04 Dec 2020 | 09:50 PM UTC
Australia: Storm system may heavy rainfall that could lead to flooding in southeastern Australia through Dec. 7.
Heavy rainfall, strong winds, and flooding forecast in southeastern Australia through at least Dec. 7. Disruptions possible.
Event
A strengthening low-pressure system will bring rounds of storms containing heavy rainfall, hail, and strong winds across portions of southeastern Australia through Dec. 7; this area includes southeastern South Australia, southern New South Wales, the Australia Capital Territory (ACT), Victoria, and Tasmania. Forecast models indicate the initial rounds of storms will occur beginning midday Dec. 5 in South Australia before tracking southeastward toward Victoria, New South Wales, ACT, and Tasmania by the evening. Rain showers will likely persist in the area until late Dec. 6 or early Dec. 7.
The Bureau of Meteorology has issued the following watches and warnings:
Severe Weather Warning (South Australia): Adelaide Metropolitan, Mount Lofty Ranges, Lower Eyre Peninsula, Kangaroo Island, Murraylands, Upper South East, Lower South East and parts of Yorke Peninsula and Mid North districts
Severe Weather Warning (Victoria): Central, South West, North Central, West and South Gippsland, Wimmera and parts of East Gippsland, Mallee, Northern Country and North East Forecast Districts
Severe Weather Warning (New South Wales): Snowy Mountains Forecast District
Additionally, strong wind warnings are also in effect for coastal regions of southern and eastern Australia. Officials will likely update and possibly extend the coverage of the relevant weather alerts over the coming days.
Hazardous Conditions
Forecast models indicate rainfall totals of 2.5-5 cm (1-2 inches) are expected across the affected area over the coming days, with the highest totals likely to be observed in Victoria and southern New South Wales. Locally higher totals are possible. Sustained heavy rainfall could trigger flooding in low-lying communities near rivers, streams, and creeks. Urban flooding is also possible in developed areas with easily overwhelmed or a lack of stormwater drainage systems. Sites located downstream from large reservoirs or rivers may be subject to flash flooding after relatively short periods of intense rainfall. Landslides cannot be discounted in hilly or mountainous areas, especially where the soil has become saturated by heavy rainfall. Disruptions to electricity and telecommunications services are possible where significant flooding, strong winds, or landslides impact utility networks.
Transport
Floodwaters and debris flows may render some bridges, rail networks, or roadways impassable, impacting overland travel in and around affected areas. Ponding on road surfaces could cause hazardous driving conditions on regional highways. Authorities could temporarily close some low-lying routes that become inundated by floodwaters.
Severe weather could also trigger flight delays and cancellations at regional airports including, but not limited to, those serving Sydney (SYD), Melbourne (MEL), and Adelaide (ADL). Authorities may temporarily suspend port operations or close beach fronts along the Great Australian Bight, Bass Strait, or Tasman Sea if strong winds trigger hazardous sea conditions. Flooding could block regional rail lines; freight and passenger train delays and cancellations are likely in areas that see heavy rainfall and potential track inundation. Localized business disruptions may occur in low-lying areas; some businesses might not operate at full capacity because of flood damage to facilities, possible evacuations, and some employees' inability to reach work sites.
Advice
Monitor local media for weather updates and related advisories. Confirm all transport reservations and business appointments prior to travel. Make allowances for localized travel delays, as well as potential supply chain disruptions, where flooding has been forecast. Do not drive on flooded roads. Charge battery-powered devices in case prolonged electricity outages occur.
