NZ Weather Forum

Some light thundery rain here mid-morning but short lived, only 5.3mm fell.
Clearing up now.

A few rumbles round here at the moment. Wind and light rain from the NE then swung round to the SW and got a couple rumbles. Nothing particularly exciting.

I use the word 'thundery' as a brief period of rain that is 'it is heavy 'as if it is thundering down', not the Met Service term for 'thundery showers'.

NZ Thunderstorm Soc wrote:not the Met Service term for 'thundery showers'.

Im with you on that John, incredibly irritating when they use that term or "Thundery falls".
They should just stick to what the actual weather is, ie: Thundershower, Thunderstorm etc etc.

Might be the first OK to good weather weekend in a bit if models are correct

A decent looking cold pool crossing NZ Friday/Saturday.

A clap of thunder/small hail possible for Auckland late Friday into Saturday morning.

Friday evening chart 500mb.

I use the term thundery when thunder is being heard.

Back on topic....looks like another round of snow for inland Otago and the McKenzie in the morning. Yesterdays dump sounded rather impressive for October

The southern webcams looked great yesterday with the snow and bright Spring light.

GFS pointing to a good chance for thunder here in the overnight hrs Friday into Sat with the cold upper trough crossing.

Cold with showers in Auckland this morning. Isolated lightning detected over Kaipara.

Daytime heating should trigger a bit of lightning/pea hail in the Bay of Plenty this afternoon maybe Waikato this morning.

Looking like Aucklands weather is finally starting to dry off in the models. There is a system however coming for Labour weekend?

Not much with this trough but day heating should generate some bigger Cbs further east.

I see some lightning strikes coromandel well
We did have some good cloud lowerings around here this morning and that shower line over Titirangi was as black as can be 10:30am or so

Manukau heads obs wrote:I see some lightning strikes coromandel well
We did have some good cloud lowerings around here this morning and that shower line over Titirangi was as black as can be 10:30am or so

Yes, that band gave us quite a heavy wee downpour with some hail just before midday. The low's centre looks good on the 3pm radar as it spirals away from Great Barrier with some lightning left in its wake…

I see Whangaparaoa recorded 18mm in the hour to 11am yesterday. However, going by nearby PWS's, I suspect most of that probably fell in less than 30 minutes, maybe even as little 15 minutes?

It's great to see places like Alexandra and Mt Cook finally get to start showing some historical daily weather stats on the Metservice website!

Nev wrote:I see Whangaparaoa recorded 18mm in the hour to 11am yesterday. However, going by nearby PWS's, I suspect most of that probably fell in less than 30 minutes, maybe even as little 15 minutes?

The dewpoint was only 10C/precipitable water 15mm, so likely that amount did not fall in 15mins.

I think that sort of moisture could support 25-30mm in an hour in the right set up.

NZstorm wrote:

Nev wrote:I see Whangaparaoa recorded 18mm in the hour to 11am yesterday. However, going by nearby PWS's, I suspect most of that probably fell in less than 30 minutes, maybe even as little 15 minutes?

The dewpoint was only 10C/precipitable water 15mm, so likely that amount did not fall in 15mins.

I think that sort of moisture could support 25-30mm in an hour in the right set up.

Just comparing an Army Bay PWS, about 2.4km west of MS's more exposed Whangaparaoa site, that recorded 11.5mm in the hour to 11:03am, 10.9mm of which fell in 30 minutes, or 10.2mm in 15 minutes - the latter giving a rate of about 41 mm/hr.

We didn't get quite that amount here, but it was pretty torrential for a time when it passed over about an hour later. Unfortunately I didn't have my rain-gauge set up, but a nearby PWS recorded 7.6mm for the hour to 12:06pm, 6.1mm of which fell in about 30 minutes.

On Saturday the upper flow was about 20 knots so everything was on the move. We had a mini downpour in the city about 10.30am from memory.

Yesterdays observed NZWP sounding showed precip water 19.5mm, so more moisture than the gfs was showing, typical of the gfs though.

update from NCEP on La Nina

weak La Nina favoured

La Niña is favored to develop (~70% chance) during the Northern Hemisphere fall 2016
and slightly favored to persist (~55% chance) during winter 2016-17

Good. That might enhance thunderstorm developments for acres, sorry areas, (spellcheck) that don't get them.

Huge gusts coming through here at the moment, the hills have been totally obscured by dust from the Hurunui river

Richard wrote:Huge gusts coming through here at the moment, the hills have been totally obscured by dust from the Hurunui river

Was a bit dusty even in town here this morning with a steady breeze too. Spring is in full noise now that's for sure

Currently 26C in Dunedin City and Hastings.

Yep, it's a warm one down here today. Currently 26.5°C at my house at the moment, and peaked at 26.9°C not long ago. Dunedin City has dropped 10°C in the last hour, so we'll be getting that soon, and I'll be looking forward to it too.

EDIT: and on cue, temp dropped from 26.5°C to 16.1°C in about 10mins. Still a stunning day, just a bit cooler.

Here's a timelapse of when that low passed over Auckland on the 15th of October looks cool when it passes over the Hauraki Gulf and out to sea.