Heavy rain/tornado/snow/wind event. 18-21 November

[Dean.]

East sound side of town copped it worse..had some good 10-15mm hail here on the westside. ...building again to the south now

[NZstorm]

Nice dusty tornado captured there. Type of thing you see in Colorado.

[TonyT]

Nice clip there

https://www.facebook.com/amykmaw/videos ... ormchasers

[Orion]

In the distance to the north-east I can see a massive cauliflower cloud, guess that's what went over earlier.

Meanwhile, the thunder begins again as the second wave approaches from the south/SE

[talbotmj15]

Another reasonable cell popped up and building around the rangitata river 5.15pm heading towards the southern edge of Ashburton. Fingers crossed there everyones okay. Alot of instability about today thats for sure.

[Orion]

Very squally gusts and rain just now and very dark.

[Richard]

Nice dusty tornado captured there. Type of thing you see in Colorado.

That would have been thanks to a farmer who cultivated a paddock

[Bradley]

Things are about to get wild for mid Canterbury

[NZ Thunderstorm Soc]

Just come back from a afternoon up the Feel Forest/ Upper Rangitata Gorge area with some visitors we have staying with us this WE. Fine but very dusty up there with NW gales.
Coming back saw that dark cloud over the plains that delivered that tornado/thunderstorms to what looked like coastal areas. Not looking very photographical from when we were coming home, so took no photos.
However approaching Geraldine the strong Southerly came through around 5pm. with the usual throw around dark statussy bits but approaching the One way bridge over the Orari River , I did notice a bit of a funnel come out of the cloud but it was very quick and dissipated very quickly,before reaching for my camera.

[Chris W]

There’s the strong southerly change coming though Chch now.

[moylanr]

Get off your cycle and walk kind of winds through Halswell/Hornby.

Lots of dirt/dust getting picked up from city edge and thrown northwest.

[NZ Thunderstorm Soc]

Nice clip there

https://www.facebook.com/amykmaw/videos ... ormchasers

That's a better clip rather than looking through those bloody curtains again.
I wish they would stop doing that
I noticed the TV One clip showed the curtains effect.

[TonyT]

Big hook echo just off the coast on the 7.13pm Rakaia scan

[Dean.]

https://www.facebook.com/roxane.darling ... 367888438/

A better view near Fairton Ashburton

[snowchaser01]

Big hook echo just off the coast on the 7.13pm Rakaia scan

Could you please clarify what these indicate, I saw one earlier as well!

[einzack]

Drove from Waikouaiti to Christchurch with a stop at the Oamaru Victorian Fete today, and had all sorts of weather!
Left in beautiful sunshine. Oamaru started off fine, then ~1:40pm, heavy rain and constant thunder and lightning for the 30mins. No hail though. Temp had dropped to 11.5°C when we left.
Then just outside Oamaru, road turned white with hail. Was in thick drifts in places. Traffic at a crawl - 50km/hr max for 10mins as the rain started, and got extremely heavy. Could only manage 60km/hr through that and then heavy large hail started to join in the party. Was concerned that the car could be damaged the hail was so large. Temp dropped to 6.5°C as hail at heaviest, then popped out the front of it and sunshine back again and temp rose very quickly to 12°C within seconds.
So Oamaru missed out of the hail, which was just as well with the Fete going on. All in all, hail etc lasted about 30mins on the road. Quite exciting.

Then north of Ashburton noticed some irrigators on their sides, and thought, wonder what happened there? Found out shortly afterwards. We didn't see the tornado, but can't have missed it by much.

[TonyT]

10 degree drop in half and hour at Chch airport 6.30pm to 7pm, wind gale force (34 knots) a 7pm.

NZCH 180600Z AUTO 20034KT 6000 -RA SCT014/// 09/07 Q1000 BECMG 20020G30KT 9999 NSW
NZCH 180530Z AUTO 28015KT 250V330 9999 NCD 19/02 Q0997 BECMG FM0600 22020G30KT

[TonyT]

Big hook echo just off the coast on the 7.13pm Rakaia scan

Could you please clarify what these indicate, I saw one earlier as well!

Potential for rotation

[Chris W]

21C day down to 6C now, chilly! Heavy rain incoming on the radar.

[Storm Struck]

A pitty we didnt see the ashburton tornado it sure was a classic EF1 atleast, i know its kicking up alot of dust but the pipe is quite wide for NZ standards.
Glad it struck just north of Ashburton, what a mess that would be if it hit the town.
Not surprised quite abit of shear today and strong upper jet around 50kts, combining good daytime heating strong NE and SE convergences and a sharp cold pool surging up.
In terms of instability numbers LIs at -1c and cape of 500 over a small area, the above general ingrediants really mattered.
This is what we are seeing more of today, low risks become severe if ingrediants are ripe.

We headed around the Leeston Springston Ellesmere areas on the other cells, me Mike and Steve.
Spotted a good random roping funnel just near Lincoln quite long and snaky, and marble hail near leeston.
Followed the storms to birdlings flat where it was just heavy rain and lightning overhead.
Not bad for a local chase didnt have to go too far, the others got the footage i was driving.

Tomorrow looks a mod risk set up around 1-2pm on the next cold surge, upper air is colder around -32c but surface temperatures are only maximum 14c.
So if theres any storm activity it will be brief and possibly embedded, hail 5-10mm at that so alot smaller than today.

[mikestormchaser]

Big hook echo just off the coast on the 7.13pm Rakaia scan

Could you please clarify what these indicate, I saw one earlier as well!

Hook echoes are a sign of rotation in supercell storms. Often indicating tornado potential with the storm.
The rain radar picks up an area of the storm in rotation and pictures it as a hook shape on the detector. If you Google hook echoes ull see some incredible images mainly from the US storms

[snowchaser01]

there was great hook echo at the rakaia river mouth on the 5pm 120km radar loop. is available to view on the "last 24 hour" radar.

[Thunder081]

#MakeHQRadarAccessCheaper

Sent from my Moto G (5S) Plus using Tapatalk

[snowchaser01]

Apparently snowing to 400m inland mid Canterbury. Going to be short lived however as the front moves north but looks to be all go tomorrow afternoon again. Hard to believe we are nearly in December!!

[Richard]

Unusual that the MS have not put up anything in there noon to midnight predictions in 'Thunderstorm Outlook"