Unstable Weather

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NZstorm
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Unstable Weather

Unread post by NZstorm »

I thought i would start off a new thread.

A very sunny day today and only Isolated cb's developing. I'm not sure why so few developed as the upper air was tending unstable with daytime heating. I suspect the air got a bit dry. Convective clouds hate low dewpoints. But I don't blame Met Service going for the showers.

I was working in the MT Eden area today and photographed this convective buildup around 1pm. I'm sure this cloud would have had hail.
Wide angle lenses here.



Image
Towering cumulus


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Glaciates forming Cumulonimbus



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Cb shows further development.

Image
I went up onto top of MT Eden to get this shot of the same convective system. The shower is about 15km distant and I had to use a wide angle lense to get the whole cloud in. :)
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Unread post by Dean. »

Those type of clouds seem to be rare in our skies nowadays.
Mt Hutt have now received 70 cm of new snow over the past 48 hours.
Surface flooding throughout Mid Canterbury this morning,only a few showers falling now in the area.
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Unread post by Thunder »

Hold on Dean! I've got a photo of a big Cb that floated past the NW of Chch about a week ago, it produced hail in Oxford and there was lightning as me and John got sferics on the radio (unfortunately not much lightning though). But I guess this didn't float past Ashburton so in your case, yes they are rare in your skies, what am I saying! they are rare in our skies to, if you compare how much Auckland gets as to what we get here in Chch I would say it's rare for us to compared to Auckland. Anyway, moving on!

Great photos Steven. Do you have an idea on the heights this cloud got to?

Cheers
Aaron Wilkinson
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Unread post by NZstorm »

Aaron, this cb developed out over NW Auckland not far from the Whenuapai upper air station. The sounding done just an hour or two earlier showed the air starting to look unstable to around 8900m (30,000ft). So, the mature cb would be around that height.
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Unread post by NZ Thunderstorm Soc »

Good photos Steven.
Those type of Cu congestus clouds I call - "Fists" as they look like a clenched fist sticking up into the clear blue sky.
Unstable and interesting sky here today. Fine now.
Despite the strong SE airflow over the SI at the moment, there was a light northerly blowing here this afternoon which resulted with a substantial convective shower here around 1:30pm. I got 2.5mm from it.
The moon here looked quite good this evening, with a halo from the cirrus up there plus Mars shining away. Would of made a good photo if I had a suitable camera!

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Unread post by Thunder »

Thanks for the info on height Steven.

Unstable sky John? Do you say this because of the shower you mention and the northerly breeze or do you say it because of the cloud stucture? I never got this shower you mention, it must of been localised.

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Aaron Wilkinson (Cheers is becoming repetative, must come up with better line <G>)
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Unread post by tich »

A big improvement in Chch's weather since yesterday. It's still cloudy, but no rain this morning in the central city (so far). BUT it does look ominous to the northeast. BTW snow came down lower than forecast in Hanmer early yesterday morning, with a covering in the township for a while.
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Unread post by Manukau heads obs »

all the rain/snow in eastern/central SI should stave off any dry conditions for a while...i.e more tradionaly dry NW winds in spring you get there..
must be la nina...
could be a summer of TC's??
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Unread post by Manukau heads obs »

good billowing cumulus around here now (1:15pm), and i see sopme showers over the city way somehwere...and a real big cb way out to sea too....
16oC now, so it could bew up this afternoon as predicted...
SE strong enough to stave off a S sea breeze change too....
DP 10oC or so
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Unread post by tich »

Light rain showers returned late morning, and while they ceased about 1/4 hour ago (in central Chch), it hasn't cleared up. Shower activity is obviously still around. The cold southerly freshened briefly a few minutes ago, but otherwise the wind has been generally light here today.
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Unread post by Thunder »

Image

Ben wrote:
BUT it does look ominous to the northeast.
I think the pic above of which I took today is what your referring to, darkish looking cloud looking from New Brighton Pier towards city center (buildings can be seen in the far background of picture). I put it on yahoo photos and it worked!

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Aaron Wilkinson
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Unread post by NZstorm »

Skies looked very unstable all day on the east to north horizon with some large looking but disant cb.

Lots of T/cu again today with one cb developing over Auckland early afternoon. The cloud was much to close to me to get a good photo of it.
I was at Howick and the anvil was blowing back over the top of me in an upper westerly. Todays wind profile is light easterly to about 7000m then westerly above that. I had a report of very heavy rain in the Balmoral area with this cloud. The shower drifted slowly westward during the afternoon and out to sea by 3pm.

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Unread post by GraemeWi »

I watched a couple of nice buildups out to the distant west and north on the drive home tonight. There was a large anvil maybe somewhere level with the top of the Kaipara. I managed to take a picture while sitting in the car going nowhere on the motorway but it didn't turn ouit very well. Nice shot of the barrier though!

Cheers,

G
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Unread post by Michael »

[quote="NZ Thunderstorm Soc"]
The moon here looked quite good this evening, with a halo from the cirrus up there plus Mars shining away. Would of made a good photo if I had a suitable camera!

Just a little off topic since it appears to be clear in most places-Does Vega in Lyra get above the horizon in Christchurch? Can you see it? It should do at declination 38 north It will be due north in the evening about now for this time of the year.
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Unread post by NZstorm »

Yet more cloud buildups today with local heavy showers. Looked to be alot of rain over the Manukau area.
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Unread post by NZstorm »

Very unstable looking out in the central and north Tasman sea this morning. The front due later today should be quite active with the possibility of thunder in the west and north. :)
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Unread post by NZ Thunderstorm Soc »

Yes, Steven, but unfortunately looks like a settled week down here in the east. A bit milder however.

JohnGaul
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Unread post by NZ Thunderstorm Soc »

Just looking at some models,at the moment Wednesday could give Canty a squally SW change. Good if the easterly hangs in????

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Unread post by Thunder »

Odd. My photo that I posted on page one of this thread has disapered. I think it's a fluke I even got it on here through yahoo photos, Oh well.

Yes John milder down here, lets hope this SW change comes through!

Convectivly yours
Aaron Wilkinson
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Unread post by Michael »

Very Cold NE up here tonight can tell there will be tons of rain for us :(
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