Australia: Adverse weather forecast across parts of New South Wales through at least May 12

Severe weather is forecast across parts of New South Wales through at least late May 12. A band of rainfall with embedded thunderstorms over central NSW is expected to move eastward over the coming days, with rainfall totals of 5-10 cm (2-4 inches) expected across central and eastern parts of the state; heavier downpours are likely in southern coastal areas.

As of May 10, the Australian Bureau of Meteorology (BOM) has issued a severe weather warning for heavy rainfall for parts of the Illawarra, South Coast, Southern Tablelands, and Snowy Mountain forecast districts, including Batemans Bay, Moruya Heads, Ulladulla, and Araluen. Heavy rainfall is expected in the affected area from early May 11 through May 12; 24-hourly rainfall totals of 7-10 cm (3-4 inches) are likely across the affected area, with isolated higher amounts of up to 20 cm (8 inches) possible in elevated areas. The heavy downpours may result in flash flooding in the region. The BOM has also issued an initial flood watch for parts of the Hawkesbury Nepean Valley and New South Wales South Coast due to the anticipated persistent heavy rainfall. A moderate flood warning is ongoing for the Warrego River following previous downpours. Hazardous surf warnings are in place for the Hunter and Sydney coasts May 11-12 and the Illawarra and Macquarie coasts May 11. 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.