Cool end to October

[Michael]

Looks a rather cool end to October with high pressure dominating the tasman with cold air affecting much of N.Z especially in the east after Labour weekend.Could be one to watch for.http://www.ecmwf.int/products/forecasts ... 9101800!!/

[JP.]

Glad I'll be away for the last 2 weeks of october then. Somewhere warm and full of sunshine

[NZ Thunderstorm Soc]

Yes, it could be Mike, but then a SW could become established next week which the pre-frontal Nw could raise the temperatures a bit.

JohnGaul
NZThS

[NZ Thunderstorm Soc]

NW strong here this evening but cool.
Here is an interesting photo I took this evening of a cloud form just overhead about 8pm.

JohnGaul
NZThS

[Storm Struck]

No strong gusty NWer here this evening, but the wind was very light breezy NW.
Its been a NE all day, i had noticed those clouds today John with a hint of mid level CU forming to the west at one stage.
What a nice mild night out though currently 14C with no wind, i dont think i will be needing the electric blanket tonight finally.
It does look like a cooler end to October with another interesting SW change coming through next Tuesday, i say no more just yet .
We have certainly had a reasonable share of rain this month so far, which is catch up for the lack of it we had in August and September.

[spwill]

Looks a rather cool end to October

A cool end to October for the NorthIsland
A continuation of the cool October for the SouthIsland, perhaps a return to winter next week.

[Michael]

I think Wellington will do quite well out of nextweeks weather,Coolish Northerlies interspersed with the odd small S change and plenty of sun,the flow should be critical.

[RWood]

That would be a change - it's been one of our worst Octobers. Climate Explorer charts for MTD show a very cool month with a large area at least 1.0C below normal and a few patches 2.0C or more below. Sunshine well below average for a large swathe of the country though SW and most of the W of the South Island have done better, especially the West Coast, along with Gisborne near normal. Substantial surplus here of rainfall, not shown of course is the unusually high number of rain days.

[Manukau heads obs]

-0.6 C below normal for month to date here so far

el nino like SW winds lately here

[Richard]

Blue Skies predicted Oct being dominated by anticyclones,higher than norm sunshine hours,lower rainfall and warmer than average temps.

[TonyT]

Correct. And it would be fair to say that anticyclones have been the driving force behind this month's pattern, but not quite in the right place. There has been a lot of ridging in the Tasman Sea, which has meant the westerlies have never really been established over New Zealand, and instead we have had a lot of troughs develop over the country. Right idea, wrong location! The rain/sun/temp arrangement just follows on from that - if the ridging had been over the South Island then Canterbury would have been drier/sunnier/milder, but with the ridging happening 10-15deg further west, its been wetter/cloudier/cooler as we have seen more of the southerly flows. (Actually, its only North Canty which has been wetter than normal so far, although that will surely change this week, and I'm not sure that sunshine hours have been much lower than normal so far, but this coming week wont help that either.)

[RWood]

Yes, to 24 Oct 9am the Explorer maps show the 120%+ rainfall line in the South Island starts at North Canterbury (with a small part of mid-Cant'y hinterland), covers Marlborough and much of Nelson, the more western and southwestern parts of the latter excluded. The sunshine hours are close to normal for N. Canty and Christchurch but less than 85% of normal for a large area extending from Ashburton to Dunedin plus a sizeable chunk of hinterland - but the number of measuring sites is relatively small and the graphs often get rejigged a bit when final monthly data is available.

[spwill]

Clearing weather here this afternoon, cool SW.

A few thunderstorms this afternoon BOP/southern Waikato.

[Tornado Tim]

and we have one here, what a nice surprise!

[MoorfNZ]

http://nz.news.yahoo.com/a/-/top-storie ... -forecast/



The cold spring is expected to continue with rain, snow, thunder and chilling winds set to hit the country from tomorrow.

Sweeping across the South Island, the cold southerly flow could be accompanied by snow down to 300m, MetService spokesman Bob McDavitt said.

Conditions were expected to clear in the South Island on Thursday, but the cold weather would reach the North Island on early Thursday.

The weather was likely to persist in the North Island through Friday, he said.

MetService forecaster Oliver Druce said the cold flow would bring thunder, hail and rain to Canterbury and would hit Wellington in the early hours of Thursday.

"It's going to be a humdinger. It's too far out to forecast road snow for the North Island, but it looks like it will get down to 600 or 700m," he told NZPA.

Snow is expected on the higher roads in the South Island.

The MetService forecasted rain in Arthurs Pass to turn into 2cm to 4cm of snow possibly accumulating on the road on Wednesday evening.

Similar conditions were forecast for Porters Pass, but with heavier falls of 4cm to 8cm on the road.

On the Milford Road, rain was expected to turn to snow on Wednesday afternoon, with 3cm to 5cm accumulating.

[Andrew Massie]

MetService forecaster Oliver Druce said the cold flow would bring thunder, hail and rain to Canterbury

Yusssss!

[Storm Struck]

Yeah but whats with the low risk MS put out , looks like a good chance to me for Canterbury definatly a moderate risk more like.
It might be NW inland but again coastal NE winds may well stick around for most of day before the very cold change, even if a westerly did kick in the air is so cold and unstable thunderstorms should well form.
Could be a chase on the cards tomorrow evening guys .

[NZ Thunderstorm Soc]

MetService forecaster Oliver Druce said the cold flow would bring thunder, hail and rain to Canterbury

Yusssss!

I must get my camera ready

JohnGaul
NZThS

[mikestormchaser]

Thoughts for Thunderstorm for Christchurch you experts?

[NZ Thunderstorm Soc]

If the NE picks up, with daylight heating,she's all on, there Mike
A bug-bear could be that surface pressures may be a bit high for an all out mother of a storm but then things could develop if a 'twist' could evolve at a higher level in the atmosphere, but that dosen't seem likely.

JohnGaul
NZThS

[NZstorm]

Thoughts for Thunderstorm for Christchurch you experts?

Looks like a big beefy cold system moving into Canterbury late in the day so there is certainly a thunderstorm risk there. The fly in the ointment is the lack of instability forecast. But I like the strong upper flow, 500mb 65kts forecast for Canterbury 06Z. If a storm does manage to develop the strong upper flow should give it a good boost.

[Michael]

We had our "spring" back in August/September.Only if there was such a thing as an anticyclone zapper, is to zap it out of the tasman

[tich]

Sure looks like a very cold southerly change coming - GASP's latest suggest thickless levels even low enough for sea-level snow in Canterbury. I would say it looks unusual for so late in the season, but then again remember early November last year.
This October seems to be shaping up as one of the wintriest for a long time; probably have to go back as far as 1982 to find a similar October.

[03Stormchaser]

Looking quickly at the models change should arrive late in the day, upper air gets very cold -32C!! early thursday morning. Southerly near gale force if not gale in exposed places. Snow to low levels looks very likely on wednesday/thursday, I see Bob picking 300m, wont be surprised if 200m or lower.
Blueskies on the other hand only picking 400m!

[Manukau heads obs]

very El Nino like weather pattern here now
(all though I had my doubts a month ago about if El Nino would start happening to have an affect)