Cold Snap 18-22 September 2015

jamie · Unread post by **jamie** » Sun 20/09/2015 20:56

Yea strange that there is no heavy rain warning in place for south Waikato. A lot more to fall by the looks. Already had enough to constitute a warning.

We have a house vibrating in the SE wind. Really whistling and thumping.

jamie · Unread post by **jamie** » Sun 20/09/2015 21:01

Oh they have now released one.

Manukau heads obs · Sun 20/09/2015 21:07

good stuff.was that a mixture of rain and hail in Te Awamutu?..as that was how it ended up like with that storm at Ramarama as well

NZstorm · Unread post by **NZstorm** » Sun 20/09/2015 21:08

brikrip wrote:Hail Storm Around 11am this morning 5min north of Te awamutu township
https://www.youtube.com/watch?v=-EUkh50DnB8

https://www.youtube.com/watch?v=uCDN6FYB9ng

great clips. thanks for postng.

brikrip · Unread post by **brikrip** » Sun 20/09/2015 21:14

Heavy Rain at start then constant pea size hail for 15min heavy rain most of day since then Enviro waikato rainfall for Te awamutu upto 97mm since midnight

spwill · Unread post by **spwill** » Sun 20/09/2015 21:29

A couple more photos, hail on the road & developing shower clouds.
All the showers I drove through today had hail.

Thunder081 · Unread post by **Thunder081** » Sun 20/09/2015 23:30

Timelapse of it

h8-sats-20-9-15_1

NZstorm · Unread post by **NZstorm** » Mon 21/09/2015 06:46

12Z run of the gfs looking to favour some afternoon convection Tuesday over the west of the North Island.
Have to see how things pan out though. A few thunderstorms/small hail possible between Auckland and Waitomo.

midday 500mb chart

spwill · Unread post by **spwill** » Mon 21/09/2015 10:54

Maybe a southwest breeze tomorrow will keep any afternoon shower development east of here

Razor · Unread post by **Razor** » Mon 21/09/2015 12:01

Metservice (and Tony

) modelling 40-50mm of rain in the next 48 hours, with more to follow after. That's a serious situation potentially for Christchurch post quake

TonyT · Unread post by **TonyT** » Mon 21/09/2015 12:28

Razor wrote:Metservice (and Tony ) modelling 40-50mm of rain in the next 48 hours, with more to follow after. That's a serious situation potentially for Christchurch post quake

No no, yesterday's data suggested that, today's is much lower.10-20mm.

Razor · Unread post by **Razor** » Mon 21/09/2015 14:19

TonyT wrote:
Razor wrote:Metservice (and Tony ) modelling 40-50mm of rain in the next 48 hours, with more to follow after. That's a serious situation potentially for Christchurch post quake
No no, yesterday's data suggested that, today's is much lower.10-20mm.

Oh? Just going off Metservice and Farmlands sites...must have been prior to an update

Good news

Richard · Unread post by **Richard** » Mon 21/09/2015 14:53

Thats bad news, i'm starting to wonder if we will get any rain at all from this system

Razor · Unread post by **Razor** » Mon 21/09/2015 14:56

Richard wrote:Thats bad news, i'm starting to wonder if we will get any rain at all from this system

Looking at the 3 day metservice maps you'll be getting plenty this time mate

Manukau heads obs · Mon 21/09/2015 15:06

what will hopefully happen Richard, and its allready starting, is that all that sub tropical moisture/cloud mass that spireled down around the low and ended up near the Chatham islands, will end up getting shunted onto eastern SI from CHCH north tomorrow, in the easterly flow

Razor · Unread post by **Razor** » Mon 21/09/2015 15:09

Yes, its been wet again in ChCh since lunchtime today

melja · Unread post by **melja** » Mon 21/09/2015 15:20

Sunny spell's north of Christchurch this afternoon.
M/S has really pulled back on the heavy rain in this afternoons SW outlook.

Razor · Unread post by **Razor** » Mon 21/09/2015 15:33

melja wrote:Sunny spell's north of Christchurch this afternoon.
M/S has really pulled back on the heavy rain in this afternoons SW outlook.

And yet their 48 hour chart still plugs for 50mm +

Richard · Unread post by **Richard** » Mon 21/09/2015 15:35

Razor wrote:
Richard wrote:Thats bad news, i'm starting to wonder if we will get any rain at all from this system
Looking at the 3 day metservice maps you'll be getting plenty this time mate

I hope you are right, ... just watching a truck go by with clouds of dust behind it

Wildland · Unread post by **Wildland** » Mon 21/09/2015 16:32

The flooding in the Gisborne district looks serious.

The drone footage in the attached Stuff article shows that the three rivers in the centre of Gisborne City are now well above their normal channels. The business part of the city is protected by higher banks at the three river junction, but lower lying areas on the other side are starting to get swamped.

http://www.stuff.co.nz/dominion-post/ne ... east-coast

NZ Thunderstorm Soc · Mon 21/09/2015 18:32

Yes, with all that rain around the Gisborne /Hawkes Bay area, looks like any idea of reinstating the rail link to Gisborne is a 'gone-burger'

NZ Thunderstorm Soc · Mon 21/09/2015 20:36

Nice clear and calm skies at the moment, looks like we're heading for a frost, down to 0.5C at the moment.
Shame the Aurora wasn't tonight although the moon is filling out and making things brighter.
Direct contrast to MetService's forecast of cloud and occasional drizzle, although that could come through later.
Nice looking convergence line to the east just before sunset.

josholiver657 · Unread post by **josholiver657** » Mon 21/09/2015 21:09

Hello all, nice to be back after a wee break from the weather. I am going back to how it was before I started CWU, so I will be following all events with interest, as a hobby only. If I have unintentionally offended anyone on here please accept my apology, no hard feelings I hope.
I am getting interested in what could potentially happen in about 24 hours time for ChCh, could be a good 40-50mm for us between midday tomorrow and even into Thursday as the drizzle stuff continues. And good news for the dry parts of North Canty (inland) looks to be some good rain on the way for you guys too!

Tornado Tim · Unread post by **Tornado Tim** » Mon 21/09/2015 21:21

Cold upper level trough moving in over the Waikato tomorrow afternoon. Wind Convergence combined should be sufficient to get quite few isolated storms over Waikato to South Auckland.

Screen Shot 2015-09-21 at 9.00.00 PM.png

Update: Seems that Metservice have a similar outlook.

Updated at 8:25pm Monday - Risk areas expanded to include parts of Taranaki. Risk of significant hail accumulation added.

The combination of cold temperatures aloft, lightish winds and afternoon heating are expected to produce scattered showers and a few thunderstorms over the central and northern North Island on Tuesday afternoon and early evening.

The main risk of thunderstorms extends from Auckland to northern Taranaki and western Bay of Plenty, with a lower risk covering surrounding areas as indicated on the chart. These thunderstorms will be accompanied by localised heavy rain of 10-20mm/hr, and hail in the 5-15mm diameter range. As the thunderstorms are likely to be slow-moving, it is possible there could be significant hail accumulation in some places, which could cause damage to crops and make driving conditions hazardous.

No other thunderstorms or significant convection expected over New Zealand on Tuesday afternoon and evening.

NZ Thunderstorm Soc · Mon 21/09/2015 22:54

Richard wrote:Thats bad news, i'm starting to wonder if we will get any rain at all from this system

Sad to say this Richard, but judging from tonight's clear weather and frosty conditions, which MetService didn't say, directly for tonight, looks like it will be a mostly drizzly scenario for eager SI areas unless a very active ULT moves across ?

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