Australia: Severe weather forecast over parts of western Northern Territory through at least March 22 /update 1

Severe weather is forecast across parts of western Northern Territory through at least March 22. The remnants of Cyclone Megan are expected to move slowly northwestward over the affected area March 21-22, bringing heavy rainfall to the region before the system moves into eastern Western Australia.

As of March 21, the Australian Bureau of Meteorology (BOM) has issued a severe weather warning for heavy rainfall across much of Tanami and parts of Barkly, Lasseter, and Simpson forecast districts. Locations that may be affected include Yuendumu, Rabbit Flat, Papunya, Nyirripi, southwest Tanami District near the WA border, and Barkly District west of Tennant Creek. Heavy rainfall, which may lead to possible flash flooding, is expected in Tanami, far western Barkly, and parts of Lasseter and Simpson districts late March 21-22; six-hourly rainfall totals of 5-8 cm (2-3 inches) and 24-hourly totals of up to 15 cm (6 inches) are possible in the affected areas. Flood watches are in place across the affected area. 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. 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.