Heavy rain over large swathes of Queensland this week could spark flash flooding, with the same wet weather system bringing less intense but prolonged showers to Sydney for up to five days.
The Bureau of Meteorology has said western and inland parts of Queensland, as well as the tropical far north, will receive the most rain. Totals could reach 250mm in some areas and pose a prolonged flood risk for areas of the state that are already on flood watch, particularly in the south.
“We’re already seeing some showers in the area, and this will increase on Monday and peak in the middle of the week, with the heaviest falls between Tuesday and Thursday,” Miriam Bradbury, a forecaster at the BoM, said.
“Generally the daily falls will be between 50mm to 100mm, but there are also thunderstorms predicted throughout Queensland and because of them we can really quickly see the rainfall totals get much higher,” she said.
“It’s the thunderstorms that can exacerbate the risk of flooding, and both flash flooding and riverine flooding are quite possible with this system.”
The Queensland premier, Annastacia Palaszczuk, said the government and agencies would be monitoring the rain event “very carefully”.
“It’s very unusual to see this type of situation occurring in far north Queensland, especially this time of year which is usually near the end of the season,” she said on Friday. “We are expecting higher rainfall totals than we’ve seen before in May.”
Bradbury said that a trough across parts of Queensland and northern New South Wales, and a high pressure system sitting over the Tasman sea, are interacting to create the prolonged and intense rain.
“Between them they’re squeezing all of this moisture down from the tropics and pushing into these parts of Queensland and down into NSW,” she said.
“We also have an upper trough in the atmosphere providing a lot of support which has the potential to make the system more intense.”
For Sydney, Bradbury said the weather system will result in “a bit of a showery period”, which would begin with lighter falls on Monday and also peak between Tuesday and Thursday, before becoming drier as the system moves east off the coast over the weekend.
She said rainfall totals in Sydney are predicted to be between 15mm to 25mm during the peak of the wet weather.
“By and large, the main intense and dangerous rain activity will be inland and in Queensland, but New South Wales will also be wet,” she said. “Things should ease by next weekend as the system moves east, but because of river rises, the flood impact could continue past the weekend.”
Bradbury said that for parts of Queensland, “I don’t know how much help an umbrella will be” and that instead, residents should have a flood plan ready.
With Australian Associated Press
