Hail, destructive winds and heavy rain are set to hit much of the eastern seaboard in coming days, with the Bureau of Meteorology issuing severe weather warnings in several states.
Victoria is expected to be inundated with potential flash flooding, with conditions forecast to worsen on Thursday.
Queensland is also facing the threat of Tropical Cyclone Owen intensifying in the Gulf of Carpentaria. It is currently a category two storm, but could be a category three when it makes landfall.
“We’ve got a low-pressure system likely to develop over south-eastern Australia, probably over Victoria on Thursday,” the BOM’s extreme weather desk manager James Taylor told the ABC.
“That will draw in moisture from the tropics and Tropical Cyclone Owen during Thursday and Friday and create a heavy rainfall risk from a cloud band with embedded thunderstorms over a large part of probably the eastern seaboard.”
Mr Taylor said the heavy rainfall risk will be for large parts of Victoria and northern and eastern Tasmania.
There is also a chance of extreme conditions in South Australia’s south-east as well as eastern NSW, and along the coast of Queensland.
A low pressure system will deepen over SE Australia on Thursday, drawing moisture from #CycloneOwen & the tropics to produce heavy rain & severe #thunderstorms over large parts of #Victoria #Tasmania & possibly parts of SA, NSW & Qld. Flooding also likely https://t.co/TtFsvb6zJa pic.twitter.com/eSplbsVdfP
— Bureau of Meteorology, Australia (@BOM_au) December 12, 2018
Mr Taylor said while most of the potential damage in the south-east would likely be rain-related, Owen could also generate damaging winds in Queensland.
“We’ve got a real risk with heavy rainfall, but there’s also damaging to destructive winds associated with [tropical cyclone] Owen that we need to worry about,” he said.
Brisbane and Townsville are both forecast to receive more than 100 millimetres of rain.
Victoria’s north-east and central areas, including Melbourne, could cop up to 100 millimetres and Sydney up to 25 millimetres.
A severe weather warning has also been issued from Cape Shield in the Northern Territory to Burketown in Queensland, with gale-force winds of 64kmh predicted.
Grace Legge, a meteorologist from the Bureau of Meteorology’s extreme weather desk, said Thursday’s weather could be one of the “larger weather events” in eastern Australia since March.
“Through the south east, we’ve got a cut-off low, which is moving over South Australia, New South Wales and Victoria, and the real risk is the heavy rainfall as, with these events, moisture will be sucked in from the Coral Sea,” Ms Legge told The New Daily.
“It’s a bit hard to see exact totals of where we’ll see those heavier falls as it will depend on things like isolated thunderstorms.”
Zombie cyclone in Queensland
Zombie Cyclone Owen, the first to develop in the Coral Sea since 1997, has continued to track westwards and re-powered in the warm waters off the Gulf of Carpentaria since Tuesday.
A zombie cyclone is an ex-tropical cyclone that has seemingly “died off” only to re-intensify and reform.
#Storms forecast for most of #Qld on Thursday. Severe storms likely over the southern interior, with locally heavy rainfall, large hail and damaging to destructive wind gusts with these storms. Heavy rainfall in storms also over the tropics. Forecasts at https://t.co/ZbOnYFPr8D pic.twitter.com/sW1yNn0j2m
— Bureau of Meteorology, Queensland (@BOM_Qld) December 12, 2018
Bureau of Meteorology weather services manager Richard Wardle said a flood watch had been updated on Wednesday to include catchments from the Daintree to Townsville and would likely be expanded in the coming days.
“Comparisons have been made with the path of Cyclone Oswald in January 2013. Cyclone Owen is a smaller system which is likely to move more quickly under the influence of strong steering winds associated with an upper trough,” Mr Wardle said.
Ms Legge said the heavier falls would be dependent on the movement and position of the system.
“Twenty four hour totals of 25 to 50 millimetres are likely through the coastal areas with heavier falls of 50 to 100 millimetres possible.”
‘Flash flood risk’
Andrew Feagan, Victorian state duty officer at SES, said thunderstorms posed a flash flooding risk.
“We’re urging people not to drive through flood water … stay away from loose trees and once the storm has passed it’s important to assess your own areas to see if there has been any damage,” Mr Feagan told The New Daily.
“It’s also important to remember that it only takes 15 centimetres of water for a car to float – about a normal size of a pen,” he said.