NZ Weather Forum

Should be a interesting couple of days coming up, mainly for us mainlanders Friday, top of the North Island as well Saturday.


Valid to: Midnight Friday 21 Dec 2018

Issued at: 11:16am Thursday 20 Dec 2018

A trough is expected to cross the South Island during Friday afternoon and evening, while a font moves onto the North Island in the evening.

For the South Island, showers are expected with the passage of the trough, and about Central Otago, Dunedin, North Otago, Canterbury south of about Christchurch, the ranges of North Canterbury, Marlborough and eastern Nelson, there is a moderate risk some of the showers could become thundery. These thunderstorms if they occur could mostly bring localised heavy rain of 10 to 25mm and hail. However about eastern parts of Central Otago, Dunedin, North Otago and Canterbury south of about Christchurch, there is also a risk some of these thunderstorms may become SEVERE bring localised heavy rain greater than 25mm per hour and hail greater than 20mm in diameter.

A lower risk of thunderstorms covers much of the remainder of the South Island.

For the North Island, there is a low risk of thunderstorms during the afternoon and evening about the ranges of Gisborne, northern Hawkes Bay, Taihape and inland areas of Taranaki and Wanganui. However the low risk of thunderstorms extends to all western areas of the North Island from Waikato to Wellington in the evening.

Thread title needs to say NI as well because boyah! there was a cool looking thunderstorm near Levin at about 12pm. It's always nice when the storms come to you

Today's the 20th tho lol

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Waihi just now

Moving away from Waihi looking towards Tauranga

wre1991 wrote: ↑Thu 20/12/2018 15:18 Waihi just now

That looks really heavy

This evenings update now has increased risk for the east of the North Island

Richard wrote: ↑Thu 20/12/2018 16:25

wre1991 wrote: ↑Thu 20/12/2018 15:18 Waihi just now

That looks really heavy

Wasn't too bad. I was packing up a Mobile Dental Unit at Katikati Primary. I do concede I hid under it for a bit about 3pm and did take a couple of photo's and some video. Was very short lived.

Tomorrow looking like the best set up all season. Will definitely be chasing if things stay the way they look.
Severe hail possibility for me

There is an elevated thunderstorm set over the north of the country tomorrow night. Have to see how it looks on the skew-t tomorrow.

The moderate risk has been extended and a low risk of severe storms added for today:

Im not sold on the great risk today, models show a lack of instability numbers over canterbury.
The only trigger is the NE vs southerly later on, no cold upper air a slight bit of shear but thats it.
Tomorrow on the other hand is definatly a high risk with a good chance of severe storms, hail 25+mm diamter and good shear over a wide area will mean plenty of funnels to be seen and maybe a tornado too.
Fresh ENE down to Ashburton up against an incoming southerly, lots of moisture -4c LIs 900 cape shes all go for a chase.

At this stage the MS are not in line with you Jase.
Cloud starting to build out to the west from here.

Not sure what MS thinking with the outlook, tomorrow the better day for canterbury

Some good boil ups visible now well to the west.

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Thick high cloud here in ChCh now, hard to believe there will be any fun today

Anything could happen when considering there's a developing rotation over the SI.

Just came back from Temuka after collecting the Xmas ham
Lots of boring looking SC cloud cover and not looking anything at the least thunderstormic here although looking very dark and with thick cloud westward and now coming onto light rain here.

Calm and now coming onto proper rain from the west.
The 'Clagg' setting in again.

Red appearing on radar in many spots

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Just had thunder to the NW

Starting to see the lightning now as its getting closer

Some of the IC lightning has been close to over head with the earthing happening to the north, that's eased and in comes the rain

Heavy rain here, like we need anymore!

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melja wrote: ↑Fri 21/12/2018 17:44 Heavy rain here, like we need anymore!

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And lots more to come over the next few hours too.

Today is the second time this spring/summer that storms have developed on days that have been totally uncharacteristic, to have ended the day with a storm after a mainly cloudy day is not normal for around here, even till about 4.00 pm it didn't look like it was going to turn electrical. Now the rain, MS had .2 mm for here on there rainfall accumulation chart, but we may end up around 20mm the way its pouring down.