TS possable This weekend ( 8-9th January)

TonyT · Unread post by **TonyT** » Wed 05/01/2005 07:43

Aaron J Wilkinson wrote:Tony, why possible thundery showers tomorrow?

Gut feel. Thats why its only "possible".

Manukau heads obs · Wed 05/01/2005 08:07

that sink hole photo with refrected rainbow light.....good stuff
i saw a large round (only half round) hole in the altocumulus near here just yesterday....with another layer of altocumulus above that...
i.e is a large area of sinking air,, and there must be reasons of a dynamic heat nature why it forms a circle

spwill · Unread post by **spwill** » Wed 05/01/2005 08:33

That excellent photo stormchaser put up looks like Iredescence, sun light diffraction through the high cloud, for some reason mostly seen over Mnts in winter.

Skywatcher · Unread post by **Skywatcher** » Wed 05/01/2005 08:41

Aaron J Wilkinson wrote:Ha, your right John. Just went on to the roof and noticed some very distant flashes from what looks like way on the other side of the peninsula. I just wonder where it's coming from. Look at the lateset weatherzone sat pic (midnight). I don't really see any Cb there except for off the Waitaki Coast as I said above, could we really be seeing flashes from way down there?

Yes

I took the opportunity of a clear night to look for Comet Machholz and the flashes to the south were bright enough to notice when I was facing north (OK, it's a fairly dark garden).

I was interested in seeing what it looked like from the coast so I drove to Taumutu. I think it might have been a bit nearer earlier on but the clouds I could see were close to the horizon and further away than the storm of the 26th. I might have a few flashes on video ... haven't checked yet.

The tweaks I've made to the ranging for the tracker to improve its accuracy over land will tend to make storms over the sea appear a lot closer than they are. In last night's case I'd guess they were at least double the distance - about 150 to 200km away.

Driving home I could also see flashes over the Alps which could have been from a storm on the West Coast.

Thunder · Unread post by **Thunder** » Wed 05/01/2005 10:05

TonyT wrote:
Aaron J Wilkinson wrote:Tony, why possible thundery showers tomorrow?
Gut feel. Thats why its only "possible".

Awwwhh.....I want to know gut feel! How long will it take for me develop these skills? lol. Can't give me any small amount of info on why possible thundery showers, sorry if that sounds rude..

Cool you went to the beach Steven G! And yes there was a storm in the alps last night/early this morning but I didn't see any flashes, only noticed it on the tracker.

TonyT · Unread post by **TonyT** » Wed 05/01/2005 10:21

Aaron J Wilkinson wrote:[Awwwhh.....I want to know gut feel! How long will it take for me develop these skills? lol.

I think you probably already have it. I think the basis of it is experience, the more you look at weather situations and tie them up with what actually happens the better your feel is for making predictions. Its a process of balancing up probabilities in your head based on what you see in front of your eyes (predictive info) and what you perceive the outcomes to be. Perceive is the key word though, you need to guard against preconceptions and try to make sure you deal with real outcomes. In your case, you have a tendency to want to see thunderstorms developing in situations where a more objective assessment would dismiss them. Its a learning process. Some people develop it to a very high degree (in the context of TS forecasting I would put John in this category - you will notice that he is mostly just working off MSL pressure charts, and doesnt put out too many false warnings).

Aaron J Wilkinson wrote: Can't give me any small amount of info on why possible thundery showers, sorry if that sounds rude..

I suppose its covering the bases a little - storms are a greater possibility in inland Otago in this pattern I think, so its probably worth mentioning them for South Canterbury just in case the region of "possible storminess" impinges a little further north. Plus we know the Fairlie area is a preferential site for storm development, plus yesterday's radar shows likely storm development in South Canterbury, plus there is a little bit of "recent historical inertia" in that we have had an uncharactertistically large number of storms in Canty in recent weeks. Put all those factors together and gut feel says its worth mentioning as a "possibility" in the forecast, even though the objective evidence points (mostly) the other way.

I hope that helps.

TonyT · Unread post by **TonyT** » Wed 05/01/2005 10:27

I should add that I dont expect storms in South Canterbury today - thats why the word "possible" is used. I would expect that at the end of the day there wont have been a storm. But there is some chance, more so than on most other days. Perhaps 30% chance.

Thunder · Unread post by **Thunder** » Wed 05/01/2005 10:48

Thanks very much Tony. Good info there.

Yes I think John only uses ecmwf charts and tends to do an excellent job. Although there was that late afternoon on the 25th November when that big gust front came through in that late hours of the afternoon. There was that rain band that went through earlier and I remember John saying no chance of storms becasue the situation didn't look good but then some did happen, so I guess one can be caught off gaurd. Ange did get that night right and I also keeped my eye on the situation and was always hopefull for something and what I thought would happen did.

But then I've been wrong aswell, I'll get better I hope.

Storm Struck · Unread post by **Storm Struck** » Wed 05/01/2005 11:56

There's some darkish CB's out to my north here which are starting to look threatning

but I wasn't all that keen on TS happening today either as I say it's looking not too bad now with 20dg out there.
They are sorta CB's but they are flattend a little or wind swept but that doesn't seem to be stoppign them from getting darker. hmmm

.
Who knows.
Yeah I also seen some flashes out to the west last night at about 1am but some nice CB's went through from 7-9pm last night with a light brief shower here must have been heavier further north I think.
Cheers
JASON TIPPET.

Storm Struck · Unread post by **Storm Struck** » Wed 05/01/2005 21:56

I have changed the post name now to later because TS are further out on forecast now which is looking at this weekend.
Friday there might be TS down south in Invercargill and southland and parts of inland or central Otago plus small part of Westland.
Saturday tells of TS on the west coast, southland,otago and maybe Canterbury later on as the southerly change moves up.
Sunday iam not sure about but it has a possability there for TS to develop over southern and northern SI and southern NI probly.
There is a low deepening in the Tasman but to how it behaves is to where and what it will deliver.
There is however for all the holiday makers and to all of us that want the Summer there is a sighn of summer to come with a nice High moving in over New Zealand for much of next week at this stage fingers crossed.

So then you can go swimming

maybe a little cold in the ocean but backyard pools like mine will heat up nicly mines already 20dg and thats not solar heated.
It already felt like summer yedterday with 26dg and today 24dg so let the high come in and give a

sour face to the SW winds and rain.
Cheers
JASON TIPPET.

NZ Thunderstorm Soc · Wed 05/01/2005 23:09

Jasestrm wrote: There is however for all the holiday makers and to all of us that want the Summer there is a sighn of summer to come with a nice High moving in over New Zealand for much of next week at this stage fingers crossed. So then you can go swimming maybe a little cold in the ocean but backyard pools like mine will heat up nicly mines already 20dg and thats not solar heated.
It already felt like summer yedterday with 26dg and today 24dg so let the high come in and give a sour face to the SW winds and rain.
Cheers
JASON TIPPET.

Yes about time too

...but I see there is a tropical cyclone going to lurk around in the seas to the NE of NZ. What this does is anyone's guess but if there are lots more of these, anticyclones should track over us, instead of heading NE over and around us.

JohnGaul
NZAAA

NZstorm · Unread post by **NZstorm** » Thu 06/01/2005 08:28

Ricky's lightning detector has a storm about 150-200km west of Auckland but satellite imagery places the cb a good 500km away. I am not getting any spherics on the am band.

These Isolated storms have developed on a weak frontal zone out to the west of northern NZ in responce to high dewpoint air.

spwill · Unread post by **spwill** » Thu 06/01/2005 09:40

Yes NZstorm, the lightning detector should be used in conjunction with a recent satellite photo for accuracy.

Our orid weather continues but atleast we had a warm night, a min of 19C with dew points of 17 - 18C.

ricky · Unread post by **ricky** » Thu 06/01/2005 12:17

I always look at http://flash.ess.washington.edu/L_plot_weather_map.jpg to place those thunderstorms..

the extremely good propagation of signals over the sea means they frequently show way too close on the detector, especially at night..
just looking now though, there is something quite close to the NW..

spwill · Unread post by **spwill** » Thu 06/01/2005 14:33

Auckland Airport this afternoon has a temp of 21C but a dewpoint of 20C which I think is the highest so far this Summer.
Gloomy here.

NZstorm · Unread post by **NZstorm** » Thu 06/01/2005 15:04

Had a couple of brief heavy showers here this afternoon from that weak front.

Currently 8/8 stratus at 100m.

Manukau heads obs · Thu 06/01/2005 18:44

i see the word orid is sticking, LOL
cloud right down on the hills here today, with a few brief heavy busts of rain...nothing like the hutt valley got!
its more like december weather rather than january weather....

Storm Struck · Unread post by **Storm Struck** » Thu 06/01/2005 21:03

Afternoon showers are forecast for Canterbury/Otago tomorrow and I also see Met service has it for Low cance of TS in east tomorrow at this stage the temperatures are meant to be over the 20's in east tomora.
Any thoughts on tomora John?.
Heavy rain band is also going to work it's way down over the northern half of the north island as a complex low makes it's way towards NI and also a low further south in the Tasman.
cheers
JASON TIPPET.

NZ Thunderstorm Soc · Thu 06/01/2005 21:24

Jasestrm wrote:Afternoon showers are forecast for Canterbury/Otago tomorrow and I also see Met service has it for Low cance of TS in east tomorrow at this stage the temperatures are meant to be over the 20's in east tomora.
Any thoughts on tomora John?.
Heavy rain band is also going to work it's way down over the northern half of the north island as a complex low makes it's way towards NI and also a low further south in the Tasman.
cheers
JASON TIPPET.

Dosen't look all that thundery for tomora but if any does occur it will be heat related.
I do have a 1 out for tomora, just incase.

Next few days after that are worth considering

JohnGaul
NZTS

Andy · Unread post by **Andy** » Fri 07/01/2005 09:53

Late thunder showers after 7pm yesterday. Alexandra had it's warmest day since some time in november

reaching 30.1 degrees.

5.5mm of rain fell with some good thunder claps to the east, with the rain arriving from the southwest.

Chris Raine · Unread post by **Chris Raine** » Fri 07/01/2005 13:52

We have Cb's building up across Southland this afternoon. The storm tracker is showing there is a thunderstorm in Northern Southland currently. Off to have a look

Fujita Phil · Unread post by **Fujita Phil** » Fri 07/01/2005 14:05

Thunder here now. Big Cb off to the west

Storm Struck · Unread post by **Storm Struck** » Fri 07/01/2005 14:29

Wow what a TS out to my SW it's brewing up fast even if you stand there and watch it you can see it pushing up into the atmosphere fast.
Havn't checked tracker yet but Aaron is going chasing with Steve Graham not sure where they currently are though.
Cheers
JASON TIPPET.

NZstorm · Unread post by **NZstorm** » Fri 07/01/2005 17:15

The weatherzone sat pics have been showing that activity over Southland/South Otago/Dunedin quite well. Hopefully you guys down south have got some good photos.

Chris Raine · Unread post by **Chris Raine** » Fri 07/01/2005 18:17

I have spent the last four hours chasing thunderstorms across Southland . One cell began over Invercargill at 2pm and tracked it all the way to Waikawa East of Tokanui. Continuous claps of thunder everytime I stopped. Spherics -heaps of on the radio. Chased another cell north of Winton -Hokanui Hills area at 4pm . Now starting to rain heavily in Invercargill again as I type this at 6.15pm. There I was at Tokanui and realised the camera was sitting at home Jeez!