A storm front is moving through Hawke's Bay bringing heavy localised downpours and - so far - more than 100 lightning strikes.
"There's a cold pool of air aloft at the moment, so basically there is some unstable air around and that's just passing over Hawke's Bay now," MetService meteorologist Mark Bowe said.
"That's what has caused the heavy rain."
Bowe said one weather station north west of Napier had reported 8.5mm of rainfall over the past hour.
There had also been 119 Lightning strikes so far today, he said.