Heavy rain weekend and very cold blast 10-16th August

[talbotmj15]

Most models seem to have consistently on a strong cold system next week. I suspect this will attract a fair amount of attention over the next 5 days hence i have started a thread for it. Low looks to be around 945hpa at 1 point. Could be a very nasty system.

[mattyj46]

Flying in to Invercargill on the 13th from Christchurch, a week holiday with some typical southern winter weather

[tornado]

WOW winter has woken up

[melja]

Not sure I would go as far as saying winter has woken up, looks like the start of the spring Westerlies to me which will mean an increase of snow for the Alps.


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[Richard]

WOW winter has woken up

Not for some, still waiting for it.

[hozza95]

Last 2 August's have been perfect for calving, no snow at all. Now it's looking likely we'll have 2 significant snowfalls in 8 days . Fortunately it's only early for us and there's not many calves being born in the bad weather.

[Chris W]

It might be worth including the couple of days before it re: potential strong westerlies and heavy rain (MetService rain maps/UKMO output) preceding any cold front. It is likely to run over several days if it evolves as per the GFS. I couldn’t get the EC frames to load up for the weekend on Weather Online.

[talbotmj15]

Now updated Chris W.

[Razor]

Screenshot_20190806-191023_Facebook.jpg

I will just leave this little spoiler here...

[Chris W]

NIWA going against GFS and UKMO at the moment, a little premature to write it off IMO.

[Bradley]

NIWA going against GFS and UKMO at the moment, a little premature to write it off IMO.

Agree Chris, in the latest EC update only a few minutes ago it is now going for the low pressure system to hit mid Canterbury on the week as a major snow event for areas above 500m (50cm +) and plenty of rain for the plains (40-80mm)...

[snowchaser01]

I'm agreeing with niwa at this stage... looks like it will be sw with low level snow showers in the deep south again.

[Razor]

NIWA going against GFS and UKMO at the moment, a little premature to write it off IMO.

They haven't written it off, just point out the obvious uncertainty. Way too early to tell

[NZstorm]

Overnight runs of EU and UKmet pointing to snow inland Canterbury/Otago this weekend.

[Bradley]

This mornings run of EC is now painting a picture of a substantial inland snow event for Canterbury with 15cm+ for areas above 300m and 50cm+ for areas above 500m. These low pressure systems are notoriously hard to nail down though so 48 hours out we will be alot more certain...

[Razor]

GFS backing right off the southerly flow next week. In line with Niwa's speculation yesterday. Easterly rain on the weekend still holding true though

[talbotmj15]

Im interested to hear Tony T and CTs opinions on next week given all the media headlines around it now. Care to enlighten us fellas?

[Dean.]

Blues Skies have put up a forecast for the weekend on Facebook

[TonyT]

Im interested to hear Tony T and CTs opinions on next week given all the media headlines around it now. Care to enlighten us fellas?

Soiling of underwear not required.

Rain & snow may be bordering on heavy in Canterbury on Saturday/Sunday, snow above 400m. Fine after that with a cold southwest breeze. All subject to change, kids ask your parents first, batteries not included.

[Growler]

But I wanted batteries!

[Cyclone Tracy]

Interesting commentary between NIWA and Weatherwatch over the last 24 hours. Weatherwatch returning fire into today's video. I'm just chewing the popcorn from a distance

I'm almost ready to give 2 cents worth, just waiting to see what that upper cyclonic vortex around the Antarctic shelf does tomorrow. GFS, UK and EC can't even agree on the real impact that upper vortex will have on the extratropical cyclone in the next 48 hours.

[Richard]

Looking more likely the coldest air will stay mostly to the south of here and will be more in a zone between that and the warmer over the NI

[Dean.]

Looking more likely the coldest air will stay mostly to the south of here and will be more in a zone between that and the warmer over the NI

Yeah looking at the models freezing levels stay around 800 metres for North Canterbury...will be in Hanmer for the weekend snow should stay above town level

[Bradley]

Interestingly ACCESS has -4C temps at 850hpa during most of Saturday over mid to south Canterbury when most of the heavy precipitation falls, at those temps snow down to 200-300m is a very good chance if the colder air undercuts the moisture laden air and the timing is right...

[Cyclone Tracy]

2 cents worth.

GFS seems to have nailed the cyclonic Tasman low development near Tasmania from a few days ago with all models now jumping onboard the upper vortex injection on Saturday. This then assists in spawning a new surface low west of the SI that is supported by a 360 km/h jet streak rocketing across the NI.


The latest GFS 18Z is showing a combination of moist subtropical air and enhanced latent and sensible heat fluxes enabling it to gain energy. It's cold core starts warming near Cook strait and starts to bomb.... Only 1 model, 1 run but needs to be watched closely over the next 24 hours in my humble opinion.