A wild storm transformed Sydney into near-darkness Saturday afternoon as golf ball-sized hail pounded parts of the city and surrounding regions. The violent system brought torrential rain, damaging winds, and flash flooding that left roads impassable and forced emergency services to respond to multiple calls for help.
The storm hit Penrith just before 4pm, with the area recording more than 17mm of rain in just half an hour and the Great Western Highway flooded at Kingswood. The Bureau of Meteorology recorded 5cm of hail at Penrith at 4pm, while a wind gust of 91km/h was recorded at Western Sydney Airport at 3.42pm.
The speed of the system caught forecasters off guard. While the Bureau of Meteorology had been warning of storms, it issued its main warning for Penrith at 4.04pm, after the storm had hit, stating the storm would arrive by 4.15pm. Emergency services dealt with the consequences across the region; police responded to numerous calls for help, including assisting a car stuck in water at Cambridge Park.
The wild western Sydney weather delayed the start of the AFL match between GWS and St Kilda at Sydney Olympic Park, which was due to start at 4.15pm but players had not yet made it onto the field. The Cars Under The Stars event planned for Nepean Village that evening was cancelled.
The system extended well beyond Penrith. Although hail can occur any time of the year, much of the damage occurs between September and March, when warm and humid weather fuels severe thunderstorms. While New South Wales and south-east Queensland are considered Australia's hail hot-spots, hailstorms can occur across all states of Australia.
Warnings remained in place across a broad area of NSW. The Bureau of Meteorology issued alerts for Central Tablelands and parts of the Hunter, Metropolitan, Illawarra, Southern Tablelands, North West Slopes and Plains, Central West Slopes and Plains, South West Slopes and Riverina, warning of continued severe thunderstorms with heavy rainfall and possible damaging wind gusts and large hail.
For Australian households in hail-prone regions, Saturday's storm is a reminder of the importance of preparation. Australian building standards still do not include hail resilience, which leaves many properties vulnerable. The research points to a troubling future. Simulations project increased hail frequency around Brisbane and Sydney/Canberra, and an increase in maximum hail size around Melbourne, Sydney/Canberra, Perth, and Kalgoorlie.
More information about severe weather safety is available through the Bureau of Meteorology and emergency services guidance.