Squally showers with possible thunder, Upper NI 6th-7th May.

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These topics are a read-only archive and may be subject to out-of-date information.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
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 showers with possible thunder, Upper NI 6th-7th May.

Unread post by Tornado Tim »

Trough expected to start greeting the NI tommorow and bring some squally type showers with possible thunder with them.

Metservice are also including the risk of small tornadoes with any storms that develop.

Upper air temps around -18°C at 500 MB and sfc wind flows from the NE.

Relatively High Cape Values too up too 1000j/kg :D, most likely due to High DP's with the NE flow.

M/S's t-storm outlook seems pretty good but I would say the most risk would be around Auckland and Waikato and BOP later on the day.......
You do not have the required permissions to view the files attached to this post.
NZAPStrike.net - NZ Aus Pacific Strike Network
User avatar
Vertigo
Posts: 1184
Joined: Sun 09/12/2007 23:50
Location: Henderson, Auckland
Has thanked: 0
Been thanked: 12 times

Re: Squally showers with possible thunder, Upper NI 6th-7th May.

Unread post by Vertigo »

i think metservice is being a bit cautious given the events of the other day. the big cape numbers are offshore by the looks of it. ill take a wait and see approach to this.
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 showers with possible thunder, Upper NI 6th-7th May.

Unread post by Manukau heads obs »

wow, the latest sat animation really shows this new low developing explosively in the central tasman
check out the squally SW flow behind it that is intensifying!
Image
Brian Hamilton, weather enthusiast. My weather dataEmail: [email protected]
Talbotm
Posts: 262
Joined: Fri 09/10/2009 10:26
Location: Waddington, Canterbury 300msl
Has thanked: 0
Been thanked: 0

Re: Squally showers with possible thunder, Upper NI 6th-7th May.

Unread post by Talbotm »

Looks to be some interesting weather around tomorrow looks to be some very unstable air masses which could cause some tornados if they keep growing in instability.
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 showers with possible thunder, Upper NI 6th-7th May.

Unread post by Tornado Tim »

Talbotm wrote:Looks to be some interesting weather around tomorrow looks to be some very unstable air masses which could cause some tornados if they keep growing in instability.
For reference: Instability in itself doesn't cause tornadoes.
NZAPStrike.net - NZ Aus Pacific Strike Network
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 showers with possible thunder, Upper NI 6th-7th May.

Unread post by Manukau heads obs »

if there is a tornado from this next weather event somewhere, then its going to be more of the "NZ garden variety type"
i.e shorter lived and weaker and smaller and of a 'Landspout" type tornado (as opposed to the Albany Tornado which was from a (small) mesocylone (rotating thunderstorm)

in september 1991 (I think that was the date), an intense cold front with a NE/ NW wind change spawned a tornado that went the full length of the peninsular here where I live, i.e around 20km, so the cold front triggered tornadoes can be relatively long tracked
Image
Brian Hamilton, weather enthusiast. My weather dataEmail: [email protected]
User avatar
NZstorm
Posts: 11333
Joined: Mon 10/03/2003 19:38
Location: Grey Lynn, Auckland
Has thanked: 342 times
Been thanked: 361 times

Re: Squally showers with possible thunder, Upper NI 6th-7th May.

Unread post by NZstorm »

Looks to be some shear there Brian so a mesocyclonic tornado on the cards. Taranaki and Bay of Plenty could be the most favoured spots. Tomorrows set up is not that different to Tuesdays but there is better upper flow tomorrow.
treetop
Posts: 316
Joined: Sun 04/02/2007 20:29
Location: katikati
Has thanked: 0
Been thanked: 6 times

Re: Squally showers with possible thunder, Upper NI 6th-7th May.

Unread post by treetop »

A NW/SE jetstream of 100/150 nkts would create ideal shear conditions. In tomorrows case the warm front moving infrom the north and low level wind from the same direction may reduce the twisting recqired for a decent tornado.
ttttttttttt
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 showers with possible thunder, Upper NI 6th-7th May.

Unread post by Manukau heads obs »

wow, big blow up to the NE again
very lightning active too

we have missed that one
but looks like others to come....
Image
Brian Hamilton, weather enthusiast. My weather dataEmail: [email protected]
User avatar
NZstorm
Posts: 11333
Joined: Mon 10/03/2003 19:38
Location: Grey Lynn, Auckland
Has thanked: 342 times
Been thanked: 361 times

Re: Squally showers with possible thunder, Upper NI 6th-7th May.

Unread post by NZstorm »

Yes, Looks to have been a big thunderstorm on the outer BOP. Its drifting SSE. I think the BOP looks to be the region in the firing line today.

I think the lack of heating at this time of year will keep thunder chances in Auckland quite low.
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 showers with possible thunder, Upper NI 6th-7th May.

Unread post by Manukau heads obs »

interesting that despite a northerly flow, surface winds are easterly
so some wind shear?
yes, currently the heat source is the warm water to the east of northland
Image
Brian Hamilton, weather enthusiast. My weather dataEmail: [email protected]
User avatar
Michael
Posts: 7210
Joined: Thu 27/03/2003 12:04
Location: Rainy Manurewa, Auckland - "City of Gales"
Has thanked: 0
Been thanked: 1 time
Contact:

Re: Squally showers with possible thunder, Upper NI 6th-7th May.

Unread post by Michael »

Why suddenly the risk of tornados because we hd one on Wednesday? Looks to me an usual Straight easterly flow as its been much of the last 2 weeks and a SW flow behind.Hope the NW flow predicted pans out and I am wrong.
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 showers with possible thunder, Upper NI 6th-7th May.

Unread post by Manukau heads obs »

once this line of showers/cloud/rain goes through, there is not much left in behind
there is a shower line moving onto the far north...
but otherwise the area of convergence /battle ground with the high to the east is once again to the east of northland/auckland
so all the warnings might need to be lifted for northland/auckland?
( BOP is in the firing line big time this morning though)
but once the sun comes out and get some heating and with the cold front approaching from the west, there might be more heavy shower lines to develop?

there is a heavy shower about to hit auckland city though from the north

instability shower lines also showing up in the western waikato/king country
Image
Brian Hamilton, weather enthusiast. My weather dataEmail: [email protected]
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 showers with possible thunder, Upper NI 6th-7th May.

Unread post by Manukau heads obs »

the sat sequence and BOP rain radar does show a small low is developing...heading south towards whakatane...
that could be something to watch
Image
Brian Hamilton, weather enthusiast. My weather dataEmail: [email protected]
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 showers with possible thunder, Upper NI 6th-7th May.

Unread post by Manukau heads obs »

that small low in the BOP is looking stronger on the rain radar
getting a big hook of rotation
heading more SSW now, somewhere between Tepuke and Whakatane could expect squally conditions as it passed through I would expect
Image
Brian Hamilton, weather enthusiast. My weather dataEmail: [email protected]
spwill
Posts: 9907
Joined: Sun 29/06/2003 22:39
Location: Mt Eden Auckland
Has thanked: 839 times
Been thanked: 866 times

Re: Squally showers with possible thunder, Upper NI 6th-7th May.

Unread post by spwill »

Looks like the persistent heavy rain will be over the BOP this morning, more like showers for Auckland.
Some small heavy showers in the Gulf right now which will catch eastern Auckland next hr.
phildan89
Posts: 15
Joined: Tue 29/09/2009 20:38
Location: Queenstown
Has thanked: 0
Been thanked: 1 time

Re: Squally showers with possible thunder, Upper NI 6th-7th May.

Unread post by phildan89 »

You know its a crappy day in Tauranga when the port cranes are in the cloud...no sign of any storms yet though. All further down the coast towards Maketu.
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 showers with possible thunder, Upper NI 6th-7th May.

Unread post by Manukau heads obs »

have patches of blue here and can see the shower tops passing to my east
I can tell you they look underwhelming at the moment

but its a dynamic situation and blow up lines could occur at any time in the hauraki gulf /northland/auckland during the day
Image
Brian Hamilton, weather enthusiast. My weather dataEmail: [email protected]
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 showers with possible thunder, Upper NI 6th-7th May.

Unread post by David »

Manukau heads obs wrote:have patches of blue here and can see the shower tops passing to my east
I can tell you they look underwhelming at the moment

but its a dynamic situation and blow up lines could occur at any time in the hauraki gulf /northland/auckland during the day
Yes, and there looks to be some surface heating possible? Big patch of blue sky moving in here after a heavy shower.
Image
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 showers with possible thunder, Upper NI 6th-7th May.

Unread post by Nev »

Moderate to heavy 17mm here in the last 1.5 hrs.
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 showers with possible thunder, Upper NI 6th-7th May.

Unread post by Tornado Tim »

Clearing is occurring to the North moving south according to the sat loops.
NZAPStrike.net - NZ Aus Pacific Strike Network
phildan89
Posts: 15
Joined: Tue 29/09/2009 20:38
Location: Queenstown
Has thanked: 0
Been thanked: 1 time

Re: Squally showers with possible thunder, Upper NI 6th-7th May.

Unread post by phildan89 »

Tornado Tim wrote:Clearing is occurring to the North moving south according to the sat loops.
Definitely cleared here inTGA now. Mainly high(ish) cloud now and patches of blue sky to the north. All looking very stable as well...
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 showers with possible thunder, Upper NI 6th-7th May.

Unread post by Manukau heads obs »

yes
I think the threat (of severe weather) is now passing,after another hour or so its much diminished, yes?
although having said that, the convergence line that is currently to the north of the NI could wrap around the low in the tasman more and basicly move more SSW and move back onto the coromandel later...
I will be in the coromandel this evening, there for weekend (our anniversary weekend), so can give updates of conditions there :)
Image
Brian Hamilton, weather enthusiast. My weather dataEmail: [email protected]
spwill
Posts: 9907
Joined: Sun 29/06/2003 22:39
Location: Mt Eden Auckland
Has thanked: 839 times
Been thanked: 866 times

Re: Squally showers with possible thunder, Upper NI 6th-7th May.

Unread post by spwill »

The Cb cloud showing up over Northland will be part of a line to come through here in perhaps a couple of hrs.
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 showers with possible thunder, Upper NI 6th-7th May.

Unread post by Manukau heads obs »

temperature and DP has risen alot behind the warm frontal line

the next thing to watch is the cold pool in the tasman as that gets closer, and all this warm moist air that has been dragged down
Image
Brian Hamilton, weather enthusiast. My weather dataEmail: [email protected]
Locked