Thunderstorms/Hail, Eastern SI Lower North 2-4th Oct!!
Forum rules
These topics are a read-only archive and may be subject to out-of-date information.
For today's weather discussion head to: New Zealand Weather & Climate
These topics are a read-only archive and may be subject to out-of-date information.
For today's weather discussion head to: New Zealand Weather & Climate
- Storm Struck
- Posts: 4871
- Joined: Wed 17/11/2004 21:25
- Location: Belfast Christchurch
- Has thanked: 23 times
- Been thanked: 391 times
Thunderstorms/Hail, Eastern SI Lower North 2-4th Oct!!
I thought it was time to create a new topic for this, as some quite unstable air moves onto the south island in the next few days.
A risk exists for Southland and Otago today as MS have indicated, maybe an isolated cell on the coastline around South Canterbury too.
But the main set up is much better for tomorrow, especially for the eastern South Island and the west coast too.
A frontal band goes through around 1pm over Mid Canterbury tomorrow, but it probaly only initially presents low/moderate chance as there is a pre frontal westerly.
However a cold pool of air is left behind as an upper level trough develops over Mid Canterbury further bringing the atmosphere more unstable and allowing some pockets of coastal E-SE winds especially through the Christchurch area.
I highlight possibly our first high risk set up of the season between Ashburton and Christchurch, where we have -3 LI's 500-600 cape -34C upper air and reasonable convergences could lead to hail of 20+mm.
Well worth the chase tomorrow especially late afternoon/evening.
A risk exists for Southland and Otago today as MS have indicated, maybe an isolated cell on the coastline around South Canterbury too.
But the main set up is much better for tomorrow, especially for the eastern South Island and the west coast too.
A frontal band goes through around 1pm over Mid Canterbury tomorrow, but it probaly only initially presents low/moderate chance as there is a pre frontal westerly.
However a cold pool of air is left behind as an upper level trough develops over Mid Canterbury further bringing the atmosphere more unstable and allowing some pockets of coastal E-SE winds especially through the Christchurch area.
I highlight possibly our first high risk set up of the season between Ashburton and Christchurch, where we have -3 LI's 500-600 cape -34C upper air and reasonable convergences could lead to hail of 20+mm.
Well worth the chase tomorrow especially late afternoon/evening.
Canterbury, home of good rugby and severe storms
- Storm Struck
- Posts: 4871
- Joined: Wed 17/11/2004 21:25
- Location: Belfast Christchurch
- Has thanked: 23 times
- Been thanked: 391 times
Re: Thunderstorms/Hail, Eastern SI Lower North 2-3rd Oct!!
I would love to know what MS is looking at
http://www.metservice.com/warnings/thunderstorm-outlook
http://www.metservice.com/warnings/thunderstorm-outlook
Canterbury, home of good rugby and severe storms
-
- Posts: 1519
- Joined: Wed 01/05/2013 21:06
- Location: Christchurch
- Has thanked: 144 times
- Been thanked: 269 times
Re: Thunderstorms/Hail, Eastern SI Lower North 2-3rd Oct!!
Wow. One of you is very wrong in their forecast! All your numbers stack up though so it will be very interesting to see what happens tomorrow afternoon...
-
- Posts: 2202
- Joined: Sun 11/06/2006 20:57
- Location: Waikawa, Picton
- Has thanked: 0
- Been thanked: 74 times
Re: Thunderstorms/Hail, Eastern SI Lower North 2-3rd Oct!!
I think the frontal band will kill off and chance of thunderstorms after it pass, just my guess
-
- Posts: 2713
- Joined: Sat 03/06/2006 20:11
- Location: Rolleston, Canterbury
- Has thanked: 356 times
- Been thanked: 608 times
Re: Thunderstorms/Hail, Eastern SI Lower North 2-3rd Oct!!
I know what you mean melja. The numbers stack up nicely as jase has pointed out. My main concern would be cloud cover. Heating not an issue for me as the upper air is so cold. But often after a frontal band it can clear then that unstable air comes in. Classic stuff really. Im going moderate risk tomorrow in canterbury. Be interesting to see what Metservice update there risks tonight.melja wrote:I think the frontal band will kill off and chance of thunderstorms after it pass, just my guess
Mike
Stormchasers.co.nz
Stormchasers.co.nz
-
- Posts: 100
- Joined: Mon 08/09/2014 15:39
- Location: Cairns QLD
- Has thanked: 0
- Been thanked: 0
Re: Thunderstorms/Hail, Eastern SI Lower North 2-3rd Oct!!
High cloud all day here and not very warm. Moderate risk of thunderstorms this arvo, evening and even tomorrow morning which seems strange. Metservice not giving you Cantabrians much hope haha.
- Storm Struck
- Posts: 4871
- Joined: Wed 17/11/2004 21:25
- Location: Belfast Christchurch
- Has thanked: 23 times
- Been thanked: 391 times
Re: Thunderstorms/Hail, Eastern SI Lower North 2-3rd Oct!!
The frontal band which comes through around midday could briefly destabilise things of course with the risk of thunderstorms, but generally once a front goes through which this will be brief will clear the skies inbehind and the SW dies off.
I guess its more a case of whether it swings back to the westerly quarter or a breezy coastal E-SE, which is quite likely looking at some of the maps especially around mid canterbury where the isobaric flow wants to open up a tad and develope a small offshore low from Banks Peninnsula.
Either way I still think it is worthy of a risk rather than giving no risk given the conditions are so fruitful.
Secondary trough in the evening with colder air boom
Take a look at this map although I am not a great fan of METVUW and thier recent map changes, this kinda shows what I mean by looking at the change in windsocks over mid canterbury compared with the rest of the south island.
It could be upper level W-SW but at the surface the winds are more coastal E-SE, which could make things rather interesting .
Worth noting I think, sometimes its best to over look these things and learn more from them.
I guess its more a case of whether it swings back to the westerly quarter or a breezy coastal E-SE, which is quite likely looking at some of the maps especially around mid canterbury where the isobaric flow wants to open up a tad and develope a small offshore low from Banks Peninnsula.
Either way I still think it is worthy of a risk rather than giving no risk given the conditions are so fruitful.
Secondary trough in the evening with colder air boom
Take a look at this map although I am not a great fan of METVUW and thier recent map changes, this kinda shows what I mean by looking at the change in windsocks over mid canterbury compared with the rest of the south island.
It could be upper level W-SW but at the surface the winds are more coastal E-SE, which could make things rather interesting .
Worth noting I think, sometimes its best to over look these things and learn more from them.
You do not have the required permissions to view the files attached to this post.
Canterbury, home of good rugby and severe storms
-
- Meteorologist (Retired)
- Posts: 406
- Joined: Thu 27/10/2005 20:44
- Location: Greytown
- Has thanked: 2 times
- Been thanked: 7 times
Re: Thunderstorms/Hail, Eastern SI Lower North 2-3rd Oct!!
The problem for Canterbury tomorrow is that although the deep atmosphere is potentially unstable, the problem is whether or not the surface wind convergence will be strong enough and will the moisture be enough. Soundings today suggested trouble getting decent parcel lift off the surface with some negative bouyancys to be overcome. If the wind convergence is strong enough, then the moisture in the easterly will likely be high enough. We did allude to this in the text for the afternoon/evening period.
Paul
Paul
- Tornado Tim
- Moderator
- Posts: 4920
- Joined: Sun 19/10/2008 17:17
- Location: Raglan, Waikato / Hillcrest, Hamilton
- Has thanked: 102 times
- Been thanked: 202 times
- Contact:
Re: Thunderstorms/Hail, Eastern SI Lower North 2-3rd Oct!!
Ah very good Paul, I knew you'd post sooner rather than later .
Ill have to schedule another time to come to the Metservice Office, next time I am coming is in November.
I hope for you folk in Canterbury get a storm tomorrow, been a while since you last had a good one.
Ill have to schedule another time to come to the Metservice Office, next time I am coming is in November.
I hope for you folk in Canterbury get a storm tomorrow, been a while since you last had a good one.
NZAPStrike.net - NZ Aus Pacific Strike Network
-
- Posts: 18489
- Joined: Wed 12/03/2003 22:08
- Location: Raukapuka Geraldine
- Has thanked: 1769 times
- Been thanked: 1412 times
Re: Thunderstorms/Hail, Eastern SI Lower North 2-3rd Oct!!
Sort of some ways, I do tend to agree with Paul.Paul Mallinson wrote:The problem for Canterbury tomorrow is that although the deep atmosphere is potentially unstable, the problem is whether or not the surface wind convergence will be strong enough and will the moisture be enough. Soundings today suggested trouble getting decent parcel lift off the surface with some negative bouyancys to be overcome. If the wind convergence is strong enough, then the moisture in the easterly will likely be high enough. We did allude to this in the text for the afternoon/evening period.
Paul
It's a matter of timing and getting things into prospective.
I'm forecasting a, basically, fine day with cold SW winds.
There could be 'Cb Coldies" off shore.
Maybe a wintry shower may move through?
JohnGaul
NZThS
NZThS
- 03Stormchaser
- Moderator
- Posts: 4428
- Joined: Tue 09/12/2003 12:11
- Location: Prebbleton
- Has thanked: 104 times
- Been thanked: 184 times
- Contact:
I'm busy tomorrow unfortunately setting up a friends wedding I'm a groomsman at. I can see the risk there, but can also see where Paul is coming from. Maybe we are just getting to excited for the first storm of the year
NZ Largest Storm Chasing Facebook Pagehttp://www.facebook.com/nzstormchasers
NZ Largest Storm Chase Community https://www.facebook.com/groups/NZStormchasersGroup
NZ Stormchasers TV https://www.youtube.com/@NZStormchasers
NZ Largest Storm Chase Community https://www.facebook.com/groups/NZStormchasersGroup
NZ Stormchasers TV https://www.youtube.com/@NZStormchasers
- NZstorm
- Posts: 11333
- Joined: Mon 10/03/2003 19:38
- Location: Grey Lynn, Auckland
- Has thanked: 342 times
- Been thanked: 361 times
Re: Thunderstorms/Hail, Eastern SI Lower North 2-3rd Oct!!
The set up looks too weak on moisture but I still expect some cloud development capable of a few lightning discharges near the coast.
- Storm Struck
- Posts: 4871
- Joined: Wed 17/11/2004 21:25
- Location: Belfast Christchurch
- Has thanked: 23 times
- Been thanked: 391 times
Re: Thunderstorms/Hail, Eastern SI Lower North 2-3rd Oct!!
Abit of an earlier than expected SW change this morning nice gust front with it and some quite heavy rain bands on the radar, could even be some lightning in the stuff down near Timaru.
Even though we have an early southerly its not a bad thing just means we boot the westerly out earlier once this stuff clears off and hopefully allows coastal winds to kick in.
Even though we have an early southerly its not a bad thing just means we boot the westerly out earlier once this stuff clears off and hopefully allows coastal winds to kick in.
Canterbury, home of good rugby and severe storms
-
- Posts: 100
- Joined: Mon 08/09/2014 15:39
- Location: Cairns QLD
- Has thanked: 0
- Been thanked: 0
Re: Thunderstorms/Hail, Eastern SI Lower North 2-3rd Oct!!
Was awoken a couple times last night by loud rolling thunder. Sometime between 2-4am.
- Nev
- Moderator
- Posts: 6230
- Joined: Tue 07/03/2006 15:24
- Location: Waiheke Island, Hauraki Gulf
- Has thanked: 474 times
- Been thanked: 1073 times
Re: Thunderstorms/Hail, Eastern SI Lower North 2-3rd Oct!!
This morn's MS update for today not too different from last night…
MetService - Thunderstorm Outlook
Valid to: Midnight Friday 3 Oct 2014
Issued at: 9:03am Friday 3 Oct 2014
The cold showery outbreak, bringing snow to low levels in the South Island, spreads over the North Island this afternoon (see Special Weather Advisory,Severe Weather Warnings and Watches for further detail).
There South Island a high risk of squally thunderstorms in most southern and western areas from Southland to northwest Nelson. Brief heavy rain, snow lowering to 2-300 metres in the far south, hail, and gusts around 90km/h are likely to accompany these storms.
A moderate risk extends into Taranaki and Manawatu during the evening and night. Here too they may be squally with small hail and gusts of 90km/h.
In Canterbury, there is a moderate risk of thunderstorms as a southwest change moves up the east coast in the afternoon. Any thunderstorms that do develop here are likely to bring localised heavy rain of 10-15mm/hr, and hail of 10-15mm diameter - possibly even 20mm.
A larger area of low risk covers much of the South Island, and the southwestern North Island, as indicated on the chart.
No thunderstorms expected elsewhere.
You do not have the required permissions to view the files attached to this post.
- Storm Struck
- Posts: 4871
- Joined: Wed 17/11/2004 21:25
- Location: Belfast Christchurch
- Has thanked: 23 times
- Been thanked: 391 times
Re: Thunderstorms/Hail, Eastern SI Lower North 2-3rd Oct!!
Clouds beginning to gradually clear now as the shower activity peters out, SW wind easing back too .
I dont see the westerly returning after this, id say it will be all coastal onshore winds before the change late this afternoon.
Abit more moisture this morning than I was expecting too going by the surface maps, just over 5mm although some of that would have been from convective deeper clouds too.
The area MS indicate is about where I would pick for the best chances of storms, Crossing everything well not everything for this afternoon and a good chase.
I dont see the westerly returning after this, id say it will be all coastal onshore winds before the change late this afternoon.
Abit more moisture this morning than I was expecting too going by the surface maps, just over 5mm although some of that would have been from convective deeper clouds too.
The area MS indicate is about where I would pick for the best chances of storms, Crossing everything well not everything for this afternoon and a good chase.
Canterbury, home of good rugby and severe storms
-
- Moderator
- Posts: 5138
- Joined: Fri 10/02/2006 15:14
- Location: Halswell, Christchurch
- Has thanked: 725 times
- Been thanked: 932 times
Re: Thunderstorms/Hail, Eastern SI Lower North 2-3rd Oct!!
We now how the requesred sun, and perhaps a wee wind shift might help. Soem towering cumulus to the far SW now, as observed from the 6th floor of the CBD
Christchurch Rocks
-
- Posts: 4003
- Joined: Sun 08/08/2010 16:49
- Location: Ashburton, Mid-Canterbury, 110m asl.
- Has thanked: 1380 times
- Been thanked: 333 times
Re: Thunderstorms/Hail, Eastern SI Lower North 2-3rd Oct!!
Some explosive-looking cloud to the south of Ashburton, can't tell yet how far away it might be.
- Storm Struck
- Posts: 4871
- Joined: Wed 17/11/2004 21:25
- Location: Belfast Christchurch
- Has thanked: 23 times
- Been thanked: 391 times
Re: Thunderstorms/Hail, Eastern SI Lower North 2-3rd Oct!!
All ingrediants are there for storms now, heating NE winds here in Rolleston and a few CB's already blowing up to the south.
New development inland near Mt Somers
New development inland near Mt Somers
Canterbury, home of good rugby and severe storms
-
- Posts: 466
- Joined: Mon 27/05/2013 19:16
- Location: Inland mayfield 310asl
- Has thanked: 1 time
- Been thanked: 7 times
Re: Thunderstorms/Hail, Eastern SI Lower North 2-3rd Oct!!
A decent looking shower heading up past mt peel, saw a flash
Auckland & Tauranga
-
- Posts: 4003
- Joined: Sun 08/08/2010 16:49
- Location: Ashburton, Mid-Canterbury, 110m asl.
- Has thanked: 1380 times
- Been thanked: 333 times
-
- Posts: 466
- Joined: Mon 27/05/2013 19:16
- Location: Inland mayfield 310asl
- Has thanked: 1 time
- Been thanked: 7 times
Re: Thunderstorms/Hail, Eastern SI Lower North 2-3rd Oct!!
Yea lots of thunder as lightning. I'm already getting small hail and it's still miles away
Auckland & Tauranga
-
- Posts: 466
- Joined: Mon 27/05/2013 19:16
- Location: Inland mayfield 310asl
- Has thanked: 1 time
- Been thanked: 7 times
Re: Thunderstorms/Hail, Eastern SI Lower North 2-3rd Oct!!
Just had a mental hail storm, 25mm hail
Auckland & Tauranga
-
- Meteorologist (Retired)
- Posts: 406
- Joined: Thu 27/10/2005 20:44
- Location: Greytown
- Has thanked: 2 times
- Been thanked: 7 times
Re: Thunderstorms/Hail, Eastern SI Lower North 2-3rd Oct!!
Interesting report. Where did this occur? HInds? Radar doesn't show anything significant around this time.matttbs wrote:Just had a mental hail storm, 25mm hail
Paul
-
- Moderator
- Posts: 5138
- Joined: Fri 10/02/2006 15:14
- Location: Halswell, Christchurch
- Has thanked: 725 times
- Been thanked: 932 times
Re: Thunderstorms/Hail, Eastern SI Lower North 2-3rd Oct!!
I think hes up nearer the foothills these days PaulPaul Mallinson wrote:Interesting report. Where did this occur? HInds? Radar doesn't show anything significant around this time.matttbs wrote:Just had a mental hail storm, 25mm hail
Paul
Christchurch Rocks