General August Weather

[NZ Thunderstorm Soc]

Terrible day here in Christchurch. Just gloom and doom and a cold easterly blowing. A few spits, now and then

[spwill]

Front cleared here around 1pm, then a reasonable afternoon, isolated showers, light winds, 14C.

[Richard]

Terrible day here in Christchurch. Just gloom and doom and a cold easterly blowing. A few spits, now and then

A day of contrasts,no wind when we left here to came down to CHCH this morning, hit the NE wind just south of Amberley, on the way back this afternoon back to close to calm at the same spot.Looking at out gum tree cant see a leaf moving.

[NZ Thunderstorm Soc]

Amberley can be a bit of a borderline when coming into/departing NE onshore flows.
I noticed this in my train-driving days.

[Richard]

Amberley can be a bit of a borderline when coming into/departing NE onshore flows.
I noticed this in my train-driving days.

yes and today was one great example of that, it was only a matter of 2-3 kms between 40kmph wind and next to no wind from then on.

[NZ Thunderstorm Soc]

Interesting.
I wonder if it has something to do with the Waipara hills?

[Richard]

Interesting.
I wonder if it has something to do with the Waipara hills?

Yes ,the wind was just running parallel with the coast

[NZ Thunderstorm Soc]

Banks Peninsula also gives a sheltered effect from the NE, as depicted in possibly another topic, somewhere? which I call the "NE Kink" where it is overcast and cloudy over Christchurch and the plains, but fine , sunny and clear to the SE around the Motukarara/Birdlings Flat area.

[Nev]

Very benign here in Takapuna, after a very blustery wet morning. Patches of blue sky to the East, a bit murky to the West. After this morning's headlines about weather bombs (lol) and battering thunderstorms, it's amusingly quiet.

Yes saw that, although not long after Stuff did replace the word 'Weatherbomb' with 'Wild weather'.

No mention on wiki of tornadoes of the mini variety yet though?

'Glossary of tornado terms' - Wikipedia

Mini-tornado – A fallacious term often used in European news media to refer to tornadoes occurring there; even large, strong, and/or long track tornadoes produced by supercells. This is apparently due to the erroneous perception that "real" tornadoes do not occur in Europe (or elsewhere where the term is applied).

Elsewhere where the media prefix tornadoes as essentially being 'miniature' include Australia and the UK.

[NZstorm]

Cold upper air over the North Island today. Will be interesting to see whether any afternoon (heat) cb/thunder can develop inland. GFS shows convergence in BOP/Gisborne.
I think Auckland should get drier today as the upper level trough moves eastward and a SW breeze develops.


Looks like the thunder risk tomorrow will be over upper Northland. But convergence showers could develop Auckland/Waikato.

[Storm Struck]

Amberley can be a bit of a borderline when coming into/departing NE onshore flows.
I noticed this in my train-driving days.

I think the hills around Kate valley create a type of sheltering affect, if its NE and low cloud or fog on the plains its normally sunny North of Amberley.
This makes for a great microclimate which is why Waipara is able to host great wines, plus the excellent soil conditions.

[Razor]

Approaching 25mm of rain here, quite waterlogged by Christchurch standards.

[Manukau heads obs]

looks like north canterybury is getting some usefull rain?

[Richard]

looks like north canterybury is getting some usefull rain?

Not here,only had 2mm this morning subsoils still bone dry

[TonyT]

Amberley can be a bit of a borderline when coming into/departing NE onshore flows.
I noticed this in my train-driving days.

I think the hills around Kate valley create a type of sheltering affect, if its NE and low cloud or fog on the plains its normally sunny North of Amberley.
This makes for a great microclimate which is why Waipara is able to host great wines, plus the excellent soil conditions.

The low cloud boundary is usually a little south of Amberley, between Salt Water Creek and Waikuku. The winds are often northeast, but not as brisk as from Waikuku southwards. Waipara will also be clear but often have virtually no northeast breeze at all.

11mm here.

[treetop]

T storms likely north of Tauranga/ Hamilton tomorrow. Should be some heating as there will be little cloud and adequate moisture.Have a pick up at the airport so ready for a detour or 2.

[NZ Thunderstorm Soc]

Should be a cloudy day here in Canterbury with some rain at times.

[Storm Struck]

In the right conditions the area of Amberley northwards can be simular to the likes of Lincoln and Tai Tapu area on a decent thunderstorm set up day a moderate Easterly inflow hitting a strong incoming southerly plus other essential ingrediants.
This can sometimes see funnels or a Tornado in the area because of the topographical influence, I know the February 23rd 2014 wasnt the only day that Amberley seen a tornado Tony?
I think its good to know especially for getting in position for future potential severe set ups, although I certainly dont wish it hitting local towns a tornado in a feild going through a hay barn in NZ on footage would be excellent

[NZstorm]

T storms likely north of Tauranga/ Hamilton tomorrow. Should be some heating as there will be little cloud and adequate moisture.Have a pick up at the airport so ready for a detour or 2.

Auckland's forecast maximum temp this afternoon is 16C which means we will have instability. The question mark is whether we will have a convergence trigger.

Eastern Northland has the best convection prospects on the gfs.


Grey Lynn has already received 100mm for August but the second half of the month does not look so wet in models.

[TonyT]

In the right conditions the area of Amberley northwards can be simular to the likes of Lincoln and Tai Tapu area on a decent thunderstorm set up day a moderate Easterly inflow hitting a strong incoming southerly plus other essential ingrediants.
This can sometimes see funnels or a Tornado in the area because of the topographical influence, I know the February 23rd 2014 wasnt the only day that Amberley seen a tornado Tony?
I think its good to know especially for getting in position for future potential severe set ups, although I certainly dont wish it hitting local towns a tornado in a feild going through a hay barn in NZ on footage would be excellent

I think the easterly inflow is more from about the Waimak to Waikuku. North of there, the easterly often drops away, as described in the posts above. The split between NE and NW wind directions is much closer to 50/50 in Amberley, compared with Christchurch where its more 70/30, so Amberley is certainly less likely to see easterly flow ahead of a cold change than the city.

The tornado you mention spawned at least as far south as Waikuku and moved northwards, more or less just west of SH1. My own suspicion is that the Amberley area probably gets less thunderstorm activity forming over or nearby than the Lincoln area, but we do sometimes get storms detaching from the hills and mountains to the west, which is probably a more common occurrence than in Lincoln (with Lincoln being so much further away from the western hills).

There is often an area of light drizzle around and near the Waimak river on days when there is thick low cloud over the region in a NE airflow (and yesterday for example, the drizzle was heaver around there than either side), and I think there is a small wind convergence zone there, which may or may not have an influence on storm strength.

[Richard]

Yes i pretty much agree with ya there Tony.

Yet another weather system has failed to produce enough rain to saturarte the dry soils (4mm), if we dont get rain in the next month many farmers around here are going to be seriously effected as they wont be able to produce enough hay to get them through what is likely to be a dry summer/autumn, here's hoping the current El Nino is like the 1982/83 event that brought a stormy spring with some rain to eastern areas.

[Nev]

Reports of an apparent 'twister' in Tuapiro Rd, Tahawai, just north of Katikati in the western BoP just after 4.30pm on Friday. It's said to have pulled tiles off roofs and ripped trees from the ground…

'Weather warning follows freak twister' - Bay of Plenty Times

'Tornado rips through Katikati' - SunLive

'Lone twister causes damage' - Waikato Times

[Tornado Tim]

T storms likely north of Tauranga/ Hamilton tomorrow. Should be some heating as there will be little cloud and adequate moisture.Have a pick up at the airport so ready for a detour or 2.

Auckland's forecast maximum temp this afternoon is 16C which means we will have instability. The question mark is whether we will have a convergence trigger.

Eastern Northland has the best convection prospects on the gfs.

The Instability extends from 900hpa to 600hpa, but after that it breaches the Lapse Rate - turning stable.
The lower parcel of air around 950hpa is quite dry , so proper lifting isnt actually occuring until around 875hpa, unless strong convergence occurs.

Models on Friday had more fruitfull prospects for today with the finger of colder air over us and trough hanging around for a little longer...... unfortunately, I dont think today is the day.....

[spwill]

Showers pepped up over Northland, NW Auckland afternoon/evening, a fairly nice day in Auckland so I could see the distant cloud tops.

[NZstorm]

Reports of an apparent 'twister' in Tuapiro Rd, Tahawai, just north of Katikati in the western BoP just after 4.30pm on Friday. It's said to have pulled tiles off roofs and ripped trees from the ground…

'Weather warning follows freak twister' - Bay of Plenty Times

'Tornado rips through Katikati' - SunLive

'Lone twister causes damage' - Waikato Times

Thanks for the report Nev. The media are using strong language to what looks to be a fairly minor event.

I had a look back and the front was crossing with NNE winds backing NW in the area at 4.30pm.