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

[NZstorm]

Met Service wrote

Could this tornado localised wind storm have been forecast?

No. Technology to forecast the very small small and short-lived wind storms like tornadoes or microbursts – as we see them in New Zealand - does not yet exist.

Technology is not required to forecast such events.

All that was needed was situational awareness by the weather forecaster.

GFS output at 06Z the day before the event for 00Z.

[spwill]

I notice Metservice have amended their blog today stating they now are of the opinion that it was not a tornado, but a severe microburst.

The weather amateurs on this forum have been largely suggesting it was a tornado that did the major damage, the weather professionals at Metservice said it was a tornado that did the damage, not possible tornado. Now Metservice are saying it was a wind storm, it is a very poor look for Metservice.

[Manukau heads obs]

I agree, not a good look at all
seems like they are cherry picking the evidence to suit in my opinion

[WIATNT]

I notice Metservice have amended their blog today stating they now are of the opinion that it was not a tornado, but a severe microburst.

The weather amateurs on this forum have been largely suggesting it was a tornado that did the major damage, the weather professionals at Metservice said it was a tornado that did the damage, not possible tornado. Now Metservice are saying it was a wind storm, it is a very poor look for Metservice.

Couldn't help myself... The 'weather amateurs' were largely 'suggesting' it was a tornado? An interesting rewrite of history.

Metservice's original blog appears to be assuming that local reports were correct. When they have looked at the visual evidence, local reports and their own data they have revised their view and concluded, subject to further detailed analysis, that the damage was caused by downdrafts (microburst) not updrafts (tornado if twisting). To me, as an outside observer, it is Metservice who actually look professional. They are saying in effect, "In light of new evidence, the original reports that it was a tornado that caused the havoc in Hobsonville on the 6th appear to be wrong.

Having seen some more videos of the event there is still no evidence of an updraft/twister, just shifting straight line wind.

I spoke to the local hair dresser who commented that none of her clients actually saw a twister... just intense wind blowing down the street. Some comment that it was blowing one way one minute then it suddenly changed direction and blew the other way, but no twister and no updraft, just intense wind and rain. A couple of vehicles were blown across a paddock, but nothing appeared to be sucked up into the air as occurs in a regular tornado.

Another person in a marine shop had been monitoring the radar every ten minutes. He said he was watching the weather come down from the north and when it got to the southern end of the Kaipara Harbour it veered inland and came toward whenuapai. He said he has painter clients who he keeps an eye on the weather for. He commented that the winds were swirling in a circular pattern about 2km across at least. When he looked across the harbour toward the city the wind was travelling approx north to south... when he looked up toward the luckens road end of hobsonville road the wind was more south to north. He thought it was a tornado, but never saw one.

These clips explain microbursts and look very similar to what has been videoed in Hobsonville. Some of these have hail which by all accounts was absent in Hobsonville. Sudden, short, intense, swirling.

http://www.youtube.com/watch?v=TkavH9aZue8
http://www.youtube.com/watch?v=4zw5rtRlj4I
http://www.youtube.com/watch?v=dOSIjoZnHwI
http://www.youtube.com/watch?v=S6ddot9jqOY
http://www.youtube.com/watch?v=kLzbJ5XQEQ8

Note tree damage description in this report...

http://ryereflections.org/servlet/pluto ... 3432373035]

MICROBURST: A small downburst with its outburst, damaging winds extending only 4 km (2.5 miles) or less. In spite of its small horizontal scale, an intense microburst could induce damaging winds as high as 75 m/sec (168 mph/270kph).
http://www-frd.fsl.noaa.gov/mab/microbu ... ourse.html

[Vertigo]

For the record, I am Joe Average with no involvement whatever with Metservice.

why do you keep repeating this?

it seems you turned up here around the same time that the criticism of the handling of this event took place.

[WIATNT]

vertigo,... because it's true! lol...

I'm not associated with weather forecasting whatsoever... personally, over my 50+ decades of life I've found them to be, mostly, no more than a lottery. Where we live 5 seasons in a day is not uncommon.

When experts or even expert wannabees can't even agree on what happened last week then what chance do we ever have for getting reliable weather forecasting.

I would still like to read what Philip Duncan's views are a week on... Philip is a credible independent weather forecaster who is claimed to have predicted the tornado... I've seen his video forecasts... he never did predict tornados... he said that tornados were possible given the weather patterns but were of low probability. In other words he said there "could" be, not that there "would" be. On the balance of probabilities he was actually saying that it was unlikely (low probability) for a tornado to occur.

Do you know if it is possible to differentiate downdraft storms versus updraught storms?

Can anyone help Joe Average understand what forecasters see when looking at a tornado versus microburst storm?

[Vertigo]

You are either a Metservice employee doing a **** job of justification of their calls, or just a run of the mill internet troll with no interest whatsoever in this topic.

Get it through your head, mate: youve had your say, voiced your opinion, we took it in and digested it. Now we dont really care anymore. Its boring now.

[Manukau heads obs]

but this is not about what Phillip Duncan said
not sure why you keep on coming back to him

There is lots of videos of tornadoes passing by in the midwest were the wind suddenly changes direction, blowing from a different 90 degree angle to before
which is what has been described by eye witnesses
(and has already been pointed out, you are not going to see a rain wrapped tornado very well..even hair dresser clients wont see it)

[Manukau heads obs]

also there is one video you linked to WAITNT which was a sped up time lapse
which showed the wind change from a moderate NE wind to a lighter NW wind (behind the trough line, at the surface initialy only (the upper clouds are moving in from the N)
that video shows the wind shear involved, an ingredient for this tornadic thunderstorm (which produced others, e.g Rotorua area)

[Flutterbye]

For the record, I am Joe Average with no involvement whatever with Metservice.

why do you keep repeating this?

it seems you turned up here around the same time that the criticism of the handling of this event took place.

My thoughts exactly. And as for the poster referring to Philip Duncan, well I can only presume that as a prominent 'private' forecaster, he probably isn't that popular with Metservice, lol.

Oh, and they can both get the forecast wrong down this way.

[Willoughby]

**This thread is going to be permanently locked at midday tomorrow. Though if it is warranted (like if there is any new information), please PM one of the moderators or myself and it will be unlocked. Thanks!

[jamie]

Thanks will. This was getting beyond a joke.

[Razor]

Thanks will. This was getting beyond a joke.

Hear hear

[Manukau heads obs]

I have only to add that it has been annoying how the waters have been muddied at times by irrellevent side tracks/deviations/etc,in my opinion

[tgsnoopy]

**This thread is going to be permanently locked at midday tomorrow. Though if it is warranted (like if there is any new information), please PM one of the moderators or myself and it will be unlocked. Thanks!

Thanks Willo. I'm tired of having the new kid on the block forcing his/her opinion and am suspect of said persons motives. Please also consider moderating postings from said person if it continues in other threads.

[spwill]

I'm not associated with weather forecasting whatsoever... personally, over my 50+ decades of life I've found them to be, mostly, no more than a lottery. Where we live 5 seasons in a day is not uncommon.

I can tell you WIATNT, weather forecasting has changed greatly over the last 20years, it is not unfair to expect a much higher standard of accuracy these days from our weather professsionals.
WIATNT wrote,

Metservice's original blog appears to be assuming that local reports were correct

So there was enough information for Meteorologists at Metservice to confirm a tornado ? It was noticed you gave the Metservice findings very little attention on this thread.

[Cook]

I have only to add that it has been annoying how the waters have been muddied at times by irrellevent side tracks/deviations/etc,in my opinion

I agree, the sooner nonsense like this: "Thanks Willo. I'm tired of having the new kid on the block forcing his/her opinion and am suspect of said persons motives. Please also consider moderating postings from said person if it continues in other threads." stops, the better.

All those who have contributed with real reports, investigations and analysis should be thanked. Those whose interest seems to be more focused on perpetuating whatever prejudice the may hold and attack those who express an honest interest in NZ weather do not deserve any thank you at all.

[WIATNT]

Spwill asked, "So there was enough information for Meteorologists at Metservice to confirm a tornado ?"

Apparently not... otherwise they would have. They thought there was based on unsubstantiated reports... but when they allowed their thinking to be enlightened by the evidence they openly changed their thinking.

Over a week has gone by and despite discussions not video, photo or descriptive accounts of the storm have demonstrated that this was a twister.

Spwill, given that mid day is approaching, list may be our last exchange... Think about this as a modus operandi. "Toward Meteorological Excellence: Learning from Experience."

As a storm chaser you should be taking a step back and asking yourself if this was a severe, no, extreme, microburst. How is a microburst different to a tornado? Well, Downdraught versus updraught is one. Straight line versus twister is another. I gather both demonstraight echo bows on ?radar (from what I've read recently.)

I find Philip Duncan's silence deafening. As I said before, I'd like to read what he thinks having a weeks hindsight to look at the evidence. Even on the Thursday afternoon he wasn't sure. Later he was 90 percent sure, but if he was wrong then he subscribed to a microburst the likes of which Nz may never have seen.

"Toward Meteorological Excellence: Learning from Experience."
"Toward Storm Chasing Excellence: Learning from Experience."

[WIATNT]

As I said, I found this place because I googled "Was it a tornado" and Hobsonville. This forum was the only hit so I joined to ask the question. At that point I was looking for a video of the said twister down the road so I could send it to family. The storm literally blew up our transformer. It had to be replaced and teh Vector boys finished the job at 11pm (ie nearly midnight.)

I joined on page 8. There had been plenty of discussion as to whether it was a tornado or not before I joined... here's my original post. Nothing sinister here.

WIATNT on Tue 11/12/2012 13:26
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?

[Razor]

Actually WIATNT if you chose to read with your eyes open you'll see Phil Duncans report today on the cyclone refers again to the fact that there was a tornado in Hobsonville,but somehow I doubt there is much point in making this post as you are entrenched in the manner of an ostrich.

Your tone and manner to long standing and respected knowledgeable members of this forum has been nothing short of offensive and rude, which is why the topic is rightfully about to be locked down - and this is an action I do not recall seeing here on this forum in a very very long time.

[Flutterbye]

Your tone and manner to long standing and respected knowledgeable members of this forum has been nothing short of offensive and rude, which is why the topic is rightfully about to be locked down - and this is an action I do not recall seeing here on this forum in a very very long time.

I'm picking it's the same person...

http://www.trademe.co.nz/Community/Mess ... 63&topic=5

[NZstorm]

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.

The Greenhithe clip confirms a tornado in the area.

Its a fallacy to believe that a tornado must be seen. Some tornadoes are rain wrapped.

[Cook]

Actually WIATNT if you chose to read with your eyes open you'll see Phil Duncans report today on the cyclone refers again to the fact that there was a tornado in Hobsonville,but somehow I doubt there is much point in making this post as you are entrenched in the manner of an ostrich.

Heaves a sigh of relief. Would you kindly provide a link to the article where PD or his team of experts present there analysis and reasoning for their conclusion? I am pleased this has been cleared up, it actually was a tornado and we can all move one. PD deserves thanks and I look forward to learn from him about this event.

Also, out of interest, did PD find that the damage was caused by a straight line gust, or the tornado?

[spwill]

Spwill asked, "So there was enough information for Meteorologists at Metservice to confirm a tornado ?"

Apparently not... otherwise they would have. They thought there was based on unsubstantiated reports... but when they allowed their thinking to be enlightened by the evidence they openly changed their thinking.

."

Metservice called it a tornado. You seem to know a lot about Metservice

[Weather Watcher]

WAITNT, I'd like to thank you for your contribution to the analysis of this event. I think it's been a very rational and logical investigation, and personally I agree with most of what you have said. I've also been impressed by some of the analysis you have done, especially determining where the 'Christina Woods' photo of the funnel cloud was taken from.

I'm a long-time reader of this forum, and an occasional contributor, and I've been appalled by the way you've been treated and some of the comments directed at you. Usually this is a nice place to hang out, and the weather discussions are quite rational. Hopefully we will see you back some time.