Queensland weather: Flood watch issued, 250mm totals possible as ‘unusual’ rain system develops

Thunderstorms and hail have been recorded in North Queensland as an “unusual” rain system tracks south, with totals up to 250mm possible, putting the southeast on flood watch.

Widespread rain forecast for Queensland starting Monday.

Drenching rain is forecast to track down the Queensland coast from tonight before intensifying over the next three days, with isolated totals up to 250mm possible for the southeast.

Thunderstorms have already started to impact North Queensland, with 2cm hailstones recorded in Townsville on Sunday morning, while there are warnings of severe storms with heavy rainfall between Cairns and Ingham.

It comes as an upper trough interacts with deep moisture and sustained onshore winds to generate widespread showers and thunderstorms over central and eastern Queensland.

The trough will start to track south tonight, with 50mm forecast for the Sunshine Coast and the Gold Coast on Monday, and 40mm for Brisbane.

Heavy rain will start tracking along the Queensland coast from Monday.

The rain will intensify on Tuesday, with the Gold Coast set for a 70mm drenching followed by another 70mm on Wednesday.

Brisbane’s three-day total could reach 170mm, according to the Bureau, with the heaviest falls coming Tuesday (70mm) and Wednesday (60mm).

Rain Tuesday

South East Queensland is officially on flood watch, with “localised river level rises and flash flooding likely within the areas of heaviest rainfall, with isolated minor to moderate riverine flooding possible”.

Queensland Police have issued a wet weather warning, urging motorists to take care on the roads and to avoid floodwaters.

Rain Wednesday

“With weather forecasts in the state’s southeast this week predicting heavy rain and increased river levels, police are expecting to see some of our roadways and thoroughfares affected.

“Motorists are reminded that road closures and conditions can change rapidly as creeks and waterways rise and fall quickly.

“Police are warning motorists not to ignore road closure signs as they are there to protect travellers from washouts, craters, and other hazards.

“During wet weather, motorists are asked to plan their trips carefully, regularly monitor the traffic and travel information site and allow additional travel time, incorporating travelling at lower speeds, delays, and diversions.”

The Bureau of Meteorology’s Shane Kennedy said the system was unusual considering August was typically a drier month for Queensland.

“But we do often get one of these be upper trough system once or twice during winter, and often be a focus of some heavier rain, potentially some flooding,” he said.

Mr Kennedy said there was significant uncertainty in the timing and location of the rainfall.

“It is a bit of a tricky forecast because it will depend a lot on where that coastal trough ends up developing … but it’s certainly a watch point if we get that trough moving further south, and expected that could bring those and heavier rainfall down to the south east,” Mr Kennedy said.

“So catchments are fairly dry in the southeast, it would likely take a couple of days of moderate to heavy rainfall to see those river responses.”