The Next Dose of Winter to Hit Us!

[CHCH Weather Chaser]

Nothings going to happen, A ridge is moving in to clear all the weather up, sadly

JohnGaul
NZTS

Lets be positive about this. Everything today had indicated much greater rainfall to hit us than what was forecast yesterday. Why this sudden turn around?

[gopolks]

SEVERE WEATHER WARNING.
ISSUED BY MetService AT 8:00 pm 21-Jul-2008

HEAVY RAIN EXPECTED OVER WEST COAST
MetService forecasters expect an active front in the Tasman Sea to
move quickly eastwards over the country on Tuesday preceded by strong
northerly winds, and a period of heavy rain in northern and western
areas of both islands. It will be followed by bands of heavy showers
and thunderstorms through to Wednesday morning.
Near the ranges of Westland and the Paparoa Range 90 to 120mm of rain
is expected over about 24 hours from around 4am on Tuesday with the
heaviest falls from Franz Josef Glacier to Otira. There is likely to
be useful spillover into the headwaters of the main hydro lakes and
rivers of Canterbury and Otago but probably not enough to justify a
warning there.
Although the amounts of rain are not expected to be unusual for these
areas,people should be prepared for streams and rivers to rise
quickly.
This front is expected to herald the start of a stormy period over
much of the country. It will continue as a deep low moves over the
South Island on Wednesday,followed by a wintry southerly blast in
southern and eastern areas through to Friday. People are advised to
keep up to date with weather forecasts.

[NZ Thunderstorm Soc]

Nothings going to happen, A ridge is moving in to clear all the weather up, sadly

JohnGaul
NZTS

Lets be positive about this. Everything today had indicated much greater rainfall to hit us than what was forecast yesterday. Why this sudden turn around?

ECMWF have a 1030hPa working away underneath NZ which should shove this low away quickly to the east of us and give us higher surface pressure. I hope I am wrong.
As being a storm buff, and founder of the NZ Thunderstorm Society,I work out a lot of my indications by surface weather movements in conjunction with 'upstairs' developments by various weather forecasting models that are available over the net.
I find ECMWF to be the best one.
JohnGaul
NZTS

[gopolks]

"So its going to be a Wednesday event now??? Conditions to ease on Thursday?"

This was just posted on stuff's website.

storm is expected to batter most of New Zealand during the next few days.

The MetService said tonight meteorologists were watching a low east of Tasmania which they expected to develop into a potentially vigorous winter storm.

The low should cross the South Island tonight and lie near the Chatham islands for a few days after that.

"This storm has the potential to affect most of the country over the next few days," said MetService spokesman Steve Ready.

"Initially, the winds will strengthen from the north with a spell of heavy rain in the north and west of both islands. A severe weather warning has already been issued for the South Island West Coast."

By Wednesday much of the North Island should be buffeted by brisk westerlies and thundery showers, and by large ocean waves on its west coast.

"The ocean waves are likely to exceed six metres and to cause some large sweeping waves along the beach," Mr Ready said.

"They will be accompanied by strong onshore winds and squally showers making conditions unsafe for rock fishing or surfing. Boaties should also check their moorings."

Cold southerly winds, bringing rain and snow, will hit the south and east of the South Island on Wednesday, Mr Ready said.

Conditions are likely to ease on Thursday and Friday.

- NZPA

[Myself]

How are the latest GFS models looking now? More than the 81.3mm that it was last indicating?

I really wouldn't pay any attention to numerical weather models' precipitation predictions.

[TonyT]

I'm with John on this one - it all seems to be getting hyped up beyond what seems realistic. I dont find the modelling on this one is very confidence inspiring.

Just a reminder to all posters - while its OK to express your excitement at potentially unusual weather, lets not get carried away with comments which could be construed by some non-weather enthusiasts as being offensive. This is a public forum, which means it can be (and is) read by anyone. I know that some media and reporters monitor it, so lets make sure our enthsusiam for severe weather events doesnt get interpreted incorrectly.

[Ryan Thomas]

Still in for a bit of rain tho? More then a typical few days rain in Christchurch? And a small likelihood that it may turn into something unusual? (I don't use the word "chance", likelihood seems to be a better word).

Awaiting the next few days to see how things turn out..

[Storm Struck]

It's definatly going to be an unsettled period put it that way, and some welcome rainfall totals the most falling on Thursday and maybe again on Saturday.
Snow levels 300-400m mark, strong winds yes but i honestly cant see where the gales come in as the isobars are not tight enough based on what the models are predicting at the moment.
Also another situation where a few CB's could skip over eastwards tomorrow night/early hours of Wednesday, but that also depends how active it is on the coast.
It does surprise me how much this thing is getting wound up via the news articles etc, its not going to be that bad really well not as bad as some of the lows we have had this winter.
I think its more a case of seeing a deep low and covering thier butts despite thier face for the public, then thats when people ask where was this snow and gales we were meant to get .
Cheers
Jason.

[CHCH Weather Chaser]

Overnight our High for Thursday from Metservice has been put down to 6 degrees with Rain and Cold Southerlies

[gllitz]

Please see attached for latest GFS run (showing a wee bit colder and has now for the past two runs)...NOGAPS does not show it getting as cold...maybe somewhere in the middle to two shall meet?
Looking impressive on the sat loop, for sure...

[NZstorm]

Yes, forecast snow levels for later Thursday may need to be lowered to 200m for Canterbury.

[gllitz]

Yes, forecast snow levels for later Thursday need to be lowered to 200m for Canterbury and Otago. Sleet to sea level.

Probably not a bad call, Steven ...I'm NOT totally convinced, though, that we WON'T get some snow to sea level with this event...will have to be patient with next few runs, for sure.

I find it interesting on the 7-day rain loops on the M/S site that a low actually "backtracks" a bit and goes east to west... I take it that doesn't happen that often?? Just curious...certainly looks like it is being steered from the high to the south and the big low forming north of NZ...

[jamie]

I see what you mean there.

Ive never seen that before . Its only one run so it will probably change on the next one. With it backtracking like MS are showing, it looks like that would give the SI some good snow??
The SI low in a way is pulled back by the new tropical low and the high south of us.

Crapy day here today....grey, steady rain..YUCK!

[gllitz]

I see what you mean there.

Ive never seen that before . Its only one run so it will probably change on the next one. With it backtracking like MS are showing, it looks like that would give the SI some good snow??
The SI low in a way is pulled back by the new tropical low and the high south of us.

Crapy day here today....grey, steady rain..YUCK!

It has been that way for several runs now...just interesting, is all...I think it's been called something-or-other to do with train wheels..can't remember...will have a sift through the forums...

[spwill]

Perhaps some low level snow well inland near the High Country but the onshore flow will be too warm for snow in Chch

I think with the last two snow events in Chch this year the surface SW dragged chilled inland air onto the coast helping produce the snow there.

[Manukau heads obs]

latest chch rain radar shows the frontal rain has made it all the way across onto the plains
sure must have been very heavy across the divide then!
Mt Hutt will have had alot of snow at the upper level me thinks
also the wgnt rain radar shows alot of rain for Blenheim area at the moment too, i,e the rain has survived crossing the ranges there too

yup, heavy rain, for Blenheim, occuring at the moment:
http://www.scientificsales.co.nz/
(5mm so far)

[Vertigo]

oh, shes a nice looking little depression now. quite nicely formed spiral, with min pressure in the 970's.

[RWood]

I'm with John on this one - it all seems to be getting hyped up beyond what seems realistic. I dont find the modelling on this one is very confidence inspiring.

Just a reminder to all posters - while its OK to express your excitement at potentially unusual weather, lets not get carried away with comments which could be construed by some non-weather enthusiasts as being offensive. This is a public forum, which means it can be (and is) read by anyone. I know that some media and reporters monitor it, so lets make sure our enthsusiam for severe weather events doesnt get interpreted incorrectly.

Given that NZ lies entirely in a zone characterised by generally changeable weather, with no general shortage of reasonably severe events, or at least ones which cause significant disruption and annoyance to everyday living, I think a typical member of the public might be quite baffled by the notion that so many people can get so pants-wettingly excited about almost anything which looks as if it might be the next one in the queue, especially in wintertime.

[Janos]

I think a typical member of the public might be quite baffled by the notion that so many people can get so pants-wettingly excited about almost anything which looks as if it might be the next one in the queue, especially in wintertime.

And the number of excitable people probably only equals about 6.

[TonyT]

I think a typical member of the public might be quite baffled by the notion that so many people can get so pants-wettingly excited about almost anything which looks as if it might be the next one in the queue, especially in wintertime.

And the number of excitable people probably only equals about 6.

You get 12 in a pack of Huggies I think...

[Vertigo]

I'm with John on this one - it all seems to be getting hyped up beyond what seems realistic. I dont find the modelling on this one is very confidence inspiring.

Just a reminder to all posters - while its OK to express your excitement at potentially unusual weather, lets not get carried away with comments which could be construed by some non-weather enthusiasts as being offensive. This is a public forum, which means it can be (and is) read by anyone. I know that some media and reporters monitor it, so lets make sure our enthsusiam for severe weather events doesnt get interpreted incorrectly.

im not sure anyone has said anything potentially offensive? if anyone takes our enthusiasm for severe weather offensively, well thats their problem! after all, this is a forum of weather enthusiasts, and if someone told me to stop being so cheerful about thunderstorms, im sure i would take offense!

not that i have a problem with the general publics love of fine weather - but i hardly think its fitting on this board to say "curb your enthusiasm".

[Manukau heads obs]

blue skies moving in from the west here now
quite a striking change!

[spwill]

RWood wrote,

I think a typical member of the public might be quite baffled by the notion that so many people can get so pants-wettingly excited about almost anything which looks as if it might be the next one in the queue, especially in wintertime

Yes, most of the public dont have a deep interest in weather.
RWood, I can recall plenty of forum chat from you in the past around weather topics that interest you, eg climate.

[TonyT]

not that i have a problem with the general publics love of fine weather - but i hardly think its fitting on this board to say "curb your enthusiasm".

Read what I wrote. I did not ask people to curb their enthusiasm. I asked them to make sure their enthusiasm wasn't easily construed as wishing harm on others. Be as enthusiastic as you like about a weather event. But if you are going to comment on the potential effects of said event on people then do it carefully and with due consideration for how it might be intepreted by not-so-enthusiastic folk.

There is a fine line to be trod here between enthusiasm and ambulance chasing.

For example this sort of comment is acceptable:
"I am really looking forward to the possibility of a tornado from tomorrow's storm"
while this is not:
"I really hope tomorrow's storm brings a tornado which is life threatening and causes widespread damage".

[gllitz]

Since I am a big boy now, I'll take the Huggies Nappy-Pants ones, thanks....

Anyway...back on-topic...please see latest GFS run attached...make of it what you will...for me, it just seems to be getting colder and colder with each run...

I, for one, personally think...based on the last THREE consistent model runs, that we will see snow to sea level starting THUR arvo...yeah, sure, it may change again, but we are less than 48 hours away from it happening.

Justification:
1) VERY strong low beginning to drag up lots of cold air in it's wake...
2) THK levels have now dropped to 523/524 mark...much more promising
3) 850 temps will be b/w -6/-7C...that is certainly cold enough for sea level snow...
4) Precip amounts, although marginal, are still there...vorticity levels are very high, so that could enhance the precip we get...?? (at least, I am pretty sure that's how you interpret that...)

Just my thoughts..please let me know what y'all think and where I have my lthinking flawed...I am very open to learning about all this...we (as a collective on the forum) have done pretty well so far this year for calling this sort of stuff, so let's make it one more, eh?

We have just had the initial arm pass over CHCH and you can see the cloud getting "sucked" from the east toward the big low...kinda cool...already up to 12C and looks to be getting warmer now with the sun shining and a nice NE breeze...