NZ Weather Forum

one interesting thing about the rain radar is the 'kink' in the line about where it occured...

MS now suggesting that it was a 'downburst'…

'Devastating Auckland wind gusts caused by collapse of air' - NZ Herald

For what it's worth, my Silverdale Spy texted last night "Great rainfall at 5:30! and all over in ten minutes. Spoutings overflowed, thunder rolled and as Ak. does, sun came out".

I thought M/S might say that going on the fact that the rain suddenly fell out of the cloud...but that occured on the city side of the harbour...not where the tornado occured

downbursts dont produce a narrow path of destruction only a few metres wide like what occured

Nev wrote:MS now suggesting that it was a 'downburst'…

'Devastating Auckland wind gusts caused by collapse of air' - NZ Herald

Metservice's Dan Corbett wrote:The downbursts are "very localised"

Hang on here, I think he has got things confused here.

How on earth can he claim that downdrafts of thunderstorms are very localised, that completely fly's in the face what Meteorologists are tought. Despite the line of storms being rather thin, the supposed downdraft would have affected much more people than it did.

It astounds me why Metservice cant take witness testimony seriously In previous articles the press interviewed a woman who actually saw things being lifted up in a shaft of rain, and yet they completely dismissed this.

They come across as very sceptical about what people see, even when I reported stuff a while back via the phone on some storms I felt that I was treated like I didn't know what I was talking about and the equipment I was using to record the event was sub-par and things needed to be verified. They seem to treat that there equipment is always correct and everyone else's equipment is wrong. What process honestly do I and my WX station need to go through in order to be taken seriously by them?

It's soooo extremely frustrating how they dont take what people say seriously.

Tornadoes were being forecast by Met Service in the two days prior to the event so they must have thought the potential was there.

Metservice obviously dont read what goes on in here! Been losing respect for them since Dan has come on-board tbh.

I don't get it, they forecasted tornadoes, one happens so you think they would be jumping up and down with glee but they don't want to confirm one actually happened...

Mind you WW called it a straight line winds, right after quoting this from a witness "

"Victoria Silvey, 12, was in her lounge when she saw timber, leaves and poles "floating in the air''.
They were whirling around in a funnel that lasted about 30 seconds before leaving the area, she said."

http://www.weatherwatch.co.nz/content/s ... m=facebook

yeah, it does not make sense
tornadoes were in the forecast and in the watches
and then when one occurs......it could not possibly be one...?

and it does not make sense to explain that a very narrow path of destruction (i.e by a small tornado...due to at surface wind shear (there are videos captured of narrow small tornadoes...that are only a few metres wide..but which can wreck half a tree or half a fence etc) was instead caused by a downdraft (which would result in a wider destruction path)

re Steve:
yes been lots of eye witness reports of swirling winds , objects floating up in the air (how else do you get roofing iron drapped over power lines ?)

I guess M/S are saying upper level dynamics did not look so good after the 1pm sounding...
but they should not go on that alone...topography can easily set off a surfaced based spinner (small twister)

Manukau heads obs wrote:I guess M/S are saying upper level dynamics did not look so good after the 1pm sounding...
but they should not go on that alone...topography can easily set off a surfaced based spinner (small twister)

Upper level dynamics were excellent apart the from the fact that there could have been more speed shear aloft. But the instability on the day was not that great and we did need that surface heating to get our storm. Spwills photos show an outflow nature to the convection so certainly some outflow gusts occurring. Grey Lynn got a 42kt gusts which is a rare strength for that site as it is a bit sheltered.

there was surface heating though, especially when the original front disentegrated and the started to come out
and especially in the area NW of Auckland
10cm soil temperatures have been as high as 16C lately too

Clouds go up and down along those lines, the ground reports at Devonport mean you have to consider tornado as a strong possibility but a very short lived and weak event.

yeah,,,it now seems like the stance from M/S is lets call it a down burst unless there is video evidence of a tornado

because down burst winds can do some strange things

but the key is that either side of the narrow path of destruction there was no wind damage

you are not going to get a down burst wind that flows along only a few metre wide path now are you
please explain that to me

Damage pics and locations, hope it makes sense, any questions ask.
https://www.dropbox.com/s/acrrkhygixnjt ... 5%20pm.jpg

2 is the first sign of damage I saw, fence knocked down and shed pulled up.
3 looking towards 2
https://www.dropbox.com/s/qc5q83or1gmb0 ... 4%20pm.jpg
4 looking towards 1, branch moved towards the track
https://www.dropbox.com/s/f8btudkruuokr ... 3%20pm.jpg


Chair thrown from half way between 2 and 4, to 4
https://www.dropbox.com/s/gfsqah9s4437d ... 7%20pm.jpg

4 looking down track the broken tree is the one at the bottom of the 4
https://www.dropbox.com/s/lln9o3jv6dvp5 ... 5%20pm.jpg

Fence fallen pointing towards track, just at the bottom of the 3
https://www.dropbox.com/s/gswvs1t1f0ono ... 9%20pm.jpg

1 looking towards 4
https://www.dropbox.com/s/cqxqt13nc1539 ... 8%20pm.jpg

6 looking towards 4
https://www.dropbox.com/s/twbr66hs4an39 ... 2%20pm.jpg

5 door pulled towards track
https://www.dropbox.com/s/gg0r3hjk9txlo ... 2%20pm.jpg

6 looking towards 4
https://www.dropbox.com/s/ib0jimaszzxz3 ... 4%20pm.jpg

7
https://www.dropbox.com/s/mz1yk03ib09vj ... 0%20pm.jpg

8
https://www.dropbox.com/s/20adgnq57y9hk ... 5%20pm.jpg

9 house with roof gone
https://www.dropbox.com/s/eix4tqwp729rr ... 2%20pm.jpg

10 looking down track
https://www.dropbox.com/s/hywc160o67cg8 ... 5%20pm.jpg

https://www.dropbox.com/s/jh421pryavi7e ... 4%20pm.jpg


Whole album
https://www.dropbox.com/sh/dyni179bbtp1yfs/QVJ4vooK0a

A great and comprehensive portfolio of photos, ben g - thankyou very much.
The two I find most interesting are: the roofing that appears to be positively wrapped around the power-lines; and the garage door that seems to have been pushed out of the garage
I'll leave it to others to draw inferences: again, well done.

Nice Ben - I find a couple of things compelling that point towards a tornado.

1) the way that roof is hanging over just some of the lines and not all of them. Says to me its dropped vertically rather than hit it horizontally.

2) the pole (trampoline pole is it?) that has gone through the fence. That takes some wikid force. To me the forces of a tornado that can carry it and throw it. I just cant see straight line winds causing that object to become such a missile.

3) the photo where the fence has fallen to the right towards the garden and path. There is a branch in the foreground that has fallen to the left and is resting on a gate.

4) the garage door has been sucked out. The only possible way that straight line winds could have done that is if the garage is not well built and air is able to freely enter the building from the opposite side to the garage door, or if the wind just happened to be blowing at the perfect angle that the garage faces (ie heading away from where the main door is).This may have caused a deep enough suction and low pressure on the door to pop it outwards.
I tend to believe the low pressure of a tornado is the more obvious answer though.

Combine all this and the very clear multiple eye witness accounts of floating and swirling debris clouds and an actual funnel, i have no idea how metservice and weather watch can claim it's not a tornado.

The roof damage on the bungalow makes this an F1 tornado event.

edited for typo

Some other points, a report saying the main rain event had already passed through the area however it was still raining at the time, the duration of the wind was very short, a report of 4 seconds.

well that then is very telling
that means it was at the "rain free base" end of the CB
and this whole CB collapse event did not occur until the city CBD side of the harbour
(which is what Ricky actually got with the 80kmh wind gusts)
so it was not a micro burst event

You make some fair arguments guys - let me forward some of this to a tornado expert at the Weather Channel in the US. See if he can shed some light. If he agrees there's a higher likelihood it was a tornado I'll happily put a story out to the media and acknowledge the forum's efforts in gathering the evidence and making the case. With regards to Dan Corbett, I would've thought his experience in the US - specifically around tornadoes - might have given him the upper hand on this one.

Cheers
Phil.

Philip Duncan wrote:You make some fair arguments guys - let me forward some of this to a tornado expert at the Weather Channel in the US. See if he can shed some light. If he agrees there's a higher likelihood it was a tornado I'll happily put a story out to the media and acknowledge the forum's efforts in gathering the evidence and making the case.

Much appreciated Phil!

Philip Duncan wrote:You make some fair arguments guys - let me forward some of this to a tornado expert at the Weather Channel in the US. See if he can shed some light. If he agrees there's a higher likelihood it was a tornado I'll happily put a story out to the media and acknowledge the forum's efforts in gathering the evidence and making the case. With regards to Dan Corbett, I would've thought his experience in the US - specifically around tornadoes - might have given him the upper hand on this one.

Cheers
Phil.

Thank you Phil

Thanks Phil - Thats a great idea

good idea
because once you have downburst tinted glasses on, its hard to be be pursuaded otherwise...