Cold easterly airflow 7th - 12th Aug

Archive of NZ Weather & Climate
User avatar
TonyT
Moderator
Posts: 2878
Joined: Thu 08/05/2003 11:09
Location: Amberley, North Canterbury
Has thanked: 352 times
Been thanked: 1146 times

Cold easterly airflow 7th - 12th Aug

Unread post by TonyT »

New thread for a notable easterly period coming up
Bradley
Posts: 1516
Joined: Wed 01/05/2013 21:06
Location: Christchurch
Has thanked: 142 times
Been thanked: 269 times

Re: Cold easterly airflow 7th - 12th Aug

Unread post by Bradley »

Interestingly GFS is not budging at all run-to-run on it's prediction of -4C or -5C over Canterbury for this period, a good 2-3C warmer then most of the other models...
Awhituobs
Posts: 2256
Joined: Tue 10/09/2019 07:20
Location: Waiuku
Has thanked: 706 times
Been thanked: 556 times
Contact:

Re: Cold easterly airflow 7th - 12th Aug

Unread post by Awhituobs »

the culprit is high pressure having to go under a low in the south tasman, which then drags up some very cold air around the top of it
sort of a "beast from the east" type setup that Europe can get in the winter sometimes almost?
User avatar
Richard
Posts: 8369
Joined: Tue 14/07/2009 07:32
Location: Medbury, Inland North Canterbury
Has thanked: 1656 times
Been thanked: 800 times

Re: Cold easterly airflow 7th - 12th Aug

Unread post by Richard »

Cant see sea level snow with this one though with air having to move over more ocean than a straight southerly, that and no air flow off the ice shelf feeding into it.
darcyplumb
Posts: 760
Joined: Sun 06/12/2020 20:15
Location: Ashburton
Has thanked: 1576 times
Been thanked: 404 times

Re: Cold easterly airflow 7th - 12th Aug

Unread post by darcyplumb »

Richard wrote: Wed 03/08/2022 17:41 Cant see sea level snow with this one though with air having to move over more ocean than a straight southerly, that and no air flow off the ice shelf feeding into it.
My relatively limited knowledge tells me that some of Canterbury’s more significant snow events (to at or near sea level) have been from East or South Easterly systems. Happy to be corrected (obviously it takes a lot more than the wind direction to make it happen).
User avatar
Richard
Posts: 8369
Joined: Tue 14/07/2009 07:32
Location: Medbury, Inland North Canterbury
Has thanked: 1656 times
Been thanked: 800 times

Re: Cold easterly airflow 7th - 12th Aug

Unread post by Richard »

Yes some of Canterbury’s more significant snow events in past have at higher elevations, but to near not sea level.
User avatar
snowstormwatcher
Posts: 1643
Joined: Wed 23/09/2009 09:45
Location: South Canterbury. 20km inland from Timaru.
Has thanked: 188 times
Been thanked: 138 times

Re: Cold easterly airflow 7th - 12th Aug

Unread post by snowstormwatcher »

Richard wrote: Wed 03/08/2022 18:04 Yes some of Canterbury’s more significant snow events in past have at higher elevations, but to near not sea level.
June 2006?
I can't remember exactly what wind direction that came from but it was definitely warm advection with 850hpa temps only suggestive of snow to around 200-300m certainly not 20cm to sea level.
darcyplumb
Posts: 760
Joined: Sun 06/12/2020 20:15
Location: Ashburton
Has thanked: 1576 times
Been thanked: 404 times

Re: Cold easterly airflow 7th - 12th Aug

Unread post by darcyplumb »

Richard wrote: Wed 03/08/2022 18:04 Yes some of Canterbury’s more significant snow events in past have at higher elevations, but to near not sea level.
July 2011 comes to mind as an easterly event.
User avatar
Richard
Posts: 8369
Joined: Tue 14/07/2009 07:32
Location: Medbury, Inland North Canterbury
Has thanked: 1656 times
Been thanked: 800 times

Re: Cold easterly airflow 7th - 12th Aug

Unread post by Richard »

Would that have been the 23-26th July event?
Bradley
Posts: 1516
Joined: Wed 01/05/2013 21:06
Location: Christchurch
Has thanked: 142 times
Been thanked: 269 times

Re: Cold easterly airflow 7th - 12th Aug

Unread post by Bradley »

darcyplumb wrote: Wed 03/08/2022 18:13
Richard wrote: Wed 03/08/2022 18:04 Yes some of Canterbury’s more significant snow events in past have at higher elevations, but to near not sea level.
July 2011 comes to mind as an easterly event.
Yeah that was -9C at 850hpa that event so it didn’t give the ocean warmth component a chance for it to kill the sea level
snow, it was just so cold…
darcyplumb
Posts: 760
Joined: Sun 06/12/2020 20:15
Location: Ashburton
Has thanked: 1576 times
Been thanked: 404 times

Re: Cold easterly airflow 7th - 12th Aug

Unread post by darcyplumb »

Richard wrote: Wed 03/08/2022 18:28 Would that have been the 23-26th July event?
Possibly. I was living a few minutes north of Ashburton at the time and we had at least 30cm.
harveyt86
Posts: 137
Joined: Tue 18/06/2013 23:29
Location: Otahuhu, Auckland
Has thanked: 48 times
Been thanked: 18 times

Re: Cold easterly airflow 7th - 12th Aug

Unread post by harveyt86 »

I'm certainly no expert but my instinct is to agree with Richard here. There was a similar event in 2013 I think which looked like almost certainly sea level snow but was just a bit too much easterly in it in the end. Hope for you snow lovers down there I am wrong though!
darcyplumb
Posts: 760
Joined: Sun 06/12/2020 20:15
Location: Ashburton
Has thanked: 1576 times
Been thanked: 404 times

Re: Cold easterly airflow 7th - 12th Aug

Unread post by darcyplumb »

Either way it looks like a decent system that will cause havoc for a number of people and their livestock. An interesting few days ahead.
trickytiger
Posts: 334
Joined: Sat 05/07/2008 10:36
Location: Timaru, New Zealand. 13m asl
Has thanked: 1 time
Been thanked: 27 times

Re: Cold easterly airflow 7th - 12th Aug

Unread post by trickytiger »

A lot of events here tend to be S - SE, but not too much E or it's just rain. Chuck some sw in and it's usually dry
User avatar
snowstormwatcher
Posts: 1643
Joined: Wed 23/09/2009 09:45
Location: South Canterbury. 20km inland from Timaru.
Has thanked: 188 times
Been thanked: 138 times

Re: Cold easterly airflow 7th - 12th Aug

Unread post by snowstormwatcher »

darcyplumb wrote: Wed 03/08/2022 18:30
Richard wrote: Wed 03/08/2022 18:28 Would that have been the 23-26th July event?
Possibly. I was living a few minutes north of Ashburton at the time and we had at least 30cm.
25 July 2011 was a SW event, was fine and dry in Canterbury south of Rakaia, was probably the 14-16th August event.
darcyplumb
Posts: 760
Joined: Sun 06/12/2020 20:15
Location: Ashburton
Has thanked: 1576 times
Been thanked: 404 times

Re: Cold easterly airflow 7th - 12th Aug

Unread post by darcyplumb »

snowstormwatcher wrote: Wed 03/08/2022 19:03
darcyplumb wrote: Wed 03/08/2022 18:30

Possibly. I was living a few minutes north of Ashburton at the time and we had at least 30cm.
25 July 2011 was a SW event, was fine and dry in Canterbury south of Rakaia, was probably the 14-16th August event.
Thanks for the correction 😊
Bradley
Posts: 1516
Joined: Wed 01/05/2013 21:06
Location: Christchurch
Has thanked: 142 times
Been thanked: 269 times

Re: Cold easterly airflow 7th - 12th Aug

Unread post by Bradley »

darcyplumb wrote: Wed 03/08/2022 19:07
snowstormwatcher wrote: Wed 03/08/2022 19:03

25 July 2011 was a SW event, was fine and dry in Canterbury south of Rakaia, was probably the 14-16th August event.
Thanks for the correction 😊
August 2011 was a southerly event
You do not have the required permissions to view the files attached to this post.
harveyt86
Posts: 137
Joined: Tue 18/06/2013 23:29
Location: Otahuhu, Auckland
Has thanked: 48 times
Been thanked: 18 times

Re: Cold easterly airflow 7th - 12th Aug

Unread post by harveyt86 »

That's a nice looking radar! Managed to snowboard down to the valley floor from coronet peak after one of the dumps that month.
spwill
Posts: 9907
Joined: Sun 29/06/2003 22:39
Location: Mt Eden Auckland
Has thanked: 839 times
Been thanked: 866 times

Re: Cold easterly airflow 7th - 12th Aug

Unread post by spwill »

harveyt86 wrote: Wed 03/08/2022 20:12 That's a nice looking radar! Managed to snowboard down to the valley floor from coronet peak after one of the dumps that month.
Coronet Peak must be having the best season this year in many years. The cold easterly event next week will bring them dry weather but good for artificial snow making.
Razor
Moderator
Posts: 5121
Joined: Fri 10/02/2006 15:14
Location: Halswell, Christchurch
Has thanked: 717 times
Been thanked: 923 times

Re: Cold easterly airflow 7th - 12th Aug

Unread post by Razor »

Enjoying today's weather. Change is "in the wind"
Christchurch Rocks
darcyplumb
Posts: 760
Joined: Sun 06/12/2020 20:15
Location: Ashburton
Has thanked: 1576 times
Been thanked: 404 times

Re: Cold easterly airflow 7th - 12th Aug

Unread post by darcyplumb »

Razor wrote: Thu 04/08/2022 12:25 Enjoying today's weather. Change is "in the wind"
Stunning day down the road here too. A good opportunity to dry things out before it gets wet again next week.
User avatar
Storm Struck
Posts: 4859
Joined: Wed 17/11/2004 21:25
Location: Belfast Christchurch
Has thanked: 23 times
Been thanked: 373 times

Re: Cold easterly airflow 7th - 12th Aug

Unread post by Storm Struck »

Can someone be kind enough to explain abit more behind how snow to sea level works in a E-SE flow? Some models are not quite picking this with warm upper air and warm mid layers too which can often help with advection prediction outputs.
I do remember perhaps around 2007 we had a day that was particularly cold with a SE flow, that was bringing in showers and snow to 200m. For about half an hour it was grappling/ hail with enough to settle as well.
So these sort of set ups can happen.
An active period once again from tomorrow onwards, the water tables have gone nowhere so any extra rain is going to cause further issues.
I will get a few photos of my work to share.
Canterbury, home of good rugby and severe storms
User avatar
TonyT
Moderator
Posts: 2878
Joined: Thu 08/05/2003 11:09
Location: Amberley, North Canterbury
Has thanked: 352 times
Been thanked: 1146 times

Re: Cold easterly airflow 7th - 12th Aug

Unread post by TonyT »

Storm Struck wrote: Thu 04/08/2022 13:27 Can someone be kind enough to explain abit more behind how snow to sea level works in a E-SE flow?
Its not complicated. Snow forms, and doesn't melt before it hits the ground. The end. :-)
User avatar
Storm Struck
Posts: 4859
Joined: Wed 17/11/2004 21:25
Location: Belfast Christchurch
Has thanked: 23 times
Been thanked: 373 times

Re: Cold easterly airflow 7th - 12th Aug

Unread post by Storm Struck »

TonyT wrote: Thu 04/08/2022 14:15
Storm Struck wrote: Thu 04/08/2022 13:27 Can someone be kind enough to explain abit more behind how snow to sea level works in a E-SE flow?
Its not complicated. Snow forms, and doesn't melt before it hits the ground. The end. :-)
:lol: yes that is a very precise yet simple answer, I like it.

I do see the latest models show 850mb temps of -8C now so that's certainly good.
Canterbury, home of good rugby and severe storms
Bradley
Posts: 1516
Joined: Wed 01/05/2013 21:06
Location: Christchurch
Has thanked: 142 times
Been thanked: 269 times

Re: Cold easterly airflow 7th - 12th Aug

Unread post by Bradley »

Latest EC ensemble is saying 15 of 50 members indicating snow for Christchurch so around a 30% chance
Locked