Moist NW flow and severe weather, Upper NI, 5 Dec -

[Manukau heads obs]

but the damage was 100m wide, not 10m wide, re the quote in that articile re the size of tornadoes
so not a small tornado by any standards
it seems like the M/S have been trying to down play the severity all along
when in fact its right up there
yes though the rain radar showed no inidication there was a rain wrapped tornado (in the midwest those take everyone by surprise too)
but the rain radar did show a bow echo

also there was reports of 150kmh winds actualy recorded, so dont know why only the 110 kmh speed is only quoted

But you can warn for a possible severe weather day.

yes, that is the whole point
this CB line did not even have a watch on it
and yet, with no change to the conditions/environment it carried on being a severe thunderstorm all the way to Gisborne

i.e the potential setup was there all along, and so you could argue could have been better predicted?
especialy as the convergence of warm moist NE wind and a NW wind over the auckland area has produced tornadoes before

[NZstorm]

i.e the potential setup was there all along, and so you could argue could have been better predicted?
especialy as the convergence of warm moist NE wind and a NW wind over the auckland area has produced tornadoes before

Pattern recognition is a good severe thunderstorm forecasting tool.

It alerts the forecaster to the possibility of severe weather if storms do develop.

[Tornado Tim]

The Damage need's or needed to be analyzed by an expert to ascertain what damage was caused by different processes within the storm.
Straight line winds can cover a much greater area than a tornado can.

Our tornados are only tens of metres wide

For the Majority of recent tornadoes in NZ that may be true , but that statement when you look at history is false.
Since Dan Corbett comes from the UK, he is obviously unaware that a very strong Tornado hit Frankton Hamilton in 1948 and nearly took it off the map.

[WIATNT]

Live in the general area. Can't find anyone who actually saw a twister... severe swirling wind and rain... intense. Looking at the trees damaged there doesn't appear to be a pattern of damage facing one way on one side and facing the other way on the other side that you'd expect with a twister.

Whilst there was low cloud twisters are at ground level. Is there any video evidence of a twister? If so, where is it? There was a video take in Greenhithe showing a very short lived whirlwind, but that isn't what hit whenuapai and hobsonville. All first hand reports I've had have been severe gale... stuff blowing down the street... not sucked up into the air. Unless the term tornado has been redefined, how can this be classified as a tornado?

[Cook]

Live in the general area. Can't find anyone who actually saw a twister... severe swirling wind and rain... intense. Looking at the trees damaged there doesn't appear to be a pattern of damage facing one way on one side and facing the other way on the other side that you'd expect with a twister.

Whilst there was low cloud twisters are at ground level. Is there any video evidence of a twister? If so, where is it? There was a video take in Greenhithe showing a very short lived whirlwind, but that isn't what hit whenuapai and hobsonville. All first hand reports I've had have been severe gale... stuff blowing down the street... not sucked up into the air. Unless the term tornado has been redefined, how can this be classified as a tornado?

The media keep saying it was a tornado, Phillip Duncan says it was a tornado, so it must have been a tornado, right???

To be honest I feel disappointed by the unscientific approach taken to this, but maybe I am expecting too much. All the evidence seems to point to a down-burst/rear inflow jet scenario but the evidence does not seem to count for much.

[Manukau heads obs]

really?


they (media) interviewed the workers at the site where the concrete wall was blown down
and they said they saw the tornado just before it hit
also a rain wrapped tornado is not easily seen anyway
NZStorm and Spwill have seen the evidence first hand
they are very experience storm chasers
and they said its a tornado

even the Met Service officialy have called it a tornado

its a relatively narrow (100m wide ) path of destruction

its easy for you Cook to say otherwise, but you have not seen the actual evidence

[spwill]

Live in the general area. Can't find anyone who actually saw a twister..?

I talked to a guy at Hobsonville ( contruction worker) on the day who claims he saw a tornado at Hobsonville. The condensation funnel on tornadoes is not always visible to ground level, I think this is the case in the Greenhithe clip, a persistent tornado there but not always clearly visible. Tornadoes can be obscured by low cloud and rain . The Greenhithe tornado clip confirms local weather conditions on the day were supportive of a tornado.

[WIATNT]

Phiip Duncan thinks it was a tournado... 90-10... Metservice have stepped back from calling it a tornado.

The tornado in Rotorua lifted people, machines and other objects into the air. There seems to have been no updraft at Hobsonville which would suggest it wasn't a tornado, unless the definition has been changed. If it was a twister the damage would be bi directional. As far as I saw when I went and looked it isn't. Tornados connect with the ground. What was seen in the greenhithe clip wasn't a tornado. We see whirlwind often on our property but would never think of suggesting they were mini tornados.

I'd like to see an expert like Philip Duncan lay out his case for it being a tornado (although he's not entirely sure. Personally, and I'm only talking from a point of view of having seen truckloads of real tornados on Te News and Te Internet, this had all the hallmarks of a seriously severe squall, If it was it would probably be the most severe ever in NZ.

[WIATNT]

they (media) interviewed the workers at the site where the concrete wall was blown down
and they said they saw the tornado just before it hit

Can you post a link to these reports in the media?

[spwill]

I'm only talking from a point of view of having seen truckloads of real tornados on Te News and Te Internet, .

I think you need to do watch a truck load more of Te News and Te internet WIANT and do some reading.

[Philip Duncan]

I don't get into debates/discussions with people who don't use real names - for all I know I could be getting into a chat with a MetService forecaster - which has happened before in this forum using a 'handle' - and no one debates anything just protects butts and calls names. I feel strongly this was a tornado based on damage, 151km/h wind gusts recorded nearby (according to Civil Defence) and the overall weather that day that I observed from just 4kms away.

Damage was well above normal squalls and more widespread - and there have been some reports of eyewitness reports of a funnel clouds. At the end of the day it's probably irrelevant - as our focus here shouldnt be so much on warning of tornados but instead doing a better job of educating NZers about the real risks of thunderstorms, which can include tornados.

Also if we freed up our rain radar - high res - people would use it more to track incoming thudnerstorms. It's not rocket science to watch heavy cells on a radar - and with high res you can even zoom in to your street even and track where the rain is, direction its moving etc. In 2013 more people will use mobile devices for this stuff than PCs so we have all the technology now to do this and you can anywhere with cell coverage to access it.

The more tools the general public have to protect themselves the better. we'll get there one day, the tide is turning on the SOE model. Not everything in life is about making a buck, especially when it comes to public safety.

Phil

[WIATNT]

[/quote]
I think you need to do watch a truck load more of Te News and Te internet WIANT and do some reading. [/quote]

When i stopped and asked several people they said it was a tornado. When I asked them what they saw they said incredibly heavy rain and wind. I specifically asked if they saw a twister they said no, but it must have been a tornado. As with many things in life, if something is got into print three times it becomes set in stone.

In this day and age it is incredible that no one got a video of a twister. All the video clips I've seen just show incredibly heavy rain and wind... horizontal... no updraft... bins and rubbish being pushed down the road not sucked up into the air as one would expect to see in a real tornado.

I don't think this discussion will end for some time because there is no direct evidence it was a tornado. There is direct evidence it was a brief, violent, intense squall of some kind.

[Manukau heads obs]

All the video clips I've seen just show incredibly heavy rain and wind... horizontal... no updraft... bins and rubbish being pushed down the road not sucked up into the air as one would expect to see in a real tornado.

I suspect that particular footage was of straight line winds
which suddenly ramps up as the emedded tornado passes by
(I have mentioned this further up the thread)

[David]

In this day and age it is incredible that no one got a video of a twister. All the video clips I've seen just show incredibly heavy rain and wind... horizontal... no updraft... bins and rubbish being pushed down the road not sucked up into the air as one would expect to see in a real tornado.

http://www.nzherald.co.nz/national/news ... _id=129676

[WIATNT]

With respect, David, that is a funnel cloud elsewhere, not the windstorm that did damage in Hobsonville. It may have been Greenhithe and the time/direction is not known. If it was Greenhithe the direction is either generally north to south if facing notheast or generally south to north if facing hobsonvill/whenuapai.

Can I assume the storm travelled from whenuapai to hobsonville? In which case that video exhibit is of something over hobsonville/whenuapai. Not the intense wind after the main exhibit has passed.

[jamie]

if you make your screens contrast a bit darker you can really see the size of that tornado. i did it by simply standing up at the computer and watching

this video along with another photo of a rather large funnel cloud which is possibly on the ground supports there were definitively tornados around.

I have no doubt there was some very strong straight line winds that have done some amazing damage. However the fact that no one seems to have seen the tornado doesnt mean there wasnt one. It sounds like it was rain wrapped and therefore invisible. Ive seen a storm in the USA that had a tornado that was rain wrapped. looking at the storm you would have never known there was a tornado on the storm. They are the most deadly tornados in the USA because you simply cant see them. There is a very good chance this one had a rain wrapped tornado.

BUT all this is getting way off the important point. Tornado or not, i dont really give a rats bum. The problem is how late the watch and warnings came out AFTER the fact.

[spwill]

. Tornados connect with the ground. .

Used Wikipedia

Also, a tornado does not necessarily need to have an associated condensation funnel—if strong cyclonic winds are occurring at the surface (and connected to a cloud base, regardless of condensation), then the feature is a tornado. Some tornadoes may appear only as a debris swirl, with no obvious funnel cloud extending below the rotating cloud base.

. There would have been severe straight line wind on the day no doubt but there is so much evidence for tornado as well .
With the Greenhithe clip we don't know where that was taken, it may have been a tornado seen from Greenhithe rather than a tornadic funnel over Greenhithe.

[WIATNT]

swill, if that was taken from Greenhithe it's going the wrong direction for it to be looking out over hobsonville... it would be toward albany.

[WIATNT]

Jamie, you should give a rats bum... the heart of any reliable forecasting system is credibility and trust. If forecasters make false claims of fact their credibility as risk managers heads south.

Has anyone plotted the path of the Whenuapai/Hobsonville storm on a map with direction and damage shafts?

[spwill]

swill, if that was taken from Greenhithe it's going the wrong direction for it to be looking out over hobsonville... it would be toward albany.

Regardless, Greenhithe is near Hobsonville and the clip shows the day was supportive of tornadic development in the area.

[tgsnoopy]

Personally I don't give a darn if it were a tornado or not. The fact is that it turns out it was severe enough to require a warning. Various people picked the risk. Metservice for whatever reason did not issue a warning in a timely manner. Tragically 3 lives were lost. That is really the guts of the situation, tornado or not isn't really that significant.

Warnings being issued in an appropriate timely manner is far more important than tornado or not.

[WIATNT]

Spwill, sure the weather may have been supportive of tornadic development in the area... it is a huge leap to say that proves it was a tornado.

Weather forecasting is about credibility. Calling something a tornado when there majority of the damage & evidence certainly wasn't caused by a tornado is not conducive to good risk management practice.

[spwill]

I should repeat I talked to someone at Hobsonville on thursday afternoon who said they saw a tornado, It is their interpretation of what they saw but still a tornado report.

[WIATNT]

tgsnoopy, The three lives lost are more to do with responding to hazards. The workers obviously never considered the wind could topple the vertical concrete slabs. I'd love to see Hawkins risk matrix of hazard identification and what workers should do if the wind came up.

It about how humans react in those few seconds we have to reduce imminent risk whether it be an earthquake, storm or fire. Most people would have known a storm was brewing that day. We we are it became very tropical... like stepping out of a plain in Fiji. Then it started raining cats and dogs with lightning... power went out Our transformer literally blew up and was physically replaced by vector at 11pm that night. Big ups to Vector.

[WIATNT]

Spwill, i talked to several people who live there. They referred to a tornado. When asked they acknowledged the extreme wind and rain, saw no twister or cyclonic wind and assumed it was a tornado. The fact others called it a tornado reinforced their conclusion. Get it in print three times and it becomes set in stone. Classic!