Very cold southerly blast NZ wide Sept 7-9th

[cbm]

Yep, some up there. Looks to about 700m.

Photos on waikato times/stuff show a very decent fall up there

Good photo posted by a flickr user
https://flic.kr/p/L3XZvb

[melja]

A standout feature of this event here has been the rain with 45mm over the last 3 days.

Sent from my X98 Air 3G(C5J6) using Tapatalk

[spwill]

Some good falls of snow around Queenstown with this system, the Remarkables ski area reporting 55cm new snow.
I visited Doubtful Sound yesterday, little or no new snow on the Mnts at Doubtful Sound.

[Bradley]

Funny old system this one with 520 thickness levels over Christchurch for around 6 hours on Thursday morning, combined with 850hpa temps of -7C should have certainly produced a little sea level snow but there was nothing, it's like it has just forgotten how to snow in Christchurch the last 3 winters with no settling snow whatsoever even with all the ingredients seemingly there

[snowchaser01]

Funny old system this one with 520 thickness levels over Christchurch for around 6 hours on Thursday morning, combined with 850hpa temps of -7C should have certainly produced a little sea level snow but there was nothing, it's like it has just forgotten how to snow in Christchurch the last 3 winters with no settling snow whatsoever even with all the ingredients seemingly there

So many things have to be there for snow to settle in ChCh. THK levels are very touch and go for sea level snow. The August 2011 snow event had a thk level of 512 over Canterbury. In my opinion, models need to be outputting a thk level of below 518, and a 850hpa temp of -8C or lower.

[NZstorm]

Funny old system this one with 520 thickness levels over for around 6 hours on Thursday morning, combined with 850hpa temps of -7C should have certainly produced a little sea level snow but there was nothing, it's like it has just forgotten how to snow in Christchurch the last 3 winters with no settling snow whatsoever even with all the ingredients seemingly there

The 500mb and 300mb charts typically will offer the best clues where heavy snow is most possible. The 500mb/300mb dynamics shifted north of Christchurch quite quickly early Thursday.

But the was some instability for low topped cb/snow flurries. Maybe BP provided some sheltering for Christchurch.

[Nev]

I see NIWA's Auckland, Mangere site recorded its 2nd coldest Sep T-max of 10.9C yesterday - the coldest being 10.3C in 1984 since records began in 1961.

[Orion]

For the record, I think yesterday's weather was the worst I've experienced in forty years of living in Mid-Canterbury - the combination of cold, wind, rain and hail for hours and hours.
Have been out in the town today and in every shop I entered, the first comment from those serving was about how cold it had been and how the wind had sneaked into the buildings.
Brrr!

[Richard]

Yes i agree Orion, that was as nasty as ive even known living here. At one point while outside hearing a roar thinking [expletive deleted] is that?, thought it might have been a quake coming, but then wham, a huge gust with sheets of hail.

[NZ Thunderstorm Soc]

Yes, as I was saying in an earlier post, that SW winds were the strongest I've experienced here at this place in West Melton. surprised there wasn't that much damage to the trees, with twigs, etc., blown around.
Went down to Geraldine today, they said it was cold down there but the storm seemed to be more coastal. a few sleety showers but that was it. There was snow to low levels along the foothills, but nothing around Mayfield which I thort there may have been.

[Storm Struck]

The strong upper level and surface winds from the SSW, probably contributed to the amount of scattered hail/grapel showers on Thursday. Of which the winds were strongest nearer the coastal fringes and banks penninsula, dragging those ice particles around in the wintry CBs before dumping them as hail closer to the ground.
Probably why inland Canterbury 100m-200m got snow and even thunder and lightning around 5am, this was not your typical polar blast set up for Canterbury as the isobars linned up just right for those eastern shores from Otago to Wellington, had winds been lighter flurries may have fallen in the city Thursday morning.
Just one ingrediant for Thursdays blast anyway, others were heating with 10mm hail around lunchtime and warmer sea surface temperatures.

[Manukau heads obs]

looks like there was a good 20 to 30mm of rain or more in north canterbury
I see the soil moisture defecit level has improved alot now
https://www.niwa.co.nz/static/climate/smd_anom.png?1234

[Richard]

Yes 20mm was common around here