30th June -2nd July 2020 cold spell and Low Snow

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talbotmj15
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30th June -2nd July 2020 cold spell and Low Snow

Unread post by talbotmj15 »

Models seem to be consistently agreeing on a cold spell of weather with Snow to low levels.

Some modeling is suggesting cold air coming from off the Antarctic shelf itself and fairly direct to NZ without much deviation.

Will be interesting to see how it plays out. Looks similar to the 2011 big snow setup. Although im not convinced on that level just yet.

One to watch.
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Re: 30th June -2nd July 2020 cold spell and Low Snow

Unread post by TonyT »

I aint seeing any "consistent agreement". I'd suggest it wont happen.
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Re: 30th June -2nd July 2020 cold spell and Low Snow

Unread post by Bradley »

talbotmj15 wrote: Wed 24/06/2020 14:42 Models seem to be consistently agreeing on a cold spell of weather with Snow to low levels.

Some modeling is suggesting cold air coming from off the Antarctic shelf itself and fairly direct to NZ without much deviation.

Will be interesting to see how it plays out. Looks similar to the 2011 big snow setup. Although im not convinced on that level just yet.

One to watch.
Which big snow setup was that Talbot? The one in late July and August were 850hpa temps of -8C and below for both events so it can’t be those you are referring to, was there another earlier event that happened that this event is similar to? I wasn’t living here at the time so I only know of those two...
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Re: 30th June -2nd July 2020 cold spell and Low Snow

Unread post by ScottyD »

Bradley wrote: Wed 24/06/2020 19:02
talbotmj15 wrote: Wed 24/06/2020 14:42 Models seem to be consistently agreeing on a cold spell of weather with Snow to low levels.

Some modeling is suggesting cold air coming from off the Antarctic shelf itself and fairly direct to NZ without much deviation.

Will be interesting to see how it plays out. Looks similar to the 2011 big snow setup. Although im not convinced on that level just yet.

One to watch.
Which big snow setup was that Talbot? The one in late July and August were 850hpa temps of -8C and below for both events so it can’t be those you are referring to, was there another earlier event that happened that this event is similar to? I wasn’t living here at the time so I only know of those two...
Around August 15th-16th 2011 from memory? Snow to low levels across NZ with Auckland receiving some flakes. Although i'd love to see snow to low levels again, I don't see that happening.
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Re: 30th June -2nd July 2020 cold spell and Low Snow

Unread post by NZstorm »

500mb jet is a good place to start looking for a decent snow set up. The jet will be prounced at both 500mb and 300mb if there is an active system there.
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Re: 30th June -2nd July 2020 cold spell and Low Snow

Unread post by snowchaser01 »

There is definitely something there... both EC and GFS are showing a significant cold spell for about Tuesday next week. Worth giving it a few more days and see how it looks.
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Re: 30th June -2nd July 2020 cold spell and Low Snow

Unread post by mikestormchaser »

snowchaser01 wrote: Wed 24/06/2020 21:15 There is definitely something there... both EC and GFS are showing a significant cold spell for about Tuesday next week. Worth giving it a few more days and see how it looks.
I dont see anything on the gfs that suggests a polar blast and low level snow for the time of week next week.
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Re: 30th June -2nd July 2020 cold spell and Low Snow

Unread post by snowchaser01 »

I think you're right Talbot. Looks like a potential snow event with advection elements on Sunday and Monday. One to watch for sure!!
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Re: 30th June -2nd July 2020 cold spell and Low Snow

Unread post by snow101 »

Models seem to be agreeing on some quite heavy snow for Alpine Canterbury on Monday, then down low for late Monday and Tuesday. GFS wants some lower elevation snow 300-400m for the North Island too.
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Re: 30th June -2nd July 2020 cold spell and Low Snow

Unread post by snowchaser01 »

Metservice now have a heavy snow watch for between twizel and lake Sumner.. above 400m. Chain shower set up later in the week looks to bring snow down to about 200-300m.
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Re: 30th June -2nd July 2020 cold spell and Low Snow

Unread post by Avalanche »

The forum is pretty quiet considering the cold Southerly outbreak this week, i notice the thickness levels are not that cold to produce sea level snow in the north island, yes i know thats rare anyway, but considering the origin of the isobars im surprised the models are not showing the thickness levels being colder. What am i missing? Thanks team
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Re: 30th June -2nd July 2020 cold spell and Low Snow

Unread post by TonyT »

Avalanche wrote: Sun 28/06/2020 11:12 What am i missing?
1000-500mb thickness is a proxy for the mean temperature of the lower half of the atmosphere (surface to approx 6000m). Isobars are a proxy for wind flow at the surface only. Apples and oranges. If you want something more meaningful, use the 850hpa heights (winds) and temperatures.
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Re: 30th June -2nd July 2020 cold spell and Low Snow

Unread post by TonyT »

talbotmj15 wrote: Wed 24/06/2020 14:42 Models seem to be consistently agreeing on a cold spell of weather with Snow to low levels.

Some modeling is suggesting cold air coming from off the Antarctic shelf itself and fairly direct to NZ without much deviation.

Will be interesting to see how it plays out. Looks similar to the 2011 big snow setup. Although im not convinced on that level just yet.

One to watch.
Its starting to look as if this was an inspired call by Mr Talbot. Well done. There still isn't consistent agreement from one model run to the next (not unusual) nor can I see much similarity to 2011, nor do I think snow to low levels is (yet) warranted in the forecast. But the general idea is becoming more and more supported.
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Re: 30th June -2nd July 2020 cold spell and Low Snow

Unread post by mikestormchaser »

This GFS data shows ' yes' colder then it has been these past few days, but no snow to ground level. 400m at best on banks peninsula. Get that temperature at 850mb and the THk totals right down to near the bottom line then ill be more convinced. Moisture drops away mid week at this stage to.
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Re: 30th June -2nd July 2020 cold spell and Low Snow

Unread post by snowchaser01 »

mikestormchaser wrote: Sun 28/06/2020 14:15 This GFS data shows ' yes' colder then it has been these past few days, but no snow to ground level. 400m at best on banks peninsula. Get that temperature at 850mb and the THk totals right down to near the bottom line then ill be more convinced. Moisture drops away mid week at this stage to.
To quote Tony... models are a guidance not a forecast.
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Re: 30th June -2nd July 2020 cold spell and Low Snow

Unread post by Bradley »

Latest run of EC has snow down to 150m asl on the plains with 6cm for Kirwee as an example, I think we can now safely say there will be at least flurries down to 200m on Wednesday night/Thursday morning - yay!!
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Re: 30th June -2nd July 2020 cold spell and Low Snow

Unread post by Chris W »

Interesting, GFS might have improved from being a bit spotty in accuracy at the 7-10 day range. Interested to see what happens this week, sea level snow looks unlikely but maybe a dusting at the top of the Port Hills. Good punt Talbot.

Seems potentially a signal for something quite cold around the 6th/7th as well, but let's deal with this one first! Edit - looking ahead though, GFS does currently show some very heavy rain around the eastern South Island for that event so it’s worth watching.
Last edited by Chris W on Mon 29/06/2020 19:53, edited 1 time in total.
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Re: 30th June -2nd July 2020 cold spell and Low Snow

Unread post by snowchaser01 »

Latest EC has very good moisture for about CHCH northwards on Wednesday night... as Bradley said last night... snow to around 200m looks a chance.
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Re: 30th June -2nd July 2020 cold spell and Low Snow

Unread post by Razor »

Looks to be some great CBs knocking on the door of Chch right now. Fun night of hail and squally showers ahead
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Re: 30th June -2nd July 2020 cold spell and Low Snow

Unread post by Chris W »

I posted in the general thread but will add here that the snowline on the Seaward Kaikõuras is around 700m but possibly snow fell lower than that. Not least because it's a very cold and biting southerly gale blowing through right now in Kaikõura.
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Re: 30th June -2nd July 2020 cold spell and Low Snow

Unread post by NZ Thunderstorm Soc »

Very cold in Wellington with some slow flurries on the Rimutaka Hill Road, according to RNZ. 8-o
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Re: 30th June -2nd July 2020 cold spell and Low Snow

Unread post by Richard »

Chain showers currently heading north west of CHCH atm are loosing most of there moisture before reaching here, only had 0.4 mm today.
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Re: 30th June -2nd July 2020 cold spell and Low Snow

Unread post by mikestormchaser »

Richard wrote: Wed 01/07/2020 18:36 Chain showers currently heading north west of CHCH atm are loosing most of there moisture before reaching here, only had 0.4 mm today.
Been hosing down here in rolleston Richard.coldest day of the year so far but expected. Sounds like the snow level stuck to around the expected level aswel.
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Re: 30th June -2nd July 2020 cold spell and Low Snow

Unread post by Razor »

Very very windy out there now. Had a run up the Port Hills earlier, no snow apparent on Mt Herbert , only the very top was in cloud, so snow line is at least 800-900m, if not higher
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Re: 30th June -2nd July 2020 cold spell and Low Snow

Unread post by Richard »

Razor wrote: Wed 01/07/2020 20:14 Very very windy out there now. Had a run up the Port Hills earlier, no snow apparent on Mt Herbert , only the very top was in cloud, so snow line is at least 800-900m, if not higher
Looked about 400m around here
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