General July Weather

[NZstorm]

GFS still looks very cold and active for the North Island Thursday. The model is probably overdoing it but it is going for heavy snow showers to low levels in the east and south of the North Island Thursday. And yes, Ruapehu ski area will start catching snow from today.

Will be watching the thunderstorm scenario over the North of the country today. I get the impression Northland will be more in the firing line but Auckland not out of it.
Lapse rates around 7C, dps 12-14C and significant forcing today.

500mb thickness thursday from gfs

[GraemeWi]

West Auckland had some thunder around 11pm last night, and again around 5am. The 5am tracker showed them just offshore, and lightening activity died as the system came over the coast. We still got a very heavy squall from it.

[SnwAddct]

And yes, Ruapehu ski area will start catching snow from today.

Reports of 15cm-20cm down to the base area and up to 60cm up high. This week should set them up nicely

[jamie]

Is that what has already fallen or expected to fall?

[SnwAddct]

Is that what has already fallen or expected to fall?

Nope that was just last night.. Been going steady all day too

[spwill]

Chilling off here now , Auckland temp down to 5C.
Current longer range modelling point to average to above average temps next week thanks to Tasman Sea low pressure, hopefully this comes off.

[itaranaki]

2°C is pretty cold for my place. http://www.waitaraweather.com/index.php

[treetop]

Later next week has a high well to the south of the South Island which is again quite unusual for this time of the year.With the associated disruption to the westerly flow in the "50 s" another VERY cold event likely soon. Watch this space !

[NZ Thunderstorm Soc]

I couldn't find that.
Seems the weather will be a bit more settled for July with more of a NE flow affecting conditions.

[treetop]

I see MetVuws update yesterday showed that scenerio gone for now. Surprised at how an outlook can change so quickly, looks like a more normal setup for a week or 2 anyway.The incoming for the North looks to be weaker Mon- Wed as well.

[iomkiwi]

Snow in Northland the other day....

http://www.nzherald.co.nz/northern-advo ... d=11479023

[SnwAddct]

Models showing a cold outbreak due around Saturday night. Im sure it will change but fun to keep an eye on anyway..

[spwill]

Its been a decent cold spell for here last 4 or 5 days but a change of air mass starts pushing onto Northland Auckland today, dps on the rise.

[Bradley]

Models showing a cold outbreak due around Saturday night. Im sure it will change but fun to keep an eye on anyway..

I can't even think about another possible cold outbreak again so soon, the last month has been so full on - I haven't got any data left on my phone after checking every model update the last month!!

[harleyb]

Can anyone explain why most cold outbreaks seem to be more intense to the east of NZ than to the west at the same latitude? All else being equal surely you'd expect the same frequency of cold outbreaks at a given latitude regardless of longitude, so I can only guess that large landmasses (eg Australia) influence the general circulation somehow causing cold outbreaks in our neck of the woods to more often move up the east of NZ rather than over the Tasman Sea.

[TonyT]

Can anyone explain why most cold outbreaks seem to be more intense to the east of NZ than to the west at the same latitude? All else being equal surely you'd expect the same frequency of cold outbreaks at a given latitude regardless of longitude, so I can only guess that large landmasses (eg Australia) influence the general circulation somehow causing cold outbreaks in our neck of the woods to more often move up the east of NZ rather than over the Tasman Sea.

You've just answered your own question.

[Bradley]

Tony are you seeing this cold outbreak on Saturday/Sunday the same as me - EC wanting nothing to do with it but ACCESS and GFS both in agreement on something happening?

[TonyT]

Tony are you seeing this cold outbreak on Saturday/Sunday the same as me - EC wanting nothing to do with it but ACCESS and GFS both in agreement on something happening?

Correct, I'm ignoring it for now.

[Bradley]

Yet EC was throwing up huge precipitation numbers for that last outbreak and GFS wasn't the entire time which turned out to be exactly correct (in almost allt he runs it was going for between 20-30mm for Christchurch), maybe GFS is the new star performer lol

[SnwAddct]

I see Metservice already have it in there Outlook. Things could become very interesting if that low crossing the NI collides with the polar air..

A low should cross the North Island on Saturday bringing rain to many areas.Some heavy falls are possible in northern and eastern areas but the track of the low is uncertain at this stage.

A cold outbreak should sweep up the South Island and lower North Island during Saturday with snow showers likely on the hills and a period of gales in eastern coastal areas.

[Avalanche]

Ive been watching this today it looks like the warm front(low) moves across and then the southerly arrives after it, But if the low was to slow down and the southerly move abit to the west it could be a very interesting scenario. Latest GFS shows the southerly moving away, will be interesting to see if things change.

[RichyDunedin]

Sorry if this is a bit off topic but what do you guys think about these articles that have been coming up about a decrease in solar activity in 15 years:
https://www.tvnz.co.nz/one-news/world/y ... 030-q01215

[NZstorm]

Sorry if this is a bit off topic but what do you guys think about these articles that have been coming up about a decrease in solar activity in 15 years:
https://www.tvnz.co.nz/one-news/world/y ... 030-q01215

The theory has been around a while but its not something I have looked into.


Trough crossing the upper North Island Wednesday does bring some moisture in 14C dewpoint and given upper levels are a little bit cold -21C, may see a thundery fall or two in the later part of the day as the wind change passes. Eastern Northland to Coromandel most likely and while I'm not overly excited about this set up will keep a watch tomorrow.

[Nev]

Sorry if this is a bit off topic but what do you guys think about these articles that have been coming up about a decrease in solar activity in 15 years:
https://www.tvnz.co.nz/one-news/world/y ... 030-q01215

Here's the original article that all those media stories were based on:

'Irregular heartbeat of the Sun driven by double dynamo' - Royal Astronomical Society

And for some more general info about Solar cycles see: 'Solar cycle' - Wikipedia

[harleyb]

Can anyone explain why most cold outbreaks seem to be more intense to the east of NZ than to the west at the same latitude? All else being equal surely you'd expect the same frequency of cold outbreaks at a given latitude regardless of longitude, so I can only guess that large landmasses (eg Australia) influence the general circulation somehow causing cold outbreaks in our neck of the woods to more often move up the east of NZ rather than over the Tasman Sea.

You've just answered your own question.

Cool, I get a gold star. But I was actually hoping someone might be kind enough to explain 'how' or 'why' this happens... just out of curiosity.