Australia: Severe weather forecast over parts of northeastern Northern Territory and far northwestern Queensland through at least March 18 /update 1

Severe weather is forecast across parts of northeastern Northern Territory and far northwestern Queensland through at least March 18. A tropical low is currently moving over northeastern parts of Northern Territory's Top End region and is expected to develop into a tropical cyclone as it moves generally southward over the Gulf of Carpentaria March 16 before making landfall over the southern Gulf of Carpentaria coast March 18. Heavy rainfall and strong winds are expected across the affected area over the coming days, with the most severe weather likely in areas close to where the storm makes landfall.

As of March 15, the Australian Bureau of Meteorology (BOM) has issued a cyclone warning from Alyangula (Groote Eylandt) in NT to the NT/QLD border, including Borroloola but not including Ngukurr. A cyclone watch has been issued from the NT/QLD border to Mornington Island, including Mornington Island and adjacent inland parts of the Carpentaria in the Northern Territory. Damaging winds gusting up to 110 kph (68 mph) are expected over Groote Eylandt March 16 and up to 100 kph (62 mph) across the rest of the warning and watches zones late March 16-17. Stronger winds are possible as the system approaches the coast from late March 17. Heavy rainfall is ongoing in northeastern parts of the Top End region as of March 15 and will likely increase particularly over island and coastal parts of northeastern NT March 16 before spreading further inland March 17. Intense rainfall is possible around coastal areas of Carperntaria District from March 17. Abnormally high tides could cause minor flooding along the southern Gulf of Carpentaria coast March 16-17. Large waves may produce minor flooding along the foreshore.

The BOM is also maintaining a severe weather warning for damaging winds and heavy rainfall across across eastern parts of Arnhem Forecast District as of March 15. Locations that may be affected include Nhulunbuy, Maningrida, Milingimbi, Galiwinku, Bulman, and Gapuwiyak. Winds gusting up to around 100 kph (62 mph) are likely along the northeast Arnhem coast east of Milingimbi late March 15 before contracting to the far eastern Arnhem coastal fringes by early March 16. Six-hourly rainfall totals of 10-15 cm (4-6 inches) and 24-hourly totals of up to 22 cm (8.7 inches) are possible in eastern parts of the Arnhem District. The heavy downpours may trigger flash flooding in the region and a flood watch has been issued over eastern Top End river catchments.

Authorities will likely issue new alerts or update/rescind existing advisories as weather conditions change over the coming hours and days.

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 downstream from large reservoirs or rivers may be subject to flash flooding after relatively short periods of intense rainfall. Landslides are possible in hilly or mountainous areas, especially where heavy rain has saturated the soil.

Floodwaters and debris flows may render further bridges or roadways impassable, impacting overland travel in and around affected areas. Ponding on road surfaces could cause hazardous driving conditions on regional highways. Authorities may temporarily suspend port operations if strong winds trigger hazardous sea conditions, impacting freight and passenger maritime traffic. Flooding could block regional rail lines; freight and passenger train delays and cancellations are possible in areas with heavy rainfall and potential track inundation. Severe weather could also trigger flight delays and cancellations at regional airports.

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 employees' inability to reach work sites. Electricity and telecommunications service disruptions are possible where significant flooding, strong winds, or landslides impact utility networks.