Storm warning from BOM
At 4.45pm, the Bureau of Meteorology (BOM) warned of large, possibly giant hailstones, damaging winds and heavy rainfall for parts of the Hawkesbury, Blue Mountains and Sydney.
BOM says at 4:25 pm, severe thunderstorms were detected on the weather radar near Silverdale, Warragamba and the Lithgow district. These thunderstorms are moving towards the northeast.
They are forecast to affect Blaxland, Glenbrook, Badgerys Creek, Erskine Park, Horsley Park and Mulgoa by 4:55 pm and Parramatta, the Yengo National Park northwest of St Albans, Blacktown, Londonderry, Penrith and Riverstone by 5:25 pm, so they could just clip the Hawkesbury - so be aware.
What you should do
* Move your car under cover or away from trees. * Secure or put away loose items around your house, yard and balcony. * Keep at least 8 metres away from fallen power lines or objects that may be energised, such as fences.
* Report fallen power lines to either Ausgrid (131 388), Endeavour Energy (131 003), Essential Energy (132 080) or Evoenergy (131 093) as shown on your power bill.
* Keep clear of creeks and storm drains. If your life is at risk, call Triple Zero (000) immediately
For SES assistance phone 132 500
More information from @bureauofmeteorology: http://www.bom.gov.au/nsw/warnings/