Labour WE Trough & Cool Change

[spwill]

Yes, active Thunderstorm activity to our west now drifting toward Waitomo and Waikato

[Manukau heads obs]

this frontal line is showing signs of reforming nicely me thinks,moving onto us from the NNW....could be an interesting night here

[NZstorm]

What are the chances of it fireing up even more when it hits warmer land? or would the land be too cold by then to help convective activity?

Yes, to late in the day now for land based storms. A frontal boundary is providing the trigger.

[gllitz]

Some nice red bits showing on the Welly radar at the moment...coming your way, RWood?

[Myself]

What the on earth are MS on I would like to know I would atleast expect to see a moderate risk up for tomorrow afternoon/evening for thunderstorms.
Everything there suggests it i would think apart from the timing but even that shouldnt be a problem, onshore NE winds before hand no NW.

For Canterbury? Why? I see an upper trough that is someway behind the surface change. It's going to be too warm aloft surely (should be NW at 500hPa until something like 6AM Sunday morning).
It looks like tomorrow there will be an upper cold pool crossing the North Island and that's where the instability will be.

[NZstorm]

For Canterbury? Why?

I think the thunderstorm risk would be well inland. The question will be whether there is enough surface heating to destablise the air mid to late afternoon. The trough may well cloud the region up too much preventing surface warming/convection.

[Storm Struck]

I say that because of how cold the change is surging up the coast coming onto an onshore NE flow, one would think this is our best shot so far this pre storm season.
Models are really pulling numbers down especially on GFS which suggests snow down to 500m atleast, I also like the fact the moisture runs have stayed with us and not bailed away.
The rain to the north coming down has increased in the last few hours getting abit more persistant to heavy, so perhaps some much needed rain here soon.
Yes that is something i did wonder about Steve a few days ago, although having said that if we get rain overnight with some brief heating by morning will that help in any way?.
I will be up inland at Hanmer, I havn't really heard of many thunderstorm occurances up there mainly around Culverdon which isnt too far from there i guess.
Cheers
Jason.

[NZstorm]

The gradient over Canterbury looks to go southerly by the middle of the day so not much chance of a NE unfortunately.

For North Island on Sunday, the system may go thru Auckland a bit early by the looks. Crossing midday and well gone by late afternoon.

[Tornado Tim]

It is very active the low with lightning! 153 strikes within 30 min.
Very Likely to have a thunderstorm in hamilton overnight.

[tich]

Maybe some undercutting cold air for Canterbury - the kind of situation which can bring snow to much lower levels than officially forecast.

[Manukau heads obs]

Waiuku getting a good soaking at the moment!
http://ps.gen.nz/~hamgap/waiuku.htm
(20mm as against 10mm here (but you can see that on the rain radar the rain band intensified as it moved south from me )

[Manukau heads obs]

lightning showing up in the next rain band heading towards the auckland area

[CHCH Weather Chaser]

A few models now suggesting snow to around the 400m-500m mark. Could be some heavy falls later tomorrow afternoon/evening. First rain band still far to the north of the city, there has been a lot of rain up the northeastern coast of SOUTH ISLAND for the past few days from radar imagerys. Hopefully the rain stays in North Canterbury only tonight and away from the city i have cricket tomorrow at 1pm so might get through it if im lucky. Hopefully the southerly front doesnt arrive till 7pm or so, looking like very strong southerly with gales possible. At the moment its dry with a northeast breeze and between 11 and 12 degrees,

[Philip Duncan]

Big flash of lightning and boom of thunder over West Auckland just then!

[Vertigo]

yes, seems to be a lightning active Cb overhead at the moment. its gone quiet for the past 10-15 minutes however..

[Philip Duncan]

Typical. Back end of the front moving through before midnight...but it doesn't look too active...most of the activity appears to be at the front. Still, good to see some flashes after a very quiet several weeks.

[Myself]

Maybe some undercutting cold air for Canterbury - the kind of situation which can bring snow to much lower levels than officially forecast.

Yes, definitely worth watching. Undercutting is inherently a highly stable situation so there'd be no chance of any thundery stuff with it either. I wonder what would people prefer
Looks like being a classic Labour Weekend cold snap by any means. We could be hearing about some significant frost damage to crops (grapes in Marlborough, Canterbury and Central Otago at risk I'd say) after skies clear from Sunday into Monday.

[Vertigo]

there looks to be a lightning heavy Cb incoming from the NW of auckland.. might be something to come still.

[mikestormchaser]

Well along with jasestrm im also heading up to hanmer tomorrow, will be interesting t see what will happen weather wise up there, but by sounds of it i may have not seen the last of falling snow flakes yet! haha
possibility of some snowy conditions up there 2mro night.

[spwill]

Quite a lot of Thunderstorm activity for the upper NorthIsland last night. Much of the Auckland activity was from Whangaporaoa to Waiheke Island.

There is a small Storm currently off the Auckland West coast . It would have been interesting if the air mass currenty over us passed through in the afternoon hours.

[NZstorm]

It would have been interesting if the air mass currenty over us passed through in the afternoon hours.

I was just thinking that. Pity its all moving thru 6 hrs too early. And we have the same problem with tomorrows trough by the looks.

[Nev]

Hmm... I must've missed any thunder near here last night. Got 16.5mm here overnight, mostly between 11pm and 2pm. More light rain atm. NE'ers in Gulf and Waitemata don't appear to have been as strong as forecast - apart from Chanel Island, winds seemed to have peaked late arvo at no more than 45 km/h.

[Tornado Tim]

It completely bypassed Hamilton, didnt hear a single thing! Damb it.

[David]

We had 14mm overnight here, from light-moderate rain (nothing heavy). The rain was accompanied by occasional lightning flashes and peels of thunder for an hour starting just before 11pm - some quite loud/close. Towards midnight there was more frequent lightning and thunder out to the east of here for a time - I was watching out my window and saw one good bolt of forked lightning flicker across the sky. About 10 rumbles heard in all

2 big cracks of thunder just then!

[Manukau heads obs]

yes, the rain radar showed the line intensified more after it crossed west/central auckland areas....Waiuku got 34mm!