New South Wales authorities are moving extra rescue personnel and equipment into the flood-hit regions of the state’s north as more wild weather looms.
The Bureau of Meteorology on Friday afternoon issued a severe weather warning for heavy rain for areas that are still recovering from floods at the start of March, as well as storms near Sydney.
Towns or cities at risk of flash flooding on Friday included Lismore, Gosford, Tenterfield, Byron Bay, Casino and Kyogle.
⛈️Slow-moving storms continue to bring a heavy rainfall threat, including near Colo Heights and Bilpin. A severe thunderstorm warning is current for the Northern Rivers, Northern Tablelands and Central West Slopes & Plains.
— Bureau of Meteorology, New South Wales (@BOM_NSW) March 25, 2022
See latest at https://t.co/o8lF3WGlu3 pic.twitter.com/Q9lQN71Ro0
The immediate source of the storm activity was a humid and unstable airmass east of an inland trough, the bureau said. An approaching upper trough would enhance the thunderstorms, leading to rapid development.
However, there was the possibility of several troughs moving across the region in coming days, with the bureau also monitoring the potential for a low-pressure system forming off the coast early next week, BoM spokesperson Morgan Pumpa said.
Similar warnings for heavy rainfall and damagingwere issued for southern parts of Queensland, including just north of the NSW border.
The floods that hit northern NSW and south-east Queensland at the end of February were mostly from a single, extended rainfall event.
For Sydney, twin east coast lows within a week caused major dams to spill, and lifted the Hawkesbury Nepean River to the city’s north and west to its highest levels since 1978 in places.
For now, the forecast for Sydney is for showers every day over the next week, with the biggest total predicted for Monday, with as much as 30mm to fall. Places such as Ballina and Lismore, though, may see as much as 60-70mm on Monday and Tuesday.
Early next week may see some of the biggest falls of the next few days, the bureau said.
Each day will see rainfall over parts of the north-east, with Monday and Tuesday looking like having the most accumulated falls (although local areas under a 'super cell' will likely pick up more.) @BOM_NSW pic.twitter.com/uX43nFfHk8
— Peter Hannam (@p_hannam) March 25, 2022
“At the moment, the focus is really over the upcoming days,” Pumpa said. “But during the first half of next week, a trough is expected to develop along the central and northern parts of NSW coast.
“While the system is forecast to bring widespread rainfall across eastern NSW, rainfall totals aren’t expected to be as high as what we saw in late February and early March.”
Early indications are that the northern rivers region – which copped severe flooding that forced thousands from their homes and killed at least four people – may collect as much as 200mm of rain, if not 300mm, Pumpa said. What will be key is if the system moves a bit closer to the coast than currently forecast.
Can see why SES and other authorities are getting a bit nervous about the return of flooding to parts of the east coast. @BOM_au pic.twitter.com/yqOYFM6VaN
— Peter Hannam (@p_hannam) March 25, 2022
The NSW State Emergency Service was deploying more crews with flood rescue capability to the mid-north coast and the north-east ahead of the coming rain, including incident managements teams.
“This is a very dynamic weather pattern which it has been for the last couple of weeks now,” said Greg Nash, an SES spokesperson.
“We are definitely preparing and resourcing appropriately,” he added, including sending crews up north. “The majority of them are currently centred around the Grafton area.” He said if needed, they can be sent to other regions.
“The ground is all extremely saturated at the moment. So, even a small intense rain period, localised, may trigger some flash flooding,” he said.
Sydney’s dams, meanwhile, remained more than 99% full, with only about 20 gigalitres of additional capacity left across the network, WaterNSW data showed.
There were also warnings for storm activity around the Hawkesbury region.
Also stormy across parts of Sydney this Friday afternoon, with heavy rainfall possible: @BOM_NSW https://t.co/AP2lGq6VWR pic.twitter.com/BTcH5HSm1X
— Peter Hannam (@p_hannam) March 25, 2022
Longer term, the La Niña weather pattern that has contributed to the above-average rainfall is not forecast to break up until late autumn, Pumpa said.
Some international climate models indicate a third consecutive La Niña could form late this year.
