NZ Weather Forum

I probably agree with MetService's scenario for tomorrow for Saturday but Tuesday might be more friutfull, at the moment?

JohnGaul
NZTS

friutfull?
I think you mean fruitful.
But yes I think Tuesday might have some action.

carrot wrote:friutfull?
I think you mean fruitful.

All depends what the weather gods throw down upon us? Apples, pears or Kiwifriut

JohnGaul
NZTS

You mean hailstones that size?

tich wrote:You mean hailstones that size?

No I don't think that they will be that big, Ben.
Now, i'm thinking of lessoning of that effect for next Tuesday as I think the potential for the action weather will come through overnight, Monday

JohnGaul
NZTS

Noticed fence post have put down possbile thundery showers for Saturday arvo, thats going to be interesting to see as the day progresses might be our first storm though! and ill be home to watch it yyeeeeeee

tornadoman18 wrote:Noticed fence post have put down possbile thundery showers for Saturday arvo, thats going to be interesting to see as the day progresses might be our first storm though! and ill be home to watch it yyeeeeeee

I doubt it as I said before of MetSerivce's explanation, sadly, for tomorrow.

A southerly change moves up the east coast of the South Island during the period, through Canterbury in the afternoon, and further north later in the day.But thunderstorms are not expected on this change as it moves through Canterbury due to continued northwesterlies aloft and the coldest air aloft still located well behind the change over the lower South Island, where showers are expected with snow lowering to about 500 metres for a time.

JohnGaul
NZTS

At least we are starting to move into a more interesting period for Canterbury weather, from start Oct till Christmas/early Jan. Metservice are bang on about tomorow, nothing will happen, monday isnt that much better but the change on wednesday looks interesting, hmmm still a way out though. Pity its in the middle of the week!!

Hardly any CAPE forecast for tomorrow arvo...500Temps are cold, but not til later...and LIFT IDX are only down to 4...so, not a very strong candidate for t'storms tomorrow, based on forecast numbers...does look to be a bit unstable over the next week, though...should be an interesting ride

A shame tomorrow I think. The upper trough is too far behind. We will actually get the classic east coast rainfall situation where the surface flow is southerly but northwesterly aloft, which is good for Canterbury snow usually, but it's too late in the season and not a cold enough change for this to occur. Wellington is going to get a fair bit of rain from the same sort of thing, it removes the sheltering effect of the mountains by having a southerly push through when the flow above is still NW.

The NW is a definate killer tomorrow for any convective development, but the chances are beggining to pop up by next week.
I agree Monday night's change comes a little late although that may not be a problem will have to see.
Wednesday does have a better set up, we are also dipping below 1000hpa next week which is usually key for unstable weather in the South Island.
Unlike previous weeks with the NW flow set up.
Cheers
Jason.

We will actually get the classic east coast rainfall situation where the surface flow is southerly but northwesterly aloft, which is good for Canterbury snow usually, but it's too late in the season and not a cold enough change for this to occur.

Not too late in the season - a few years ago, Canterbury got snow to low levels on the plains in November.

No I don't think that they will be that big, Ben.

Yeah that would be pretty extreme (and dangerous too) hail size, not something NZ's likely to get.

You guys could be correct about Wednesday for Canterbury. Current guidance suggests thunderstorms/hail from Southland to Canterbury on that day. Lifted index chart here for 6pm Wednesday. The instability progresses further onto the North Island for Thursday. One to watch.

Up to 19C with the sun which made an appearance for half an hour, but here comes the southerly i can see a gust front coming to the south.
Heard the C17 again roaring from here in Kaiapoi before too Beautiful sound .
Some heavy rain moving into south canterbury on the midday radar too nothing thundery as expected but still should be a reasonable bit of rain.
Cheers
Jason.

Southerly coming thru fast.
dropped 3 degrees in 5 mins, risen 3hPa in 20 mins and very strong gusts in the last few minutes and a few drops of rain now.
was 16.5 at 12:50 now a chilly 11.5 at 1:05

1300 radar looking mighty suspicious to me....Tekapo webcam showing white....hmmmm...still don't think it'll happen, though...maybe up on the hills, but not for us....we'll see...

Gone from 19.2C to 12.3C in half an hour, this is why New Zealand is famous for the saying Four Seasons in One day.
Gale force gusts wafting on through at times and giving the new spring growth a battering.
Cheers
Jason.

Obviously the modeling has changed a bit. It now looks like it will be the east of the North Island that gets the afternoon thundery SW change on Wednesday. The change crosses the South Island early in the day with thunder/hail possible around coastal Southland early Wednesday.

Some nice CU heading up from south now, apparently some lightning being picked up down south too, cant get into the tracker still an error on my computer anyway.
NE currently and with this cold front coming up against it, will make for an interesting couple of hours ahead.
still warm not that cold.

Skies are looking thundery out there this afternoon with some very nice convective clouds going up.
Just had some small hail from a developing CU shower cloud .
Cheers
Jason.

Cleared up near Akaroa after overnight rain, and a fresh dusting of snow above about 550-600m. (now mostly melted)

Jasestrm wrote:Skies are looking thundery out there this afternoon with some very nice convective clouds going up.
Just had some small hail from a developing CU shower cloud .
Cheers
Jason.

Yeah, I'm getting that feeling too... Had a short burst of rain in Brighton 15 minutes ago..
<Waiting with baited breath>

CU not as scatterd as before but still some nice heads popping up.
Tomorrow might be an ok set up for thunderstorms if it comes through from early afternoon, i would have to say a moderate risk rather than low at this stage.
Few snaps i took of this this afternoon's clouds.
Cheers
Jason.

Timing might be a crutial factor for a spring thunderstorm in Canterbury tomorrow and possibly a a maintenance of a NE inflow?
Todays ground heating produced the Cu mediocris and humulus forms but not enough uummmph to get things mobile.. Yes. Jason, I saw those clouds in your direction and they looked as though there was a weak sort of convergence factor there.
Some weak castellatus forms this evening here indicating a bit of instability.

JohnGaul
NZTS

castellanus
Had to be said
sorry