Thunder Watch No2

Michael · Unread post by **Michael** » Sat 15/11/2003 12:50

Very wintry in Auckland today but little rain so far today

Thunder · Unread post by **Thunder** » Sat 15/11/2003 15:37

Yes Ben, rained for about a half hour here in Southshore, was sunny beforehand then cold and rainy but has warmed up a bit again with the sun coming out. Wind was NE then SW but has gone back to a NE again (I think, I'm just looking at the trees for my wind direction). As the big Cb went offshore mammantis could be seen in its anvil, wasn't hugely spectacular, ok though. Something was just lacking hence it never went thundery.

Cheers
Aaron Wilkinson

Willoughby · Unread post by **Willoughby** » Sat 15/11/2003 16:09

At lunch on Friday, Hamilton city central apparently had a 15-minute downpour of hail. While in Hillcrest (Hamilton south-east) it was always sunny. At around 3.45 we had a thunderstorm, possibly with hail somewhere else in Hamilton. It left Hamilton and was going north towards Ngaruwahia at about 4.30. After it left it was a chilly 13c. The CB's were quite large. Then we got another one! at about 7.45pm with beautiful sunset light rain. I didn't hear any thunder under this CB. MetSerive didn't predict any hailstorms for Hamilton, but they did for Taupo. Did Taupo get any?

NZstorm · Unread post by **NZstorm** » Sat 15/11/2003 18:51

Thanks for the interesting report Foggy.

I noticed the odd cb top over the Waikato on friday. I was expecting Isolated weak thunderstorms with hail and that is pretty much what happened. About midday I photographed this cb, looking south from Auckland. Photo taken from Botany Downs. The cloud lacked an anvil but looked quite punchy and very glaciated. I tuned into the am band and got static, about every minute. But I knew this cloud would have had a good downpour of hail with it given the cold upper air.

NZstorm · Unread post by **NZstorm** » Sat 15/11/2003 19:38

Thanks for the photos Aaron.

I agree the 27th October 2002 event would have been a supercell.
Looking at the Invercargill sounding on the day and surface obs from Canterbury a good wind shear environment existed. And given the large size of the hail, CAPE must have been locally quite high over Canterbury.
It takes a very strong, and persistent updraught to produce hail stones of 2cm+ size.

Michael · Unread post by **Michael** » Sun 16/11/2003 06:04

Unfortunately we lost the Rugby semis' like the dismal weather we keep getting in NZ

Manukau heads obs · Sun 16/11/2003 06:30

they played a better game...less mistakes, tried harder, defended well.....
so they deserved to win
but..
BUGGER!!!!!!!!!!!!

NZstorm · Unread post by **NZstorm** » Sun 16/11/2003 06:51

World Cup Rugby finals are about performing on the day. The Wallabies rose to the occasion. So yet another WC were the AB's don't make the final. It is a BUGGER.

As for dismal weather....should get plenty of that bright stuff this week Michael. No good for storm watchers though.

NZstorm · Unread post by **NZstorm** » Sun 16/11/2003 14:22

Clear and just a few puffs of a southwester here, about 03kts, 21C.

Todays freezing level at Invercargill is around 3000m, thickness 5579.
Forecast for Southland is for snow to 700m tonight so a big change coming in with the front. Typical spring conditions.

NZ Thunderstorm Soc · Sun 16/11/2003 21:29

Just come back from a WE in Oamaru where the weather today was quite warm and blustery with NW winds. I don't know what temperature it was must of been in the mid-twenties. No sign of the impending cold front that is suposed to move up over us overnight which is a bit of a shame.
I don't think I'll bother with a thunder-watch for tomorrow as I think it will pass quickly over with a lot of wind. Mild here at the moment. 19c with hardly any wind.

JohnGaul
NZTS

Michael · Unread post by **Michael** » Sun 16/11/2003 21:51

According to TV1 news it was 30C in Timaru today the lucky buggers-We maybe lucky to score that once every 4 or 5 years 1 day in the whole year

Thunder · Unread post by **Thunder** » Mon 17/11/2003 23:46

Thanks Steven, does anyone reckon that first and second shot is a funnel cloud? Yes or no, I can take it!

No world cup this year, life will go on! You'll be going to your job or business, doing your various things and activities and 4 years will pass and another chance will come for the AB's to do the're thing! Until next time. Now to see if we come third or fourth?

Cheers
Aaron Wilkinson

P.S We had very small hail here today with good rain in the morning, cleared up to a more sunny afternoon but the breeze was and still is cold from the south.

NZstorm · Unread post by **NZstorm** » Tue 18/11/2003 17:19

No, not a funnel cloud there, rather a downward cloud protrusion brought about by turbulence.

I think there will be a drought this summer in Auckland. Starting to dry out now and we are due for a drought. Thats my prediction.

Thunder · Unread post by **Thunder** » Wed 19/11/2003 17:48

Thought so, thanks Steven. I couldn't see any rotation and it came and went quickly.

What about that pic you took of an Auckland thunderstorm not long back, I remember you saying that a runner or biker went passed you as you were taking the photo and commented on the cloud formations and how they looked spectacular, you said you agreed but you couldn't quite get it in any of your photos. What I'm trying to say is that in one of those pics you took that day you can see what looks like a funnel cloud in it, me and John commented on it but never heard whether it was one or not. Do you remember that day Steven and was there a funnel cloud?

Cheers
Aaron Wilkinson

TonyT · Unread post by **TonyT** » Wed 19/11/2003 18:54

Aaron - if you are close enough to the bottom of a CB to see what you think is a funnel cloud then if it is one you will hear it, and feel a dramatic increase in wind speed as well. If you dont hear or feel this, then it aint a funnel cloud. Now, I am no expert on funnel cloud dynamics, but it would be very unlikely to get a funnel cloud developing from a small airmass CB of the type we get in cold SW flow here in Canty. You really need a large cloud, several km across, which more usually generate convectively over a warm surface.

Sometimes if you happen to be under a large cloud of this type you can look up and see rotation occuring in the bottom of the cloud - it doesnt look like a funnel cloud, but rather you can see that different parts of the base of the cloud are moving in different (often opposite) directions. I think this pattern is what is needed as a precursor to the development of the funnel cloud itself, which generates around the vortex once the rotation really gets going and narrows down.

Believe me once you have seen this rotation, and then seen a funnel cloud develop, you come to realise that the small cloud features you have been geting excited about are just that - small cloud features, not the main event

NZstorm · Unread post by **NZstorm** » Wed 19/11/2003 19:03

No, that was not a funnel Aaron, just cloud being stirred around by turbulence.

I would like to photgraph a funnel cloud, but I havn't seen one now for a few years. As I have stated before, I once observed a series of funnel clouds in one day, about 12. And on that day I never had a camera with me.

Weather in Auckland is particularly stable at the moment and has been for the last month.

Thunder · Unread post by **Thunder** » Thu 20/11/2003 21:59

Awsome Tony, ya got me excited! (Are they really that loud?) When was the last time one of those big convective type storms occured near Chch, I've only seen ones that come from Southerly changes (the 27th Oct 02 storm with tornado was a southerly type change one though). I haven't lived long enough!

Thanks Steven, yes I've noticed it's been relatively stable lately over the Auckland area, not like a we while ago where you took all those awsome pictures of those Auckland area Cb's. Chch has allready had it's thunder quota for this year with a storm earlier this year, one in August or was it September?, that day with the inland thunderstorms not long ago and then just recently with that day with my pictures earlier on in this thread, there has also been a few days where Cb's have been close for e.g. the ones that Deano recorded lightning bolts out to sea not long ago near Ashburton. Overall there hasn't been anything overly exciting this year, best storm this year was the one in January with marble sized hail in Chch. Hopefully there's more to come with summer only just beggining but as I've heard it's meant to be more of a La nina year that discourages me slightly.

Cheers
Aaron Wilkinson