NZ Weather Forum

Nev wrote: ↑Tue 19/11/2019 09:27 Correlation does not imply causation.
Happy to be corrected if someone could explain why the Sydenham event wasn't a gustnado? …

In one vid there was some sort of a rotation the person was looking up at. then all the debris started to get picked up and spun around.

Sorry off topic but now only joined the forum this year but have been reading since 2010 and when the " hobsonville tornado" happened that thread ended up being locked due to people kept on disagreeing with each others opinions wether that was a tornado or a wet microburst. i dont want this thread to be locked cause of people disagreeing on other peoples opinions.

Im of the opinion that gustnados only form on true defined gust fronts as ive seen in the past, yesterday had the characteristics of rotation in isolation.
Oposing winds at all levels causing general rotation, and a strong upper jet.

tornado wrote:
In one vid there was some sort of a rotation the person was looking up at. then all the debris started to get picked up and spun around.

That would be this one
https://www.tvnz.co.nz/one-news/new-zea ... ristchurch

Storm Struck wrote: ↑Tue 19/11/2019 10:22 Im of the opinion that gustnados only form on true defined gust fronts as ive seen in the past, yesterday had the characteristics of rotation in isolation.
Oposing winds at all levels causing general rotation, and a strong upper jet.

Just before the storm hit I noticed a dramatic and sudden increase in inflow wind from the NE and observed clouds flying into the path of the cell from that direction. I thought at that moment it was going to be a big deal, and got a message seconds later from my wife at home in Halswell that they had large hail and dramatic lightning, just 10km away

It hung around off the coast for an hour afterwards I got thinking possible supercell? Not sure on that keen to know others thoughts.

Razor wrote: ↑Tue 19/11/2019 10:32

Storm Struck wrote: ↑Tue 19/11/2019 10:22 Im of the opinion that gustnados only form on true defined gust fronts as ive seen in the past, yesterday had the characteristics of rotation in isolation.
Oposing winds at all levels causing general rotation, and a strong upper jet.

Just before the storm hit I noticed a dramatic and sudden increase in inflow wind from the NE and observed clouds flying into the path of the cell from that direction. I thought at that moment it was going to be a big deal, and got a message seconds later from my wife at home in Halswell that they had large hail and dramatic lightning, just 10km away

The was it hung around off the coast for an hour afterwards I got thinking possible supercell? Not sure on that keen to know others thoughts.

Im not sure if it was a supercell, if it was it would of only been small or very brief, as to me it didnt have those characteristics of supercell structure. Yesterdays storm was a good one but we have had bigger in the past that have showen much more defined LP structure storms.

it might of been a weak supercell. strong enough to drop that tornado and the waterspout at new brighton.

mikestormchaser wrote: ↑Tue 19/11/2019 11:10

Razor wrote: ↑Tue 19/11/2019 10:32
Just before the storm hit I noticed a dramatic and sudden increase in inflow wind from the NE and observed clouds flying into the path of the cell from that direction. I thought at that moment it was going to be a big deal, and got a message seconds later from my wife at home in Halswell that they had large hail and dramatic lightning, just 10km away

The was it hung around off the coast for an hour afterwards I got thinking possible supercell? Not sure on that keen to know others thoughts.

Im not sure if it was a supercell, if it was it would of only been small or very brief, as to me it didnt have those characteristics of supercell structure. Yesterdays storm was a good one but we have had bigger in the past that have showen much more defined LP structure storms.

I got a long look at it driving home from Amberley in the later afternoon. It had a strong-looking soithwest-to-northeast tilted updraught at the rear and what looked for all money like a forward-flanking downdraught ahead of that. It was fairly low-topped but perhaps that was due to it dying away at that stage. No photos as I was driving, but I could believe it was a supercell from what I saw, just I'm no expert on them.