The hailstorm of 20th December 2018 will go down as the most catastrophic event in Australia's history in terms of coverage and likely overall damage. Reports are coming in of violent hailstorms from the southwestern suburbs central suburbs, eastern, northeastern suburbs, the central coast and Blue Mountains as well as regions south of Sydney.
During the afternoon, energy from deep moist air capped at the surface was ready to explode at any time with "loaded gun" profiles. By mid-afternoon, thunderstorms had already begun to develop near Nowra and Wollongong - a precursor of what was to evolve in the afternoon as the lid on convection held the now excessive amounts of energy across Sydney.
The hailstorm event unfolds explosively
The first storms began to develop and quickly warnings of destructive supercells had been put out immediately - one in the southwestern suburbs and another in the western Suburbs moving towards the northern Suburbs. Hailstones the size of cricket balls already were being reported. Another cell developed around Dural and quickly developed into a monster supercell - its course the Central Coast.
As if this unprecedented behaviour was not enough, more cells developed across southwestern Sydney almost lined up behind the original cells feeding on high CAPE environments. More cells were entering the basin from the northwest as the Central Coast was being pounded by cricket balls after leaving a mess at Berowra and the M1.
It was now the Blue Mountains turn with Katoomba, Blackheath and Lithgow to join in a stream of supercell warnings. The cells left extreme wind and hail destruction and headed straight for the unutilised air within the western Sydney basin. Meanwhile, another hailstorm with hail to cricket ball sized was pounding south western Sydney. These two cells finally merged near Wentworthville. Let's not forget another structured storm with supercell characteristics to follow these mergers. In the end, the cells formed a major complex and gradually exited the coastline leaving in its wake a major damage bill probably never observed from a single event with any Australian city and possibly rivaling any such event within any Australian region.
Concluding comments and things to consider
With this Sydney hailstorm nightmare slowly unfolding, many people may be focused on their cars. For anyone, or if you know of anyone who was affected by hailstones larger than golf balls, it's important they check their rooves or roof tiles for damage or cracks as future storms may see water getting in and nothing may be known at that time that this is what did it! This is not excluding the solar panels and skylights, aluminium gutters and car ports.
As to hail damage to cars anyone with hail larger than 2 to 3cm please get your car checked EVEN if you can’t see the hail dents. Under lights PDR Technicians can see at least 10x more dents than with the naked eye! If you have hail damage to your vehicle you are obliged to get it repaired. Too often people find out about their vehicles well after the event and this does mean that you face an excess from insurance at some point if not repaired.
Although insurance companies are in the process of setting up for repairs, do not be surprised at all if you are waiting up to 2 years to get your vehicle repaired in this hailstorm event especially if the total number of vehicles affected reach beyond 100000 vehicles.