Weak tornadoes and funnel clouds spotted over Tauranga

A mini tornado was spotted moving across the Tauranga Harbour on Monday. Photo/Supplied

Meteorologists have confirmed an "unstable, showery air mass" over the region caused weak tornadoes and funnel clouds to form yesterday, inviting many local residents to point their cameras to the skies.

MetService's Rob Kerr said meteorologists received "a number of" reports and photographs of weak tornadoes and funnel clouds over parts of the North Island yesterday. "An unstable, showery air mass swept over the region, and we had a moderate thunderstorm risk in place," he said.

Tauranga residents reported a funnel-shaped mini tornado forming over the Tauranga Harbour about 2.30pm on Monday. Tornadoes were also spotted near Hamilton.

Kerr said weak tornadoes or funnel clouds were fairly common with thunderstorms, although they were "usually fleeting and rather insignificant".

"Once the low-level wind conditions are favourable for formation, local terrain can often be final the trigger to set one off," he said.

Kerr said anywhere which commonly has thunderstorm activity and steep local terrain carried a good potential for tornadoes to form and the Bay of Plenty met that criteria.

"As more people have a video camera in their pocket now than ever before, we would expect an increase in reports of these things, but we do not record the observations," he said.

Looking to the rest of the week, Kerr said spring will continue to hurry through a number of weather systems across New Zealand, with a ridge building over the Bay of Plenty tomorrow and bringing fine weather, but getting windy in the evening.

"Another front brings more rain and showers Thursday morning with stronger winds, then showers clearing and winds easing in the afternoon and evening," he said.

"Friday should be dry with gusty southwest winds, then a dry start to Saturday, but a change to northwest winds later in the day will bring rain."