A Change in Weather Pattern

[Storm Struck]

Early 20's where i was today out the back of Loburn on the plains not far from Mt Thomas.
Fresh NW winds there got abit stronger in the afternoon but still the temperature stayed warm. Unusual as in it doesn't often get this warm in July, although it has happend before.
Felt rather silly in my thermals today only wore them because i thought it would be a cool start to the day .
At the moment I can see some welcome rain on Sunday,Monday with a good SE flow perhaps.
Cheers
Jason.

[NZ Thunderstorm Soc]

At the moment I can see some welcome rain on Sunday,Monday with a good SE flow perhaps.
Cheers
Jason.

We haven't had a "50mm" drop scenario for a while in Canterbury, so we must be due for one

JohnGaul
NZTS

[tich]

We haven't had a "50mm" drop scenario for a while in Canterbury, so we must be due for one

What about 29th June? Didn't we get about 50mm in Chch that day?
This weeks looks similar to that of late July 1975 (from NZ Gazette summary), when there was a spell of mild westerlies/northwesterlies to end the month. In 1975, that followed soon after a very cold southerly with snow in Chch and to unusually low levels in the central and eastern North Island. The west/northwesterlies to end that month culminated in the record northwesterly windstorm that devastated Canterbury at the beginnining of August. At least, this current spell doesn't appear to be leading to a similar storm.

[gopolks]

Nice and warm, and should get warmer, a NW is due to arrive.

16.4°C Warmer 1.1°C than last hour.
Heat Index 16.4°C
Wind Chill 16.4°C

Humidity: 52 %
Dewpoint: 6.6°C
Wind Speed: Calm
Gust Speed: None
Gust Last Hour: 11.3 kmh E
Barometer: 1014.1 hpa (1014.0 hPa)Rising 0.80 hPa/hour.
Today's Rain: 0.0 mm
Days with no rain: 4 days
Sunshine Today: 03:08
Time of Last Lightning: 05:49:48 2007/07/26
Last strike recorded: 1000 KM @ 352°

[Michael]

Hpefully it will get a more NW or N tilt to clear the scundge and light showers away also raise the temperature during the day,at least the wind speeds are only moderate though

[Manukau heads obs]

a cold wet and windy SW change rain band heading your way Michael, going through here now

[Michael]

Wasnt even forecasted.

[Razor]

Temperatures in the early 20's here again, summery sundrenched ChCh . I'd hate to live in a cold wet climate like Auckland

[tich]

Hard to tell what'll happen this weekend and early next week. For Cantebury, MetService is going for cold, gale southeasterlies and heavy rain by Monday, while Blue Skies is forecasting it to remain dry with northeasterlies. I guess it all depends on where the low(s) move.

[Gary Roberts]

Temperatures in the early 20's here again, summery sundrenched ChCh .

Perfect day in the Mackenzie. Nice and warm with barely a cloud or breeze. Spring is here!

I'd hate to live in a cold wet climate like Auckland

Yeah, that would totally suck!

[gopolks]

Hard to tell what'll happen this weekend and early next week. For Cantebury, MetService is going for cold, gale southeasterlies and heavy rain by Monday, while Blue Skies is forecasting it to remain dry with northeasterlies. I guess it all depends on where the low(s) move.

Stunner of a day here, cant wait till summer now. I think I will go with the metservice, even though this winter has been nothing but NE, we normally have very cold weather in winter if we have a run of NW.

[spwill]

I'd hate to live in a cold wet climate like Auckland

Great latte drinking weather and helps keep the yaught clean.( Climate stats for the end of this month will be interesting))
I must admit I do prefer the warmer climates and I dont mind the rain ( keeps the weather interest alive).

looks like a spell of rain on the way for Eastern area's, perhaps some very heavy falls for some locations eg Gisborne.

[Manukau heads obs]

its surprising the depth of the showers around here despite a 1026hpa barometer
must be an upper level ridge?
(surface instablity)

you can see the sundays low starting to draw in alot of moisture now in the NW tasman ->big rains coming for areas exposed to the NE alright

[NZstorm]

Gopolks wrote

Hard to tell what'll happen this weekend and early next week.

No its an easy on for Met Service. Onshore easterlies with rain. There looks still to be a fair chance of a warm advective snow event in Central Otago with this system. Skiers stay tuned.

Severe gales/heavy rain forecast for Northland. The last thing they need up there.

its surprising the depth of the showers around here despite a 1026hpa barometer

Yes, I have noticed. Some of the showers yesterday and to day quite heavy. I guess the mild humid surface conditions create a lot of low level instability.

[mikestormchaser]

Temperatures in the early 20's here again, summery sundrenched ChCh . I'd hate to live in a cold wet climate like Auckland

A cold wet climate i could say there wet but hardly cold, it would be warm as up there
Another stunner of a day in chch with little or no wind at all, spring is certainly in the air.
I have too say if theres a cold S outbreak coming i wouldn't be surprised if we got snow with this very warm weather in winter, this is unseasonal

cheers

[Gary Roberts]

I have too say if theres a cold S outbreak coming i wouldn't be surprised if we got snow with this very warm weather in winter, this is unseasonal

cheers

Maybe, maybe not. It was like this (in the Mackenzie) in 2004 and 2005. I suspect it would have been like this in (July) 2006 too were it not for the cooling effects of the lingering snow. Even so it warmed up nicely in August that year. The winter season is short in NZ. I guess it comes down to whether the long period between it and summer is coolish or warmish. The past few years it's been very warmish, so I don't know if this year's nice weather can truly be described as "unseasonal".

[gopolks]

"and the thunder rolls"

SPECIAL WEATHER ADVISORY FOR ALL OF NEW ZEALAND
ISSUED BY METSERVICE AT 02:38pm Thursday 26-Jul-2007

HEAVY RAIN AND NORTHEAST GALES ARE EXPECTED TO SPREAD OVER NORTHERN NORTH ISLAND
AREAS DURING SUNDAY.
STORMY WEATHER FOR MANY PARTS OF NEW ZEALAND DURING SUNDAY AND MONDAY.

The weather in many parts of New Zealand is expected to rapidly deteriorate on
Sunday. It is looking increasingly likely that a deepening low will move from
the north Tasman Sea on Sunday to lie west of Northland Sunday night.

This low is expected to bring a period of heavy rain and northeast gales to the
northern half of the North Island during Sunday. The areas most at risk for
heavy rainfalls are Northland, Auckland, Coromandel Peninsula and Bay of Plenty.
It is expected that during Friday and Saturday MetService will issue warnings
for many of these areas giving more detail of the duration and intensity of the
wind and rain.

At this stage there is great uncertainty about what happens after Sunday.It is
possible that many other parts of New Zealand will experience severe weather as
the low system moves south across the country.
People are advised to keep up to date with any warnings and the severe weather
outlook at http://www.metservice.com/default/index ... erwarnings" target="_blank


The next Special Weather Advisory will be issued by midday Friday 27-Jul-2007

[gopolks]

"seems the best Canterbury can hope for is heavy rain"


SWO Threat Situation valid from Saturday 28-Jul-2007 to Tuesday 31-Jul-2007

Issued by MetService at 2:09pm Thursday 26th July 2007

A front is forecast to slowly cross Southland and southern Fiordland during Saturday, bringing rain to the area, with some heavy falls likely. Snow could also lower below 500 metres later in the day. There is a risk that either the rainfall or snowfall accumulations could reach warning criteria there during Saturday and early Sunday .

A strengthening easterly flow is forecast to spread over the remainder of the South Island during Sunday, between high pressure to the south and a deepening low approaching from the north. Widespread rain is expected in eastern parts of the South Island, with heavy falls likely through to Monday night. There is a risk of rainfall totals reaching significant levels, with heavy snow also possible south of about the Rangitata River. East to southeast gales are likely in parts of the South Island, most especially about and west of the Southern Alps and also exposed coastal areas.

As mentioned above, a deepening low is expected to approach northern New Zealand on Sunday and lie west of the country on Monday. This low is likely to bring a period of heavy rain and easterly gales to northern and eastern parts of the North Island, especially about Northland, Northern Auckland, Coromandel Peninsula, Bay of Plenty and northern Gisborne as per the chart. Also, gales are possible over other parts of the North Island, although it is unclear if the winds will reach severe gale at this time.

This has the potential to be another significant weather event, especially for those areas recently affected by severe weather. Given the uncertainty of the depth and track of this low, people throughout the country and are advised to stay up to date with the latest forecasts and warnings.

[Manukau heads obs]

this very warm weather in winter, this is unseasonal

you will know this, but, note, that its the NW fohn affect coming over the southern divide
which causes the warm temperatures (helped by the ridge of high pressure making the air stable and also the fact that the origin of the air mass is coming from around the high, from areas futher north)....
i.e, if you get the right weather conditions, you get warm temperatures in the east of the SI any time of the year

only 13 to 15 C up this way most of the day, average for the time of the year...e.g what are the temperatures on the SI west coast?
(i see Puysegor point is only 10oC)

[gopolks]

Its now 5pm in chch and still 15 degrees.

[Gary Roberts]

Its now 5pm in chch and still 15 degrees.

Yep, been t-shirt weather all week! Gotta love spring time! Even the gentle W-WSW breeze of the past few days hasn't done much to diminish the sense that winter is well-gone!

[Manukau heads obs]

Gotta love spring time! Even the gentle W-WSW breeze of the past few days hasn't done much to diminish the sense that winter is well-gone!

its along way from spring time (september)
just the current weather pattern over the SI at the moment bringing warm temperatures to the east coast

that pattern is going to change in the next few days with cold SE winds and possibly snow for the SI east coast areas instead

[mikestormchaser]

Yup winter isnt over completely until like late September. depends really

[Storm Struck]

[quote="Manukau heads observer"][quote] you will know this, but, note, that its the NW fohn affect coming over the southern divide
which causes the warm temperatures (helped by the ridge of high pressure making the air stable and also the fact that the origin of the air mass is coming from around the high, from areas futher north)....
i.e, if you get the right weather conditions, you get warm temperatures in the east of the SI any time of the year



Yes but it's also unusual because the NW flow during winter is not often that warm due to the snow on the mountains and of course shorter sunhine hours. Most times W-NW winds are cool during the winter because of this, but this doesn't seem to be the case this week.
Another mild one indeed, I even noticed some high cloud shaped like a tornado like the rough sqiggly ones you draw on A4 .
This low is one to watch for a majority of the country, lets just not jump the gun just yet.
Cheers
Jason.

[TonyT]

I think its more to do with the temperature of the airmass coming from the Tasman sea Jason, if the snow were the main factor then all winter NWers would have the same temperature.

The Fencepost servers are playing up and I cant upload the latest forecasts just now, should be reset later this evening.