A man has died after a tree fell onto a moving car during a severe storm lashing Sydney this afternoon.  The man was a passenger in the car when the tree fell on it as it travelled easterly on Nepean Street in Emu Plains just after 2pm.  He died at the scene, while the female driver was taken to Westmead Hospital in a critical condition with pelvic and abdominal injuries.  The man died at the scene. (9NEWS)  Trees have been downed across Sydney in heavy winds. (9NEWS)  For the latest on power outages, visit the Ausgrid alerts page.  CCTV from a nearby storage facility showed the full force of the damaging winds, as a wall collapsed and a roof was lifted from a structure under the strain of heavy gusts.  A home in Mount Druitt was badly damaged after a fell through the home's facade, narrowly missing an 84-year-old woman inside.  East Hills Girls High School was damaged by fire. (Laura Ashleigh)  Lightning is also believed to have sparked a fire which tore though a section of East Hills Girls High School in Panania.  The Princes Highway in Rockdale was closed after a section of a building collapsed onto the street.  Energy provider Ausgrid is working to restore power across the state, with at least 38,000 homes left without electricity at one point this afternoon.  Motorists are advised to delay travel where possible and take care as the storm passes over.  The collapsed building facade in Rockdale. (Gorana Coric)  A fallen tree damaged a home in Mount Druitt. (9NEWS)  • Rockdale: the Princes Highway remains closed in both directions due to a partial building collapse at Bestic Street.  • Blakehurst: fallen wires are causing heavy northbound traffic near Blake Avenue.  • Hammondville: Fallen trees are causing hazards for motorists at several locations on Heathcote Road.  • Wetherill Park: The Horsley Drive is closed in both directions between the M7 and Ferrers Road due to fallen trees.  • Clarendon: Hawkesbury Valley Way is closed in both directions between Moses Street and Percival Street due to a fallen tree.  • Cranebrook: The Northern Road has reopened after being closed southbound due to a fallen tree earlier.  A man has died after tree fell on a car in Emu Plains. (9NEWS)  Earlier, the Bureau of Meteorology issued a severe thunderstorm warning for south west Sydney.  Wind gusts of up to 96km/h were detected at Camden Airport and up to 122km/h at Sydney Airport.  A severe thunderstorm warning is now in place for Sydney. Fairfield, Leppington and Liverpool are expected to bear the brunt of the wild weather.  Thunderstorms are also set to hit the Central Tablelands, Hunter and Illawarra regions this evening.  It follows a spate of wild weather at the beginning of 2016 that saw the heaviest rain in the city since April last year and flooding that devastated the state’s mid-north coast and Hunter region.  The warning area as of 2pm AEDT.  The Bureau of Meteorology said that despite today’s heat, a forecast of light north-westerly winds reaching speeds of about 20-35km/h meant any fire danger was likely to stay in the low-moderate range.  The BOM advises beachgoers seeking respite from the heat to take extreme protective measures in the sun, with the UV Index expected to reach an extreme level.  Full warning from the Bureau of Meteorology. (Visit the BoM site here for updated details)  The State Emergency Service advises that people should:  * Move your car under cover or away from trees. * Secure or put away loose items around your house, yard and balcony. * Keep clear of fallen power lines. * Keep clear of creeks and storm drains. * Don't walk, ride your bike or drive through flood water. * If you are trapped by flash flooding, seek refuge in the highest available place and ring 000 if you need rescue. * Unplug computers and appliances. * Avoid using the phone during the storm. * Stay indoors away from windows, and keep children and pets indoors as well. * For emergency help in floods and storms, ring the SES (NSW and ACT) on 132 500.
Sydneysiders are already sweltering with temperatures nudging 40 degrees today - but relief will be swift, with the city likely to receive a downpour and thunderstorm late this afternoon.