Severe thunderstorms expected to hit Canterbury this evening could cause a tornado and hail the size of one-dollar-coins.
Metservice says a storm spreading north over Christchurch and the Canterbury Plains will bring 30mm an hour of rain, and hail up to 2.5cm in diameter that could shatter glasshouses.
It says it could also cause a small tornado, and warns the rain could lead to flooding and slips.
Metservice says people should keep an eye on the weather conditions, and check the Civil Defence guidelines for keeping safe in a
A great shot of the outflow boundary of a storm (the curved cloud at the base of the storm) over North Canterbury this afternoon! Thanks for sharing the photo @grenow! Active storms throughout Canterbury; check the radar at https://t.co/1rQfBmVPzQ ^JM https://t.co/7jOTASBK3V— MetService (@MetService) December 22, 2018
A complex low pressure system is forecast to spread onto the upper North Island tomorrow, then slowly drift off to the east on Monday and Tuesday.
The system is expected to bring rain to most parts of the North Island during this period, with the risk of the heaviest falls across the northern districts.