Squally Thunderstorms - May 13 -15

Archive of NZ Weather & Climate
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These topics are a read-only archive and may be subject to out-of-date information.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
Orion
Posts: 3994
Joined: Sun 08/08/2010 16:49
Location: Ashburton, Mid-Canterbury, 110m asl.
Has thanked: 1367 times
Been thanked: 329 times

Re: General May Weather

Unread post by Orion »

Have just noticed a couple of flashes of distant lightning to the north-west.
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: General May Weather

Unread post by Richard »

Cool,might throw the curtains open
User avatar
Nev
Moderator
Posts: 6216
Joined: Tue 07/03/2006 15:24
Location: Waiheke Island, Hauraki Gulf
Has thanked: 468 times
Been thanked: 1064 times

Re: General May Weather

Unread post by Nev »

I see MS have upgraded most of the N.I. T-storm risk for later today to high with possible tornadoes…
MetService - Thunderstorm Outlook

Valid to: Midnight Thursday 14 May 2015
Issued at: 9:11am Thursday 14 May 2015

A large complex trough over New Zealand is moving slowly eastwards. Combined with cooling temperatures in the upper atmosphere, very unstable conditions are likely over much of the country.

The highest risk of thunderstorms is with a front and trough moving over the North Island during the day. For Waikato, Waitomo, western Taupo, Taumarunui and Taranaki there is a high risk of thunderstorms during the afternoon and evening and these are likely to be accompanied by localised heavy rain with intensities of 10 to 25mm per hour and winds gusts of 90 to 100 km/h. In this area there is also a moderate risk of SEVERE THUNDERSTORMS until about 10pm due to rainfalls reaching 25 to 30mm per hour and a low risk of small tornadoes.

For Northland, Auckland, the Coromandel Peninsula, Bay of Plenty and eastern Taupo there is a high risk of thunderstorms this evening and these are likely to be accompanied by localised heavy rain of 10 to 20mm per hour and wind gusts around 90 km/h. In these areas there is a low risk that these thunderstorms could become SEVERE due to rainfall intensities reaching 25 to 30mm per hour. There is also a low risk of tornadoes, especially about the Coromandel Peninsula and Bay of Plenty.

Another high risk of thunderstorms exists over Fiordland and southern Westland where localised heavy rain of 10 to 25mm per hour and small hail is possible. Here the risk may reduce for a time during the afternoon.

For the remainder of Westland, Buller, northwest Nelson, northern Wellington,Kapiti and Horowhenua there is a moderate risk of thunderstorms this morning and afternoon. These thunderstorms are likely to be accompanied by localised heavy rain of 10 to 25mm per hour and strong wind gusts of 90 km/h. About Kapiti and Horowhenua the likelihood of thunderstorms is slightly reduced but localised heavy rainfall is likely.

As shown on the chart, a low risk of thunderstorms exists during the day for Stewart Island, the eastern slopes of the Southern Alps, Nelson, Marlborough Sounds, Manawatu north of Horowhenua, Wanganui, Taihape and western Hawkes Bay and Gisborne.

During the early afternoon there is also a low risk of thunderstorms about Dunedin and North Otago.

No other areas of thunderstorms or severe convection are expected.
MetService T-storm Outlook map - May 14.png
You do not have the required permissions to view the files attached to this post.
User avatar
Nev
Moderator
Posts: 6216
Joined: Tue 07/03/2006 15:24
Location: Waiheke Island, Hauraki Gulf
Has thanked: 468 times
Been thanked: 1064 times

Re: General May Weather

Unread post by Nev »

MS also currently have a Severe T-storm Watch out for this arvo/evening from Waikato to Taranaki…
MetService - Severe Thunderstorm Watch
MetService T-storm Watch map - May 14.png
SEVERE THUNDERSTORM WATCH

Issued by MetService at 09:21 am Thursday 14 May 2015
Valid until 10:00 pm Thursday 14 May 2015
This watch affects people in the following weather forecast districts:
Waikato
Waitomo
Taumarunui
Taupo
Taranaki


A front is expected to move over the North Island today bringing frequent squally thunderstorms. For Taranaki, Taumarunui, western Taupo, Waitomo and Waikato there is a possibility of these thunderstorms becoming SEVERE this afternoon and early evening due to rainfalls reaching 25 to 30mm per hour in localised places. Rainfall of this intensity can cause flash flooding, especially about low-lying areas such as streams, rivers or narrow valleys, and may also lead to slips. Driving conditions will also be hazardous with surface flooding and poor visibility in heavy rain.

Some severe thunderstorms also produce tornadoes, although the risk of these is considered low.

Issued by: Allister Gorman

This watch will be updated by: 02:30 pm Thursday 14 May 2015
You do not have the required permissions to view the files attached to this post.
User avatar
SnwAddct
Posts: 252
Joined: Fri 09/05/2014 09:37
Location: Swanson, Auckland
Has thanked: 21 times
Been thanked: 0

Re: General May Weather

Unread post by SnwAddct »

All the Ski fields in the bottom half of the SI have had a wicked dumping in the past 36 hours..
User avatar
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:

Squally Thunderstorms - May 13 -15

Unread post by Tornado Tim »

New Thread in Order (Non Wellington Flood related).
NZAPStrike.net - NZ Aus Pacific Strike Network
User avatar
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: Squally Thunderstorms - May 13 -15

Unread post by Tornado Tim »

Last 24 hours worth of Lightning Activity:
NZAPStrike.net - NZ Aus Pacific Strike Network
User avatar
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: Squally Thunderstorms - May 13 -15

Unread post by Tornado Tim »

Thunderstorm Watch issued:
Another interesting night ahead :)
Metservice wrote:Issued by MetService at 02:19 pm Thursday 14 May 2015
Valid until Midnight Thursday 14 May 2015
This watch affects people in the following weather forecast districts:
Waikato
Waitomo
Taumarunui
Taupo
Taranaki

A front is expected to move over the North Island today bringing frequent squally thunderstorms. For Taranaki, Taumarunui, western Taupo, Waitomo and Waikato there is a possibility of these thunderstorms becoming SEVERE this afternoon and evening due to rainfalls reaching 25 to 30mm per hour in localised places. Rainfall of this intensity can cause flash flooding, especially about low-lying areas such as streams, rivers or narrow valleys, and may also lead to slips. Driving conditions will also be hazardous with surface flooding and poor visibility in heavy rain.


Some severe thunderstorms also produce tornadoes, although the risk of these is considered low.

Issued by: Allister Gorman

This watch will be updated by: 09:00 pm Thursday 14 May 2015
You do not have the required permissions to view the files attached to this post.
NZAPStrike.net - NZ Aus Pacific Strike Network
User avatar
David
Posts: 7578
Joined: Sat 18/08/2007 21:02
Location: Howick, Auckland
Has thanked: 416 times
Been thanked: 825 times
Contact:

Re: Squally Thunderstorms - May 13 -15

Unread post by David »

Cant see much of interest on the radar heading towards Auckland sadly...
Image
Manukau heads obs
Posts: 12305
Joined: Mon 10/03/2003 16:30
Location: West Coast Road, Manukau Peninsula, North Island
Has thanked: 0
Been thanked: 0
Contact:

Re: Squally Thunderstorms - May 13 -15

Unread post by Manukau heads obs »

NW wind change here,...wind is very unstable..very gusty...something brewing...
Image
Brian Hamilton, weather enthusiast. My weather dataEmail: [email protected]
User avatar
Nev
Moderator
Posts: 6216
Joined: Tue 07/03/2006 15:24
Location: Waiheke Island, Hauraki Gulf
Has thanked: 468 times
Been thanked: 1064 times

Re: Squally Thunderstorms - May 13 -15

Unread post by Nev »

Report of a small tornado in the Far North's Coopers Beach around 3pm this arvo…

'Small tornado hits Far North community' - TVNZ
User avatar
Nev
Moderator
Posts: 6216
Joined: Tue 07/03/2006 15:24
Location: Waiheke Island, Hauraki Gulf
Has thanked: 468 times
Been thanked: 1064 times

Re: Squally Thunderstorms - May 13 -15

Unread post by Nev »

And another report of an apparent damaging tornado in Mt Maunganui around 8.45pm tonight…

'Mini-tornados reported in Far North, Tauranga' - NZ Herald
Razor
Moderator
Posts: 5121
Joined: Fri 10/02/2006 15:14
Location: Halswell, Christchurch
Has thanked: 717 times
Been thanked: 923 times

Re: Squally Thunderstorms - May 13 -15

Unread post by Razor »

yes sounds quite serious in the Mount, could be more than one 'small' tornado? Or a microburst?
Christchurch Rocks
phildan89
Posts: 15
Joined: Tue 29/09/2009 20:38
Location: Queenstown
Has thanked: 0
Been thanked: 1 time

Re: Squally Thunderstorms - May 13 -15

Unread post by phildan89 »

Definitely a tornado. I work in the control tower at the airport here and it passed just east of us. First noticed a powerflash just northeast of the airport, and the latest from police scanners is that part of the baypark stadium has collapsed as a result which is about 3km away from the first sighting.
User avatar
Nev
Moderator
Posts: 6216
Joined: Tue 07/03/2006 15:24
Location: Waiheke Island, Hauraki Gulf
Has thanked: 468 times
Been thanked: 1064 times

Re: Squally Thunderstorms - May 13 -15

Unread post by Nev »

Wow! Thanks for the confirmation phildan89. Stuff report says just before 8:30pm…

'Tornado strikes Mt Maunganui, powerlines down' - Stuff

'Mini tornado hits Mount' - Bay of Plenty Times
Manukau heads obs
Posts: 12305
Joined: Mon 10/03/2003 16:30
Location: West Coast Road, Manukau Peninsula, North Island
Has thanked: 0
Been thanked: 0
Contact:

Re: Squally Thunderstorms - May 13 -15

Unread post by Manukau heads obs »

M/S did well having possible tornadoes in the warnings :)
sounds like a good one at Mt Maunganui...which is a bit of a hot spot....ironicly Tgsnoopy has just left for the USA to chase tornadoes...and this was one on his door step
Image
Brian Hamilton, weather enthusiast. My weather dataEmail: [email protected]
BeaconHill
Posts: 239
Joined: Sat 16/05/2009 21:10
Location: Strathmore/Seatoun (on the ridgeline), Wellington
Has thanked: 196 times
Been thanked: 344 times

Re: Squally Thunderstorms - May 13 -15

Unread post by BeaconHill »

Wonder if the MetService can provide a radar image from around the time it occurred. There could be some remnants of the cell visible to the SE in the image from 9pm
image.jpg
You do not have the required permissions to view the files attached to this post.
Manukau heads obs
Posts: 12305
Joined: Mon 10/03/2003 16:30
Location: West Coast Road, Manukau Peninsula, North Island
Has thanked: 0
Been thanked: 0
Contact:

Re: Squally Thunderstorms - May 13 -15

Unread post by Manukau heads obs »

I did see the radar around that time...was a series of descrete CB's moving down the coast line east of the coro peninsular
there would have been a NE surface flow into the bay...and an upper level NNW wind ..hence some wind sheer
Image
Brian Hamilton, weather enthusiast. My weather dataEmail: [email protected]
User avatar
Nev
Moderator
Posts: 6216
Joined: Tue 07/03/2006 15:24
Location: Waiheke Island, Hauraki Gulf
Has thanked: 468 times
Been thanked: 1064 times

Re: Squally Thunderstorms - May 13 -15

Unread post by Nev »

This close-up of the 8:30pm radar has some intense rain just inland of the Mount…
MetService BoP Radar - May 14, 8.30pm.png
You do not have the required permissions to view the files attached to this post.
Area51
Posts: 133
Joined: Mon 31/01/2005 18:57
Location: South Auckland
Has thanked: 0
Been thanked: 0

Re: Squally Thunderstorms - May 13 -15

Unread post by Area51 »

As another airport worker, I'm pretty sure there was a clap of thunder here at Auckland Intl and looking at the radar there is a good line of weather rolling in!
Manukau heads obs
Posts: 12305
Joined: Mon 10/03/2003 16:30
Location: West Coast Road, Manukau Peninsula, North Island
Has thanked: 0
Been thanked: 0
Contact:

Re: Squally Thunderstorms - May 13 -15

Unread post by Manukau heads obs »

thunder woke me up here at 3:30am :)
Image
Brian Hamilton, weather enthusiast. My weather dataEmail: [email protected]
jamie
Posts: 5907
Joined: Fri 25/02/2011 21:35
Location: Hamilton NZ
Has thanked: 22 times
Been thanked: 273 times
Contact:

Squally Thunderstorms - May 13 -15

Unread post by jamie »

Round 1 for today came thru in the early hours. Round 2 isn't far away. Round 3 looks the best. That's a while away but that has the look of a nasty cold pool. Lots of lightning strikes in that pool.
treetop
Posts: 316
Joined: Sun 04/02/2007 20:29
Location: katikati
Has thanked: 0
Been thanked: 6 times

Re: Squally Thunderstorms - May 13 -15

Unread post by treetop »

Just out at Tepuna where I live [near Mt Maunganui] No thunder heard . Unfortunatly it went through at night. Very localised looking at the radar.Was probably a water spout following the coast.Mt Maunganui itself has had a few Tornadoes hitting it over the years. Expect a similar settup this after noon.NW/NE convergence does cause some isscues here at times . Very localised but with 100-200 mm rain in 2-4 hours, often with downburst and or Tornado/Hail. Easy to chase but hard to pinpoint or predict. Stay safe out there !
ttttttttttt
User avatar
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: Squally Thunderstorms - May 13 -15

Unread post by Tornado Tim »

Thunderstorm Outlook Today:
Metservice wrote:An unstable westerly or northwesterly flow is expected to affect much of the North Island today. Thunderstorms are likely, especially associated with troughs embedded in the westerly flow and with areas of strong surface convergence.

In the south of Hawkes Bay, the east of Manawatu and the north of Wairarapa convergence at the surface is expected to become strong this afternoon and there is a moderate risk of thunderstorms with heavy rain as indicated on the map.There is a low risk that one or two of these could be SEVERE with downpours,bringing 25 to 35mm per hour of localised rain.

in the north of Northland there is a moderate risk of thunderstorms. These storms could be accompanied by strong wind gusts, 90 to 110 km/h and hail. There is a low risk of thunderstorms with strong wind gusts, 100 km/h in the south of Northland and in Auckland.

There is a moderate risk of thunderstorms this afternoon in Coromandel, Waikato ,Waitomo, the north of Taranaki, Taumarunui, Bay of Plenty and Taupo. These storms could be accompanied by strong wind gusts, 90 to 110 km/h and heavy rain,10 to 25mm per hour. Small tornadoes are possible from Waikato to Taranaki.

A low risk covers the remainder of the North Island north of Wellington.
You do not have the required permissions to view the files attached to this post.
NZAPStrike.net - NZ Aus Pacific Strike Network
treetop
Posts: 316
Joined: Sun 04/02/2007 20:29
Location: katikati
Has thanked: 0
Been thanked: 6 times

Re: Squally Thunderstorms - May 13 -15

Unread post by treetop »

I would be expecting a severe alert into BOP region for the evening , looks nasty and slow moving. Convergence will be the key. If its late and dark we way get a nice light show anyway.
ttttttttttt
Locked