Widespread Storms, South Island 23/2/14

[Orion]

Pleasant-sounding rain, a southerly, and 13,1 degrees here now.

[Orion]

Thunder! At this time of day!

[Orion]

Lots of thunder!

[Nev]

Lucky you!

Shows up well on the radar and Steven's Boltek tracker.
Really sparked up over the lower south this morn too by the looks.

A good omen for the rest of today's activity down there maybe...

[Richard]

Some good looking activity moving onto CHCH atm,lucky buggers

[tgsnoopy]

Some good looking activity moving onto CHCH atm,lucky buggers

I see Metservice did some nowcasting with the outlook

[Nev]

Yes, MS haven't updated this arvo's outlook yet, but they did update this morn's not long ago…

MetService - Thunderstorm Outlook

Valid to: Noon Sunday 23 Feb 2014
Issued at: 7:29am Sunday 23 Feb 2014

Updated at 7:15am Sunday to add moderate risk of thunderstorms about Canterbury with hail.

A cold front lying from South Westland to near Dunedin at midnight Saturday continues northwards over the South Island during the morning, while an upper level cold pool moves over southern New Zealand. Scattered heavy showers are forecast for the west and south of the South Island, with a few also expected to spread up eastern coasts with the southerly change.

There is a moderate risk of isolated thunderstorms in the west and south of the South Island, but mainly before dawn in Westland with the passage of the front.Any thunderstorms that do occur will bring brief heavy rain, along with small hail and strong wind gusts about southern coasts. A lower risk of isolated thunderstorms extends up to Buller in the west and about the east coast, however thunderstorms have developed about the Canterbury Plains this morning with hail,and threat has therefore been increased to moderate on the chart.

Elsewhere, no thunderstorms or significant convection expected.

MetService T-Storm Outlook Map to Noon, Feb 23.png

Valid to: Midnight Sunday 23 Feb 2014
Issued at: 9:10pm Saturday 22 Feb 2014

Updated at 9:10pm Saturday to increase the risk of thunderstorms over coastal parts of Canterbury to moderate for the afternoon.

An upper level cold trough over the lower South Island at midday Sunday moves eastwards during the afternoon and evening. This cold trough will support scattered heavy showers over the west and south of the South Island, a few of which could still be thundery in the afternoon, especially from Foveaux Strait through Clutha to Dunedin. Any thunderstorms in these areas will bring brief heavy rain, small hail and strong wind gusts, but showers should gradually ease from late afternoon as the trough departs to the east.

In Canterbury, winds are forecast to turn onshore in the afternoon triggering showers about the coast and Plains, with a broad low risk of isolated thunderstorms. However, this risk of thunderstorms is now considered moderate near the coast north of Timaru up to about Amberley early to mid afternoon. Any thunderstorms that occur here are likely to produce localised heavy rain and hail of 5 to 15mm in diameter. Again, any convective showers should ease into the evening in the wake of the cold trough.

Elsewhere, no thunderstorms or significant convection expected.

MetService T-Storm Outlook Map to Midnight, Feb 23.png

[Skywatcher]

Heavy shower with small hail here.

[NZstorm]

GFS has it sparking up again later in the day, more likely Banks Peninsula way.

[NZ Thunderstorm Soc]

Rain and hail showers here, with a cool SE.
No thunder sounds, however.

[Captain Salty]

A little snow on Torlesse

[Richard]

Given the Met Service have most of the South Island with thunderstorm warmings,a thread is needed.

Valid to: Midnight Sunday 23 Feb 2014

Issued at: 8:54am Sunday 23 Feb 2014

An upper cold trough is expected to move across the South Island today making the atmosphere very unstable over southern New Zealand.

Isolated thunderstorms have already been occurring about coastal Westland,Fiordland and Southland, and also the Canterbury Plains this morning. Further thunderstorms are expected about these areas into the afternoon and early evening, as well as affecting parts of inland Southland and eastern Otago. Brief heavy rain and hail will accompany the thunderstorms.

About North Otago and the Canterbury Plains however, it is possible that some of the thunderstorms could be SEVERE for a time this afternoon producing large damaging hail (20+mm diameter), localised heavy rain, and squally wind gusts of 100km/hr. Large hail can cause significant damage to crops, orchards, vines,glasshouses and vehicles, as well as make driving conditions hazardous.

A lower risk of thunderstorms covers remaining parts of the South Island from Buller and southern Marlborough southwards, and also southern Wairarapa, as indicated on the chart.

[NZ Thunderstorm Soc]

Well, it's not stormy yet but apart from the brief hail we had earlier on, the rain is most welcome as we haven't had a good drop for ages.
Once this clears, there may be some good ground heating for storms later, if the upper sky is what it was like yesterday. ??

[Nev]

Given the Met Service have most of the South Island with thunderstorm warmings,a thread is needed.

Ok, have moved this morn's comments to this thread.

[NZ Thunderstorm Soc]

Clearing away from the west now so when the sun comes out that should create some good instability.
Only 8.6C outside compared to 27C it was this time yesterday.
6.5mm sofa for today.

[03Stormchaser]

http://metservice.com/warnings/severe-t ... torm-watch

SEVERE THUNDERSTORM WATCH

Issued by MetService at 09:35 am Sunday 23 February 2014
Valid until 07:00 pm Sunday 23 February 2014
This watch affects people in the following weather forecast districts:
Christchurch
Canterbury Plains
North Otago

Scattered thunderstorms are expected to develop about North Otago, the Canterbury Plains and Christchurch this afternoon.

A few of these thunderstorms are likely to be severe producing large damaging hail, strong squally winds, and localised heavy rain.

Large hail can cause significant damage to crops, orchards, vines, glasshouses and vehicles, as well as make driving conditions hazardous.

The thunderstorm activity should clear these areas by early evening.

Note: A Severe Thunderstorm Watch means conditions are favourable for severe thunderstorms in and close to the watch area. People in these areas should be on the lookout for threatening weather conditions and listen for possible Severe Thunderstorm Warnings.


Issued by: John Crouch

[NZstorm]

GFS 500mb wind showing curved jet across South Island with 500mb winds 40-50kts over Canterbury.

Its a great set up for an LP supercell or two along the Canterbury coast if a sea breeze (E,NE) can develop.

[Richard]

Given the Met Service have most of the South Island with thunderstorm warmings,a thread is needed.

Ok, have moved this morn's comments to this thread.

Thanks Nev

Good sign for my area,the NW wind has been replaced with a SE ,just what's needed

[CHCH Weather Chaser]

10.5mm in the couple of hours this morning. Fine and sunny now with little wind for the past hour or so.

[mikestormchaser]

beautiful conditions out there today, sun out, heating, and a light N-NE wind blowing through, im out in lincoln so good spot to be in already!

[Richard]

Yes same here,light SE now,worried that the NW might come back though.

[Storm Struck]

Today is definatly right up there in terms of good ingrediants coming together at once, and some big ingrediants at that.
My main concern is the potential hail size, but i am sure as chasers we will try and keep out of it as best we can.
Also a risk of a brief damaging tornado somewhere too.

[CHCH Weather Chaser]

GFS 500mb wind showing curved jet across South Island with 500mb winds 40-50kts over Canterbury.

Its a great set up for an LP supercell or two along the Canterbury coast if a sea breeze (E,NE) can develop.

20 degrees here now with a very light easterly breeze and plenty of sunshine.

[Thunder]

Coastal areas would be better, am expecting a light ENE as have some noted allready. Air looks very dry inland at the surface otherwise.

[NZ Thunderstorm Soc]

Keeping an ardent eye towards TC @ the moment. Looking promising