NZ Weather Forum

Early warnings now out from the MS for a good half of NZ with a cold unstable airmass due to cross Thursday afternoon

This sat pic shows a good storm line in the Tasman currently, just need to move NZ a 1000km west. Almost no storm activity over Australia, it has been a quiet October for storms over there, not enough moisture I would say.

There will be a good NW before the southwest comes through, so that is never any good. In saying that we've had a few times where they do happen, sort of recently the one that came through with really strong southwesterlies and there was minor flooding plus some hail etc, can't remember the date. Uprooted that tree near the Avon.

A mod risk if I remember correctly is only a 40% chance of something happening anyway, and high risk is like 60% chance. Low is only 20%. Please correct me if I'm wrong so it never garatuees something will happen but highlights a chance is there. Look forward to something potentially happening!

Yeah im abit iffy its not the best ideal set up so anything that is to develope would be as indicated through the foothills where some variance in wind directions or sheltering in valleys could get brief storms firing.
I am thinking Friday might see something as that cold upper air still stays around and the SW flow eases at ground level to let in coastal breezes, kinda the left over scraps of cold air as the heating comes through.

A bit early, but coming onto rain here and just viewed a couple of flashes of lightning to the west

This site showing lots of spherics

http://www.blitzortung.org/

Plenty of flashes along the Alps currently and in the Tasman

Fine here now but flashing away,occasionally to the NW now, should get to Richard's this evening.
Saw a good shooting star along Scorpio to the west, also

Thats what i'm hoping John ,might go out and have look.

Wow, quite an active live of storms in the Tasman, more scattered activity it seems over the Alps of the South Island.

Yes some good flashes out there to the west,close enough to hear the rumbles too.

Very bright flashes indeed, one blue flash which would be CC went all the way along the alps and there was even a small bolt that popped its head up at the end.
Nice to see none the less

Yeah good spotting!! good flashes to the west indeed. doesnt look that far away however i think if u were to chase u would be driving for an hour, if it was the weekend i would indeed do so!! standing out there now observing the flashes and serferics

The front crossing the Waikato could have a bit of isolated lightning activity going by forecasts, however thunderstorms will be more likely on the through and upper level cold pool.
While upper levels temps expected to be unduly cold, has some very dry air at around 700mb and this diminishes the risk for Thunderstorms over more central regions of the North Island.
I see there is plenty of lift but without moisture, clouds are expected to take on a more fibrousy appearance and therfor won't hold a charge as well.

Yes, looks like isolated thunderstorms on the front as it crosses the North Island this morning. Could be squally on the front.

Tornado Tim wrote: While upper levels temps expected to be unduly cold, has some very dry air at around 700mb and this diminishes the risk for Thunderstorms over more central regions of the North Island.

I've observed that a really dry slot about about 750 seems to often result in Stronger lightning, as long as there is still good moisture in the surface layer

some very heavy rain coming through now. Wouldnt be suprised if i hear a rumble.

ohhhh looks like a ripper squally line approaching auckland west coast and Raglan coast. Have had nearly 20mm here at work going by tims station but just 5mm at my home.

Great to see this morning warnings still on track from yesterdays

Yeah there was some flashes out west here last night too.
not much chance of anything here today with a strong Westerly and high cloud cover.

Some weak storm activity South Auckland/north Waikato with that line,had gusty showers here , 7.4mm at Greylynn, the clearance arriving here now.

Dont think the risk here is very high.

30mm at Matangi and Hamilton airport. 22mm at Horshamdowns.

Not a bad drop!

Nice day now after a no surprises front. The 13C dewpoints here weren't moist enough for thunder. The system had 14-15C dewpoints out in the Tasman and there was plenty of lightning there. Shows how subtle the instability is with these winter style set ups.

ricky wrote:

Tornado Tim wrote: While upper levels temps expected to be unduly cold, has some very dry air at around 700mb and this diminishes the risk for Thunderstorms over more central regions of the North Island.

I've observed that a really dry slot about about 750 seems to often result in Stronger lightning, as long as there is still good moisture in the surface layer

I have noticed USA storm chasers look for dry mid level air (700mb). It makes the air more unstable.

Very nice squall came though, just now. Gusted up to 61km/hr and torrential rain