A severe thunderstorm warning has been issued for much of southern New South Wales.
The Bureau of Meteorology says hailstones, heavy rain and possible flash flooding may occur this afternoon in Batemans Bay, Orange, Canberra, Goulburn Cooma and Yass.
Damaging winds may also affect parts of the central west, including Parkes, Wagga Wagga, Albury, Griffith and Narrandera.
Emergency services are urging people to secure loose items around their homes and stay indoors.
© ABC 2012
12:38 EST Tropical Cyclone Jack has rapidly developed over the warm waters of the Indian Ocean in the past 24 hours, making it the 10th system to be named this season.