General August Weather

[mikestormchaser]

Interesting nothing much forecast down here but its very unstable over Christchurch this afternoon. And there is heavy showers on radar.
500mb temp -30 so some cold upper air hanging about and that sun has some warmth to it now.

[Growler]

Interesting nothing much forecast down here but its very unstable over Christchurch this afternoon. And there is heavy showers on radar.
500mb temp -30 so some cold upper air hanging about and that sun has some warmth to it now.

Was just thinking that, looked out the window and saw some great towers on the way up over Hornby way.

[Orion]

Rain just started here and the dark grey thick cloud has quite an ominous look to it
Rain sounds a bit rattly too.

[Chris W]

Just been out for a run from Amberley and I can see a cb approaching from the southwest. There's a purple radar echo that might match it.

[Dean.]

Rain just started here and the dark grey thick cloud has quite an ominous look to it
Rain sounds a bit rattly too.

A good hail storm in town here

[melja]

Couple of rumbels of thunder Rangiora

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[Razor]

Certainly some good convection about

[Chris W]

Very dark east of Amberley, more coming from the south that may miss here.

[JP.]

My office is in addington and we had a small hail shower about 10 mins ago. Lots of dark clouds around though

[melja]

Good thunder and lightning over head in Rangiora just now again

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[Richard]

Photo taken near Greta Valley, no thunder heard though

[TonyT]

Thunder and brief rain here around 3.30pm and again now.

[Chris W]

Tantalising here, so dark.

[NZ Thunderstorm Soc]

Just come in back from Timaru. Another nice sunny day.
Nothing much here or there but there were some CBs moving up the coast out to sea.
Some cloud build ups around MT. Peel area.

Some photos looking out to sea from the CBD Timaru.

[TonyT]

Heavy rain on and off here for the last 45 mins, and some decent sized hail also. Ground starting to turn white.

[NZ Thunderstorm Soc]

There were other wintry CB forms out to sea, which I didn't photo moving north which was probably the ones that delivered the storms around the Amberley/Rangiora areas.

[TonyT]

https://www.facebook.com/photo.php?fbid ... =3&theater

[mikestormchaser]

Nice pics Tony! I never even looked at today, and there were no risks out from MS but the sky gave me enough signs to check all the data and sure enough made sence.
Cold upper air being the main factor.. surface winds have been southerly all day

[Richard]

The signs were there at about 10.30 yesterday morning with that line of cu clouds off BP. No thunder heard at all around these parts but some of the blackest cloud ive seen for a while, nice to have received more rain than what was forecast too, makes a change, 7mm

[melja]

Yes we had 3mm yesterday and 2.5mm over night.

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[Bradley]

Heard a rumble or 2 here but missed the main action. More to come though this afternoon and evening....

Just performed my change of season health check:

Currently stratospheric polar vortex looking very tight and strong

https://earth.nullschool.net/#current/w ... 100.84,347


>GEFS has a peaking of the upcoming sudden stratospheric warming in the upper stratosphere over Antarctica around 70S 140E due in 60 hours.

>Large pressure anomaly appearing 2 days later at the same height and similar location.

>Surface of Antarctica now getting colder with a strong tropospheric polar vortex in place.

I’m now on full alert for zonal downward mixing and changes to the jet streams. Once this gets underway, I would expect upper cold core cyclones to penetrate into the mid latitudes across the southern hemisphere in late August to early September connecting with subtropical moisture. EC starting to hint this around OZ, with the synoptics looking volatile.

Next batch of popcorn has been served

Looks like southern Australia will bear the brunt of this event over the next few weeks with multiple cold snaps hitting there, story of the winter really that Oz has received all the cold outbreaks and hardly any at all for NZ. Quite remarkable this run of no polar outbreaks this winter...

[Cyclone Tracy]

Looks like southern Australia will bear the brunt of this event over the next few weeks with multiple cold snaps hitting there, story of the winter really that Oz has received all the cold outbreaks and hardly any at all for NZ. Quite remarkable this run of no polar outbreaks this winter...

Yes, significant polar troughs now lining up for Southern OZ. A couple of those will interact with tropical moisture for NI / parts of SI events. I wouldn't write off a cold snap for NZ yet though, GFS latest has the long wave trough moving into the Tasman at the end of next week. September looks quite volatile

[spwill]

Some rain this weekend for parts of inland Queensland/NSW, badly drought affected this Winter.

[NZ Thunderstorm Soc]

A bit of rain overnight dropped a bit of snow over Mt' Peel and a sprinkling along the 4 peaks.
First for a while.

[Richard]

The hail in Amberley was still laying on the side of SH1 just north of the town at 3.00PM