A top weather expert has said the country is "not out of the woods yet" after yesterday's deadly tornado.
MetService's Daniel Corbett said New Zealand could expect the potential for more severe thunderstorms and strong winds again today, after the tornado which swept across west Auckland yesterday afternoon, leaving three dead in its wake.
As storm-ravaged communities in Hobsonville and Whenuapai pick up the pieces today, other parts of the country could be preparing for similar weather conditions which prompted the deadly twister.
"The next threat we have is the centre of this low pressure - the upper level cold pool as we call it - which provides some unstable air," Corbett told TV ONE's Breakfast programme.
"So heating the air, meeting the cold air, and boom, there'll be thunderstorms again today.
"They'll be more hit-and-miss, but they're currently sitting west of the South Island and west of much of the North Island, and through the middle of the day into the afternoon from about Waikato to Taranaki, down to say Kapiti and as far south as Buller, another risk of some thunderstorms."
Corbett said "we've already seen some very strong winds, we could see some strong straight line winds up to 100km/h to 110km/h".
"And of course, whenever you get these storms coming onto the coast, because of the differences in the frictions between the sea and the land, that always provides that little bit of extra twist that can sometimes lead to these, what we call, low-level circulations, the small tornados," he said.
"Are we out of the woods completely? Not just yet, lets get through the day, things slowly improve as we get into the weekend."
Corbett said yesterday's tornado, thought to be some tens of metres wide, was coupled with strong 'straight line winds', which were gusting at over 110km/h. The two combined created some very "damaging" conditions, he said.
Corbett said the geography of the upper North Island formed conditions which act as "the fuel for these storm to erupt".
"Because you've got water on both sides, the land in the middle, as you get a strong nor-easter coming across the water, say the Hauraki Gulf, that comes across the land too, and because of the difference in friction that can add a little bit of a twist, just enough to nudge things along to sometimes cause our lower level circulations," the meteorologist explained.
"They're not to the extent of the American ones that are half-a-mile, or a mile-wide, but nonetheless they can do damage, on top of as well, the strong straight line wind gusts that we can see with some of the severe thunderstorms."
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