Thunderstorms possible North Island 8 October

spwill · Unread post by **spwill** » Wed 09/10/2013 08:21

Manukau heads obs wrote:great video clip
weatherwatch and metservice need to wathc that video and then see if they still think it was straight line winds

Metservice had signalled yesterday as a possible tornado day.

Manukau heads obs · Wed 09/10/2013 08:23

yes.,,,which is why I cant understand why their first impressions were it would not have been
instead of....need to get eye witness reports and damage reports to confirm if it was or not....sort of thing...

jamie · Unread post by **jamie** » Wed 09/10/2013 08:28

looks like tornado damage to me...... no doubt

Manukau heads obs · Wed 09/10/2013 08:30

and now Stuff is just calling it a sudden squall
makes a mockery of the whole thing
http://www.stuff.co.nz/national/9260370 ... w-in-south
I hope that is not on (bad) advice from weatherwatch

jamie · Unread post by **jamie** » Wed 09/10/2013 08:35

i sense another was it or wasnt it an auckland tornado episode

Manukau heads obs · Wed 09/10/2013 08:47

and nzhearld also has taken wrong bad advice to call it a squall
http://www.nzherald.co.nz/nz/news/artic ... d=11137080

evidence is overwhelming for a small tornado

NZstorm · Unread post by **NZstorm** » Wed 09/10/2013 08:57

Met Service radar is 50km away and will not necessarily detect small scale mesocyclone features over Auckland.

Manukau heads obs · Wed 09/10/2013 09:08

the thing is the new replacement front started to show up on the rain radar just off the west coast here (up and down the coastline) an hour before the tornado struck
and there was a good descrete CB over the kaipara developing just ahead of that line...I could see it from here...and was impressed....I tried to get a photo to put up...but too much cloud in the way...and then David posted about how good it looked on the rain radar in the south kaipare...this is before it all hit...so there was time to re instate the severe thunder storm watch mentioning tornadoes etc...
(at least the auckland area was still in the severe thunderstorm outlook at that time

)

Nev · Unread post by **Nev** » Wed 09/10/2013 09:12

Good video by Geoff Mackley in that NZ Herald story..

Also an interesting snippet from the Otago Daily Times...

Auckland storm causes havoc

Ester Dawbin and Jonathon Baker had a good view of the incident from their elevated house near Mt Victoria. Ms Dawbin saw the twister travelling from Narrow Neck, along Vauxhall Rd to North Head - a distance of more than 1km. Mr Baker heard a loud bang and looked out the window to see what was going on. "I could see this really weird shimmery raincloud going across the ground and then we could see swirling debris and stuff floating up. It was spinning around but there wasn't that traditional funnel shape that you see on TV." ...

Manukau heads obs · Wed 09/10/2013 09:21

from the nzhearld article

The city had been earlier warned to expect thunderstorms and tornadoes, but weather experts were reluctant to classify the Devonport event as a tornado.

WeatherWatch head forecaster Philip Duncan, said the weather system that passed through Auckland was unlikely to have had enough energy to cause a tornado.

"It needs a lot of hot air rushing up to do that and Auckland didn't have that.

Come on Phillip
There was a good high dew point of 15C
and a newly developed descrete CB that formed over sun warmed southern kaipara...and a surface NNE and a strengthening NW flow coming in

perfect ingredients

ben g · Unread post by **ben g** » Wed 09/10/2013 09:35

No way it was strait line winds or a squall, sheds had been lifted 70m the smashed to smithereens when they hit the ground, the trees and fences along the edge of the damage track had fallen inwards, garage doors sucked towards the middle. I will add more details to the pics I took as time allows over the next few days.

NZstorm · Unread post by **NZstorm** » Wed 09/10/2013 10:35

the weather system that passed through Auckland was unlikely to have had enough energy to cause a tornado.

Quite the opposite, there was an energetic upper trough with jet stream support. Instability was not strong though but for tornadoes that's not important. And as Brian says low level shear and moisture were good.

ben g · Unread post by **ben g** » Wed 09/10/2013 10:47

The herald article it a joke, it says it was an easterly squall.
It clearly traveled from the nor west to the south east.

ImageUploadedByTapatalk1381268809.214879.jpg

Tornado Tim · Unread post by **Tornado Tim** » Wed 09/10/2013 11:12

I dont think this was a outflow based event (microburst/squall), The damage path based on photos shows that it was very localised, and the damage path didnt have a uniform feature (eg: trees all falling down the same way)..
An outflow feature is much broader than a Tornado and covers a much larger area as well, So I am very surprised Metservice would say this is a squall so soon without having someone go out an investigate. Heck get Georgina Griffiths out to check. They have Auckland representatives, use them! Honestly do you see the NWS staff in the U.S make a call on a event from the office, come on!

I think a Landspout or ex-waterspout turn Landspout is responsible for this, although we can't access the Doppler Base Velocity scan to verify.

More Meteorological Investigations need to take place in NZ to verify these types of events.

jamie · Unread post by **jamie** » Wed 09/10/2013 11:21

Yea the damage and eye witness reports are pretty complelling yet we are still not seeing any change in the wording of this event.

Poor reporting in my eyes. Very poor!

NZstorm · Unread post by **NZstorm** » Wed 09/10/2013 12:02

I think a Landspout or ex-waterspout turn Landspout is responsible for this, although we can't access the Doppler Base Velocity scan to verify.

More of a shear induced tornado and so I think technically in the supercell category.

Manukau heads obs · Wed 09/10/2013 13:11

this is Weather Watch explanation for their stance
"
Waterspout reports were apparently false, came from a photo from Feb 2012 that the Herald put up online for a short time before it was pointed out. And there are documented squalls in NZ that have caused similar damage - in fact worse damage which we have been involved in across NZ. Squalls can flatten buildings in extreme cases. We provided our opinion, supported by MetServce - you are more than welcome to disagree!"

Tornado Tim · Unread post by **Tornado Tim** » Wed 09/10/2013 14:09

NZstorm wrote:
More of a shear induced tornado and so I think technically in the supercell category.

If it was indeed a Supercellular Tornado, the damage would be much stronger than what it is.

Its seems too weak to be Supercelluler in my eyes, also the damage path would have been longer.

There may have been local relative SFC shear that could cause this, but I strongly doubt its super cellular.
It doesn't add up in my eyes.

Manukau heads obs · Wed 09/10/2013 14:20

it had an overshooting top
I could see the CB easily from here
it was impressive

ben g · Unread post by **ben g** » Wed 09/10/2013 15:06

Pic of the anvil about 20 min before the action

ImageUploadedByTapatalk1381284308.486774.jpg

Edit, looking north west

spwill · Unread post by **spwill** » Wed 09/10/2013 15:54

The Albany and Cambridge tornadoes occurred in non thunderstorm Cbs

Manukau heads obs · Wed 09/10/2013 16:07

yes
but though there was a report of loud thunder right at the same time as the tornado by the residents there

The anvil of the CB had a real circular shape to it from my view point from here
Looked like a super cell space ship from the Midwest to be honest
I was cooking dinner for the kids at time ...and trying to watch the dam thing ...dinner got a bit burnt...wish I had taken photos of it now...

ben g · Unread post by **ben g** » Wed 09/10/2013 16:29

My mates mates sisters husband sent me this radar grab from about 6pm (time stamp is Utc)

spwill · Unread post by **spwill** » Wed 09/10/2013 16:35

A couple more photos from me, the front over West Auckland at 5.45pm yesterday seen from Mt Roskill, the 2nd photo is the same view just 5 mins later.

jamie · Unread post by **jamie** » Wed 09/10/2013 18:38

That radar you have put up there Ben is an interesting one. It looks like its smoothed. Also the distance rings work from what I believe as location of computer rather than the location of radar.

Hard to make anything of the radar image but from the number of we witnesses saying there was a tube and spinning debris it's hard to rule out a tornado.

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