A perfect storm - or rather a sea breeze convergence - brought heavy hail to Onerahi yesterday, leaving a white blanket over parts of the suburb.

MetService Meteorologist Mariken van Laanen said the weather conditions were perfect shortly after 3.30pm yesterday for the hail to land and leave people wondering what was happening on what, until then, had been a relatively fine spring day.

Ms van Laanen said at 3.30pm the temperature at Whangarei Airport at Onerahi was 14.7C, but it then dropped dramatically over the next 30 minutes, but was back up to 10.8C at 4pm.

She said a ridge brought a sea breeze convergence on to land and with it the hail.


"What happens is if it's quite warm and you get cooler breezes coming off the sea in two different directions - in this case from the east and west - when they come together it creates a lift and that causes thermal streams that can lead to thunderstorms or hail showers like you saw today."

Ms van Laanen said it was unlikely there would be more hail today as a trough was coming across Northland that was probably going to bring rain.

Onerahi residents who contacted the Northern Advocate said the hail was preceded by a dramatic drop in temperature and the heavy falls left much of the suburb with a white blanket.