A severe thunderstorm warning has been issued for some of the Central Coast this afternoon, with heavy rainfall and large hailstones predicted.
Flash flooding may also be on the way, with hail expected to be under 2cm in diameter.
The storm is mainly expected to affect the southern half of the Coast.
The State Emergency Service has warned that people should move their cars undercover and unplug computers and appliances.
Phones should also not be used during the storm, and it is advised that people should stay away from windows and keep children and pets indoors.