe tomorrow, by understanding your risk and planning what you will do and where you will go if you are impacted by flash flooding or riverine rises.”

The BOM has issued an initial flood warning for several NSW catchments including the Hawkesbury-Nepean, Georges, Cooks, Sydney Coast, and Illawarra Coast.

Chilly conditions across much of south east and Central Australia. Picture: Supplied

Mr Hayes said flood warnings had been issued to cover “a fairly wide area” at this stage, given uncertainty of the system’s movements.

“We could see some flash flooding as well as river flooding out of this system, depending on just how quickly some of this rainfall falls and how concentrated those falls are in local areas,” he said.

“We do expect to see further warnings issued for NSW today, basically for the developing situation.

“Once the system starts to have some significant impacts, there could be additional, more localised warnings issued ... so certainly people (should) keep an eye out for warnings and track the situation.”

Inland areas of NSW and Victoria were tipped to see frost and fog on Monday morning, with frost warnings issued for the Northern Country, North East, and East Gippsland forecast districts.

Melbourne is expected to hit a top of 14C with partly cloudy conditions and the chance of a shower.

Those in Brisbane are likely in for a rainy day with a top of 17C, while Adelaide residents can expect a mostly sunny day with a maximum of 15C.

Temperatures are tipped to reach 13C in Canberra after a freezing start, with a similarly chilly 12C forecast for Hobart.

Monday is likely to be warm and sunny for those in Darwin with a high of 31C.

Perth is expected to reach 23C with a mostly sunny morning before a high chance of showers in the afternoon and evening.

Originally published as Powerful ‘bomb cyclone’ to smash NSW, residents urged to prepare now