Northwesterly storm 10-12/08/07

[tich]

http://www.metservice.co.nz/default/ind ... s=warnings

250-350mm - big amounts even for the West Coast. Look out for flooded rivers, even on this side of the Alps. At least it should be warm here.

[Storm Struck]

Yes and the isobars will be running horizontal like train tracks packed tightly.
Looks like a breif period of severe NW winds overnight Saturday and into early Sunday at this stage especailly inland, i dont think it will get as strong as MS suggests for tomorrow eg. gusts to 90kmh on some exposed hilltops of BP, but it will be strong.
Could be some nice embedded thunderstorms along the Alps on Saturday night perhaps spilling as far east as the foothills or plains, and weak tornado material for the west coast too maybe.
The colder change inbehind shouldnt bring overly much apart from breif showers .
A balmy 19C in the sun today and the NWer didnt even get up at all great for August.
Cheers
Jason.

[NZ Thunderstorm Soc]

Thanks Ben for bringing this topic up. I was thinking about it.
Lots of rain coming up for the Southern Alps and the West Coast and windy condtions on the lee side. It's a bit windy here at the moment tonight but stronger gusts could develop tomorrow.
I was thinking of the 1975 NW windstorm which did a lot of damage here in Canterbury - "The Big Blow" as locals called it.

JohnGaul
NZTS

[tich]

I was thinking of the 1975 NW windstorm which did a lot of damage here in Canterbury - "The Big Blow" as locals called it.

So was I, after the MetService press release. But their warnings are for gusts 'only' up to about 120kph. Bigger than we've had for a few months, but hardly like 1975. It's the rain about and west of the Alps that looks to be the major feature of this storm. The big Canterbury rivers should be raging by Saturday. I wouldn't want to be stuck up in the high country at say, Arthurs Pass.

[Lawrence]

A flash of lightening this morning to the southwest of Rolleston,the type that just lights up the low layer cloud,few blustery winds during the night too,but is'nt it warm.

[tich]

Strangely calm in central Chch now. Doesn't mean that other parts of Canterbury aren't getting buffeted.

[gopolks]

Its beautiful here in chch, too nice to be inside.

[Lawrence]

Strangely calm in central Chch now. Doesn't mean that other parts of Canterbury aren't getting buffeted.

That be the calm before the storm, oo,arrr,me hartys.Just while I'm here any one else see a dumping of snow to low levels in Canty between Sunday and Tuesday or am I reading things wrong .I really think It's going to be really cold next week,could say winters going out with a bang

[Andy]

Windy at times, but no gales here yet. Warm as well with mostly clear skies.

[gllitz]

That be the calm before the storm, oo,arrr,me hartys.Just while I'm here any one else see a dumping of snow to low levels in Canty between Sunday and Tuesday or am I reading things wrong .I really think It's going to be really cold next week,could say winters going out with a bang

Don't see snow happening...(for us here in CHCH, anyway)...sorry!

The hills/mountains might get a bit...there may even be some thunder embedded...

It has been said before, and I believe it: To get snow here to sea level in CHCH it is best to have a good low nearby (planted off the Canty coast, for example) and not going anywhere...cold fronts racing up the country just won't do...whilst it DOES bring cold air behind it, there is usually not much precip with these types of events...just short, sharp bursts of precip that has no chance to get to sea level as snow...

Ithink we are starting to see, though, a typical spring-like pattern...warm nw/warm nw/COLD SW w/hail...warm nw/warm nw/ COLD SW w/hail...hmmmm...

[tich]

Gale force winds in Chch, according to news report - well certainly not (yet) in central Chch. Still light winds here.

[Lawrence]

Yes, very warm and hardly a breeze here in CBD,noticed a small low on metservice has appeared on the chart just to the east of the top of the south.

[kiwisk8er]

warm, the wind is starting to blow a little and sunny in Dunedin about 20ËšC.

[spwill]

Cold weather back next week by the looks and perhaps some wet weather for the far north.

Dry day here for a change, sunny 18c dp12C.

[Lawrence]

Cold weather back next week by the looks and perhaps some wet weather for the far north.

Dry day here for a change, sunny 18c dp12C.

I knew it,can't wait.Come to daddy.Let it snow, let it snow, let it snow.

[Storm Struck]

I dont really know about snow, but being in august with such a big NW system anything can follow.
Just look at August 2004 i believe that was followed by a simular pattern with severe NW winds even a weak tornado up in oxford when the rain spread eastwards.
I think a system like this has the potential to bring something interesting inbehind it for example snow or thunder. Even though there isnt overly much in the way of precipitation by then, but saturday night should see a significant spillover of rain resulting in maybe a rogue thundery downpour in south canty.
I dont want to sound all hopes high, but it's just with this system being so very typical for August and quite reliable in a sense of because there have been simular systems during August before.
We will see what happens, at the moment its rather calm with a fresh NW wind and 18C.
Cheers
Jason.

[TonyT]

Theres a lot of oomph on the leading edge of this system, and often that means not so much energy left over for what happens after it passes through. Most westerly systems like this are either strong and stormy in the NW part, or the SW part, but rarely both. However, this is the sort of pattern which can put a lot of rain into Southland - some of their biggest floods in recent decades have come from similar systems.

[spwill]

I knew it,can't wait.Come to daddy.Let it snow, let it snow, let it snow.

I was meaning cold air with the High, clear nights, Frosts.

[Gary Roberts]

Windy in the Mackenzie today, but looking like rain, not snow. It was a lovely day, real t-shirt weather. The people I've listened to are expecting what snow remains on the divide to be washed away.

[Manukau heads obs]

Theres a lot of oomph on the leading edge of this system, and often that means not so much energy left over for what happens after it passes through.

yes I agree
my 2 cents worth:
its an unstable NW flow, so it rises over the main divide relatively easily

its when you have a stable NW flow (e.g high pressure ridge) that does not want to rise over the main divide that you get the big lee trough forming on the east coast and the severe gales where there are release valves (gaps in the ranges etc)

[Gary Roberts]

Wind is SW, has been all day. Coming up from the Lindis Pass. Definitely typical spring weather.

[gllitz]

What impresses me most about this system is that the clouds which wrap around the low extend from just south of NZ aaaaalllll the way back to Western Aus and then some!! (based on most recent sat loops as at 2100NZST)

[03Stormchaser]

Yesterday morning while driving toward the alps at about 6am, noticed quite a few flashes from over the alps.

Good articles in todays paper (The Press) about flooding that has happened in South Island and possiblities of future flooding.

[Andy]

25cms for Treble Cone and Remarks overnight.

Mild in town 13 degrees with partly cloudy skies, light to moderate NW at times, dark towards the west.

[tich]

Calm in Chch so far this morning - calm before the storm?