The thunderstorms can bring very heavy rain, so watch for surface flooding and rising streams & rivers. There's also the possibility of very localised strong wind gusts and tornadoes, just like yesterday's one in Waikanae.
Also expect severe NW gales overnight tonight with wind speeds of 70km/h gusting to 140km/h in exposed places.
Winds that strong can damage buildings, trees & powerlines and make driving dangerous.
It's all a bit of a nasty mix, so take extra care when you are out and about over the next couple of days!