Thunderstorms, 12 July-

[C-Nimbus]

oh man, looks like Hamilton's getting it AGAIN! I hate Aucklands weather! It might just be me, but when I look at all sat pics, lightning trackers and radar pics, storms seem to switch off to the South west of Auckland out to sea before making land fall. Why does this constantly happen? It can't be land topography because it often happens 50km off shore. Is there a cold surface water current out there or something? It can't be put down to chance because it happens so frequently. It is very frustrating

i have thought the same Cameo, i live in sunnyvale up on the hill and they always seem to go past us. Just so you know, i was chatting with some metservice dudes who had historical lightning data for the area, and sunnyvale had been hit twice in the last 10 years!!!!

i think some of it has to do with our proximity to the waitaks and we are almost in the shadow as it were so that may explain it. However storms that start on the gulf and then move eastwards can sometimes get us...but i know what you mean.

on the flip, we get great sunsets and superb side-views of other Cb's expecially from the cemetery where we can see right out over to Coromandel.

either way west is still best IMO

[Razor]

StormVue has just gone past 20,000 strikes for the day.

Is there any sort of record being broken here? Looks like drama about to unleash on the lower North island....

[Shepherds Valley WX]

Low rumbling thunder heard here in Upper Hutt with light rain..... Baro 1002.5 dropping with a gusty NW and 12 degrees C. Good strong sferic recorded on low AM band on my old FRG-7

[Flutterbye]

Low rumbling thunder heard here in Upper Hutt with light rain..... Baro 1002.5 dropping with a gusty NW and 12 degrees C.

I see MS have put out an advisory for the lower NI - squally thunderstorms with some heavy rain.

[Shepherds Valley WX]

Wellington Lightning Detector showing good activity:
http://home.xtra.co.nz/hosts/zl2tsweath ... rmVue.html

[C-Nimbus]

heres the 2pm sat image showing the WLZ deluge approaching.

quite a nice Cb line in the NW -SE orientation is clearly visible in this image.

[spike_01]

Thunder, lightening and heavy rain for the last 30 minutes here...

[Razor]

Ya can't say you weren't warned Spike!

[Cameo1]

oh man, looks like Hamilton's getting it AGAIN! I hate Aucklands weather! It might just be me, but when I look at all sat pics, lightning trackers and radar pics, storms seem to switch off to the South west of Auckland out to sea before making land fall. Why does this constantly happen? It can't be land topography because it often happens 50km off shore. Is there a cold surface water current out there or something? It can't be put down to chance because it happens so frequently. It is very frustrating

i have thought the same Cameo, i live in sunnyvale up on the hill and they always seem to go past us. Just so you know, i was chatting with some metservice dudes who had historical lightning data for the area, and sunnyvale had been hit twice in the last 10 years!!!!

i think some of it has to do with our proximity to the waitaks and we are almost in the shadow as it were so that may explain it. However storms that start on the gulf and then move eastwards can sometimes get us...but i know what you mean.

on the flip, we get great sunsets and superb side-views of other Cb's expecially from the cemetery where we can see right out over to Coromandel.

either way west is still best IMO

Yeah, west is still the best. You must get to see some pretty great lightning from up there at the cemetery. I personally have never heard a close lightning strike in New Lynn. We generally get deep loud, distant rumbles and see only a small amount of lightning, but the storms never come closer than 2km to us. I think you are right about the Waitakere shadow thingy. I wrote to Bob McDavitt a few times discussing it and he said New Lynn was in the North western shadow of the Waitaks, and that basically meant that storms can be deflected around the range to north and south Auckland and I suspect the land distance between west Auckland and east Auckland gives rise to the development of new storm cells for east Aucklanders. In regards to the funny situation out to sea to the south west, McDavitt said that I may have noticed(along with you thankfully ) a weather divergence pattern(whatever that means) which is why I wanted to get other peoples opinions and I'm happy you have noticed the same thing It's really anoying watching them fly past like that.

[Cameo1]

check these out

[Cameo1]

no.2

[KiwiWeather]

Totally agree.

Its so damned frustrating.

Getting all excited at the possibility of action, but alas just when you think the cork is going to pop out of the top, it either fizzles into oblivion or simply moves on.

Heard a (SINGLE) thunder clap about 1020 this morning, apart from that, all the clouds are around but no one has turned on the switch !

Going to pour myself a glass of wine and try to ignore the wx - sigh

[C-Nimbus]

My understanding of divergence is that its opposite to convergence, whic is the coming together of two air masses.

NZstorm, spwill and MHO (Brian) are pretty much experts on auckland T/S occurance and they may be able to help you out on the divergence thing.

I'm particularly interested in the summer time convergence storms that we get here in auckland. Sometimes the convergence line can stretch from Northland thru the waikato etc etc. This forms due to a number of factors in auckland, these are:-

1) Summertime heating of the landmass (isthmus) creates and influx of colder, moist air from the sea to 'replace' the hot air that has risen. This also gives us our moisture source

2) We have ocean on both sides so that can sometimes lead to a western convergence and an eastern convergence. Funny enuff, this summer it was the eastern convergence that fired up with the most T/S hence why auckland city had buggar all thunder days this summer. Hunua thru to Thames and Coromandel had a number of these afternoon 'heat showers' etc etc.

3) A cold unstable upper atmosphere for the Cb's to try and punch thru. You will see this on clear summer days when the Cb's have a lovely crisp edge and attain height very quickly.

but yeah auckland is a fickle place, although i personally enjoy watching the summer convergence storms, as they say, "from humilis to cumulonimbus in a few hours". You also get water spouts which is always neat.

I think May - July are typicall the bigger thunder months for aucks, although some of the more expert people on here may correct me on that one.

Still if you wanna see the best storms in the country (IMO) go to the waikato during the summer.....absolutely flawless!

Hope this helps

Cheers

cn

[C-Nimbus]

no.2

just one thing to remember on that chart cameo is that these are 24 hour plots, and most of the green is 12 hours old.

i think its the purple bits that we are more interested in.

unless of course i have the wrong end of the stick, which is highly likely!

[Cameo1]

My understanding of divergence is that its opposite to convergence, whic is the coming together of two air masses.

NZstorm, spwill and MHO (Brian) are pretty much experts on auckland T/S occurance and they may be able to help you out on the divergence thing.

I'm particularly interested in the summer time convergence storms that we get here in auckland. Sometimes the convergence line can stretch from Northland thru the waikato etc etc. This forms due to a number of factors in auckland, these are:-

1) Summertime heating of the landmass (isthmus) creates and influx of colder, moist air from the sea to 'replace' the hot air that has risen. This also gives us our moisture source


2) We have ocean on both sides so that can sometimes lead to a western convergence and an eastern convergence. Funny enuff, this summer it was the eastern convergence that fired up with the most T/S hence why auckland city had buggar all thunder days this summer. Hunua thru to Thames and Coromandel had a number of these afternoon 'heat showers' etc etc.

3) A cold unstable upper atmosphere for the Cb's to try and punch thru. You will see this on clear summer days when the Cb's have a lovely crisp edge and attain height very quickly.

but yeah auckland is a fickle place, although i personally enjoy watching the summer convergence storms, as they say, "from humilis to cumulonimbus in a few hours". You also get water spouts which is always neat.

I think May - July are typicall the bigger thunder months for aucks, although some of the more expert people on here may correct me on that one.

Still if you wanna see the best storms in the country (IMO) go to the waikato during the summer.....absolutely flawless!

Hope this helps

Cheers

cn

Thanks for that, it did answer a thing or two One of my wishes is to actually go down to the Waikato in Summer and observe some storms, but I also want to go to Auzzie and check out some supercells .
It's getting dark to my south west now and and anvil over north Auk is streatching over us here. Also, I can see very distant huge anvil tops to my west with the sun behind them. The forcast now is for rain tonight. Welly is being totally hammered and so has the central north island.

[spwill]

Tstorms moving in from the Tasman Sea generally drift in from the NW so quite a long land track to get to Aucklandk City, usually need good dewpoints and/or wind convergence for them to survive once they make land fall.

[C-Nimbus]

no doubt they'll be a summer chase that will involve the waikato cameo.

they did one in dec last year (i had to miss out cos of a stoopid, stoopid wedding thing for me missus's sister dagnammit!)

but they got a friggin' tornado on that day.

as homer would say...whyioughta grrrrr!

[Cameo1]

no.2

just one thing to remember on that chart cameo is that these are 24 hour plots, and most of the green is 12 hours old.

i think its the purple bits that we are more interested in.

unless of course i have the wrong end of the stick, which is highly likely!

Ha ha ha Thats cool. Yeah, I was just amazed at the lightning NZ has had recently, it looks pretty amazing on the map though eh?

[spike_01]

Still blasting away here... Prolly the best ( worst ) storm in 15 years...

[Shepherds Valley WX]

strong sferics here with booming thunder!! Great sound show...lightning more difficult to see... still very enjoyable, we don't get alot of thunde rin the Upper Hutt region it would seem...others may be able to confirm?

Currently heavy rain, very windy and 12 degrees C. Barometer on my WX station graph showing those characteristic rises and dips as the small squalls come thru.... (is that called a gust front?)

[huttcrazy]

Hi Andy

Yes, at about 6pm saw three lightning flashes and heard four thunderclaps. A rare event in Lower Hutt. Sounds like the kapiti coast are taking the real action.

Its only the second time I have seen visible lightning in 3.5 years of living in Lower Hutt.

Cheers

James

[Shepherds Valley WX]

Gidday James,

Looks like we tend to get a bit sheltered to the west by the Haywoods/Tararuas and the Rimutakas to the east.

I have to say though that living in Pinehaven, we are quite exposed to the NW and the wind is fair whistling up the valley... thunder seems to have cleared now, but looks to be more rain activity heading our way on the METJET WGN radar...

Good to hear from a "local"

[NZstorm]

Some hail in Hamilton today according to TV1 weather.
Looks like the Kapiti region as well as parts of Waikato have had the storm action today. Thunderstorms moving into Taranaki now from the west.


cnimbus wrote

wondering what was happening with your website

I had Ihug remove the website as it was carrying a lot of cyber junk. The plan is to re-upload a revised site.

[Manukau heads obs]

photographed this CB developing near Taupiri nth waikato....
yes the waitaks split the weather up...i like to think of it like water flowing around rocks in a stream....but the waitaks also lead to wind shear and tornadoes for the otahuhu area.....(seems to the case)
us out here on the coast SW of auckland often see great CB's just missing us and sliding down into port waikato or further south but we do sometimes get some real doozies too

but yes its the cold land surface in the winter that makes them fizzle as they move inland....but having said they we saw a good flash of lightning near patauru this arvo during heavy rain on the way home...the slowly rising ground there might lead to some rejuvination?
also often auckland is just a bit too far north for instability....which is often best just south of us here ......(i.e the cold upper air just does not often come far enough north) global warming might put that line even further south??.....but having said that the ranges in northland can produce some good cb's that were not out to sea....
anyway sorry for the ramble

[03Stormchaser]

cnimbus wrote

wondering what was happening with your website

I had Ihug remove the website as it was carrying a lot of cyber junk. The plan is to re-upload a revised site.

Its till up on the internet though, well only the 2006 USA events.